Hello,

I have BMW CD54 Professional Radios sitting around. For hobby project I dissembled one of it to see how it is working. I quickly realized that cd drive outputs audio to mainboard via I2S. There are 12 IO and power pins + 6 pin connector for I2S lines. Same Becker design used in different car brands as well, thats why I thought that if I can find out how is it working, it will be so easy to integrate an ESP32 for bluetooth music streaming.

I2S lines are connected to the SAA7325 however control lines and SAA7325 I2C lines are connected to the other proprietary Philips chip CM30430 that I cannot find the datasheet. So far the pinouts that I can traced are like this:



Do you have any suggestion for me to find out how the control working? Should I get an oscilloscope? I am adding CD Drive PCB and mainboard too.

I'm going to use one-half of a PAM8403 module as a part of a larger system. Its job is to produce short bursts of a fixed tone. I have two questions about this:

1) Is it OK to leave the unused output pins open?
2) Is it best to short the unused input pin to ground?

Hello Everyone!
I'm Raimonds. Thank You for accepting me in the club. I'm electronics Hobbyist designing electronic circuits mainly analogue synthesizer stuff. I came across this forum while looking for Amber 4400A test set service manual. Hope to learn something new from diyAudio members. Thank You!

Product chars :

Input method: SPDIF & I2S

Support sampling rate: SPDIF 44.1khz 88.2khz 96khz 192khz

I2S:44.1khz~384khz



I`m trying to modify this board to accept pcm56, but without any success, as the datasheet states both dacs are pin compatible, but when trying direct swap, the pcm56p is playing music but with noise. Should I assume that the WM8805 is the main issue in this configuration or something else? Another question, can I use the I/Out of the pcm`s in parallel? Removing the single op amps and feeding to valve output?

The RD-75 is extremely rare, no longer in production. It is the late David Graebener’s “ultimate transducer” magnum opus. 88dB sensitivity, 100Hz-17KHz response; they combine incredibly low moving mass with the surface area of a 12” woofer and 200 watts power handling. They play very loud with no visible excursion, and have a light, transparent, fast sound with large presentation and big stereo image.

For 12 years these Bohlender-Graebener RD-75 ribbons were the centerpiece of my “Ultimate 2 Way System”.

These RD-75s are mounted in a closed-back box (monopole, not dipole). The speakers are in excellent condition, built in 2005. Well cared-for. The cabinet was custom made for me, matte black finish and has no significant scratches or blemishes. Baby grand piano not included 🙂



They need no crossover in the ultra-sensitive 2-5K region where the ear is most sensitive. This is why the sound is so top-to-bottom coherent.

These line-source handcrafted ribbon drivers deliver transparency, resolution, and transient ability. The proprietary RD-75 ribbon driver uses an ultra-lightweight aluminum foil diaphragm suspended between powerful neodymium magnets.

Properly integrated, the response is smooth and level everywhere throughout the room. You can stand up, sit down, or even lay on the floor, and sound is consistent everywhere. This design minimizes floor and ceiling reflections. As soon as your ear rises above 6 feet elevation, the high frequencies vanish. That’s because the ribbon emits a cylindrical wave that does not reach the ceiling. You clearly hear every layer of detail in the recording. Vocals are lush and full and transparent. Percussion has clarity and drive. Plucked strings are almost visceral, when they need to be.

One of the most remarkable aspects of the RD-75 is its ability to capture the attack and decay of musical notes with startling realism. The ribbon drivers' lightning-fast response, combined with their exceptional linearity, ensures that even the most dynamic passages are reproduced with effortless precision and authority.

Measurements and photos I took this morning:


Above: Frequency response, several distances, on axis, left and right channels averaged together.


Above: Step response. Extremely clean with no phase reversals.


Above: Impulse response.


Above: 2nd and 3rd harmonic distortion.


Above: Phase response, which is +/-30 degrees from 200Hz-15Khz. Unheard of.


Above: left/right responses overlaid in real room. I'm 95% sure the differences below 500Hz are because of the different position of the speaker in the room, not differences between the drivers; which match to within 1dB for great imaging.

Impedance is 6 ohms, resistive and almost straight-line flat. Super easy to drive.

I used these in biamp configuration with active DSP crossovers. You can also use these with passive crossovers. If so, they need a notch filter to pad down the area around 5K. The schematic is online https://techtalk.parts-express.com/filedata/fetch?id=1317741

I recommend using them above 200Hz with 12dB/octave crossovers. I wrote up the system I used these with, you can read all about it here:

https://www.perrymarshall.com/articles/ultimate2way/

If you have a couple of subwoofers with good midrange response and a DSP, it's pretty easy to put together a fantastic sounding system that rivals commercial designs costing 10-20X the price. If you wish to use these dipole, you can take the backs off of the enclosures or take the RD-75’s out of the enclosures. Any mods are up to you.

As you can see from the article, I was easily able to attain near perfect frequency, impulse, step and phase response with a 2-way system - at listener position in a real room with no crossover voodoo (no exotic FIR filters, just standard 12dB slopes). Not easy to pull off with almost any other driver.

DIMENSIONS:
Main part of enclosure: 76.75H x 14"W x 5.5"D
Base: 18"W x 14"D

Price: $1950 OBO for the pair. Pick up from my home in Chicago. Estimated shipping (continental USA via truck, will take time to arrange): $1000.

Here is my first attempt at a mini (actually an micro-amp) using the Russian equivalent of the 6BM8. I have an octet of tubes on the way, and a a pair of bitty output transformers in fab at Edcor. The boards are in process at PCBway. I plan to power the amp using a DC-DC converter run by a 12V, 3.5A switching adapter. The amp takes its inspiration right from the Sylvania data sheet, with the power pentode being running full tilt at its 7W dissipation rating. I am running the input triode at 1ma plate current with an LND150 current source load. This will go into a proletarian bud box (so not all that pretty), with transformers on the bottom to keep the thing from tipping over. They will drive a set of Klipsch speakers that are actually pretty efficient (they have no problem making lots of noise with the 20W/channel Class A amp currently driving them). The amp will get a full characterization on the bench for frequency response and gain-phase, as I have a gain-phase analyzer available at work that goes up to 5 MHz. The values on the output Zobel network will be adjusted so as to keep the output gain from going back up through 0dB (gain margin as well as phase margin).

I’ve been into Hifi for a looooooooong time, and still loving it!

I have way too many amps. Willing to part with one of my wolverines. Its in 4U modushop, with massive external power supply. Its ef3-3. Perfect sound. I will not ship it, but i can deliver within 100 miles of metro DC area. Asking $2000.

Hi, I hope it's ok to open a thread here to cover more basic issues. As I'm used to building speakers for hifi use (and taking the room into consideration!), I'm constantly feeling a bit, let's call it, "philosophically alienated" when entering the car audio world. Perhaps someone with a similar background can help me increase my understanding...? In general, yes I know and have experienced myself that car systems can sound decent. So there must be reasons why that is in spite of the issues I have in my mind, and guess it might actually be useful to find some answers as to what these reasons are. Those issues would be:

a) everything is off-axis, the individual chassis are far removed from each other, the listeners are sitting very close to the speakers (extreme near-field), and basically always outside of the stereo listening triangle. How does one come up with a proper sound setting for that, which works well and creates a stereo illusion for all occupant numbers, and also not a noticable change in response from different passenger heights/positions? I can only guess, does one routinely use speakers that have basically non-linear frequency responses on-axis (rising treble), to have a linear response at the off-axis listener position?

b) is a point source characteristic, and with that, stereo imaging and "virtual stage size" even a consideration? apart from coax speakers, which rarely are positioned anywhere near to creating an acoustic stage (in front of the listeners), I'd say there are very few system configurations that would allow for a classical point source (generous rule of thumb: distance between speaker centers less than the wavelength at crossover frequency - meaning about 17cm between tweeter and mid/woofer at 2kHz)?

c) since there are no regularly shaped acoustic baffles, various predetermined speaker positions, and a lot of hard, acoustically reflective surfaces including glass of varying curvature, which are pretty much acoustic mirrors for any mid-high frequency waves and therefore highly influential - how (apart from creating complex 3d models including the acoustic properties of seats and dashboard lining) does one even have a concept of a plan to find out how a given system might sound when installed in a different car? I guess that will also be the reason why just about no manufacturers publish any sort of frequency response charts for their systems, right?

Hello everyone!! I never build a speaker before, but I have some experience with DIY stuff. For the sake of simplicity and acoustical characteristics I first decided to build a voight pipe, but the size was a problem, so I settled on the single folded design, with front facing port. I have a pair of Lii Audio Fast 8 but I am struggling to get the right dimensions for the build. I thought that the online calculators were enough, but I saw that is heavily recommended to use hornresp for modeling. The problem is that I use a macbook, so I need to borrow a windows pc first, to then try figuring out how to use the software. Furthermore, based on what I saw of hornresp on youtube, I'm not exactly confident that I will get the dimensions right that quickly. That said, I thought of getting help here first, because maybe some wise kind soul could roughly estimate that for me, if that is not asking too much.
For placement sake, I can not afford a width larger than 30cm and a depth bigger than 36cm. The height is more flexible, but it is preferable to be around 100~115cm. I imagine that it need to be taller, but I rather sacrifice some bass extension (I live in a apartment with leaky bass problem)

The image bellow its one of the recommend designs from Lii Audio, with aprox. 136L of volume (its actually less because of the fold)

Technical data of the driver:
1. PMSE-Free 0.42 Ohms
2. Fs 47 Hz
3. Re 6.33 Ohms(dc)
4. Res 64.66 Ohms
5. Qms 7.10
6. Qes 0.69
7. Qts 0.62
8. L1 0.10 mH
9. L2 0.68 mH
10.R2 3.73 Ohms
11.RMSE-load 0.36 Ohms
13.Vas(sd) 69.7 liters
14.Mms 10.28 grams
15.Cms 1084 uM/Newton
16.Bl 5.15 Tesla-M
17.Splref(sd) 94 dB(Re)
18.Rub-index 0.02

Area (Sd): 213.82 sq cm

I do not need a perfect speaker cabinet for my frist build, just a 'good enough' so I can at least start to burn in the drivers. So if anyone at all could help me with that I would be forever grateful. But again, if that is too much to ask I will proceed trying out myself. I'm only asking because from my point of view, it seems that for those already used to the software, its not that hard of a task, but could be just my sheer ignorance of the subject. Thanks!!

We have an apartment in Azerbaijan which is a bare concrete core & shell, so we will fit out everything including a suspended plasterboard ceiling, around 15cm below the concrete that defines the floor/ceiling levels. I'm planning to put ceiling speakers, but have never really used them before, though I am familiar with building (but not designing) speakers in cabinets.

We have two bedrooms and a living room, the idea is to have one pair of Polk RC80i in each of the bedrooms and two pairs in the living room, all powered by 3x WiiM amplifiers (60wpc) which can be linked in-app to provide multi-room capability.

So my question...if I fix a speaker in the ceiling, it if effectively in a cabinet that is around 15cm x 5m x 4m - which doesn't feel like a good size of cabinet for an 8" speaker. Since we are building the ceiling from scratch, it occurred to me that I could make an in-ceiling speaker cabinet behind the speaker using a double-layer of plasterboard, that is a more appropriate size for the speaker. And I'm wondering if this is a good idea, or not?

At the moment I've no idea what size of cabinet it would be (except 15cm deep) or the Thiele Small parameters for the Polk RC80i.

Good day. I am working with Stetsom HL1200.4. The amp is totally dead without any light. I found out that the 4 power supply Fets are shorted, It has the IRFB448 mosfets in the power supply. This mosfet is hard to source from reliable sources. Did anybody tried for a similar substitiute of this mosfet that is available in reliable sources. Please share if you had luck replacing it. Thank you.

Translated from Mr Ohashi's Blog (Google translator)​

True Frequency Response​

October 1, 2024
Today I would like to show you the frequency characteristics of vacuum tube amplifiers, which you basically do not know (usually manufacturers do not provide them).

The data I will publish today is the data stored as in-house records at the time of shipment of the assembled products, converted into a semi-logarithmic graph, and all of them are true frequency characteristics without any corrections.

Catalogs often state "frequency characteristics 20Hz~20kHz", but this only indicates the standard -3dB point and is not a document to evaluate the performance or actual state of the amplifier. This is because what has the greatest impact on sound quality is "behavior within the audible range", which can be said to be the individuality (character) of the amplifier.

Now let's take a look at the frequency characteristics of our representative model.

SV-S1616D/KT150 Specifications

SV-S1616D / PSVANE WE300B Specifications

The reason there is no big difference between these two models is that they share the same basic platform and use the same output transformer. Please note that the 300B has a slightly "sloping shoulder" on the high-frequency side.

Next, we will show the difference in push-pull. This is the difference in sound between multi-electrode and triode amplifiers, and it is a big difference.

SV-P1616D/KT170 Specifications

SV-P1616D / Western Electric 300B specifications

I think many people will be surprised to see how different they are. The KT170 specification is super flat, while the 300B specification has a natural roll-off at both the top and bottom. This roll-off is actually closely related to the plot position on the voicing chart, and to put it simply, we tend to feel that the flatter the response of an amplifier, the more to the upper right (sharper and cooler), and the larger the roll-off, the more to the lower left (softer and warmer), which coincides perfectly with the frequency characteristics.

Next is the transmitting tube amplifier.

SV-S1628D/845 Specifications

SV-S1628D/211 Specifications
These two data were obtained when two types of vacuum tubes were delivered on the same machine, so they are quite similar, but they match the frequency characteristics of a typical triode amplifier. However, please note that there is a "shoulder" on the higher frequency side than the 300B. In this case, the PSVANE WE211 has a higher high frequency extension than the regular 211, so it should be noted that the roll-off point of the regular 211 is often a little lower.

Next, let's look at the SV-8800SE.

SV-8800SE / KT170 Specifications
What I want you to pay attention to here is the difference with the SV-P1616D / KT170 specifications above. Basically, it has a wonderfully flat response, but while the P1616D is flat down to 10Hz, the 8800SE is flat up to 100kHz (and above) and actually extends to 200kHz and above.

The reason why the P1616D is positioned towards the top right of the chart in terms of tone is that the 8800SE has a gentler (or, if you will, more natural) roll-off at both the top and bottom ends. As mentioned above, this roll-off has a sensitive effect on the sense of hearing, but it is the "coupling capacitor" that filters the DC component superimposed on the signal that gives the sense of density to the ear. It is safe to say that this difference in frequency characteristics has a major impact, and that is why many people feel that it is particularly effective with multi-electrode amplifiers.

Finally, the SV-91B.

SV-91B / Western Electric 300B specifications
One of the features of our amplifiers is that they are slightly higher at around 35Hz, which is actually the lowest frequency we feel, slightly above 20Hz. However, what is important in voicing an amplifier is not how far it is extended numerically, but the overall balance.

If there is a "swaying balance" of sound, what Hz would be the center?
Generally, the audio world considers 1kHz as the standard, and we also set many reference points at 1kHz in our measurements. On the other hand, when it comes to creating sound, if humans can perceive 20Hz to 20kHz, 5 octaves above 20Hz is 640Hz, and 5 octaves below 20kHz is 625Hz, so I personally create sounds with the idea that the center of gravity of sound is at 600Hz to 650Hz. As the

audio industry has moved from vacuum tubes to semiconductors, flat sounds have become the norm. However, without even taking the example of wood used in guitars, I think it's fine and should be possible for there to be amplifiers with a clear, bright tone like maple, and a warm, rich tone like mahogany.

The rich musical quality of a vacuum tube amplifier is ultimately achieved by bringing out the inherent resonance of the material. We always aim to create an amplifier that has a "good sound" rather than just "good characteristics."

Hi all,

Firstly, please forgive me if this has been discussed (or beaten to death) elsewhere.

Way back in 2011 I made this post (https://www.diyaudio.com/community/...lrangers-help-me-pick-a-design-please.184703/), looking for recommendations for my second speaker build. I never ended up building anything, but I'm itching to now.

I'm a fan of diyAudio primarily because I believe it allows for a "high value" listening experience without the corresponding cash outlay. To put it more clearly, I am much more into listening to diyAudio than building diyAudio, and I'm hoping I can leverage the incredible experience of those on this forum to help me decide what to build next. Because ideally whatever I build lasts me a good long while!

Can you please recommend full-range enclosure designs (and sub designs if you have recommendations!) which prioritise sound quality, WAF, and which are tolerant of "sub-optimal" room placement? I really like clean, detailed bass with good extension. In fact I would say that bass performance is a little more important than imaging to me, particularly as this setup will often be enjoyed from the adjoining kitchen, or otherwise "not in the sweet spot". Ease of build would be nice too. I'm just looking for a shortlist of enclosure designs that I can exhaustively research on my own hahaha. And maybe some "explain like I'm 5" wisdom on diy subwoofers and integration with a pair of full range speakers. I've done a tiny bit of reading on calibration/REW corrections with a USB mic & DSP... but still have much to learn.

Proposed signal chain:
Tidal - Wiim amp or Wiim streamer into a <$800 DAC + AMP bundle (like SMSL DA9 + SU9n). I want to keep it simple and relatively affordable on the amplification side of things. EQ/DSP would be nice.

Use:
100% music. I listen to (truly) everything, but these days a fair bit of techno, IDM, DnB, deep house, hip hop, motown, jazz, and a little classic rock. Volumes are restrained, I live in a townhome/rowhouse and love my neighbours.

I've been leaning towards the Frugelhorn XL or Joan plus a sub, but wondering if I'm going to run a sub or two if I can get away just fine with the standard Frugelhorn? The Pensil and variants have also caught my eye. In my 2011 post, I was recommended the Castle microtower as well. And how about a sub(s)? What would work best with the full range enclosures you recommend (and isn't too picky about room placement)? Should I run one or two?

-----Boring and long-winded background/history-----
Years ago I built some B0FU BIBs and loved them for 6+ years before they succumbed to a slowly climbing WAF threshold. I drove them with a Sonic Impact T-Amp and ran them both alone as well as with a B&W 10" sub (which I loved, taking a little bass load off helped the BIBs shine even more imo).

Since, I've been using an old pair of cheap Polk bookshelves (driven by the same trusty T-Amp) in conjunction with the same older B&W sub and it's been okay, until my sub decided it'd had enough and packed 'er in.

The signal chain I've been using will make most of you groan. It's been chromecast HDMI - TV - RCA line out - sub (w/ crossover) - RCA-1/8" - T-Amp.

I have a headphone setup at work with a standalone DAC and headphone amp. I used to listen to lossless and high-bitrate rips before I succumbed to laziness and spotify. Spotify has been driving me nuts though, I just tried Tidal and I'm loving it. Now I want to stream high bitrate to my home stereo.

Between determining whether my sub can be repaired or not and switching to Tidal (and hence looking into better streamers than a chromecast plugged into my TV) I started thinking about the entire system. I'm planning to keep the TV paired with my old bookshelves and build a music-only system from scratch, with the goal of bettering the SQ I enjoyed with the BIBs + sub.
-----background history over------

I appreciate everyone's feedback and suggestions - mainly I'm looking for a short list to research to death on my own and select a design from.

Thanks a million!
Cheers,
Cam

Has anyone tried using fleece like maybe the thickness of a blanket to use as sound deadening inside a sub enclosure. Seems to me it would work. I'm curious because I have a couple of old blankets that I've used for storing various items. I thought maybe I could repurpose them into lining the inside of an enclosure

My speakers are designed to be used with a 100 Hz first order high-pass filter. A pair of these RCA filters were included with the speakers: https://www.vandersteen.com/products/m5-hp

I want to design and build my own version of this filter, adding the ability to accept balanced and single-ended inputs/outputs, and maintaining the ability to adjust to match different amplifier input impedances.

The spec from the manual is a signal measuring 1v at the filter output at 1000 Hz should measure 0.707v at 100 Hz. The filter should be adjustable so that this attenuation can be achieved with a variety of amplifier input impedance values.

I know the basics of designing an RC filter, but I need help picking the resistance and capacitance values, and designing switchable loading.

I have an Orion cobalt 2100 that has a similar issue to problems that have been discussed here before. Problem is it doesn’t look like it was ever solved in the other threads.

This amp started taking out speakers then the magic smoke came out. Opened it to find a fried rail cap that also took out a trace. A couple of resistors desoldered themselves too.

I replaced all electrolytic capacitors. I tested the output fets and found one to be very leaky. I replaced all output fets with some equivalent parts that were recommended on a different thread. I also replaced all resistors that looked burnt in the middle.

The problem is the amp draws too much current at idle and heats up rapidly. The output fets get warm. I placed my meter in series with the source resistor and got about 60mA before the current limit on my power supply kicked in.
The driver transistors get really hot. I have already replaced them with no luck. They are marked with silver on top.

Any suggestions on what to check next?

Cheers

Has anyone played with the SUOS (Stream Unlimited Optical Systems) Blue Tiger CD Drives? They seem to be an affordable option. I have used many of the old now defunkt Phillips CDpro2 drives and there are still currently many options for those and Infact there is a guy in germany that has cloned the drive and will start remaking them again, but they are VERY expensive. nearly 3x the cost of the SUOS drives. So I am curious if anyone has played with them. built their own transport/player etc. or if there would even be any interest in a DIY drive???

So, thanks to a very generous forum member I got some fostex 208 sigma drivers for a great price, and decided to build the kirishimia cabinets (should have gone to the gym for 6 weeks!)
Already having the fostex t90a (as the 208 sigma is a 'wide range driver, not full range it needs upper support imo)
So.
I am lucky that I work for a small furniture company (I am no maker!) And have access to some very expensive saws etc.
Cut a long story short here are some pics.
They are progressing in an American black walnut veneer finish with plain grey sides.

Any questions please let me know.

For the veneering I only (now) use contact adhesive, the evostick thixatropic is just a joy to work with, and any bits that don't stick, nothing that a hot iron won't sort.

Hi,
Hope you all are well. I need some help with converting my BenQ DLP projector lamp from halogen to LED. Am I right saying that I need to bypass the ballast to trick the mainboard to say stock lamp is connected?

There is a vertical circuit board connected to main power supply board and 5 wires coming from that to mainboard (connection port J13). Do I have to connect one of these wires to the ground and then I can use LED directly connected the ports?

I know this has 2 step converions:
1. Bypassing or fooling the ballast
2. LED lighting source

Any advice would be highly appreciated.

Cheers

Zaky



from Schematic diagram...







Mainboard...
The Lamp cover switch (thick red and black wires) should be depressed to power up the system.

Sold

Hey guys

Recently I picked up a Krell KRS 2 preamplifier that had supposedly been sitting in storage for the last 20 years. It looks brand new both inside and out but upon further inspection it appears that a few of the electrolytic caps are cracking. I've seen caps bulging before but never cracks, one would assume this unit is due for a re-cap? I have not yet tested any of the caps with a meter.

I did take a quick look around Mouser and Digikey for the cap values but I'm having a really hard time finding anything in 14.5MM diameter. If it does indeed need a re-cap I'd like to keep the form factor the same as factory if possible.

Ignore the broken phono ground in the last 2 photos, Shipping wasn't kind.

I was......Loving these speakers until the drivers started failing. I have listened to new JBL monitors and klipsch r7iii that cost over 10k AUD. Came home and the IMF's were better in every way. Wow. the xo has been redone but the b139 has gone and now the hp1300 is crackling and spitting. I'd love to keep them and upgrade with all falcon drivers but am not sure if I will gain anymore headroom . I think the falcon b1399 can handle higher spls but not sure about the tweeters . I know they are not party speakers but they should be able to rock up to 100db without failure. Goddamn they sound good but reliability is the line. Has anyone done the falcon kit upgrade or should I search for a JBL or klipsch that sounds like an imf but handles higher spl? Under 10k AUD?
Thanks for any insights or guidance going ahead.

Guys,

For plywood (I will not use MDF)
What router bit or bits do you use and or recommend for sub and top cabinets building.

Baffle ,handles and back plate jacks or plate amps.

I just scored a budget router that was in clearance to be my beginner training tool.

Hello, my name is Chris. I live in Kerrville, Texas. I'm a complete newb amateur, determined to learn the art and science of designing and building a tube hybrid headphone amplifier by doing it. I am using AI to teach me what I need to know: how to read and understand and create schematics using kicad, how to read and understand datasheets, how to make sure the parts we are wanting to use will work together, how to use kicad to create a schematic, assign footprints, and design a pcb. I'll save technical questions for the specific thread I intend to create to document my progress with this project.
I am coming here mostly for community, to talk about my design with people who are interested in such things.

Let me try to address some concerns up front:

You should not begin by designing your own amp. You should get a bottlehead crack or similar kit, and build that first.

Click to expand...

Yes, probably. However, I have looked all over the internet for a tube hybrid amplifier that will supply at least 1W per channel into 32 Ohm headphones, and also at least 300mW into 300 Ohm headphones. An OTL design just won't work for me. Also, I prefer to use only tubes and mosfets, no opamps. I'm going for a very old-school sound. I don't see any point in wasting my time and money building an amp that I won't want to use. I just want this one, specific amp. If I tried to buy something like this already made, it would cost thousands of dollars. I hope to build this amp for less than $500, not including tools and test equipment.

You are going to fry yourself, you fool!

Click to expand...

No, I won't. I'm going to build it such that the PS connects to the pcb through screw terminals. I will not connect the PS. I'll build and test it as best I can without ever plugging it into the wall. Then, I will take it to my local electrician / electronics repair shop, show them the schematics, and let them test it if they feel safe doing so.

If you got it all sorted out, coming in here like you're not going to even listen to people who are legitimate experts, why are you even here?

Click to expand...

I will listen to people encouraging me to do things differently, if their suggestions are clearly going to get me where I want to go better than what I had planned. I just don't want blanket discouragement, which is what I had encountered on another website, which just removed my posts. I don't mean to disrespect or devalue anyone's expertise or advice. I just want to be sure that your advice will get me closer to my goal of owning a tube-mosfet stereo amplifier that can give a lot of power to both high and low impedance headphones.

Thanks for reading! I look forward to engaging with this community, and working on my project, and learning-- really learning-- everything I need to know to end up with the amp I want.

Hello all. I am new as a member here but have used this place as a reference many time. I am from Phoenix, but England originally. Got the audio bug working at Circuit City in the early 90's. I don't have anything outlandish for equipment, but am always trying to upgrade. Currently running rebuilt Infinity Crescendo 3008s with a Def Tech Supercube. Onkyo Flagship receivers have changed out a few times. I am a novice, but my father is an electrical engineer, so I know enough to be dangerous.

Hi guys.
This regarding a Kurzweil PC1x keybord.
A few days ago I asked for a replacement for the TLC2272CP.
Today I inspected the pcb on the pitch / mod assembly once again and it turns out that trimpot R15 is missing its tiny adjusting wheel...
To all Kurzweil PC1x users out there:
Can anyone tell me the value of this R15 trimpot? Please?

Just wonder is someone has pictures of the boards ( component/solder side ) from this amp.
Asking for a friend😉

I have a polk psw11 sub. Recently hooked up to my 6LU8 tube amp. I use the speaker level inputs. After a bit of trial and error, I have the frequency and volume adjustments where I think they sound best.; Here is the problem. With low level bass there is often a bit of noise on top of the bass. At higher levels, like playing loud, or with bass heavy modern not acoustic, there is no noise. It sounds like a dirty pot, but does not come and go with turning either vol, or freq knobs. Speaker wires are all hooked up solidly.

My question is whether this is a repairable problem or not. If not, is there a 'replacement' sub amp that is very affordable?

Roger

This was one of my first veneering jobs a number of years ago. I've done quite a few cabinets and counter-tops using plastic laminate (Formica) so had plenty of experience using water based contact adhesive. The paper-backed veneer was very easy to work with, much easier to install and trim than p-lam but there are obviously extra steps involved in the final finishing.

The client inherited the console from his grandfather who had it stored in a basement. Hope this inspires someone to save an old piece of audio gear that may otherwise be sent to the dumpster.

Here is the finished product, I'll follow-up with some "before" images as well as the process.

The amp on my powered sub psw10 is crapping out, I thought I could do a cheap diy fix with a 40W mono tpa3116(8?) Board from China. Add a 24vdc smps, and an op amp low pass preamp. Total cost would be around $15.

Am I crazy? I really like my system with the sub. I am using a DIY 6LU8 tube amp, without any sub out. I was using speaker level inputs on the powered sub.

I have a source selector that I built that holds my DAC board, and phono board. I can easily fit the low pass subpre amp inside the selector, and provide a mono combined line out to the sub. I would like to rip out the faulty amp in the sub and install both the smps and class D amp on the plate, use the e listing 120vac input to the sub.

Questions:

Will my phono and dac boards drive BOTH the sub low pass pre-amp?
Will the smps 24vdc/3A get too hot for installation inside the sub?

I know there are not a whole lot of specificshere, but in general, is this doable? I know it is likely not going to be high end, but I listen at very moderate levels.

Anyway, any feedback is welcome.

Roger

Hello I'm Tony and hope I can find help here in repairing my class D amp and look foward to learning a thing or two along the way <3

Hello,

For sale is an Allo usbridge signature. currently running ropieee.

Please note that the USB Clean port does not work. Only 2 usb ports work. This is how i got it. It seems like there was a repair made on the usb port. I never bothered repairing it since i used the module using its i2s from gpio.

This will not come with the power supply.

Im asking $100.

Buyer pays shipping and paypal fees.

Thanks for looking

I have the phono board of the DMC-20 and I’m planning to run it by itself. I don’t have the actual preamp, just the phono pcb.
Anybody who knows the +/- feed voltages for the DMC20 phono board?


Never mind the attached photo☺️

Hello all! I’ve been stalking the threads here for a while now and I’m finally ready to start asking some questions to the talented people here. I started building speakers about two years ago. So far, I’ve made about 9 or 10 designs. 3 of these were boomboxes made with 2.1 amplifiers, full range drivers and small “subwoofers”. The rest have been several bookshelf speakers, 2 floor standers, a beefy wtmw center channel, and surround speakers for a 5.1 matching set, oh and two subwoofers. I’d like to build me a set of rs225-8 FASTs using ps95-8 in the future and I hope you all will be able to help me out a bit with that! Thanks!

I have a Marantz CDR-500 and 2) CDR-510. All produce static at certain points in certain songs and it is pretty consistent. There is static on both CD and CDR drive outputs. The components for left and right channel are the same but are done with separate components. That the distortion appears on both channels, means two units manufactured months apart, are exhibiting the same issue.

Elton John "Blue eyes"
01 seconds "Blue"
18 sec "On a"
27 sec "Blue"
39 sec "Morning"
46 sec "Far"
1:11 "Alone"

• Lady Gaga "Enigma" when she starts singing at 4 seconds has the static.
• Harry Styles Daydreaming" the opening has static

There is no static when used as a transport with an outboard DAC.


So I sent it to the repair guru who had a CDR-510 on hand. Once he was aware of the static, he could replicate it on his CD R-510 and was not there on his Denon CD Player nor did it occur in the headphone.

He pulled the main PCB and checked the output circuitry (including caps) and connectors with nothing found.

Any thoughts? Is this a design flaw or am I missing something?

They were some Gb with this regulators. Does anybody have empty pcbs to sell ... 10x for lt3045-42 and 5x for lt3094. Eu please.
Thank you.

stigigemla is my nickname and it is derived from my name Stig Ljunggren and the place where I live, Gemla in the south of Sweden
I build my first amplifier in 1960 (with a schematic of my own) and used my first transistors in amplifier 1967.
Since then I have had a problem all my life with schematics just bubbling out of my head. I am very fond of reducing the number of components in circuits without degrading performance.
I have been working in electronic service and as an electronic teacher.
I retired about ten years ago and now I have my little home lab with SMD equipment. I use 90% SMD in my constructions because it is so much easier with low temperature solder and a controlled hot air gun.

Went to post to comment on this years Burning Amp Festival but was stopped because apparently I need to introduce myself first.
I started my audio design journey in 1971 after university, never looked back and now I am a semi-retired Engineer/Executive getting back into analog audio design.
Some people put ships in bottles, I love researching, designing and building audio stuff that I really have no use for.
I find the diyAudio forum very interesting for observing and learning from knowledgable individuals as well as for a perspective into the minds of individuals who are serious about building audio gear but really have no background to help them along.

The path to the ultimate LM317 is well trodden with the VRDN, the D-Noizator, etc. Inspired by Pa's F5m I'm going
to ponder and post a minimum LM317 that has maximum performance with a minimum number of parts. Perhaps ten?

Quick notes on using 3-Pin Voltage regulators

Feel free to offer your thoughts.

Regards,
Dan

Hi all,

This is Takomania from the Netherlands. I'm not a newbie in vintage electronics home audio. But I'm not a technician. Don't own a scope etc. yet etc. I trouble shooted till date mainly by reading forums and on the eye and ear. But I can handle a soldering iron well etc. It's only recent I try reading schematics etc.

Dear Audiofreaks
I am very motivated to build some Loudspeakers in the next month to come.
So i come up with a Backloaded Horn based on a coax driver wich serves my needs perfect.

Login to view embedded media Is there someone who can provide a Drawing on a German design called Cobra Horn 2?
Thanx in advance: Marti

The slew rate you need is always at least 15-20% more than the slew rate of the op-amp you have.

I've recently had the idea of making a portable (quite compact) bluetooth speaker and after a bit of research I'd like to think I've come to a nice set-up that'd give decent-ish results (no way anything up to "audiophile" standards of course).
I'll be using 2 DMA45-8, one for each channel and 2 ND65 passive radiators. After playing a lot around in winISD I've found that if I pair one of each in an enclosure opposite of each other with 0.3L air I'd be getting best results. I've found a BT module from TinySine I'll be using for connection and for power I'll be stripping down a xiomi powerbank for the power supply.
The amplifier is an issue. I've found one small amp I can source locally, based on the TPA3110 chip. I understand this most likely is not a good option, and so I was also looking at the BVS25 with which I could drop the BT chip entirely, or the TA2024 which also looked good and compact enough for my application. Do I keep the one I've already chosen, or do I want to look into the other options.

Regarding the drivers and PRs, so far the set-up makes sense in my head. Am I missing something here? Should I look into getting other drivers and/or radiators? Should I perhaps not be placing them opposite of each other?

In conclusion I know there are a lot of things to cover and the science behind designing these things goes very deep, but I'd like a general overview of the project as a whole.

Hello.

I've been digging around and trying to know more about making an amplifier. I have decided to make something, that is hopefully not too big of a mouthful for me. We all have to start somewhere, and for me, that somewhere is here.

I hope i can get some feedback of the parts list and possible some recommendations for changes to the parts list. As soon as I, hopefully, have received some feedback, and corrected the parts list, I will try to make the PCB layout and post it in here.

The end goal is to have a couple of boards for my own use.


What do i want out of this project:
I want a PBTL mono amp (switchable to BTL Stereo if possible), that also has a build in 5v 1a output for an Arylic Bluetooth Receiver.
Be somewhat on a budget.
Has to play clean, but I do not need something over the top.
Possible a change of OPamps if it is worth it, to spend some extra
A reliable amplifier, that can be used for a party speaker and/or some nice mono speaker for the living room.


... I considered adding PFFP to the board, but i honestly do not think it is worth it for this project. Correct me if I am wrong.

I also dreamt about having 3 chips on the board, and DSP, making it real easy for crossovers for my projects, but unless I have a schematic I can follow, this will be too complicated.


Parts list:
I listed my parts list below. That is including the schematic and parts list for the voltage converter for the 5V 1A.
All the green markings are items, that have been changed from the reference design schematic. If you have any tips of changes in values, parts etc., please let met know.

Having a bit of a clear out from the DIY speaker stuff, I’ll keep some of the drivers and bits and move the rest on so the following are up for sale.

For anyone in Mainland UK, postage included in the price, and can be collected from Oxfordshire. Happy to quote for postage outside of UK but might not be competitive cost wise.

Pair of Hypex Fusion FA123 3-Way DSP Amplifiers £SOLD inc Postage
Comes with all the various cables and the remote unit too.



Pair of Faital Pro HF10AK £SOLD inc Postage
Superb condition and come with the original boxes.
Happy to include the pair of LTH102 with these for £220 in postage all in.



Pair of Faital Pro LTH102 £60 inc Postage
Essentially as new, only used a couple of times.

Pair of Seos 12 £100 inc Postage
These are in an unfinished white primer, these were sold as made by Autotech although I have no paperwork to confirm that.

A nice pair of LXMinis. I bought them off someone without the plans.
£380

I have a minidsp with the lxmini settings loaded into it, that is included in the sale.


I'm in Guildford, Surrey, UK. Collection only as these don't post well.
Thanks, David

Selling a pair of Musical Affairs Mini Baffles

With EMS Fertin LB12EX field coil drivers

Beautifully hand built by Hans Kortenbach and the power supply for the field coil drivers has been made by Cees Pel

Speakers can be listened to and picked up in Eindhout, Belgium
If needed I can also deliver the speakers or meet in the middle

Asking 2900€obo

Hello all! I've ended up in this forum after I embarked on my journey to make a portable bluetooth speaker. After a bit of research I believe I've found a decent-ish set-up for an entry level hobbyist and I'm here to share that and ask some questions in hopes of getting feedback on it before I go ahead and order everything.

I have a pair of Fostex FW305 woofers which are 12 inch -95db /watt sensitivity.I have found this 3 way design in the Madisound library.I was hoping to achieve a medium sensitivity easy to drive speaker and this appears on paper to achieve this.I would have preferred a paper cone midrange but happy to give the Scanspeak treated fibreglass Discovery mid a try as they are not too expensive.The Peerless ring radiator tweeter I am familiar with and have always found it neutral and reasonably detailed.
Any thoughts?
What is the purpose of the two 20 R resistors on the woofer/ A Zoebel network?
There is no recommended baffle width.I am guessing given that the mid and tweeter are estimated to retain close to their natural sensitivity it would need to be reasonably wide.Is this a likely to be a correct assumption?
https://www.google.com/url?sa=t&sou...cQFnoECCkQAQ&usg=AOvVaw2pMh272qqTLXjm37FG-M-T

What is the consensus? Which type of speaker gives the best coverage, intelligibility and wide sweet spot (forget about pinpoint imaging for 100 people....just the best vague general stereo image for the maximum amount of people)

Let's assume a 3m or 3.50m ceiling height. Part of the room can have a raised floor for better line of sight over the front of the crowd.

You can choose a maximum of 2 options.

Hi all,
Just a quick intro into me, Hi im Lee, I live in Queensland Australia and im currently looking at building an IanCanada Stream and Gabster TDA1541A DAC with UCPure Quad power Supplies...

Just currently doing a lot of reading on some VERY long DIYAudio threads, but so much great experience and info, its really useful.

Cheers,

Lee.

Hi everyone.

Maybe someone can advice.
I got a Hypex UCD2K power amp module and a Hypex SMPS3KA700 PSU.
1 one these are faulty. The Amp doesn't work..
How can I find out which one is broken ?

I tried to measure the SMPS one the pins I think is secondary power. It did,nt show anything but I,m not sure if I,m doing it right.
Or if there is some "sense" funktion waiting for input signal to function..

Can someone advice?

Regards
/JZ

Hey all,

A few years ago I started modifying a Harman Kardon Citation 12 per Nelson Pass’ article. Long story short, life got in the way, had a kid, and I have no time to complete it. Is there anyone in the San Francisco Bay Area willing to complete it for me? Willing to pay for your services.

Thanks!

can anyone share a geber file of a good p3a amplifier pcb?

Hi,

If possible, how would you go about getting 80-5000Hz from a sealed 14L (internal volume) cube, if not, what subset of that FR would be achievable?

According to the sub datasheet (SVS 3000 Micro) they can go as high as 240Hz and perhaps I could possibly cut over to the tweeter (Fountek NeoX 3.0) a bit lower or even higher?

I'm thinking of the new speaker sitting in front of my subs (dual 8" opposing) and a separate ribbon.

I'm going to use an 8-ch DAC and CamillaDSP for the crossover and so only two drivers max in this cabinet.

I don't listen to music particularly loud, 50% volume, room is 5x5m. Current system is around 30w of amplification going into 88dB speakers.

Thanks.

Hi and thank you for taking the time to read my post,

I have searched and yet to find anything relating to this subwoofer

I have a Monitor Audio RXW-12 powered subwoofer, now the amp just appeared to be dead with no signs of life at all and i love a DIY challenge, I've looked around inside and couldn't get any worth while voltage readings ect from the power supply, so I'm hoping it's just the power supply failure however after my recent experience trying to recap the power supply in my Behringer DDX3216 went badly (so that's going to be a future project hopefully as all the ADC and DAC boards are fine if i can find something to take the 8 I2s input data buses and the 4 out using 16 inputs & 8 outputs, USB or Adat ?)
anyway I've given up on switch mode power supplies and wishing to just replace it with a good old transformer as i already have some from my past project's and salvaged from other gear that's been past repair,

Dose anyone have the service manual please ?

the digital amp board has dual rail power input feeding 2 regulator's L7912CV/L7812CV so that gives the 12V dual rail for the opamps ect

there's another single power supply by the look's of it however i cant see the code on the regulator right next to it because of a cap in the way but chances are it's the 5V supply however will check before applying any power

now there's the dual rail for the main power amp and apart from the main filter cap's being rated at 50v and i haven't had the heat sink off yet to see what class D amp chip's ect it uses so that need's further investigation to see what voltage it need's

any advice on suitable power supply rating's and voltages, specially the main amp supply ?

has anyone else attempted anything like this before ?
modified one of these sub's ?
any advice welcome.....

Service manual would be priceless if any one could help,

If all else fail's i will be looking for another suitable Class D amp board to replace it and building a DIY power supply for it

Cheer's

I've seen in a few threads people have put pictures of large plywood construction folded horns where they did CNC manufacture. I'm going down that path with one of the Woden designs horns for some Alpair 10P that I've been breaking in. There's a couple local shops that do custom CNC plywood work and claim to have a decent supply of good voidless plywood since that's usually what you want for CNC anyway. I'm doing the CAD work and things like board thickness, cutting tool size (for dogbone corners) are all constrained so I can adjust after they bring in the material and let me know what tooling they'd use. Generally I'm interested in any advice from anyone who has gone through it, but I did have a couple specific thoughts/questions:

Any advice on how much tolerance to add to the board width when cutting slots? I'll try to ask them to check how much variation there is in the material once they get it, but there's also how much to add just so I'm not having to sand or hammer stuff together. I can't decide if it's worth adding much tolerance on the board length (at each end of the slot) as well, since presumably the CNC itself cuts the length quite precisely.

Any thoughts on how deep to go with slots? It seems like really it's just to align them, the glue is doing the work. I was thinking only 3mm or so deep out of 18mm thick plywood. Going deeper would probably just weaken the sides and would make it more sensitive to aligning the other side when gluing up.

Sold.

Just done up today, one set of complete and tested Miro PCM63 DAC + JLSounds i2sOverUSB stack.
In my opinion, this is the most direct and best combo implementation of the Miro PCM63 DAC.
Sounds wonderful. It is a full, completed DAC, with a pair of AD797 op amp for the IV.
You would need two single op amp to tune the DAC to your taste.

You need +5/-5V and +5/-5v directly to the DAC board. The JLSounds board's 'dirty side' is configured to be powered by the USB Bus ie. drawing +5V from your USB source. This can be changed to be powered from a PSU of your choice if you wish. Can be done very easily by cutting a pcb track under the JLSounds board as instructed by the user guide, and then soldering two wires from pads available on the DAC board out to the PSU. The XO and reclock circuit of the JLSounds is drawing +5V (digital supply) from the DAC board when you stacked and isolation from the USB 'dirty side' is achieved. Very neat and clean design, with full isolation achieved.

Case it up with transformers, PSU, connectors, a pair of op amps , connect it to a USB music source and you are ready to rock and roll.
All high quality parts are eg. Nichicon gold caps, vishay film caps etc etc.
All parts are BRAND NEW including the PCM63P-K chips. They are installed for the completion and testing to commission the DAC.
Even the JLSounds board is delivered today 24 September.

MIRO PCM63 + JLSounds i2sOverUSB III FIO + shipping tracked & registered = USD 345
I am only ready to accept Paypal Family and Friends as payment.
As usual, I will also buy Miro some coffee as a token for his generous sharing.
I have shipped 58 packages to members here to US, UK , asia and Europe, not a single glitch so far.

More information of this DAC here :
https://electrodac.blogspot.com/p/dac-ad1862-almost-tht-i2s-input-nos-r.html
https://www.diyaudio.com/community/...s-input-nos-r-2r.354078/page-209#post-7049224

Information of the JLSounds i2soverUSB board. This is the USB interface that most members agree to be very good for the DAC.
http://jlsounds.com/i2soverusb.html

I'm not sure what kind of Diode this is ? 1960 or 1961 years , maybe a zenor or tunnel ? It's got positive 158 vac in on one side and 6 volts out on the other side and no negative voltage. It's on The negative Bias circuit on Two 6l6 GC , goes through two resistors into two 150 volt e caps installed backwards with the positives grounded and it goes out to pins 5 on The 6l6 tubes. I've been trying to look it up but I can't find anything like it . Maybe someone knows what it is or something else I can use in it's place ?

Hello, Fellow Audio Enthusiasts,

I'm excited to share the results of a year-long DIY adventure with you all! After many hours tinkering, I've developed a solution to stream audio from Raspberry Pi 4B with a HiFiBerry Digi2 Pro card to my old and rusty Yamaha RN-602 MusicCast device via optical cable. And now, I'm thrilled to open up the software to the community under the GPLv3 license.

The project is split into two main parts:

1. Server: Designed to run on any Linux machine with ALSA support.
2. Client: Works on mobile, desktop, or browser platforms. Currently, the most supported client is Android, with a ready-to-use APK available, and the Raspberry Pi 4B (raspbian) is the most tested server device, with a deb package provided.

Key Features:​

• Gapless, Bit-Perfect Playback: No resampling is supported at this stage by the player itself, ensuring pure audio quality, you can still configure ALSA or any other framework that has ALSA compatibility layer (i.g. pipewire) to resample, if needed.
• Qobuz Streaming: Currently, Qobuz is the only supported streaming service (a valid subscription is required), with FLAC as the sole supported format. There are plans to add other formats and sources, including playing from file library.
• Versatile Client App: Connects to the server over the network and can even run on the same device as the server.
• Extensible Code: The software includes an addon mechanism, making it easy to extend with other input sources or device plugins. At this point, it has a MusicCast plugin to control the volume manually and automatically using ReplayGain track data provided by Qobuz.

This project is offered "as is," with no guarantees, but I hope it proves useful to others when building their custom audio systems.

Contributions and feedback are very much welcome!

GitHub Link to the Server
GitHub Link to the App

Yours,
MadEnvel

I've been surface finishing some 6061 aluminum bar stock making a chassis. These 3M sanding disks with a small spritz of Alumicut are working great and last long. In fact the finish is better as the abrasive clogs, smoother.

https://www.amazon.com/gp/product/B098RL6Q2Z/ref=ewc_pr_img_1?smid=A1ALTAZ4J6A4L6&psc=1

https://www.amazon.com/ALUMICUT-Lubricant-Aluminum-Copper-Plastic/dp/B071K7PNYW/ref=sr_1_1?crid=3E7I9VZ8B09G6&dib=eyJ2IjoiMSJ9.PjCasEKVdsXvlN31vFXVL-jpX0BR_PRGFfCU4OEvskmq3J_uDmh3Yz66DNxHDOVNaTsAsruCP5OiVqIvMH5xcDGLrkxC9FIfhIXIa4EYh6EhOqOZvXdXz9WP8fZpMFgXZIEorLU2kk9YlMqLHBMbfsBSJKgOPODI33hrDq-OuusjIlCs2psvHH8EURk5lwGgwG5ALTA_WxjUMJ_WoiczHe90p6J_4MCFoiGQM_-BC233-j0d_KR2W9NgoAG4JhzMT95HCWokKOu0vVSw0CN7UsOdkrzuL2BCFrGStzxnA2A.OFWV_hkQR67ydlTe1JZ3C2Pxtv3MVouJOQz8s7pZc4U&dib_tag=se&keywords=alumicut&qid=1727740876&s=industrial&sprefix=alumicut,industrial,236&sr=1-1

I thought I'd have to go to finer grits, but I can start and stop at 320! After sanding I'll burnish the outsides to get a typical "brushed finish" aluminum. These are really great sanding disks for aluminum. One tip, keep the orbital sander moving in circles across the piece, not moving longitudinally. This pattern gives a satin finish with no patterns created. I'm using a 5 inch Dewalt cordless random orbital sander.

https://www.amazon.com/ZFE-Burnishi...trial&sprefix=burnisher,industrial,174&sr=1-8

Hi everyone!
At Andy's Site of Audio Engineering Topics (diy-audio-engineering.org) I found a link to download several LTspice models for Vented Box designs. I would like to make a small contribution to them adding two more models for closed box and 4th order bandpass designs. To verify the correctness of these two simulations, I compared their results with those obtained with Brian’s Steele spreadsheets which were offered to download time ago in his site diysubwoofer.org.
I use the Dayton Audio DC160-8 spec's for a closed box with Qtc = 0.5, 0.7, 1.0 and 1.5 and the same for a Qbp = 0.714 with S = 0.7 and a Qbp = 0.833 with S = 0.6 bandpass. I found good agreement between them as can be seen in attached plots.
If you try the LTspice models I'm attaching, I would like to read your comments.
Have fun!

I am collecting drivers for my next build, and I now got Ciare 15” bass driver and an 18Sound 10” midrange.
Only the tweeter is missing.

I have fallen in love witht the ESS Heil Air Motion Transformer….I simply must try it.

My question, is regarding the minimum cross over frequence: I have seen various specs, some says 800 Hz, and some 1500 Hz.
If I look at the specs of the AMT 1 speakers, they cross at 700 Hz….?

I need a cross over frequence areound 1200 Hz.

Any thoughts

The silly Dane is confused ☺️

I have this 800a2 amplifier, can someone tell me what parts I need? In the photo where it is selected, what parts does it have? Was burn can't read if someone can email a picture email me at jorgevserna@gmail.com Thank you.

Simple question; has anyone ever tried chamfering out a small tweeter waveguide just using a 45 degree router bit?

Hi
There are two tubes which carry oil to the motor. I got some oil with my new belt order. Should I just squirt this oil down these tubes (see pic).
Also where should I place oil for the spindle and where (if anywhere) should a apply silicon grease?
Ta.

Hello
I got a Classe CA-300 in trouble. It doesn't work. I opened the top and saw that R132-133-134-135 are severely toasted on the mosfets drivers. The problem is the same on both channels. I didn't test the mosfets but they are probably also bad. The outputs will also be checked. Is there a specific reason why drivers resistors burn like that ? Thanks

hi all im new to el34 - do i need a probe - also in an amp with one el34 does it need to be bias adjusted?

Hello,

My name is Doug Moore and I have been into home audio all my life. I used to modify speakers and build them years ago before all of the software and measurement tools we have today. I am currently involved in taking my Spatial Audio M3 open baffle speakers to the next level with upgrades. I have always loved how learning how to DIY speaker mods and new designs can save you money and also allow you to build exactly what you want instead of relying on the speaker market. I have learned a lot about the software and stuff but still need to learn more

Hello everyone i'm new here

Im working on a hybrid 5 channel car amp called a Kicker CXA660.5 which has A/B audio rail power on the front/rear outputs and D audio rail power on the subwoofer channel. It appears to have two separate primary power supply circuits, one being for the A/B amp and other being for the D amp. The primary FETs for that sub amp side are blown and burned so badly that I cannot see the part ID, its a TO220 package for both parts, I compared it to a cx300.1 kicker amp and I think its supposed to have AOT460 FETs in those spots but not sure on that. Can anyone confirm if that is the correct part and if so what parts might be sufficient to replace the AOT460 since it comes up as obsolete and not available on digikey or mouser.

Looking to by a tube lab SE board or similar

Hi
I'm looking for a counter weight, headshell, cartridge and a lid for a Toshiba SR 300C
Thanks

I just made this preamp circuit, its performance is very good. But its gain is 37db and this is very high. What do I need to do to change gain? Or can I make variabke gain? I put a potentiometer on the output. This reduces the gain, but the his noise does not decrease.

For replace the speaker protection relays and main switch on rear panel I have in the moment two different PA150B on the desk. I would like to use this opportunity to provide a description of early modifications I made to this model between 2003 and 2010.

Outside images of this model with serial-No 2143031 (used main board EM1015 Rev7 or newer) are to find in image No 2-5 and No 7-9

In the attached schematic you will find also the preamp section - this means, it is the integrated amp version IA150B (EM1015, Rev0).
Unfortunately this schematic is not in all details identical to these devices of this model - but it is better than nothing.

I know two different PCB-versions, both with dual mono power supply (and both used for the integrated amp IA150B and power amp version PA150B) :

1) Mainboard EM1015 <rev.7 (offered 1997- 1999) for each channel with one BHC (Aerovox) T-Power elcap C25/C26 - go to image No 10 and No 11 and
https://www.dnm.co.uk/capbhc.html
and one usual elcap 10.000uF/63V C27/C28 (image No 12) in the kind of this under
https://www.rs-online.vn/p/capacitor-snap-in-series-158-10000uf-63v/8773715/
so as voltage regulators LM317/337 in a SO-8 outline behind the voltage doubler circuit for the front end (differential amp + VAS) of power amplifier.
Basic description under
https://www.electronics-tutorials.ws/blog/voltage-multiplier-circuit.html

2) Mainboard EM1015 rev7 (offered after 1999) without BHC T-Power for C25/C26 instead this also only two usual (same) elcaps like C27/C28 (image No 12) in the kind of this:
https://www.rs-online.vn/p/capacitor-snap-in-series-158-10000uf-63v/8773715/
so as voltage regulators LM317/337, now in a TO220 instead the SO-8 outline used in the previous PCB versions

In both versions it is important to perform modification steps as follow in order to increasing reliability and reducing thermal stress as to see in image No: 6 around the mentioned voltage regulators - in the attached schematic (first image) Reg 7 - Reg 10

1) Removing the voltage doubler circuit for the front end completely (because no space present for voltage regulator heat sinks in necessary sizes).
more details and consequences are to read in post #13 under
https://www.diyaudio.com/community/threads/repair-thule-ia150b-no-sound-except-humming.303712/
BTW - this integrated amp from this topic use also the above mentioned main board versions.

2) Introducing an additional zobel network before relay switch contact (image 13-15, R15/C57 so as R115/C157 in the attached schematic diagram) are in real live not in use and the already present zobel network R220/221 and C204/205 on main PCB are behind the relay contact and only in operation when the speaker relay is switched on.

The additional modification step, which I had perform on main board EM1015 <rev.7, is as follow:
The BHC (Aerovox) T-Power elcap C25 and C26 was replace by the same usual elcap version as for C27 and C28. For getting similar sonic results as with BHC T-Power I introduce resistors 0R22 between C25 and C27 so as C26 and C28 (both in the "+" and the "-" rail) - check out images in post #2.
The main disadvantage of BHC T-Power caps was the very short life time. The excellent sonic performance with this caps was only present in the first few months of use and for this reason Thule Audio has decided to use usual Elcap versions from Rev. 7 onwards.

Hi all,

I'm trying to design a pcb for CS5381 saved from a broken soundcard. Previous attempt with a CS4272 was successful and this one looks similar, however there are a few pins that datasheet doesn't make it clear how to configure, so I could use your help with this.

1. Pin#12 I2S/LJ. I want I2S. I think it should go to VDD. Is this correct and does it need a pull up resistor?
2. Pin#2 M/S. I want slave mode. So, connect to ground? Pull down resistor necessary?
3. Pin#11 HPF. Low pass filter for DC offset correction. Unless you suggest otherwise, I don't need it for one ADC, one source application. Where to
connect it and how?

Also, I have a question about the low value resistors typically found in series with the I2S lines. I haven't used any with CS4272 with no obvious problems. Are these mandatory? I'm using them with DAC chips and there will be one on board for that matter. Could both ADC and DAC share the same resistors?

Attached CS5381 datasheet and pin out diagram.

Looks good - at least at first glance.
I couldn't find any negative reviews (except than the lack of room correction options).
Has anyone here heard the sonic performance?
Many thanks for any comments..

Manufacturer URL's:
https://www.eversolo.com
https://www.eversolo.de/policies/legal-notice
https://www.eversolo.de/products/eversolo-dmp-a8-digital-media-player-streamer

Various reviews in German and English language:
https://magnahifi.com/de/eversolo-dmp-a8-ultimate-streamer-dac-ak4499ex-ak4191eq/
https://hifi-suite.de/produkt/evers...m-768khz-wifi-bluetooth-5-0-aptx-hd-mqa-roon/
https://www.hifistatement.net/tests/item/3881-eversolo-dmp-a8
https://www.audiosciencereview.com/...lo-dmp-a8-balanced-streamer-dac-review.55826/
https://www.stereophile.com/content/eversolo-dmp-a8-streaming-preamplifier
https://www.stevehuffphoto.com/2023...treamer-that-you-want-the-dmp-a8-by-eversolo/

k303 microphone pre amp kit with NE5532 op amp
breadboard, components and schematic.
I bought it from Taydaelectronics.com
Would like $4 plus shipping but I also don't want to throw away so I could go down to free+shipping.

Hi My name is Magnus. Im interested in tube amps and diy speakers. My current setup is Line Magnetic 211ia and css criton 1tdx speakers.