Under
https://glass-ware.stores.yahoo.net/nostmfbcr.html
I read follow:
The multiple-feedback filter is based on the inverting amplifier topology, whereas the Sallen-Key is based on the non-inverting topology. This makes a big difference, as the assumption behind the Sallen-Key topology is that the buffer's output actually realizes absolute unity-gain; no buffers do. In contrast, the multiple-feedback filter relies on there being phase inversion of the input signal, which there always is. In addition, the MFB's initial RC filter are outside the feedback loop, so this pre-filter is essentially passive, therefore incapable of overload.

Usual both commercial and diy active crossover network units are in general wired according the best known Sallen-Key topology - here is present the great benefit of variable XO frequency with help of simple pots.
Maybe this is an important reason of the very low popularity of active XO in MFB topology.
Mostly the ask of the best op amp I note often - e. g.
https://www.diyaudio.com/community/threads/which-opamp-for-active-crossover.187095/
https://www.diyaudio.com/community/threads/op-amps-for-active-crossover.88513/
https://www.diyaudio.com/community/threads/op-amps-for-active-xover-and-line-drivers.249499/
https://www.diyaudio.com/community/...r-active-crossover-design-for-speaker.383631/
https://www.diyaudio.com/community/threads/active-crossover-parts-selection.378555/

But nobody ask about differences concerning the topology. Therefore the question:

Who have heard both versions especially in the high frequency rail e. g. with JBL or BMS drivers or any AMT driver ? - like those under
https://www.diyaudio.com/community/threads/amt-ess-1-vs-stage-accompany-sa8535-sa-8535.164153/
https://www.diyaudio.com/community/...401-sa8535-ess-amt-or-beymas-tpl-150h.267960/

Thanks for comments and URL's.

Upcoming trip to the US, the first since Covid hit. I usually order some Dayton drivers and buyout stuff, since much of the PE stuff is either not availalbe or more expensive in Europe.

I'm interested in low distortion midbass, midranges, and planar, compression or AMT tweeters.

Any new and exciting stuff or great deals I should look at? I was thinking about getting a pair of the Epique 150, even if the cone edge resonance and associated distortion in Vance Dickason's test wasn't all that great.

Fyi
I was looking at Zilla's site.
https://speakerprojects.wordpress.com/speaker-projects/loudspeaker-drivers/pro-sound-drivers/

Hmm. So let's check out some Pro Sound drivers.
Here's some interesting drivers-

says fullrange
https://qcomponents.ca/collections/...tion-f12m-150-8-ohm-200w-guitar-speaker-t6467

https://qcomponents.ca/collections/...m-12-300w-neodymium-bass-guitar-speaker-t5619

4 ohm version
https://nextgenguitars.ca/products/celestion-bn12-300s-300w-8ohm.html

says Bass Speakers (?)
https://www.jensentone.com/bass-speakers

BIGDOGBRODAVE shout out to Perry Babin and diyAudio for providing guidance and advice and endless information paths that eventually lead to me feeling very happy after bench testing for several hours.... amplifiers that have not seen the light of day in over 40 years. THEY LIVE!!!!....... Thank You for this great feeling that I never expected..... Happy. BDBD/2022

Good day folks,
I got in an Orion XTR 2200.1D with blown output filter caps (electrolytics), replaced those with new. Amplifier powers up, good rails and reg LV supplies, passes clean audio.
I've noticed however without audio and a 2-ohm load connected if left connected at idle the heatsink gets hot to touch (after ~15mins). I did some probing around and found some ringing on the output FETs gate drive.
The output section appears to be original, how can I go about to reduce this?

I have TWO Logitech Transporters that have stopped working. The original symptom, in both cases, was a dead display. Both of them continued working for a while after the display died, but eventually that stopped. I thought I'd see if anyone wanted them here, for parts or repair, before taking them to the recycling center. You can take one or take both.

They're free, though I'll ask you to pay shipping, which we'll calculate if anyone wants them.

I'm in the USA (Rhode Island, specifically). Shipping within the US shouldn't be too much. Probably we're looking at something like 15lbs and a box that's 20x16x6 or something like that (for each one).

Hi all
Above amp came with power supply failure. I changed mosfets to 3205 with 47ohm resistor. Also changed driver transistors to A1015. Amp power supply failed in just two songs.
I have a doubt on A1015 as I bought them from ebay. Can anybody suggest best driver transistors for this type of amp. Thank you.

Hello all!
Im new on the forum and more or less new in HIFI world.
Im also a carpenter and have my own shop so i decide to make some speakers for me 🙂
Right now i have pair of AR18EJ and Pioneer SA-608. So,nothing special.
I want to upgrade to Dallas II loaded with Fostex FE206EN and Monocor HT 958 PA/SI.And afkors class A tube amp.
Tweeters i find cheep,unused so i decide to upgrade high spectrum right away.
So,i have few question.

1.For tweeter i order SCR Silver MKP Capacitor, 0.68µF, AgM serie (700VDC),is that good choice?

2.For damping in back of speaker,can i use
Pair of damping foam, dimensions 100 x 50 cm each, 20 mm thick
?
Or its better for this use

Pair of daming wool, 100% polyester, white, 24.8 x 13 x 1.38 inch each

or

100Pcs Magic Sponge Eraser Melamine Foam Stain Dirt Mark Remover Cleaning Block | eBay

?

Some guys say this melamin foam is the best for back of the speaker.

3.For filling empty places in box,is it ok to fill it with polyester damping wool?
I see some guys say that the best,in low budgett is regular cotton wool,better than polyester.

4.For lower filling part of speaker,triangular one,is it ok to fill it with quartz sand to get nice stability?
I dont know if i lose something with sand,but my logic tells me it can only benefit the overall sound.

This are main question what i have.
I study for some long time Dallas II and Dallas III design.
Dallas III looks much nicer but i cant find enough feedback about how this cabinet works.It looks to me it can work only better than Dallas II.
But for now,i decide to make things easy as posible and build Dallas II.
I find some error in drawings.I take all diferent srawings from internet and make a new one.The error was on the places where horn is folded.
So i corect this places and make it nice,parallel and in constant expanding.
The worst was first fold of horn.There was horn going from 52mm to 38mm and then expanding again to 52mm.
Im gona put some pictures so you can see what i change from redrawn plans from 2013.
What do you think?
Yelow are new board position and added boards,green is old from 2013 redraw.

I make complet plans 2D and 3D,and im gona make board cutting list,so this is my contribute to all of you and all new builders to make thing easyer for buiding.
Can i upload somewhere this plans?
Or i can send it to you on email.

And sorry for not so good english!
Cheers!

Well I have had some time on my hands again, and as the saying goes "Idle hands almost always lead to bizarre things happening".

At least that is the case at my place.

Last time I got this bored, I ended up building a power amplifier entirely from small signal transistors, using 100 devices in the output stage.

This time my idle hands turned their attention to the discrete operational amplifiers that lay unused on my desk (yes, I don't even use the things...). The challenge was "Can I make these using through hole components, but still fit generally onto a DIP8"?

The answer is below...








To add to the challenge, as I firmly believe that simulating or "CAD" designing things is a cop out, i set about making them. By doing the PCB's in my shed.

The design is pretty straight forward - I am an engineer, and not such a believer in esoterica - there is little need to go off the planet if making a BJT DOA...

View attachment Schematic Sht1.pdf

View attachment Schematic Sht2.pdf

This would not normally be such a big deal - but these things use 50 thou pads, and include "normal" 0.25w resistors and TO92 transistors. Getting the top and bottom layers of the PCBs to line up was fiddly - and in a couple of areas the bottom layer hole alignment to the top is a touch off.

But they worked.

A PCB from a fab would make assembly really (really) simple. Doing it soldering top and bottom was a hassle!

They work a treat - I haven't measured their performance yet, but considering that they are with the exception of device packaging utterly identical to these:



I am assuming they work pretty well the same...

In the end I reckon they look pretty cool. I guess that shows how sad an individual I become when bored. Or how evil my idle hands can become!

If you want to make something like this, I would very (very) strongly recommend using a PCB fro a fab with plated through holes and soldermask!

I have the files if you really want to go old school. Else if you like some microscope work, I have a bunch of PCB's for the surface mount work that I will happily share a few of with anyone needing distraction as much as I do!

After I had great help here searching for a specific grounding post for my ongoing Sony PS-X9 turntable restoration I’m encountering new problems regarding the inbuilt phonopreamplifier of the deck…

There is one defective DA-2801 integrated amplifier module in the MC headamp and since it’s potted in it’s little enclosure there is no way for me to repair it…

The same DA-2801 module was used at least in the Sony HA-55 headamplifier and the Sony TAE-88 preamplifier…

If anyone has a spare part DA-2801 or a defective HA-55 with one chanel working I would be happy to buy…

Any other ideas how I could solve this problem are very welcome…

I know of someone who reproduces these modules, but this takes a longe time for preordering and I’m trying in my restorations to get the gear as original as possible…

Thanks for your advices and your help…

Best regards

Michael

What would be the effects of using a 100k pot instead of the 50k pot for the vol control.

Source impedance is only around 600r

Attached is a schematic showing a JFET SRPP RIAA preamp using the PN4303 JFET , which is available form Goldmine Electronics and from Mouser. Distortion was (according to simulation) lower for the 4303 than for higher gain devices like the 2SK170, PN4393, or J110, which was the rationale for chosing a MOR device like the 4303. The 2N5459 might also be suitable for this application, but the breakdown voltage is marginal at 25V. FETs were selected in pairs for equal VGS at 2ma drain current using a homebrew matching jig. The circuitry at the right is a discrete shunt regulator used to knock down a 40V unregulated power supply to +30V. Gain is 38 dB each side at 1kHz into a 20k load, with 0.1dB gain matching between channels. I intend to use this preamp to replace a modified Pacifiic RIAA already used in a test setup in my living room (subject of a previous thread about 6 months ago) The Pacific was (and still is) pretty satisfactory working with a Kenwood KD-2055 turntable with a Grado Gold cartridge. However, the high level distortion (as simulated ) for the SRPP should be better than for the Pacific. I am eager to make the replacement to see if I notice any difference. When I replaced the stock Nikko preamp with my current setup, I immediately noticed the change. I would never go back to the Nikko.

As a side note, yes, I'm aware that Elektor has published an SRPP circuit, but I haven't seen it, as I didn't fork out the money to download it. People who have seen the Elektor circuit are free to comment on the similarities/differences. I will follow with a picture of the completed board when I can charge the batteries for my camera...

In the attachment from page 8/15 to 10/15 there are to find a description of an active crossover network.
The following special feature is noticeable:
No additional line-level gain stages for the filter stages as commonly usual, i. e. the op-amp for the low-, high- and band pass is the power amp itself.
Except the example from attachment I don't find more information on the web.
Nevertheless there are probably several additional papers concerning this (NXP, Texas Instruments, OnSemi and so on).

Thank you for sending appropriate URL's therefore.

I can't find a diagram with the configuration similar to that of the datasheet, but in inverting mode.
Or if there are similar inverting and non-inverting equivalent schemes, so I can compare them as they sound differently.
can someone show me some links?

I get emails about answer in a Conversation session that are many hours late. Quite confusing.

//

PS. 24h clock 😉

Hi,

I was wondering if anyone knew of any good pre existing 12" isobaric designs. I'm looking to make four boxes. I'm also new to making isobaric subs and am open to suggestions, concepts, and advice on making them.

Thanks regardless!

As requested, I'm starting a thread about my latest HP amp build.

It's an actively loaded triode design based in part on Broskie's Aikido.

It uses a 6N3P as the voltage amp, and a 6N6P as a follower.

I designed it to use a 6N3 or 5670 or 2C51 because they are perfectly good tubes, easy to get, and not very expensive yet. ECC99 could be used instead of 6N6P.

The circuit board was designed for a line stage, but a couple of changed values along with a larger cap in parallel to the film cap on the board makes it sing.

It's setup to be a single ended design pushing up to 20mA through the load. It's designed for higher Z headphones, but it will drive 32R without a problem as long as your headphones are loud with only 20mA of current. You can increase the current by changing 100R to 68R.

I have extra boards available as blanks, kit, or complete for headphone or line stage duty.
Anyone want one? 😀

A noob question. Is there any sonic advantage to either of the filter topologies? Is there a clear reason to pick Sallen and Key over MFB? and vice versa.

Dear All,


I am looking for some D3A tubes and came across some Siemens CV10804. Sound wise, is it as good as the (previously) more common seen Siemens 7721 D3A? Thanks in advance for your inputs.


Sincerely,

Wayne

Hello,
i am trying to fix the strobe light on a RP-1000MK2 turntable. I cannot find a proper service manual, so i'm asking for some help.
The strobe light is very dim, flickers and turns of when starting the platter. Looks like a bad connection, but its not. The "light bulb" itself looks very black and burned out.

It is connected directly to 230V mains with a 12k 1/2W resistor after the power switch and before the transformer. Which replacement "light bulb" (red or orange) can i use here.

I only found service manuals for the newer Reloop models, but they are not useful because these models all use Led's for the strobe light.

Many thanks!
EXTC

Hi Guys.
I'm looking for the counterpart or P-channel version for the 2SK1940 mosfet. So far I could not find anything. Any ideas?

With solid state it's pretty easy, and for the sake of simplicity I'd start off with guitar amplifiers. Take your favourite overdrive pedal, connect it to the power amplifier chip and you have your custom guitar amplifier done.

How doable is it with tubes?

Say, I want to build a Orange Tiny Terror clone but make a low power design, and use 12AU7 in PP as a power amp section. Is it just a matter of taking the preamp section of a Tiny Terror and a power amp section of a Marshall DSL1 and just connecting them up?

The usual procedure for realizing active loudspeakers is to add an active crossover network device between the pre-amplifier output and the inputs of each power amplifiers.

However, this is always associated with the disadvantage that additional semiconductors (transistors or in most cases operational amplifiers in the signal pad) add their own sound signature. This disadvantage is audible only in the upper frequency area, so that this approach would be of no advantage for subwoofers but of great advantage for the high frequency range especially with very high resolution tweeters.


What about the approach to implement the associated filter network in the already exist power amplifier (and not in additional introduced gain stages) as describe under the below URLs ?
TDA2030 active speaker audio systems circuit with 60 watt output power
and page 12/23 under
https://www.st.com/resource/en/datasheet/cd00000129.pdf

Are there any experiences ?

I have implemented this approach only once on a "ZEN" - go to
ZEN include active crossover without additional OP AMP for ultimate sounding PHL1230
but have recorded a considerable increase in sound quality compared to the normal procedure of using before (i. e. a separate device for the active crossover network equipped with OPA627 and Sallen-Key topology).

DCSTB Power Supply for Salas preamp, fully built and fully working. Looking for €.80 plus postage

Have any of you used them yet? What is the experience like?

600:10K

Hi,

I'd like to install a crowbar circuit as overvoltage protection on a 24V power supply. I require an SCR that can withstand 3A for long enough to blow the fuse! (Equipment draws approximately 2A at most). Is BT151 capable?

Can anyone recommend a 'ballpark' device? Ideally, one that is inexpensive ;-)

One weird thing: you can drag the "Attach files" button into your message.
Attach files

And it will accept files, but they seem to go to limbo. And can majorly crap-up your HTML.

i need the oki chip M6404A-174 for the sony cdp-555esd / 705esd

Maybe someone has a spare chip like this?

Hi everyone. I have a Technics SL-1700 turntable (1977). It was not used for about 10 years. It has developed a speed stability fault where the turntable is very slow to stabilise and will overshoot badly if the turntable is loaded to slow it below the normal speed (both 33 and 45 RPM) . I suspected corrosion on the pots (4of them) or something wrong with the speed selector switch. Unfortunately after extensive cleaning of the parts and checking their working with a meter the fault is still there. I have also cleaned and checked the multiway connection of the multi-wires from the PCB to motor assembly...nothing wrong here. I have now replaced every electrolytic capacitor but it made no difference. I have the manual and the circuit is pretty simple. Before I replace all the resistors and film capacitors, I wondered if there is anyone reading this who might have solved the problem please? It really is so depressing and time wasting to remove and replace good components for nothing. Summing up the fault I would say it caused by a slow or weak speed feedback as the motor has full power on start up and will eventually stabilise over a minute or two if the load level is not changed on the platter....Bench testing is slightly tricky as I would imagine the motor needs to be connected to the PCB before voltage checks are made but if necessary I can strip the entire parts out to do this, before binning it. Thanks in advance...🙁

I just got a Denon TU-800 and on the fmtunerinfo website JohnC has posted his component upgrades to take the tuner to the next level.
one of his upgrades is 6 Schottky diodes in the power supply section.
Power Supply
D703/704/710/711/712/713 - 11DQ10 Schottky diodes
C716 - 3300/25
C709 - 33/35
C703/710 - 47/25
C701 - 68/35
C705/708 - 470/50
C704 - 100/50

https://www.fmtunerinfo.com/DIY.html#TU-800

I have done a bunch of reading and do not understand how using Schottky diodes in this case will upgrade the tuner.
Can someone help me understand.

TIA

Hi all,

My Yamaha TC-520 Cassette Deck appears to have a power transformer problem with the voltages supplying power to the single DC motor.

Voltages measured directly off the soldered wires (black & red) from the back of the DC motor are reading around 11.3 to 11.5 volts and the motor is labeled as a 12 volt device. When measured directly off the transformer secondaries I'm also seeing about 11.5 VCA

I have a schematic, but I'm not sure if I'm reading it right as it looks to me as the voltages from the transformer yellow lead should be around 14 volts leading to the DC drive motor. The secondaries have 5 wires coming out which are 2 yellow, 1 orange, 1 brown, and 1 red.

I will post the schematic below which is taken directly from the last page of the original instruction manual. I have had this deck for more than 35 years and the only things I have ever needed to do was replace the belts 3 times and Deoxit the potentiometers and switches.

Any help would be greatly appreciated.

Hello.
I am really puzzled about acoustical materials like foam on walls, polyfil or other materials, that supposed to remove standing waves from enclosure.
I tried reading lots of threads about it, but I never succesfuly reached decision what to do 😕
I am building little ported subwoofer with 8" driver. Box will have 20L (0.71cu ft) It will not play higher than 90hz. Do i need anything on walls?

Looking for Sony RM-D55A remote for 75ES DAT.

​

Helo friends I am building class Ab Amp using this schematic Do i need some changes for better performance?
Thanks In Advance...

Hi,

I'm a furniture builder local to Northern Utah (Ogden). I'm building cabinets & assembling speakers for customers as well as building furniture.

I enjoy learning all there is to learn about audio and I'm sure I'll have a lot of questions for years to come.

I had a question specifically for a user that built a set of speakers (he modified it from the original plans) and I wanted to understand how that impacted the sound, if at all. How can I start a conversation? I promise I'm a human and am not looking to invade people's inboxes with sales calls.



Cheers!

Hey Great Folks,

I have designed a miniature PCB for OPA1656 amp (schematics from it's datasheet) I wanted to build into my new old Thorens TD166, so here it is if anyone is interested in similar endeavor.



Have a great New Year ahead.

Anyone know where I can buy this style jack and have a good part number ?

so my notifications have stopped coming again,i dont get any for anything,messages or forum updates from threads

thanks

I have a Focal FP 2.150 amp (actually two but only this one is having issues) that is turning on, playing, and then shortly after will go into protection.

Let me start by saying that I used to be a professional installer and the install is good. Positive for three amps comes from a dist block and grounds all go to the same JL Audio ground post.

I SWEAR that the amp was doing this when I would hit the brakes. I don't think that's actually the case anymore. I pulled the speaker outputs first and it still went into protection after a few minutes. So, I pulled the RCA's, and it did the same thing. So basically the amp just turning on is sending this thing into protection. I have the schematics. Where do I start?

My Punch 250.2 two channel car audio amplifier is working with 1.5 channels. How can I fix or who can I pay to fix the burned out channel on my amplifier? Is it possible for me to fix it myself?

So I recently built the B1K preamp and its sound great. I would like to ditch the wall wart, however, and build a dedicated linear power supply to feed it. From my understanding this needs to be a regulated 24V design.

Using Digikey's Schemeit I came up with a rough design I have seen in a few different places.




For the transformer, T1, I was thinking of using something like the Antek AS-0520, which is rated as 50VA. The regulator would be something like the LM7824 shown above.

Looking for suggestions or improvements for the rest of the design, size and make of capacitors, etc. I probably should also add a bleeder resister and possibly a power led as well. Also there is only one switch, but its labeled as S2, I am still getting used to the Schemeit interface.

I will probably put this is a small chassis, maybe one of the Dissipante models, 2U if it fits, or 3U otherwise, so I will have some heatsink capacity to work with for the rectifier and regulators.

Bonus if I can also get a regulated 5V out if this PS as well to power my external DAC. It would probably take a bit more than tossing in a 5V regulator due to the large voltage differential. Open to ideas.

I broke the screen on my OWON SDS1102 scope, now looking for a replacement, so far OWON haven't replied to my enquiries. Googling the part numbers on it didn't show a direct replacement.
Numbers that I can see:
TS070BF07-08E
H207-21A.AIOGAI
7DD-NTE250RJLC (ribbon cable) (50 pin)
Screen size is nominal 7 inches with 800 x 480 pixels
outer metal measures 165 x 100 mm

PRODUCTS | .Kartesian

Saw these on the TLHP website. They look good on paper. Interesting mix of prosound and hifi drivers.

Up for sale are the two boards assembled and perfectly operational Salas phono simplistic Preamp. Premium grade component. Missing the power supply section. Wonderfull sound, detailed and fast but not aggressive. Asking €.200 plus shipping.

Hi guys,

I found some yellowish deposits one some Mica capacitors and trying to identify them in case they need replacement.
Does anyone know how these long 5-legs Mica capacitors are called (photo).

In the service manual (it is a Sony boombox) the description is this:
1-107-253-00 (Sony part number), - (15+18+22+27)p 500V Mica.

I have also attached a picture of the board diagram and circled those capacitors in RED ink.

Is anyone out there still playing with home build Walsh drivers?

For sale matched pair of tubes in nos condition. Verry nice sounding tubes. Price is 50eu plus shipping inside EU it would be around 7-9 euro with tracking. For more info plese contact me.

Good day brothers. I just received this amp B2 mono from a friend but no model written on it. I checked it and found out no gate drive signal at Hi and Lo banks. Power supply section is normal and rail voltage +53 and - 53 are present. Actually the driver chip was located under the blue capacitor which I relocated it and connected it with red wire as shown in the picture. I did this in order to check the drive signal from the Driver chip U9. As I did, tracing backward from Fets gate, there are no drive signal from the chip itself. But my problem is that the part number of the drive chip U9 was erased due to heat I believed as well as the adjacent chip U10. As I traced, the Lo signal out is Pin 1 and Hi signal out is Pin 8. Can anybody tell me the part number of the chips U9 and U10 as shown encircled in yellow. I can not find any model written in it on the amp. . Thanks in advance bros.

Selling a pair of Linlai WE845 Western Electric replica vacuum tubes:

https://www.ebay.com/itm/275281326800

Selling a pair of Beyma 12XA30ND 12" Coaxial Neodymium Speaker Driver Pair New + FD2XA Crossovers:

https://www.ebay.com/itm/275278959959

Selling a pair of Faital Pro HF1440 1.4" Compression drivers here:

https://www.ebay.com/itm/275281311416

Selling a pair of RCF HF99 90x90° 1.4" Throat 9.84"x9.84" Loudspeaker Aluminum Speaker Horns. See here:

https://www.ebay.com/itm/275281303356

Hello friends.
I have a 300B SE amp. I am waiting for new Khozmo stepped attenuators. I put at first tube grid a 70k resistor, for use the amp without potentiometer and protect them a little. Know, i have 2kz noise at both speakers. I put a picture.

Slightly odd question;

When using the PGA series digital volume control IC's is there any noticeable delay in varying the volume, any audio artifacts? or is the behavior much like a conventional resistive control?

My application is that I want to use them in a DJ idolator (type of EQ) but need the response to be percived as instant and smooth. The digipots are attractive as they avoid running the audio signal through the pot and reduce the requirments of the control pots.

For sale holfi cd player Xara, upgreded by Holfi to Xara DC. Player is in top working condition with remote. You can use the remote for volume control by this cd player also. Player hase some scratches on top plate, but face is in nice condition and remote is like new. Player is known for his analogue sound with output in pure class A and battery power operation. The new price was 1590 euro back in 2011.More info on contact. Price is 300 eu plus shipping or best offer.

When my Pioneer DV-535 DVD/CDA player started to fail, after trying to repair it and failing, I went looking for a new CDA player. But, the market (when not!) had already stopped the production of these dual DVD/CDA players, and exclusive CDA players like Marantz had very high prices. Streaming music and Netflix movies were here to stay!
So I bought a product made in China, which had on its forehead a brand that was synonymous with quality at the time. I'm talking about Philco. I remember that after putting together several TV kits in my beginnings as a technician - the ones that copied the original Wells Gardner circuit - and having cursed for that 50 C/S oscillation (here
in Argentina, in the USA and other countries it is 60 Hertz, as you know ) on the screen that refused to disappear after changes of rectifier tubes, filter capacitors, etc. , I bought an original Philco TV for personal use - manufactured here under license and strict quality control - I never saw such a high quality black and white image in those years! (Possibly Westinghouse would have been, but it was never made here).
So the Chinese generic outfit "Philco" manufactured wholesale and with the brand and model "on request" that I bought, - DVP-500 -, ultra thin, fashion rules, they call it "slim" has been working perfectly a few years ago Already.
I have to admit that it has an excellent behavior as a CDA player, MP3 player; WMA etc The big drawback is its slow process for selecting tracks and the poor information on the display. And well, for the money it cost, you couldn't ask for more, that's clear to me. As a DVD player, very limited too, but since the Optoma projector blew up, there was no more cinema in my home.
Having said all this, and having used the optical connection from the beginning and coupled the Philco to an Oppo Sonica Dac, - the idea was to use it as a transport and take advantage of the virtues of the ES9038PRO chip of the Oppo Sonica DAC -, I had a doubt.
Lately I have read that to listen to music the coaxial cable connection is better than the optical one ..... and a demanding audiophile like me cannot ignore this just like that!
Delving deeper into the subject, in favor of the optical cable is the null interference of nearby electromagnetic fields, and against its lower bandwidth, also against the fact that the cable should not be bent, and the poor quality of many "generic" cables that in instead of a crystal center conductor they use plastic, which would degrade the entire bit path. Well I use the one that came with the Pioneer.......
In favor of the coaxial cable we have a greater bandwidth, against which it is prone to pick up electromagnetic signals from nearby equipment and that the cable must have a characteristic impedance of 75 Ohms, so common analog interconnection cables should not be used. RCA.
Thinking ? Am I missing some SQ (sound quality) when using the optical connection? I want to do the experience, should I buy a specific "boutique" coaxial cable or is it the same to prepare one with a generic 75 Ohm cable and two RCA connectors?

I’ve built 2, 3, and 4 way speakers but now I’m building full range speakers with 10” drivers. I plan on building ported cabs and while looking at a number of designs I see many have an f3 around 35 to 40 hz.

is that the normal f3 for full range?

on page 8/15 to 10/15 under
https://pdf.dzsc.com/88889/4193.pdf
(save in the attachment) there is to find the circuit description to such an active crossover network.
Colloquially, this term is obviously totally outdated, since I can't find any further publications on the web in this case.

The special feature of this active crossover network is the absence of additional gain stages consist mostly of operational amplifiers.

Who can me send the currently usual term for this topology (maybe to find in the application notes from TI, NS, LT or Analog devices) ?

Thank you very much

Follows the schematics of a 5W amp I have built using the 832A transmitting double tetrode. The original schematic belongs to Ultra Analog whose site is off line for some time now.

Sounds fairly good.

There's my universal smps from parts from pc power supply.If it don't start to oscillate,reverse feedback windings (15k resistor).I'll test it on some amps,and it works great.PCB is without rectifier,I'll finish it later.

Hello Everyone! First time in a forum since the old days of DTMpower (the early 2000s)

I recently have been building DIY audio projects and I have dove deeper into the rabbit hole with this latest build. I did not want to use a prebuilt passive crossover nor rely on an active configuration like mini DSP so I began to research crossover design and ended up taking Audio Judgement's Udemy course on room acoustics and crossover design. 100% worth the 30 bucks I spent.

So I have spent a few days tinkering with XSim for the drivers I have ordered and I get a good response and a good phase correction (i think that is what its called) Then I go to parts express to order parts and the parts I used are not available or super expensive. What I have below is the closest thing I can get with available parts that don't cost hundreds of dollars. This configuration is $51 and has a good phase correction but it has a 3db dip at the crossover point. Will I actually notice that? I know that I can use active to correct and I will use REW for room corrections but I hate it not being as linear as I think it can be, well I know it can be more linear it just costs gobs of money...I'm not paying 200 bucks for a single inductor.

Secondly, the midbass has a pretty nasty dip around 300hz and nothing I do seems to remotely affect that so what is the best course of action there? I come from the car audio world so my first reaction is to add another driver to the equation like a tang band w5 and have like a 2 1/2 way setup and let the tang band handle a bit of the 80-400 bit subtlety to create a more linear response in the room... am I overthinking a 4db dip here or is my train of thought correct?

Anyways thanks for any advice, happy to have found a DIY audio platform to participate in.

SOLD

I have these NOS 3.5mm plugs and jacks for sale, 8 plugs and 10 jacks. Shown are the Digi-key labels so you can look up specs if you need. That lot for $10 + ship.

Also a package of Bourns 1.0K ohm 9mm plastic pots. Again, label shown so you can look up specs. $10 + ship for this package of pots.

Buy both to combine shipping, which should only be about $5 or so for USA.

If you are interested in these, private message me and we can discuss other stuff I want to sell... lots of 1/4 watt carbon film resistors, standoffs and spacers, chip resistors, NOS Digi-key kits of film caps and polyester caps, trimmers, lots of other stuff I haven't had time to photograph and list yet.

Thanks,
Keith

Bass reflex systems have been discussed ad infinitum but speakers systems have changed. Yes, a port offers bass extension but like I said: speakers systems have changed. In its most basic definition a port offers +3dB at whatever frequency you desire.

I'm one of those consumers who have replaced home theatre satellites with 'real' speakers. For example one of my AV amplifiers has a relatively high (160hz) crossover point. The connected fronts are Sony bookshelf speakers with a 5" ported bass driver. There are a couple of phenomena that I struggle to understand, (1) blocking the port reduces SPL (even though the port is tuned to a frequency the cabinet never receives). (2) The port remains 'active'. Even at high volume levels the satellite bass driver exhibits no movement discernible to the naked eye. However, the port remains active, moving air.

It's a ridiculous question: where do you tune the port on a satellite speaker?

not sure if this belongs in the 'Parts' category, my apologies if this is in the wrong place.

i've gotten the attention of someone at Electro-Harmonix/New Sensor in regards to the many confusing, incomplete or absent data points on their KT120, 150 and 170 datasheets. this person is very motivated to rectify this lack of usable information, and make these tubes more accessible to designers.

this is an official open call to the public, for any and all requests for additions and revisions to said datasheets. these requests will be delivered directly to the New Sensor design and testing technicians on April 22nd, so please post before then.

please be exhasutive and state all your requests, even if they have already been mentioned. please also feel free to indicate which requests you would like to be prioritized the most. i will be compiling a final list to send to them, and will be sure to accentuate items that got the most requests and placed the most highly on folx's lists.

please understand this is not a guarantee that any of these requests will procure published data, nor is it a guarantee of the timeline in which this might occur.

please also understand this is not a thread on which to discuss or compare the various merits of these tube models or the companies that make them. there are many other threads for such discussions - this is a thread to collect requests for datasheet revisions and additions, only.

one last note, and single exception to the above paragraph - since EHX/NS seems to be at least somewhat willing to innovate and create new tube models, i am personally taking this opportunity to provide some requests for what sort of tubes they prioritize the development of in the future. i have been told that these ideas are welcome and will be sent to the technicians as well. so by all means, please share your desires for what sorts of new tube models you'd like to see!

personally, i want to see subminiature pencil tubes, especially the frame grid types, see more focus. they were a brilliant idea too soon overshadowed by the rise of the transistor. just think of how awesome a new line of 6111/6112 style tubes would be! less space needed, more flexibility as to placement, less vulnerability to physical damage, high shock tolerance, lower operating voltages...

Hi all, a small problem with my B-2 that i'd like to diagnose before I go replacing un-necessary parts..

It has been cutting out on the left hand channel most days, rhs stays level, just the left drops out - it goes quieter sometimes and then cuts out completely sometimes, no pattern no continuity.

I thought the first port of call might be the front panel switches, so cleaned all these with deoxit. It seemed to help but doesn't solve it - it's still cutting out on the lhs.

So I swapped the rca inputs from one input to the other (controlled by a switch on the front panel) and the same problem persists.

Then swapped the speaker output from speakers A to speakers B and it seems to work perfectly.

So is my problem the speaker A selection switch on the front panel? Or the internal relays??

Thanks!!

hi folks,
a noob question here (should that not be clear from what follows 😱)
I have hooked up a cheap 48V supply to a couple of TDA7293 amps through a DIY voltage divider to get +/-24V:

When I don't hook up the TDA's, I get a nice +/-24V, but as soon as the TDA's are connected, the led on the power supply immediately starts blinking, indicating that the overcurrent of shortcut protection kick in, I guess.
Which beginner's mistake did I make?
Thanks in advance!

Hi All.
A friend of mine brought around a pair of Sansui D-40 Loudspeakers this weekend just gone. He knows I collect speakers.
A very unusual design, the covers are screwed in place from behind. A bad design flaw. I always remove the covers when playing loudspeakers.
I found that the wiring on one of the tweeter had snapped off, and the cap on the other was an empty shell.
I replaced the 0.47µF Tweeter electrolytic caps (old one measured .057µF) with equivalent poly caps, but left the 2.2µF electrolytics inplace (fresh out of spares).
Result. Very acceptable sound. Very listenable.
I think replacing the mid caps and adding inductors might further improve the sound.
My question is:
As I'm trying to stick to a budget (zero dollars so far), I was wondering whether fitting the iron core inductors junked from my TDL RTL3's?
It's a 10" woofer. The Sansui's are 8 ohm, 65w/c , & 93Db/1m.

I have available a very small quantity of PCBs for building the headphone amplifier as described in my article in Audioxpress June 2013.
You can find the article online if you have missed it :
Build A High-Quality, High-Power Headphone Amplifier | audioXpress
If you are interested, send me an email at: gntanavaras@gmail.com

I am looking at this schematic and it is not entirely clear to me what the resistors R21 and R22 are doing in the filament supply.

My best guess is that they are providing a ground reference for the 6.3V winding.

My other question is whether a center tapped 6.3V winding AC coupled to ground through a 30-50uf capacitor would have lower noise.

This is an earlier version of the schematic; the one I am working from omits the 12AU7 stage and has paralleled EL34 power tubes but is otherwise identical. I don’t have permission to post it whereas the above schematic is publicly available.

Thanks in advance.

SOLD

I bought this to refurbish an old B&W subwoofer but it is too deep and I missed the return policy window. It has only been removed from the box for fitment and never used. Currently back-ordered until mid-April. $300 shipped. Thanks!

Dear Colleagues,

I am trying to find out about the availability of 3-phase AC mains supply at the point of installation of High-power Audio equipment (i.e. amplifiers).

I am neither an audio- nor a power-engineer. So, before asking my questions, let me first give my understanding briefly.

Some possible locations for high-power audio amplifier installations are:

• Live Concerts (open air)
• Stadiums
• Concert Halls
• Discotheques/Night clubs
• Cinemas
• Shopping Centres
• Churches (esp. in the USA)
• Music studios
• etc. etc.

The total output power of the installed equipment, and hence the total input power required from the AC supply, can be in the order of multiple tens of kilowatts, even over 100kW in large installations, just for audio amplifiers alone (excluding any other AV or lighting equipment).

Most of professional high-power audio amplifiers come in 19"-rack mountable enclosures. As far as I know, all such commercially-available amplifiers provide only a single-phase AC mains power-supply input (which may accept a universal voltage range: e.g. 85-265V AC 1-ph). I think, this is true even for the highest-power audio amplifiers recently introduced to the market, e.g. 20KW output (music/program) power and ~ 3-5KW input (1-ph AC mains) power.

A similar situation exists with 19"-rack mountable DC power supplies (AC-DC converters in the KW range) for Computer Data Centres (CDC), with such high-power DC supplies accepting only 1-phase AC mains input. However, a recent tendency in CDC installations is to distribute AC power in 3-phase form and make it available to 19"-rack equipment also in 3-phase AC form.

Clearly, at high power levels, power transmission and distribution is less costly and more efficient in 3-phase AC form than 1-phase AC form.

My questions are:

1. For high-power audio installations, why are audio amplifiers not available with 3-phase AC (400V or 200V class line voltage) power supply input?
   
   
2. Is it because 3-phase AC mains supply is not readily available at such installation points/locations (as listed above)?
   
   
3. If 3-phase AC mains supply is available in such installation points/locations, are there any reasons as to why high-power audio amplifier manufacturers do not make amplifiers accepting 3-phase AC mains for their power supply input?

I will appreciate any contributions, suggestions, ideas or feedback you may be able to offer.

what is happening?

when i use the room simulator and set up a perfectly symmetric left and right subwoofer to listener and room layout i get different frequency responses from the left and right subwoofer, why is that?

in a perfectly symmetric layout i expect to have identicle responses from the left and the right subwoofer.

As per the title, I'm looking for a single Raal 70-20xr tweeter. I know that these are normally OEM only, so they're hard to come by for DIY. However I own one already, and it's sitting doing nothing because I don't have a second one. I'm hoping someone might be able to help.

Bought a pair of LK1 kit speakers from Mike at Lenehan Audio.

1st dry run to see how the cabinets go together.

hello at all

I did a multiroom system I like to show to you. All is done with arylic.com diy streaming boards. There are two rooms on the same floor and I apreciate the same music or other audio in those rooms. I had some older passive Hi-Fi speakers and one passive closed subwoofer I did myself.
I apreciate to have the IR-control to do volume changes or to tweak the bass and treble. If a customer is calling I can mute the system suddenly without having to use the App on the smartphone. The freedom to change the sound in detail with the APC-Workbench software is a great feature I don't like to miss. I also did some 2 way crossover stuff in another setup, easy peasy! Everything works nice. What I did here is no rocket sience. But I like the sound and how it integrates to the rooms and my use case. When I had a issue the team of Arylic responded fast and friendly.

Kitchen
A simple but nice sounding setup. The Up2Stream Amp (V3 I guess) is driving a pair of Infinity Modulus speakers mounted in the upper corners of the room. The setup of the amplifier itself is stock, I did not changed anything with the APC-Workbench software. The Up2Stream board is enclosed in the a Arylic case. Before this board was at a different place. That is why it has a volume knop and a 3.5 mm input in a hight nobody can reach.





Material used or mentioned
https://www.arylic.com/products/up2stream-amp-amplifier-board
https://www.arylic.com/products/up2stream-case
https://www.arylic.com/products/2-u...bluetooth-wireless-amplifier-and-pre-amplifer
https://www.arylic.com/products/expansion-boards?variant=32778796105813
https://www.arylic.com/products/ary...mote-control-usb-aux-in-opt-in-wifi-bluetooth
https://www.arylic.com/products/acp-work-bench-audio-effect-tool

Living room
The Arylic Up2Stream Amp 2.1 is enclosed by a low end wooden case with plastic studs I did. A friend of mine sold a pair of JBL TLX 320 floor standing speakers for a good price to me. The are not high end but ok sounding to me. In this 2.1 setup they go up 100 Hz. Some EQ-ing I did to make them better to my ears. The bass comes from a closed subwoofer with a 12 inch hard suspended bass driver (Monacor SP-12/200PA). The subwoofer does 100 Hz and below. All in all the sound of the system is huge, clear, loud enough and goes deep. If I like to practice bass guitar I plug the subwoofer over to may bass amp and jam along the JBL's without the bass support.













Material used or mentioned
https://www.arylic.com/products/up2stream-amp-2-1-amp-board
https://www.arylic.com/products/ary...mote-control-usb-aux-in-opt-in-wifi-bluetooth
https://www.arylic.com/products/acp-work-bench-audio-effect-tool

Hi, some help please! I am running a three way active system with a horn top end. Obviously the cd driver is a distance behind the mid.

When implementing a dsp crossover it is a relatively simple matter to adjust for the time delay caused by the physical offset of the driver voice coils..in this case around 225mm which results in approximately 600micro seconds delay to the mid.

Using arta and Omnimic one can monitor the frequency response at the selected crossover frequency and watch the effect of the time delay dialling in an amount to achieve the flattest response?

But my question is this!! The dsp also has a phase control option in 10deg steps from zero to reverse (180 of course) . The filters are set to 4th order LR which have zero degrees polar tilt at crossover. Is there any requirement for Phase Control adjustment with 4th order LR once the time delay to account for driver offset has been set? I understand the signal can be adjusted to "exit" at the "same time" but may still not be "in phase"?

Is there any way of checking one is both minimum phase and time aligned? Both arta and omnimic will plot minimum phase against FR...but I'm not sure what I'm looking for in regard to this phase plot!!

Anybody help with this!

Hi everyone,

I am a serious (but amateur) classical pianist that no longer has the ability to use an acoustic grand piano due to noise constraints, so I purchased the Kawai Novus NV10 digital piano. This is a hybrid instrument that uses a real acoustic grand action mated to optical sensors and a digital piano cabinet. So, you get all of the feel of a real acoustic without the noise.

There is just one problem - the built in audio is atrocious given the cost of the instrument. The only way I can get good sound out of it is to hook it up to my computer and use it as a midi controller with Pianoteq software and my Sennheiser HD650 headphones. But the speakers are horrendous, so I figured I would open it up and take a look.

Frankly, this sound system seems like a complete afterthought to me from both an architectural and quality standpoint. The woofers feel cheap, there is no real crossover network, there is point-to-point "fix it" wiring on the mainboard, and the system is generally underpowered.

Given the poor design and components of the system, I am wondering if I can simply take the audio output off of the mainboard, run it through something like a miniDSP and then directly to my own amplifiers and replacement drivers?

I spent some time today and drew up a schematic of the way the sound system currently works.



Looking at it, I have several questions:

1. It seems that the mainboard has separate audio outputs for L/R channel and bass. I assume this means a digital crossover for the bass woofer? This is one issue that I may have to figure out that could impact driver selection.

2. I do not understand the pinouts or number of wires used on this system, it does not seem logical. For example, there are five wires coming off of the mainboard for the L/R channel output, which corresponds with five pins in the input of the Amp. But when the output of Amp 2 is daisy chained with the input of Amp 1, there are only three wires. Why?

3. Why does the bass signal need to be pre-amped, but the L/R channels do not?

4. Is there a way I can find out whether or not the signal coming off the mainboard is flat or processed to hell?

Here are some more pictures of the system. I would really appreciate any help!

View of the action with the cover off



Amplifier Section



Bass amp and Preamp



"Crossover"



How the drivers are mounted to the lid of the piano



View with back cover removed



Close up of L/R channel amps



Mainboard



Mainboard 2



Mainboard output section

hi everyone

I want to build Apex amplifier (HV23)(that I founded in page below (thread 44) :
http://www.diyaudio.com/forums/solid-state/162043-mosfet-amplifier-irfp240-irfp9240-5.html

I found all the parts in this schematic except Q9 (2sc4793) and Q10 (2SA1837)

but the salesman suggested me to use 2SC2073 and 2SA940 instead

and I'm so confused😕 that are they right for replacement??????
If anyone could help me I'll be grateful

Hey toute la monde (everyone).
I rig my preamps up so that the phono stage isn't powered until you select it rather than it being lit up all the time.

It seems like a waste of cathode and electric to light and power the phono stage just to save 15 seconds when you need it?
I switch inputs with relays by switching the grounds AKA if you ground it, it turns on (BMW does this - I used to switch positive). I simply add another relay on the phono setting to hit a relay that will connect 12V/B+.

Anyone else do this?

I just received Triode Electronics EF86 input board for for the ST-70. The parts list specifies four resistors at 18K (R3, R6, R9, R15). Supplied resistors are 20K (not high measuring 18K, but actual 20K, as indicated by the bands). I have 18K resistors on hand. Should i use my 18K resistors or the 20K ones supplied?