There are a great amount of threads regarding replacement, but not regarding implement of backup batteries.
There are a lot of vintage FM stereo tuner models in which the programmed stations are not saved for long after disconnect the power cord (instead battery or super cap only usual electrolytic cap arround 470uF or 1mF resp. 1000uF), because the electrolytic capacitor only supplies power only short timt for the memory cell.
That's why it is mentioned in the user manuals, that the programming is lost after unplugging the power plug longer than some minutes.

Some examples from Luxman:
T-530, T240, T-105 and R-113 (Receiver - i. e. include pre- and power amp).
https://hilberink.nl/luxmanl30/t530/luxmant530tuner.pdf
https://www.techtrader.ch/auction/2015/06/Luxman-T530-manual.pdf
https://www.diyaudio.com/community/attachments/luxman-r-113-service-manual-pdf.1023003/
https://elektrotanya.com/luxman_t240_sm.pdf/download.html

What should one consider in general, when retrofitting storage batteries (usually versions with 3.6 volts) ??
In the datasheets of used MCU's there are only an explanation in short form - go to pg. 682 of pdf attachment of NEC's uPD1704C resp. µPD1704C datasheet for an example.

To learning the general rules I want to know some such projects.
Thank you for calling of associated URLs.

I know there in the store but shipping to the UK is just too pricey .

Looking for 2 x Pass F5 amplifier boards, preferably unused. Will need shipping to the UK.

Thanks

Hi,

I am recapping my old DMagic as everything has leaked and wondered about the design of the main +/- 15V supply with the capacitors C400 and C401, can anyone explain the circuit as it looks like C400 receives voltage agains the capacitor polarity, and they are just normal electrolytic and not BP

Hello everyone!
I'm planning on building a pair of rear surround speakers for my system. They will be used mainly for music, but movies too. I have quite a few 5.1 albums which I'd love to listen.
I have a pair of Dayton Audio RS100-4 (4", long-throw, aluminium cone, 4 ohm fullrange speakers) laying around that I would like to use for this job.
Usually, I'd use them alone by themselves without any tweeters, but since I'd be listening mostly off axis I'd love them to have a good off axis response. Therefore I think I need to add a tweeter.

I've been thinking on how to do this and every approach I can come off with has its own set of drawbacks and I can't decide. I'll list them here.

1. Just to add the tweeter, let the RS100 run full range and filter the tweeter at about 3.5kHz (30 degree off axis FR plot here, green line it's for the 8ohm variant but the 4 ohm version should be pretty similar).
I think this is the simplest approach but if I aim for a flat off-axis response, the on-axis will look like trash because it will be both tilted upwards and I will also have to deal with comb filtering because the tweeter and the woofer will play the same frequencies, and due to the wave travel paths not being equal based on how I move it might look a little be better or worse. Impedance also might become an issue. I have no idea how bad this might be.

2. Treat the RS100 as a regular midwoofer and use a regular 2-way LP/HP 1st or 2nd order crossover and cross lower (I'm thinking in the 2.5kHz/3kHz ballpark). In theory this should be the approach the will provide the best on-axis and off-axis, closely matching the directivity between the two speakers. However, the damping factor will be pretty low. The RS100 already have a high Qts, which is already somewhat compromised by the 10m (32ft) of wire that I will have to run from my receiver to the speakers. I would prefer to avoid adding another choke point in the form of an inductor.
2b. What if I did this but instead of using an electrical crossover on the RS100 I used a "mechanical" one (eg. a piece of cloth in front of the woofer)? Would this work? Has anyone had any experience with this?

3. Get a very small tweeter (I'm thinking SB Acoustics SB14ST-C000-4), remove the phase plug of the woofer, and make it into a coaxial. Then I'd just filter the tweeter and let the RS100 run full-range. This way I'd have to deal only with the rising response on-axis and not with comb filtering, because the wave paths of the woofer and the tweeter would be equal.

4. Sell the RS100 and get something else :'

I can use DSP on the entire channel, I'm using a PC as a source that is running Equalizer APO so I have access to many filters. The speakers will be hanged on to a wall, at the two opposite corners of the room, near the ceiling. I don't think I have to deal with baffle step because of such placement.

Has anyone had any success with the spice model for the VOM1271T given on the Vishay website?
https://www.vishay.com/docs/80045/spicemodelvom1271.zip

At best, I can get it to work with 100s of mA on the input, mostly it just stops the spice simulation converging.
If the spice model is not trustworthy, please could someone post a circuit of a SSR using the VOM that is known to work.

Thanks

My system is a complete 1980s ADS atelier system. Regrettably, it’s considered to be obsolete now.

At present, I’ve switched my listening behavior from CD to streaming. My current digital source is a combination of Yamaha YBA-11 bluetooth receiver and a/d/s/ DA20e car’s DAC. Currently, I’m looking for a hi-end DAC, with limited budget (secondhand), to fulfill my system.

Since my system is a complete ADS system, I’m thinking to go for a higher model DAC from ADS. I’ve known that the flagship ADS’s DAC is the “a/d/s/ DA44” where it was actually the twin of “Museatex IDAT-44”. Both models were designed by an audiophile engineer, Ed Meitner of EMM labs/Meitner Audio and had used the same chip.

However, my local shop has a rare item hi-end DVD player; Denon DVD-5000 for sale. Both Museatex (Meitner) and Denon have similar price (secondhand).

To date, I’m hesitating which way I should go. So, I’d like to ask everyone’s opinion and comparison about these two models.

Note: The chips of them are as follows:
Meitner’s IDAT44: 2 x TDA1549T – SAA7274P
Denon DVD-5000: 4 x PCM1704-J – PMD100 – CS8414-CS

Hi all. I believe that this is the best options of what I have available as the DACs inside of my computers are so so at best and are subject to so much interference. Let me know if this is untrue.

With this solution in mind How would I go about determining which of my AVR's has the best DAC. I have Pioneer Elite, Onkyo TX-SRs, Sony DH series.

What are your opinions on the various manufacturers?

Jeremy

3 new in box ,
End up not needing them for my project
Fostex T96A super tweeter

600$ shipped

I have an 18" sealed Ultimax in a sealed & perfectly painted box, and it has a Behringer NU3000dps. I want a 15" ported sub to use with my home theater because the 18" is a bit too much for my current setup. It seems to overpower my other subs even at lower volumes. If you've got a 15" and were hoping to buy an 18" someday. This is a great opportunity for anyone looking to trade up! Take a look at the pics, and contact me if interested.

My Denon PMA-280 started to occasionally play at lower volume and to occasionally produce crackle in the right channel. The crackle doesn't happen by itself, but only with a signal, most easily heard with a sine wave.
I'm attaching a recording of the crackle with a 60Hz sine wave playing. I'm changing the volume a little bit throughout the recording. The crackle is more or less intense at different volumes, but this varies wildly over time. It's not the volume pot that's causing it, because it happens with the changes in input volume as well.

I can hear it through the headphones output too, but only if a load is present on the speaker out (a speaker or a resistor). Without that load, it sounds just fine on headphones.

I've read in some other threads that you can find the faulty component by freezing them, but I'm clueless about this stuff and I was hoping at least to get some pointers and to narrow down the issue. I also have a multimeter I could use to measure something, if it helps.

Since there has been a lot of focus on driver distortion lately with Purify entering the scene, I thought I would post a question on distortion measurements.
I like running multitone measurements on amps to get a 'general overview', so I thought why not do it on speakers? I think it gives a good visual overall indication of the 'signal to distortion' vs frequency. I find two tone tests a bit hard to interpret, and it seems the tones used can influence the result if they happen to hit 'problem areas' of the driver or not. More tones, more excitement 🙂 'More is more' like Yngwie Malmsteen claimed (guitar nerd joke)! 😀
(Edit: Login to view embedded media )

Is there a reason for not doing it?

I ran some quick measurements where I took seven averages/measurement because of a noisy garage environment. One is a PA 8" woofer, the other is an old Mission speaker with a 8" woofer & 1" tweeter. I have no SPL reference, just my ears, and the level in this graph was what I would call normal listening level, so this is not really a scientific example, just a general question about the concept. I'm hoping Lars or other smart people would comment on using multitone for driver testing, and I would also be curious to see what a similar measurement on a purify driver looks like.

I have a new DVC 2 ohm Alpine S Series 2 ohm sub

I plan to run it at 4 ohm to the amp. I want the dampening and I think wiring to 1 ohm is muddy.

I don't have a ton of money to dump into this (I'm wasting some running at 4 ohm but I think it's worth it) so my choice are this stinger 1500 or the D4S mm1000

Heard the D4S units run dirty as hell. Not sure I'll notice as this is actually a track car with zero sound deadening so not a quiet ride (yup, I run a full system in my track car, come at me)

Heard stingers are great units but can't find a lot of info on them. So far found nothing negative about them. Larger, simple bass knob. Bigger so heavier than the mm1000 (track car, weight is a consideration. Let's not get into weight transfer equations)

Mm1000 seems nicer. It has a fan and the clip light on the bass knob which I like. The "dirty power" reports are plentiful. I don't need this sound super loud, I want it tight and crisp.

These will be tucked into a tight spot but I'll have some brushless fans wired up to cool them off.

Let me know what you'd do with your money.

You can sell under your own brand.
The material and weight of the turntable and base can be customized.
The number of tone arms that can be installed can be customized, and up to 4 tone arms can be installed at the same time.
Currently, there are two types of turntables to choose from: magnetic levitation and air levitation.

Due to the large workload of individual customization, OEM products start with 5 units. Prices are quoted individually and privately based on quantity and specific design requirements.
The price of a single customized unit is around US$2,000-8,000 on average depending on the configuration and requirements.

ebay link：https://www.ebay.com/itm/204391721784
Email：cengruyue@gmail.com

Need help with REW for measuring speakers. My setup is with the Behringer 8000 into an audio interface then into my laptop. Last night I measured my current two way project and came up with the top graph which is "normal". Today all my readings / graphs. have the distortion dropoffs at 2.4Hz, 7.6 Hz, 13.Hz, and 18.8Hz. Anybody know what settings or equipment connections could be causing this. Anyone every encountered this and figured out what is doing this.
Thanks much!

Hello, I have a PCIe card with AES/EBU 110 Ohm output that I want to connect to the AES/EBU 110 Ohm input of my DAC through a cable.
I would like to add galvanic isolation to this connection using the 1:1 transformer LL1572 by Lundahl.
Which schematics do you suggest, among the solutions A-B-C below? Thank you in advance.

Solution A:


Solution B:


Solution C:

I've bought a FAST cabinet and driver set from an eBayer. Its the RS225-8/Visaton B80, 25mm MDF cabinet with 25mm ply baffle, which is not yet attached.

My plan is to have two sets of binding posts so I can have an external crossover (and use my active setup). And also, to drill the 104mm baffle hole for the B80 and also (at 45degree offset) an SB29 tweeter, so I can see how the RS225 sounds in both cases.

Now the interior of the cabinet is not treated yet. I have (mostly Monacor):

• 3mm bitumen panels
• 10mm high density foam panels
• BAF wadding
• some acoustic tiles (not actually eggshell but similar)

The volume of the cabinet (excluding driver, brace, and the enclosure for the B80) is about 21l after allowing for foam panels so I don't think I need/want 'heavy fill'.

I feel with the 25mm enclosure the bitumen might be redundant. I will probably add the 10mm foam, put the acoustic panels on top on the back, and some BAF wadding on the sides (and maybe top/bottom). Maybe a bit at the back.

Is that sane? Any other suggestions?

Talema 2x25Vac transformer 500VA. 50€

Hi,

Not sure if this is the best thread for such question, but I will take the risk...

I am a complete beginner in audio tube world. I have intermediate knowledge and experience in electronics, but I face tubes for the first time in my life. However, that is my goal - to learn how to build an audio system based only on tubes (not a product or any kind of homework, just sole knowledge expansion...) I want it to be universal, so the source could possibly be a 3.5mm jack, USB stick or even BT, Ill take care of the digital part myself, but how about:

I have heard that GM70 are really powerful tubes used in the last stage of any amplifier. However, can you suggest me, what parameters should I consider (or even better) or exact tube part numbers should I use for lets say first stage (or even first and second stages, considering the GM70 to sit in the third stage) preamplification. I intend to use 2x GM70 in a push-pull configuration for the full audio band. I guess I am looking for an answer that no book could give me, I am looking for pure knowledge and experience, considering audio tubes to be somewhat beyond regular electronics...

Some of you will say that this project is not for a beginner and I should start with something way easier. But Ill take the risk, as I mentioned, the goal is only the knowledge and experience, so time and money (to some extent) are not an object to me.

Hi All,

Bit of a noob here regarding audio. I am currently planning to create an Arduino powered radio for one of my vintage cars, and I am looking for a small amplifier for it. It will only run 1 speaker of 4 ohm, 25 watts. I would like to have it all in 1 unit, so not in a seperate case.

If you guys could perhaps give me some suggestions that would be helpful. Thanks in advance.

Greetings to all of you on the forum. I'm a new member and I've actually known the forum for a few years.

Good. I state that I am a self-builder technician and I am writing to you because I am thinking of buying the pair of audioresearch classic 150 model amplifiers, one of which is not working. The seller says one works and the other is broken. Missing 2 transistors inside. Do you think they are worth buying? For both, 3,500 euros are being asked. As far as I know, audioresearch doesn't release codes for broken transistors, how can this be done? Can you help me understand what is right to do? Is it worth it? Thank you.

Hello,

I hope I am not breaking the rules, but I have too many things to list and I don't have a fixed price for them (all being auctioned) I can only send here a notification diyAudio members that I am getting rid of my collection of MC cartridges and SUTs.
All can be found on the famous auction site (.de or .com) where my username is LACUNIA.
Since it is being auctioned it would it is impossible to list all of them here. All prices start from 1 euro and the auction will end on Tuesday.
Location is Budapest and as usually all are in very good or excellent condition. Photos can be found on the site.
Each cartridge has been checked and tested before advertising them.

These gathered during many years, some of them I received broken so I repaired them to original or better specifications with the usual care as some of you had already experienced from me.

Please feel free to ask questions here.

There are some rare and interesting cartridges.
I hope you will be able to find something for yourself and make a good deal.

Thanks for checking them and I apologize if I am breaking any rules here.

Best regards,
Vencel

Hey,

Im having trouble finding why the output stage rails are 0V.
Friend brought the receiver to me. Told me that out of the blue there were sparks flying inside the case while he was casually listening to music while doing house repairs.
Took it apart, on the primary side the main mosfet had gone kaboom and took some diodes/pwm controller with it.
Swapped everything out and now receiver powers up fine but output stage is silent. EVERY other accessory voltage is present and at correct voltage but +/- rails for the output is at 0V. I have checked all the semiconductors and even took the transformer off to get to the optocouplers that are underneath it and everything seems to be okay.
Output stage itself seems to be okay and rail caps start charging when checking in continuity mode.
Maybe someone has come across similar problem?
Attached a pic of the psu unit.

This week a pair of MarkAudio Alpair 10.3 drivers are arriving. There has been much discussion about these drivers in particular as needing quite a bit of break in (200-400 hours ultimately before any fine tuning is done).

My plan is to place the two raw drivers in my sauna downstairs (speaker boxes are not yet built, and the sauna will not be in operation). I'll run a pair of wires under the door and simply let them play what ever is on the radio 24 hours a day (168 hours in a week). This will probably be 70's pop music and not too bass heavy. Acoustically, the sauna is fairly isolated from the rest of the house so 24/day is not a problem.

For the first several days the level will be about 55 dB. The remainder of the week will be about 60 dB (level of conversation). After that will be several days at 65 dB, and then several days at 70 dB. That should give me two weeks of break in (about 300+ hours).

For folks who have gone through similar procedures, I would appreciate your thoughts?
-Tom


BTW, I am planing on building the "Eland cabinet" graciously supplied by S. Lindgren
https://www.diyaudio.com/community/...audio-fostex-tb-dayton-seas-etc.323051/page-3

Hi all,

I've been recently looking at grounding in the purpose to make a high end mixer with multiple balanced inputs and I won't lie, it is giving me some headaches.

I've read a lot, but couldn't find concrete answers about this. For a balanced line input, Rane Note : "Grounding and Shielding Audio Devices" suggests to chassis-grounding the pin 1 of XLR with the smallest path to chassis as shield is the carrier of interferences and the length of this wire determines the filter frequency in RF domain.

The best way to do so that I've found is to use Neutrik XLR connectors such as the NC3FAAH1 which incorporate a direct path from pin 1 to the chassis with a sharp piercing tab.

But in star grounding, we often talk about connecting ground of our system to one point of the chassis only, as it is difficult to predict return path currents and that can cause internal ground loops to happen.

So I'm kind of torn between having the shortest path to chassis and therefore having all Neutrik XLRs with individual connections to chassis, or connecting all pins 1 together with a thick wire and sending it to only one chassis point but with the risk of sending more RF interferences to others PCBs.

What do you guys think or would do?

Thanks for solid explanations or experience feedback.
Cheers,

It's a good time to be alive - to see this kind of pioneering continue. I was too young to appreciate the Apollo Missions so for me, Artemis is my chance to live the same excitement that my parents did.

Since I wanted to run my small 2 way MEH (https://www.diyaudio.com/community/threads/ikea-kallax-meh-unity-synergy-speaker.382400/) with a single 300B amplifier, I built a simple first order crossover. The sensitivity of the planar tweeter is almost matching the sensitivity of the LF part and the overall FR is equalized with a DSP (basically a low Q cut of a few dBs to make the midrange flatter). Sounds fine and measures reasonably well.

I remember reading that for a MEH it is beneficial for the tweeter to have an inductor in parallel so that it is effectively shorted at low frequencies - to protect the tweeter from the pressure caused by the LF part. For the powers involved (300B SET), it does not probably matter much - but would there be any benefit in using a series crossover, where the inductor is in parallel with the tweeter?

And if I extended this to my larger 3 way builds, I could save 2 channels of amplification by using a first order crossover between HF and MF. I can see some potential issues with the upper end of midrange above the cancelation notch.

Would it be worth using higher order passive filters (parallel) with this hybrid approach?

Hi there -- I'm building an SSE to work on UK voltage (nominally 230v). Apart from making sure I get the correct power transformer (thinking the Hammond 374BX), are there any additional modifications I need to make? Does the 50 vs. 60Hz have any influence, for example? Or is the output from the transformer identical regardless of the input voltage?

Thanks!

Was wondering what specifications a Single Ended transformer would have for a 450TL ?
I'm thinking 145 watts class A-1, with 2500 volts to 3000 volts. The transformer would probably be rated for 4KV @ 175 watts perhaps?
I was more interested in the Plate load resistance?
Thoughts, ideas?

Hello there!

The potentiometer (ref : CVV9Y13B503Z)of the master volume of my marrantz pm4001 is actually dead.
I would like to replace it, but i can't find it on internet .
I've seen some say that's the RK16812MG099 from ALPS is an equivalent, but after buying it, it's not...

Can someone can help me ?
Thanks

Hello, All --
Was looking at this design for a 140 Watt Mosfet Power amplifier. The Claimed figures for this are less than 0.005% THD, and also less than 0.006% Intermodulation Distortion at
a 4:1 Ratio of 50Hz and 7Khz; these look like good figures. Yes, it uses the older TO3 cased Hitachi Made Lateral Mosfets, - (which I have), and was wondering if anyone on the forum had built something similar, or have any ideas on how this could be improved?
Circuit Schematic is attached --
Thanks, Telnet100

are there some Ribbons or amt which go down around 500 hz ?

Thanks to a very fruitful cooperation with Dr. Bernd Ahlswede from www.sphericalhorns.net, I can introduce my second large 3D printed horn (the first being the multicell horn for JBL2445). It consists of 9 parts and almost 3 kg of PLA. The 62 cm wide horn was cut to fit my Flsun Super Racer printer, it took more than 60 hours of printing time.

It is glued with Mamut construction glue with a few M3 bolts and nuts for alignment. The inside is only roughly sanded, coated with photo resin and two layers of grey spray paint.

The pictures show the construction and building process. It is still work in progress, the prototype was put together as a feasibility test. It seems to resonate quite strongly, so I will try various ways of damping the horn walls and also second unit with added ribs was printed and is waiting for assembly.

It is intended for BC DCX464 coaxial driver.

I decided to document my Visaton LTS 50 experiment of two drivers here. I saw some usage of LTS50 on some full range drivers before, but all are long time ago, and without any modern drivers. So here it is.

First on some basics. Doping drivers might improve or worsen a driver. But one thing is for sure: It will decrease HF response and extension since it adds weight to drivers cone. So I will not choose drivers with limited HF extension. "Overly bright" drivers are good starting point. Better if they have shorting rings in motor, so the response will raise with frequency. I choose FF125WK because it fits these requirements and has a very high peak at 7khz. I use a modified IKEA turntable to apply LTS50 as smooth as I can:

Here's before and after:


Overall I think the coated driver looks great. Like Seas CA* coated paper drivers. Coating was easy too, use a few layers until you satisfied. And here's frequency before/after:

It's easy to see one 12db peak has now became two much smaller peaks. I think it works great. It's very obvious when the original driver connected to a noisy amplifier, you hear a SSS noise at 7khz but with the coated driver, it sounds like a white noise with even frequencies.

Next is the famous FE103SOL. Actually I was a bit nervous on coating this driver since it's a limited edition driver, but the reason is the paper cone started to develop some yellowing, and I think it looks awful. And I know how it will develop in the future. You can see the yellow stuff grown on the center dustcap, it was used to be beautiful white when new:


But apply coating on FE103SOL is MUCH MORE difficult. The "metallic eyelets" will affect coating, and the paper absorb the liquid with different rates. In the end, it's much more difficult to get an even result.

Finally here it is:


I think they looks better with actual driver, the shinny texture still looks good to me. Frequency response wise, the real improvement is driver matching. Before the pair of driver don't match quite well:

You can see these two drivers peaks and dips at slightly different frequencies, one of the reasons the sound stage is not as good as it can be. Also, the dip at 1.8khz was very significant and high-q (~6db) (Also found in hobby-hifi)


After coating:

The two FE103-SOLs basically peak and dips at very similar place. Although the curve looks a bit more "rough" than uncoated drivers. It's easier to EQ this time. The biggest improvement was the surround dip at 1.8khz. BTW I lost around 1khz high-frequency extension due to added weight, but it's still a bright sounding driver due to strong energy at 10~12khz.

With thick black coating(black is perfect for absorbing UV), and additional protection, hopefully I will no longer be bothered by aging issues of the Fostex Banana cones.

I have for sale stereo amplifer, based on Holton HPA-NXL200 R4.2 modules, precisely installed in custom build beautiful enclosure. I could say this is one of the nicest and solid built of this amplifier around. It`s superb sound desire top notch components, so amplifier consist of one 500 VA (230V) transformer, made by my own specifications, with separate windings for each channel. Special part of this amplifier are top notch separate power supply for each channel. Power supply not only provide +-50V to the amplifier output stage, but also has built in capacitance multiplier for delivering clean +-55V to the amplifier front stage (amplifier boards already provide this option). Power supply consist of high end components as soft recovery diodes, Vishay main 4x10000uF 63V capacitors (per PSU) and Nichicon FG capacitors for capacitance multiplifer. Amplifier also has special soft start circuit which is connected to the mosfet DC protection pcb boards (prototype version) on speaker terminals. In case of DC on speaker terminals, amplifier (soft start) will shut down. For wiring speaker lines, Jantzen solid core wire was used. For power supply wiring, Jantzen stranded wire was used. Dimensions of amplifier are: 33x31x12,5 cm (WxDXH). Amplifier is in perfect operating condition. Amplifier should put out minimum 120W/8 ohms and 180W/4 ohms (in practice possible even more, due higher input stage voltage). Input is provided with high quality Neutrik XLR terminals.

Link to the (R4.5 boards): https://holtonprecisionaudio.com/co...xv200l-r4-balanced-xlr-input-amplifier-module

Price is 650 EUR + PayPal fee + post costs


NOTE: I am not responsible for any customs fees, taxes, import duties.

There is no doubt that I should improve my stereo system. The next step, however, has to involve the proper placement of speakers in the room. At present I have the Diamond IV next to my desk, on either side, great for near-field. If I am ever to get out the near-field, though, I need the speakers to be placed in the room. about one third of the way into the room. Many other arrangements have been tried: open baffle speakers, on wall open baffle speakers, and even attempting at home to move the floorstanders to the floor where they belong (Sony SS-333). That did not work out well.

Initial tests with this arrangement have been encouraging. Paul McGowan of PS Audio ("Ask Paul") talks about attempting to design speakers that can be placed "2 -3 feet' from the walls, this seems to be the minimum. One third into the room, and if I sit one third of the way into the room, things get quite good as far as listening goes. The equilateral triangle means then that the speakers have to be placed apart. In all my years of listening I did not experience the stereo effect (outside of headphones) until 2019 or so, at my desktop.

We had a rack "home H-Fi" system (1980s) but the speakers were placed on either side of the rack, like large blocks, the stereo effect was unheard of, we just wanted to play it loud and fill the room with sound. That we did.

Since any room will look strange with a set of boxes on stands in the middle of the room, these will have to be pushed back after use each time, and be able to be stored unobtrusively. There is a potential problem here. Wikipedia, with rare literary flair, puts it this way:

The JBL TI 5000 loudspeaker boxes are 1.15 m tall and, like all large HiFi boxes, ideally should be placed distinct from room corners. Such devices are an example for a rather low WAF.

Click to expand...

https://en.wikipedia.org/wiki/Wife_acceptance_factor

Click to expand...

This thread will then describe results.

How fast can a LF353N be turn off and on.

Dave

I'm working on my other 1002, the previous one is a 1000-2, (newer version) which is now working well.
The 1002 is the one that gets very hot. All final output semi's are NOS along with the front-end boards and VAS stage semi's. Rail voltage is +- 49.5 and about 2mV ripple.
DC offset is 0.5/2.0 mV. Power for the opamps is +- 16. Bias is set to 1.5mV.

So during some sound testing with a 25amp power supply and powering two small speakers at a moderate level it would pull too much current from the supply and make the over current lights blink.
The heat is coming from one of the channels, on the finals. I did not check or change the Zobel networks.
I can't find anything wrong.
Could it be an oscillation problem caused by the Zobel network? I think I read something about this...
Any advice is welcome.

I had a gigabyte ddr4 intel 1700 motherboard which worked fine.
In my infinite wisdom I decided to update the bios in case I went to 13th gen cpu.
After that the system would only boot to Windows every second boot cycle.
I messed about with different USB inputs and sometimes without any flash drives inserted it would boot ok.
I went around and around with gigabyte support who couldnt give any answers except they couldnt see the problem at their end.
So put back old bios version and sold the motherboard on.

Bought another gigabyte motherboard but ddr5 version.
Worked great.
Updated bios to latest version and same problem again !
Then it got worse and would only boot every second boot cycle despite no flash drives connected.
Got in touch with gigabyte again and same routine, cant see problem at their end.

So decided to go through different bios's to find which one the problem started with.
So went from version F2 through to F5.
Each time bios would work ok then to my surprise even latest version started to work !

Stepping through the bios's seems to have fixed the problem but I cant see why as each has a different file.
But PC is working fine now so will see how it goes.
And the latest bios hasnt been updated its still same date on the file.

This came from a a very large commercial UPS.
Had bunches of TO-247 and TO-220 devices
attached to a large heat sink. I doesn’t stretch
and has fibers (see photo) embedded in it. If it
is Keratherm would it be better than the Alumina
Ceramic insulators that I have on order now?
Sorry if this is in the wrong forum but I am in
process of building an Aleph J. I’m a little lost
If it doesn’t have a glowing filament inside it.
Best Regards, Mark

Both of these capacitors are bulging at the top and need to be replaced, they are CE FHS 100V 1000uf. I looked for direct replacements however I was not able to find any from mouser or digikey. On Daewoo’s datasheet, http://info.incomp.hu/NETPDF/FHS.pdf ,the features for the FHS series were low esr, low dissipation. I tried finding a similiar capacitor and found the CDE SLPX
https://www.mouser.com/datasheet/2/88/SLPX-3081876.pdf
And the Vishay MAL series
https://www.vishay.com/docs/28340/056057psmsi.pdf

Would either of those work well or would you recommend a different one.

Looking for advice. I am going to set up a course on audio electronics design and am looking for a simple, free PCB layout app.
I am using a professional paid-for set which I don't want to use for this case.
What would you guys recommend?
Keywords: free, 'good enough' for audio, not too hard to learn to get going.

Jan

Folks:

I'm building an integrated amp with my daughter and don't understand how to design a bipolar voltage divider for the project. I've never built a project with a voltage divider before but generally understand how the circuit works. What I'm unclear on is whether I essentially need two separate voltage dividers or a circuit that combines two voltage dividers to achieve the result my daughter and I want.

Specifically, I'm looking for +/- 17 VDC to power the buffers. The amp's toroid has two pairs of 15 VAC secondaries for this purpose and each pair will connect to its own bridge rectifier. We'll get just over 20 VDC off of the bridge rectifiers (after diode losses) and we need to reduce that by roughly 3 VDC. The voltage dividers (presumably consisting of 1.9k and 10k resistors) will go between those rectifiers and the bipolar capacitor bank that will feed the buffers. What I can't figure out is how to wire the two voltage dividers in relation to each other (I've come up with a few alternatives but have no idea which of them -- if any -- is correct). My search online for a bipolar voltage divider variant wasn't fruitful.

Can someone provide some guidance?

Thank you,
Scott

I've recently bought a non working Mitsubishi x-12 turntable and I was trying to find a copy of the service manual however the only free one available is on hifiengine and I cant download a copy of the manual because I dont have an account and I cant make one. If anyone could point me in the right direction or get a copy of it for me that would be brilliant. Dont fancy spending $15 on an old manual.

Hi guys, a question that has nothing to do with audio per se, but needs some math/trig chops.
See attached drawing. I need to find the radius of the circle, given X, Y and offset O.
How do I do that? I guess only X and O are required?

Jan

I want to use a DPDT relay to switch my positive and negative voltage rail on or off. If my rails are at +/- 25V and the relay is rated for DC 30V, does that work? Or would I need a relay rated for more than 50V? One relay leg is switching +25 and the other -25V, but I'm not sure if that's considered less than 30V, or more. Thanks.

Greetings everyone. Sorry for my English.
the final transistors of my M2 burned out by mistake (2sa1051+2sc2461). I tried to replace them but the new ones burned out immediately so they turned out to be fake.
I'm trying to replace them with sanken 2sa1386 2sc3519. This happens: I adjust the quiescent current to 10 mV on 0.47 ohm therefore to 21.3 mA but it is unstable, it tends to increase. they burned out the first time, now I have to continually adjust to keep it in range. Are the Sanken fake? Idle current with the original 2sa1051+2sc2461 corresponds to 50 55 mV across 0.47 Ohm CT and PE terminals on the schematic. By fitting the original 2sa1051+2sc2461of the other channel , everything works perfectly.
Thanks for your help

Most unreliable and most inferior Electrolytic (Bad and Leaked) Caps - Overview wanted of affected CD-Player, DAC and Amps

Here are threads concerning overviews of capacitor manufacturers:
List of Bad Cap Manufacturers - Badcaps Forums
Be aware of Fake Capacitors. : electronics
and
Most and Least Reliable Electrolytic Capacitors | Page 2 | Audio Science Review (ASR) Forum

but I want to have an overview of audio components like CD DAT DA-converter and all kind of amps that have one of these capacitor brands built in.
This is important to know before one purchase anything in used condition.

I remember this straight away:

1) Kenwood: Even with audio devices that were already released in the early 90s, a short time later one had to deal with heavily oxidized conductor tracks due leaked ELNA electrolytic capacitors - see images of Kenwood's CD player models DP7030 or DP5030 in the attachment and under
Klassiker-Service - DP-7030

2) Sony CD Player ESPRIT (e. g. motor control for spindle motor) - leaked caps (mostly SMD versions without brand name) and broken connection between conductor tracks from top (component side) to bottom (solder side) of PCB

3) Philips e. g. DCC-900
DCC900 Capacitor replacement - Recorders, Players, etc. - DCC Museum Forum
https://www.audiovintage.fr/leforum/viewtopic.php?t=14466&start=20

P.S.: The idea to start this thread comes in my mind after reading post #7-14 under
Audiolab M-DAC Inside/PCB

you're looking at the rear of the front fascia. so the transformers are mounted vertically. I am trying to move it away as far as possible from the amp circuit.

so the layout goes like

• transformers in front (mounted to the front fascia vertically)
• amp circuit in the rear and on the sides
• power supply in the rear and in the middle

feedback/thoughts/suggestions?

Thank you.

EDIT: how about mounting to the sides of the chassis instead? the transformer will be at least 6-8inches (or 150-200mm if you're using metric) away from the amp circuit.

I have a Marantz TT-15s1 that has a stand-alone AC motor that powers the platter via a belt. I've recently moved to the UK so I'm trying to find some way to make this work with the 220-240v here (my current motor is 120v). I've contacted Marantz suppliers and they're looking into it, but it doesn't look hopefull. Does anyone have any suggestions for a kit or another standalone motor that I could jerry-rig to work in this setup?

I am thinking about building a DIY 2 to 1 BT mixer as an alternative solution to the limited functionality (for my use) of bluetooth multipoint

Some background: I ride a mountain snowmobile and would like to be able to use in-helmet audio for music and communication. To communicate, we use FRS Push to Talk Radios (AKA Walkie Talkies). I have a BT PTT radio but for one reason or another, the experience leaves much to be desired when used with multipoint headphones. It seems to be super late to switch from Music to PTT, meaning I miss the majority of what is being said. After the PTT transmission is over, it simply does not ever switch back to music.

I realize there are a lot of things at play here that could be leading to a less than desirable experience. The nature of the PTT signal, PTT Radio software, Headphone software, BT Standards, etc. As such, it feels like my best solution is to simultaneously stream both audio sources and find a mix level where I can hear the radio over the music.


I am hoping to have this run on 12v battery power so that it can run while the sled is off. I would wire it into the 12v accessory power to ensure it can charge the battery while the sled is running.


I will always have my primary PTT radio on my backpack shoulder strap and will use that for speaking or hearing comms when my helmet is off. I do not need the BT mixer/radio to be able to receive voice.


How scary is this project? It seems relatively simple in principle but maybe I am overestimating. Has anyone found any guides doing something similar I can use as a starting point? Any recommendations on things to look into or things to stay away from?

A few years ago, and after more than 20 years of service, my tube power amp broke down. I just never got around to rebuilding it, and I've been thinking I should try something new. I'm interested in the Baby Huey PP EL84, but I was thinking of adapting it to PP UL EL86 (actually 6P43P-E). The problem is that the max plate and screen grid voltage for EL86 in UL is likely to be about 275V at the very most. Since I'd like to go with self bias for simplicity's sake, a 300V B+ minus about 25V of Vk should get me there. I have a Triad N-77A 115V:230V 150VA isolation transformer that should work with plenty of headroom. BUT...

Here's the Baby Huey EL86 circuit I was thinking of building:



The phase splitter/driver stage (12AX7 LTP) has to work from a measly 300V B+. That looks like a limiting factor. So I got to thinking...

I have a couple of 700VCT 40mA power transformers. I could use one to get about 430V for the B+ to the phase splitter/driver stages, but still use the beefy isolation xfmr for the output stage 300V B+. But to do that, I'd have to abandon the Baby Huey's clever feedback loop arrangement and go with the traditional single stage inverter/'anode follower'/plate-to-grid feedback arrangement. With 300V to the output stage and 430V to the driver stage, I came up with this:



This would be my first build with a shunt feedback output stage. I'm hoping to get a more 'push-pull triode' kind of sound but with a nice 15W max from the pair of EL86s. I'd be very appreciative if anyone cares to give that a look and let me know what they think.

Thanks!

So a few years back I had to change my PSB sub transformer as I moved from the US to Ireland.
I replaced the transformer with a toroidal one and all was working perfectly for a few years.
A few days ago I have very little output next to zero... When I put the volume up, a rapid noise occurs, and increases rate the higher the volume. The power light also dims.
I have a sound file I'll try to link.
I noticed the transformer is bulging a bit on two sides, all the caps look good.
I'm getting 17.1v from each lead but I didn't check amps yet.
Could this be caused by the transformer?
Not sure if the board uses jfets or what type but I'm not familiar with this symptom really.

Listen to Sub sound.m4a by Joseph O'Brien on #SoundCloud
https://soundcloud.app.goo.gl/J9D3i

Hi,

I am new to the DIY Amplifier world. I would like to setup a passive stereo PA speaker pair that runs on a Class D amp. But I would like to power it directly from a 48V LiFePO4 battery pack.

The speaker I am looking at is something like JBL PRX 425.
Passive 2-way, dual 15" loudspeaker with 1,200 watt power rating at 4 ohms

This is a Burning Man project and we are experimenting with running off of large battery banks vs. running an inverter/generator. We may end up building the baffle and DIYing the speakers if we have time...

Hi guys,

Just a quick question here. How do I calculate the cut-off frequency of this stage of the graphic eq?
Thank you very much.

Clearing out old projects, these are all new in packaging. Can ship worldwide from Canada.

Curryman DAC - 13 pcs - 7 LEFT - $10 each
miniSharc - 8 pcs - SOLD
vol-fp - 3 pcs - SOLD
digi-fp - 7 pcs - SOLD
nano-digi - 1 pc - SOLD
nano-digi kit - 1 pc - SOLD

Open to offers.

Thanks

Hello..!!

I’m new to the world of FR drivers and cabinets so naturally one does research and makes observations. It’s obvious that different enclosures types do different things, construction principles vary, material types and damping somewhat similar. There is something that I have seen that has sparked interest and I cannot seem to find any specific information, this is where the driver seems to be mounted from the inside of the cabinet and the baffle cutout has an outward 45deg (just a guess at the angle) opening. Could someone please explain if this is a thing?? Good / bad / driver specific or just a visual design cue which I wouldn’t think it is..
“picture below for reference”

Pardon the pun but it’s baffling me..😝😝

Cheers
🔫

I've got a LP12 (somewhere 1985 model) that stopped turning.

All symptoms are similar to the ones as described in this old post (copy form the audio asylum):

Yes, there are two items which experience failures that you can service yourself and fairly easily. Does the led in the switch light up? If so then the following is most likely the problem and it will just leave the motor vibrating or turning verrrry slowly. With the table plugged into the mains VERY CAREFULLY (enough voltage in there to end you listening career) measure the output to the motor between the red and blue wires, it should be between ~85 to 90+vts a/c (as I recall), depending on if you have the zener diode update. The large P/S caps will fail over time, just measure the each of the two them across the board for 160vts, if less they need to be replaced. The other field readily field serviceable failure will require a Valhalla repair kit from Linn which consists of the necessary parts. I don't remember the price. This failure is noted by blown fuses and a related triac and resistor. Hope this helps.

So I followed the instructions to repair it and replaced the capcitors with new ones. But the problem remainded the same.
The voltages were 139VTS with the old capacitors and 140 with the new, os hardly any difference. This was in line with the output voltage on the rectifier which was 280V (SHouldn't that be 311??)

Output voltage on blue connection was 35V/50HZ and on the red 28V/50HZ

I found the schematics of this board and have attached them. I also tried to figure out how it works, but I'm to electronically ignorant to understand this so I was hoping to get some help over here. The schematics say: RV1 to be set to 85V+/- 1V. But when I measure that I only find 6 volts or so so this might indicate what is wrong.

Does anybody have some suggestions how to proceed?

Its come to my attention that I may have too many tonearms... I think its 6 now...maybe 7.

Anyway, even having a few other turntable projects in the future it seems that perhaps I’ve had my fun with this tonearm.

It has been rewired with the Incognito wire kit. It also has the Mitchell techno weight and adjustable VTA base collar.

I also have the original weight and stub for it in my storage closet somewhere.

The Clearaudio Rosewood Virtuoso is not included in the sale.

I poked around on the web looking for a pricing guideline...they seem to vary based on condition and mods.

I would say this arm is in good condition. Normal light wear from mounting of cartridge in screw slots. It works as it should.

The only other thing I ever noticed was some flaking of the gold plating on the plug where the wires enter the bottom of the bearing housing. I couldn’t get a pic as it is currently still mounted on my turntable.

I’m asking $375 for it. Additional cost for shipping and fees would be the buyers responsibility.

While looking for a tube playback amp for reel to reel tape machines and reading some of the threads from here I couldn`t find any schematic to try.
After studying different schematics for playback (Ampex 351, Studer C37 and my Fostex E2), simulating and learning from them, I came up with a hybrid design ala Allen Wright.

Gain is around 57dB and can be adjusted by changing value of resistor R3.
R2 and C3 values are suited for my Fostex E2 tape head (taken from service manual schematic)
EQ can be adjusted using R7 and output level using R13/18.
EQ was calculated for CCIR 15ips.
Added a mosfet source follower to lower the output impedance.

I did some simulations in LTSpice and the figures looks pretty good.

Let me know what you think. Attached some photos and simulation file.

FYI this is my first attempt to design a circuit, I`m no EE, I`m just a self taught diyer.




View attachment TAPE REPRO HYBRID.asc

Hello,

Has anyone ever come across a series of resistive opto isolators that can handle higher cell voltages than the popular types such as the Xvive VTL5 line and the NSL photo type opto isolators? I see most of these have a max cell voltage of about 60 volts and max power of about 50mW.

Reason I ask is that I'm implimenting some switchable mods on 12ax7 cathodes. All is well with the aforementioned opto's until I get to the cathode follower, at which point we are seeing voltages around 160volts.

It would be nice to have a means of switching in various bypass caps and resistors in parallel with the cathode resistors on the cathode follower sections.

Thank you!
Best,
Phil D

Ok. I'm new to WinISD but getting it figured out I think. My question is when sizing my port for net box volume and tuning Hz the number of subs makes zero difference in port size/length. Is port size calculated solely on net volume and tuning? Four 10" subs in one 5.7 cu. ft. tuned at 32Hz. Thanks for any help.

Hello dear forum members,

I'm a designing a commercial preamplifier with tape recorder support. It will contain:

• dedicated tape input,
• dedicated tape output,
• "monitor" switch allowing to route main output signal from tape input to the tape output

The monitor switch purpose is to listen for what is being recorded, if a tape recorder is equipped with a separate playback head. The goal is to make this switch operating correctly, without level and volume jumps when used. My dummy idea of making it of a gain of 1 resulted in a volume mismatch. There is also another consideration that the input level could be overdriven, because of high level, so the record level control knob won't be operating properly.

So my question is mostly about the tape recorder input level and gain which will be applied to the signal before the output. Is there any right assumption? Perhaps any standard on what a recorder should do to the levels on the input and outputs?

Quick investigation shows that my Revox B77 is applying about 32.3 dB of amplification, when input level knobs are fully open, meaning its input is expecting about 18.8 mV for its nominal output of 0.775 dBu. Having signals of tens of millivolts is rather weird, when most of the todays consumer equipment is having output levels of volts.

PS: My internal preamp nominal level is 150mV.

Will appreciate your suggestions, and feel free to suggest the right forum category.

UPDATE: Correction: the B77 nominal output is 0.775 Vrms, 0 dBu, not 0.775 dBu.

5lbs of 0.040", some oxidation on the outside so call it 4lb
4lb of 0.032", pretty clean
Bonus ~1lb of ~28ga solid code

60/40 so non-eutectic but good general solder. $120 OBO shipped in the US, elsewhere at cost.

Dear all,

inspired by this forum post from ASR, I decided to prepare for my next project in advance.. and build something distorting next year. 😉

No, not a guitar amp, I mean I'd like to stay at HiFi quality but rather aiming for insanely low THD, I'd be happy to build a more triode-close amplifier, preferably with 0 feedback (or at least adjustable between 0 and full) and don't care of measurements. If it sounds sweet and great to my ears, my goal is achieved.

Efficiency is no aim either.

I have right now

• 2x NOS JJ KT88
• 2x NOS JJ E88CC
• 2x NOS JJ ECC99

I can have power and output transformers wound in exceptional quality, not begun yet. Trying to estimate load (with KT-150 in mind).

Are there any good, reliable KT88 designs out there you are aware of which could be sized/extended with very minor modifications (maybe 1-2 switches, etc) to accomodate KT120s and KT150s too ?
I'm also a fan of microcontrollers so mechanical (or even solid state) relays are not an issue to use (if they don't degrade signal in the intended application and I can double them if needed for safety).
But if circuit design allows with very minimal modification I could live with that hard-wired option too. A switch (or bypass or any kind of quickly adjustable thing) on the amp's outside itself would be more convenient of course.

I'd really like to build 2 very simple Class-A monoblocks, tubes in triode mode with aforementioned tubes first, designed so that these amps could later also be happy with the heaviest KT-150 guys.
Just out of pure fun and learning - and wasting not only heat but time too. 😊

Any tips, ideas ?

Howdy everyone, as it usually happens in the life of the diy enthusiast I have came upon the quest of the 300b. Upon much reading and research I have opted to seek out a single driver design, be it a la we91a and driven by a pentode or maybe a different topography with a suitable triode.
What do you guys think? I was nearly ready to order all the parts necessary for Thorsten's legacy using c3m driver but before I pull the trigger I was wondering if there was any other design I should take into account. My only criteria is that its a single stage driver design. Please advise.

D.

Hey DIYA
Is there any MOSFET's in production today in TO220 packed that is particular popular as outputs in a preamp?

My knowledge of these is quite limited, but might try to design my own preamp in the near future.
My preamp now is Acurus LS11 modded to a state where I need to move forward towards something else. I found much inspiration from the Aragon lineup (28K and Aurum for example) with their enhanced MOSFET.

Regards

The highest I've ever seen is 700V, is anyone selling thousand volt ones? Thanks.

24V 3A PSU. This is the higher current item supplied as part of the ACP+ preamp kit (green LED, IEC inlet.

Unmarked and little used. looking for £20+4 postage in the UK

Thanks

Hi,

This amp had its bridge rectifier and darlington power transistor STD03P blown. This transistor is obsolete. I have 3 pairs of SAP16P transistors and heard that they can be used as substitutes. As per datasheet, the STD03P does not have an inbuilt emitter resistor whereas the SAP16P has the inbuilt resistor. So If I replace it with the SAP16P, then, do I have to remove R14 and R21 from the circuit. Schematic attached, Please assist.

Thanks

I have a Cambridge Audio Topaz AM1. Occasionally a buzzing sound can be heard coming from inside the amplifier. If I tap the case, the noise stops. Any ideas?

Hey all. I am trying to select a replacement tweeter compression driver to be suitable for use with my existing 2-way crossover and woofer. I will be adding an L-pad (or resistor network) to match sensitivities.

My crossover is 2.5KHz @ 12 db/oct and my woofer is 15" rated at 150W and about 98 db 1W/m. I've heard of a rule of thumb that the power rating of the tweeter should be about 1/5 of that of the woofer. So this would suggest a 30W tweeter.

Most compression drivers I've been looking at are about 107 db 1W/m, so in order to equalize the sensitivities the L-pad will consume a larger portion of the system power. I gather -10 db is 1/2 of the power.

For a pair of speakers there is considerable difference in price between a 30+ watt tweeter and, say a 15W or 20W tweeter. Question: can I safely use a lower powered tweeter in this application? What are your thoughts?

Thanks in advance.
R

as above. (in the schematic below, it's the 10uF highlighted in orange)

Thanks for the reply.

Hi,

I am quite sure this has been discussed before but I did not find it using the search function.

I am going to bulid a DAC using CS8420, DF1704/06 and 2xPCM1704; followed by opamp for I/V conversion, passive HF filter and another opamp as output buffer.

The output buffer will be Analog Devices AD8610, but I am not sure which one would be best for I/V conversion. Maybe AD8065? Any suggestions are welcome.

Cheers
Christian.

Hello everyone.

I'm building a capacitance multiplier PSU based on this article.
(for who can't link to site : https://sound-au.com/project15.htm)

Looking at the Figure 3 - Complete Dual Capacitance Multiplier (Darlington Pair) schematic, there are 2 transistors and 1 diode per supply rail to make up "darlington pair" topology.

At first, I've tried to build a pcb following above schematic, but soon I realized there are no much space to place those transistors and the distance of transistor's heat sink and caps are too short.
So I gooogled it to find solution and I noticed about the "Darlington Transistors".

After while then, I found npn and pnp darlington transistors, manufactured by on semiconductor, looks okay to replace transistors above schematic.
The MJH6284G and MJH6287G. (here's the datasheet : https://www.mouser.kr/datasheet/2/308/1/MJH6284_D-2315692.pdf)

( also the datasheets of TIP35C and BD139G's
TIP35C : https://www.mouser.kr/datasheet/2/389/tip35c-1852460.pdf
BD139G : https://www.mouser.kr/datasheet/2/308/1/BD135_D-2310428.pdf )

According to the datasheet, The maximum dc current gain of 6284G is greater than the gains of tip35c*bd139.
Also the VCEO max and VCBO, VEBO value of TIP35C and MJH6284G are same, gain bandwidth of 6284G is larger than TIP35C's.
Most of the electrical characteristic of 6284G are same or better than the TIP35C, so can it be a replacement of "darlington pair" parts?


One thing I concern about is Continuous Collector Current. The TIP35C's is 25A, while the 6284G's is 20A.
Would the max current of transistor degrade performance of power supply?

The power requirements in my case is maximum 18V 2A per rail, so supplying that power seems not problem.
But I wonder lower collector current could be lead to higher ripple noise.

Giving me your opinion would be highly appreciated.
Thank you.

Looking to build a very interesting design, need to know the internal volume from this triangle shape box. Also with the ports, anyone have a good cad/3d software?

Hello

I'm new to passive crossovers. Forgive me if this is a dumb question.

I found the following old thread : https://www.diyaudio.com/community/...h-order-linkwitz-riley-2-way-at-3-khz.339215/

I am also trying to use a 4th order linkwitz riley crossover(in my case 2.5k), and I found the following values through a calculator.

C1=8.44 µF
C2=16.88 µF
L1=0.16 mH
L2=0.72 mH
C3=25.33 µF
C4=5.63 µF
L3=0.48 mH
L4=0.24 mH

However, I have no idea how to "standardize" them as the thread I found says.
(e.g. changing 8.44uF to 10uF)

As I understand it, the calculator multiplies cratio and lratio by a certain value, and it seems that increasing or decreasing these ratios by the same percentage will result in a completely different filter.
Can anyone tell me how to "standardize" specifically?

Did quite a research but couldn't find the answer 🙁

SOLD - For sale a set of EF3-3 Wolverine PCBs partially assembled using parts as recommended in the BOM for a 100W build. Build guide revision 24 dated 08/09/2022 was used. These boards passed the first set of tests as outlined in the build guide. Only the output transistors and Q104 transistors left to be installed. Price $300, this is less than the cost of PCBs and parts.

I also have a Antek AN-5435, caps, bridge rectifiers and assembled Mark Johnson H9KPXG soft start board available that I was going to use for this build if interested. - SOLD

Just wanted to know if I should be adding volume to offset bracing.? I’m hoping the answer is yes because I’ve somehow ended up with 2.4lt of additional volume lol.!
17.1 to 19.4, subsequently the internal height is now 20mm shorter and the internal depth is 40mm deeper..!!! I at least got the width correct..!! It’s a ported enclosure using Markaudio 10p

My question is, would the above shape changes have any impact? The original design was 369mm internal height so would I need to place the driver and port a little higher to compensate?

Thanks in advance, it’s my first build so hopefully someone can help..!! It’s not really an issue to cut more ply to the right size but I prefer the look of this cab being a tad shorter and deeper.

Cheers
🔫

My roommate and I picked up some full-range 3” and 4” drivers at BAF23 raffle, with the intention of taking our very first foray into DIY speakers.
I had long put off building speakers on account of the dizzying amount of considerations, optimizations, and calculations one could leverage to design a (good) speaker.
My roommate assured me it’s well within our abilities to make a bad speaker, and perhaps we would learn something along the way—so no more excuses.

The result was a shootout between competing spherical designs (with a bonus fake “TL” concept speaker cab). Misprints aside, the results actually sounded surprisingly good to us. The biggest glow-up was the 3” driver, which really sounded far better then I gauged it would just off the unmounted listening test.

Dear diyaudio members
It´s been a few weeks i try to repair one audio amplifier. Special one for me, because of these keywords: cascoded current mirrors, fully symmetrical design, direct coupled with DC-servo. Voltage feedback is taken from the "darlington driver" stage which drives the IGBTs and for zero DC output is responsible the only not discrete component on the board - the OP07.
The main problem was "invisible" but while checking with the scope I found the problem in defective via in PCB under one of the main caps pins. This cap filtered the -56V rail. The result was overloaded power stage. This was audible while turning on the machine. The logic board watched this status carefully and immediately disconnected this faulty channel off. After this procedure I powered the amp again but another issue appeared. Voltages on gates of power IGBT´s are not symmetric for N and P and also it is impossible to set any quiescent current thru output transistors. The "thermal sensing" BD139 which is responsible for idle current setting doesn´t allow to open them.
I already soldered out these nice Toshiba IGBTs and measured gate treshold voltages and these sits around 2,5V.
The problem is that whole output from the input module is DC shifted and I could not find any way to set this correctly.
The input module was small PCB completely sealed in plastic enclosure with 10pin board to board connector. In the schematic this module is highlited as INPUT MODULE. The manufacturer of this amp wasn´t much helpful so I made some cruel reverse engineering and redrawn the full schematic of power amplifier board.

1: repaired faulty via in PCB
2: checked output transistors and I also measured them on curvetracer
3: checked OP07, it was good, but replaced with new one
4: found some BC550/560´s with very low beta(can´t remember which exactly)
5: paired and combined the transistors to match positive/negative 15 and 16V rails
6: paired transistors in outer current mirrors which are biasing the input transistors inside input module
7: the same was done for inner cascoded current mirrors

Pairing was in a sense of chooding the Vbe, h21e and reverse biased EB breakdown. I played with everything at this board but there is still assymetry on input module outputs..I gave up and posted this thread. Any advices ladies and gentlemen?