Hello, 🙂

Could you please help in choosing a audio amplifier IC for building DIY home speakers (2.1 system)?

Whether to go for class AB amplifier like LM1875 or TDA7295. Or go for a class D/T amplifier like TPA3116 or TA2020 or TK2050 etc.

Looking at the datasheets of these class-AB and class-D amplifiers, the performance are looking similar, referring the graphs for THD+noice vs frequency and output power etc.
For all of these the THD was at least below 0.1% across the output power values under the given max for the chip. "THD vs Frequency" graphs were more smoother for TK2050, and LM1875 and on TPA3116 graphs THD was bit higher at around 5KHz region.

From what I have read, class-D is more efficient and so I may have a smaller power supply driving it and will have smaller or no heat sink. Thus a overall compact and small amplifier will result. But heard they have some EMI issues.

On the other hand with class-AB amplifier, sound quality will be very good and not sure if these currently available class-D amplifier are producing such sound quality. But they need bigger power supply as they are less efficient, and need a bigger heat sink, so overall it will be bit bulky.

Please help in selecting the suitable amplifier IC for DIY 2.1 channel home speaker system.

thanks and regards to all.

Hi there.

I've been handed an entire old RS DIY system to go over.
Pre amp, amps, speakers.
One of the amps is faulty, but I haven't had a chance to look at them properly yet so I don't know 'how' it's faulty.
Before I spend time and money on these, I was hoping someone may have the biasing info or any info other than what I have posted here.

Thanks..

I made the mods on the first photo Removed output caps, added the two blue jumpers, and made the 5 cuts marked with the xs and that was all I did. I know, I lost my headphone output after that but, I purchased a used Parasound p5 preamp and thought I would try the optical option input but I'm getting no audio now. Can anyone please, tell me if any of the cuts I made during the modding would cause the loss of optical output as well, as the headphone out put? I'm trying to determine if the modding caused no optical output or, if the preamp is at fault I only have 14 days to return the preamp if it's at fault. I'd sure appreciate the help if possible I only did the mods shown in the 1st photo, out of the 4 shown! MARANTZ CD5004 Modifications optical cable is 6 feet long.

So, to be sure about which panels are dedicated to bass and to high frequencies, I am guessing the bass panels are at the top and bottom and the high freqency panels at the center. Is this so? And is there an actual xover for this? Thanks.

Greetings,


I am working on a preamp for a guitar amplifier with opamps and you see the circuit i have come up with other circuits and experimenting. It seems to do well at least for my ears. Dont say that its low quality in know it is i would like to keep it smple. I would like to add a uper mid boost, say at 4 - 6 khz and a control for that(potentiometer). Where in this circuit could i do that, while keeping everything simple. I dont know how to design circuits so any help would be much Appreciated. And i forgot to mention I would like to add it after the switch which switches between clean and overdrive channels.



Best regards and many thanks in advance to anyone who repiles

Up for sale is an excellent condition Focusrite Saffire PRO24 external sound card. I used to use this with Reaper on my MacBook Pro as a digital crossover for my LXmini speakers, but have since then upgraded to a MiniDSP SHD. I've also used it for speaker measurements, and can attest that it is very handy for that. If you're looking to get into speaker or amplifier measurements (possibly using Pete Millett's sound card interface, this could be your ticket). Do note that it is Firewire only. No USB. The sound card has Firewire 400. I've used it with the included Firewire 400 -> Firewire 800 cable.

Included:

• Focusrite Saffire PRO24
• Original install CDs (you can download newer versions of the software Focusrite's website)
• Power supply (with US, EU, and UK plugs)
• Firewire 400 to Firewire 800 cable
• Original box

$79 USD + shipping (see estimates below). (SOLD)

The best way to reach me is by email. You're welcome to PM me as well, but I check email more frequently than PM. Just take my user ID here and add @neurochrome.com.

When you contact me, please include your shipping address and phone number. This allows me to invoice you through my website (Neurochrome.com), which allows you to pay by credit card or paypal. Your choice, though I prefer credit card as the fees are lower.
If you're in Canada, I'm happy to take payment by eTransfer. That'll save you 3-4% in exchange fees.

I have commercial accounts with the various shippers, thus, get a pretty decent discount. I'll happily pass those discounts on to you, hence, my low rates on UPS and FedEx.
Below are examples of shipping rates for this sound card. All rates are in USD.

Canada (H9K..., QC): $22 by UPS (or $21 by Canada Post)
US (90210, CA): $35 by Canada Post or $43 by UPS 3-day
Europe (4600, Denmark): $73 by FedEx IE

Tom

Hey everyone, still new to this but I'm working on a Arduino smart-speaker type project, and to start I have this cheap driver lying around. It's one of those small thin ones that's only ~1.5 inches in diameter. I'm trying to learn what I can do to make it sound the best in an enclosure.

My first thoughts were to use WINISD to optimize the volume, BUT I can only find the below info so not much I can do in WINISD without the T/S parameters:

• Frequency response chart
• Voltage, sensitivity, impedance (no charts)

So should I try to measure the T/S parameters, or estimate them somehow to get started? OR am I thinking about this in completely the wrong way?

YouTube

Gajanan Phadte

I've been a forum lurker and posting newbie, but a longtime audio geek. I had a chance to give a presentation to the Pacific Northwest Section of the Audio Engineering Society in March. I wrote them a very nice White Paper of original work.

The paper address what it takes to achieve a desired performance from a bass reflex (ported or passive radiator) speaker. This is usually a trail and error process. The technique outlined in the paper will let you home in on what it takes in literally a few minutes (once you understand it!).

The download includes the White Paper as a pdf along with a couple of Excel spread sheets related to the paper. There are also general purpose Excel models for both ported and passive radiator designs.

The whole package can be downloaded here:

Vanatoo Transparent One Encore Speaker Software Downloads

Hi,
Anyone know what is inside those ground box like the Entreq Atlantis Ground Box and how do they work?

Hello everyone 🙂

i would like to upgrade the oamp from my sony str-k7000. i'm thinking to use the lm4562 or opa2604 over the NJM4565 (have a lot of them in the board) . any Suggestions?


service manual:

Sony STR-K7000, Service Manual, Repair Schematics

How likely is this mixed feedback to fail?

If resistors are carefully tweaked, could this work at all?

Hi There,

I have a tube pre-amp guitar pedal which uses a 16VAC power supply like this one: 16VAC 1.25A Unregulated Power Supply BareEnds | Jaycar Electronics New Zealand

However, wall-warts don't last long in the touring environment compared to DC pedal power supplies like this one: Zuma - High Current DC Pedal Power Supply - Strymon

Specifically:
- World mains 100-240v switch
- IEC mains plug
- 2.1mm pedal jacks
- Flatter, longer, wider form-factor

Can a 16VAC 1.25A power supply be built into a similar form-factor by someone who's only ever made DC guitar pedals? I'm pretty green when it comes to this stuff.

And if so, where would I start? Does anyone know of a good circuit, layout and BOM?

Any pointers in the right direction or even good search terms would be much appreciated because I keep finding DIY DC power supplies, not AC.

And sorry if this isn't the right place to be asking.

Cheers

Ben

I'm hoping to power a TPA3116D2 with a 20v 4.5A PSU.

(1) Will it work?
(2) Is 2 x 30w into 5ohms a reasonable expectation?

Hi! So, I am a complete noob on audio. I am a woodworker building a bluetooth speaker and I have a bluetooth amplifier shown in the image below and I would like to add a potentiometer for controlling the volume, mainly for the design of the speaker. I am wondering if I can switch out the buttons on the amp controlling volume and replace it with a potentiometer?


Thanks!

Woohoo!

I have a TDA7492 25w+25w Bluetooth amplifier board by sanwu. I've been using this board from past 1 month and I had no issues. But today when I plugged in a 3.5mm audio jack, it didn't recognize. This board always switches from Bluetooth to line in whenever we plug in an audio jack. But now it's not happening
Can anyone help in solving this issue...

Dear forum members!

I have bought a defective Yamaha A-520 amp, and according to my measurements, it has a weird clipping problem, and it can be measured even at the RCA inputs at full volume, overloading my CD player's output. I have been trying to repair the amp, and all i could find was that if i remove the preamplifier stage PNP transistors after the input JFETs, the input is not distorted anymore. As soon as i put the transistors back, the distortion comes back again. The transistors seem to be good though, i have measured them with my multimeter.

Is there any of you who would be willing to assist me in repairing this amp?

Here is the service manual: YAMAHA A-520 SERVICE MANUAL Pdf Download.

Is it true that some speaker manufacturers deliberately provide for what is known as "BBC dip" in their speakers' frequency response. What is the purpose of providing a "BBC dip" in a loud-speaker? Whether any research has been done on its effect on musicality of the speakers? Since fidelity is the acurate reproduction of the original recorded sound, is it not against the tenets of high-end audio to design speakers with a "BBC dip". Isn't the sound coloured this way?

Dave Greenfield, keyboard player and founder member of The Stranglers passed away after contracting Covid 19.

Stranglers’ keyboardist Dave Greenfield dies after contracting Covid-19 | World news | The Guardian

Some newer power amp designs found here, by AK members, and the commercial high-end accept anything from the venerable 6L6 to KT-150s. A few very expensive offerings continue using KT-88s rather than the newer and more powerful "replacements".

Besides cost, is sound preference what usually drives the choice of output tube? Availability of the usual suspects doesn't seem to be an issue, unless the amp is one of more exotic design using less popular tubes.

I've read high praise for all the common types and heard good sounding amps of most every ilk. Clue me in, please.

Big 'ol howdy to all y'all! Can't wait to contribute to the community!🙂

A while back I was playing with a small boxer 115v ac fan rated at .15 A. I tried runing it from 115v AC through a capacitor. When I used a 1mf cap the fan didn't turn at all but it seemed to run at about 1/4 speed when I used a 1.5 mf cap. So I tried a 2.2 mf cap expecting it now to be about 1/2 speed but instead it seemed to run at full speed. Any ideas what was happening ?

Hello,
I’m currently trying to build new subwoofer enclosure from a Mosscade Titan 7.3 that I have recently acquired. The enclosure of the Titan 7.3 is unfortunately cracked in a few different places from the poor care of its previous owner. Unfortunately I cannot find the necessary specs of the driver to be able to design the enclosure on WinISD. Does anyone have an idea where I could find such information or have an alternative solution to bypass this problem? Thank you.

Simply to hit a voltage with a transformer I could find in my junk bin I built a choke input power supply for the first time. Silicon full wave rectifier (each diode capacitor bypassed), 280 V AC to 250V DC, 50 ma. Big-a55 150ma 10Hy choke (garage sale prize) for the input, then 220 uF cap and a smaller choke to supply the output stage for a 3w SE amp, still kind of slop-built on my bench. So far so good.

After putting it into use the buzz and hum in the amp was very noticeably worse. Dinking around a bit I found that just touching the big choke, or moving tools or my hand around it, hugely affected the hum. Wrapping it with a couple layers of grounded copper foil and sticking a grounded piece of steel sheet between it and the amp minimized the problem, but it's still there

Is this just inevitable with choke input power supplies, or is there a smarter way to put them together? Right now putting the power supply at a distance from the amp is as good an idea as I have.

I am attempting to create a digital playback device (i believe they are called 'renderers' now) to feed hi res audio to a dac. I would build this device based on either PC or Pi hardware.

As these do not tend to have spdif outputs, I am relegated to using USB or optical. I read that USB is the 'best' choice.


I also read that the clocking on onboard USB is bad and I either need a precision clocked USB card or an external 'reclocker' ( I fail to see how this could work. But I'm stupid). Incidentally, a 'recommended' add on board manufacturer claims the crystals supplied with his board are just for 'proof of concept', and for best results I should replace them with better ones. Eh ?


What would be the best solution here without breaking the bank ? The external dac I have is quite good. Or supposed to be.


Thanks,


Pete

I am the owner of a TVA-1 , one of the erly amplifier types from Michaelson and Austin with the small powertransformer, and I need a picture of the original ground wiring.

The amplifier was received with some soldering changes made for the ground connection. Its difficult to keep the weak 50-60 Hz hum away from the speakers.

A hole has been drilled in the midle of the TVA-1 for gnd., but the central ground point should be close to the large psu capacitors under the psu-PCB? ...or?

thanks

I have just installed a SPRO 2 module which sounds nice and powerful . But , once I connect it to my Sunfire subs via HL inputs , it muted . Even not power on the subs . Anybody have some idea on what may going wrong ? Thanks.

Is it worth 'upgrading' the output transformers on this KT88 SE UL amp:
KT88, (ect) Single ended amp, SEUL | Audiokarma Home Audio Stereo Discussion Forums
or would it be strongly into the region of very diminishing returns and I should save the money for a new build at a later date?

Currently I'm running edcor CXSE25-5K.

If it is worth it what would you suggest?

I've got Electraprint iron in my PP 6V6 amp and like it but have also looked at the ISO FC-20S. I've also looked at toroidy but not sure if that is an upgrade or just something different and it wouldn't fit on the current chassis.

Sold! DG 300B Amp

Sold!

For sale all boards needed to build Neurochromes DG 300B amp.
Includes 21st Century Madera High Voltage Regulator
Filament supply boards for 5V (2 boards) and 6.3V (1 board)
Power supply board
Amp board. Board has been attached to a plate (with screws) machined by Front Panel Design.
All the power supply/regulator boards have been tested. Amp board has not.
As shown, all boards have been populated.

$125.00 includes shipping (US only). Also, only PayPal gift.

Hi folks!

Starting little. Years not soldering a transistor at all..

Feel i'm in some need for some experiences exchange a bit bread than just in Br platforms. If U can just be patient 🙂D) cos i'm not into electronics properly for years - except electric guitars internals. As second labor on my sats & sunds 🙁 - important to consider.

I helped a friend change his F4 to an F5 and I have these completely working F4 boards for sale or trade. I already have 2 F4's and do not want to build another one. The boards have Linear System Jfets.

I am either looking to trade or sell the boards for any of the options below:

- $150 cash plus Ship

I prefer to ship only to CONUS.

A voltage input is converted to current by R10, fed to the resistors R8 and R7 which convert back to voltage to drive the lateral MOSFET gates. The inner quad Q1/2/3/4 is like a translinear loop and serves to set the bias as well as cancel the Vbe drops of Q3/Q1 on the signal path.

Some local feedback via R11 serves to increase linearity somewhat, but the driver stage can be opamp-based as the signal swing needed into R10 is about 10V and 20mA peak.

The current-mirror style cascode transistors Q5/Q6 serve to keep the dissipation in Q/1/2/3/4 all low to reduce self-heating.effects.

I haven't investigated real-world thermal stability of the configuration yet, but it should be possible to do that at low voltage without output devices since R7 and R8 are current driven, which is rather convenient - next step is choosing a breadboard to stripdown and reuse, mine are all full ATM!

All sold, thank you for your interest.

Tpa3255 or Irs2092 - My first amplifier

Hi all,

It's one of my first posts here but I spend a lot of time to read your valuable forum. I am a beginner in electronic so please don't be too much rude with me... ;-)

I want build my first amplifier during this period of quarantine, to try to learn something and spend my time a little bit better.

I have a lot of concern about it, but the first, is which type of board I have to pick. The 2 main options are tpa3255 or Irs2092.

The tpa3255 seems that the best one is the one provided by 3e audio.

For Irs2092 I have some options. The first 2, is an already build and tested boards:

Sure Electronics 2x125w

WONDOM | STORE


LJM L15D-power (It is good because have integrated already speaker protection and rectifier.

LJM de Audio ensamblados L15D POWER IRS2092 300W Mono placa amplificadora de potencia con proteccion de energia HiFi Digital AMPLIFICADOR DE POTENCIA DE Audio|power amplifier board|amplifier boardmono power amplifier board - AliExpress


The second option (and it is my preferred) is buy a DIY kit, to build manually my amp with the solder.

LJM L15D-PRO is the only available kit that I found, and I don't know if it is LJM original one, with a good set components (And the rectify part is missing, only the speaker protection circuit is available)

Nuevo Dual canal L15D PRO Clase D IRS2092 IRFB4019 AMPLIFICADOR DE POTENCIA ESTEREO DIY Kit (, 2) 300W|amplifier diy|amplifier classpower amplifier - AliExpress


In theory my target is build an integrated amplifier with a preamp and a DAC included.
My objective is that the quality of sound must be best of possible (HIFI?) and have a really quite output in idle without hiss, pop, or ommm noises. (I own a DENON 3500, and could be nice if my selfmade amp could be better that this)

The preamplifier that I have in mind to build and use with the above boards is this one:

Mezmerize B1 Buffer – diyAudio Store

What do you think about it?

Could you help me? (@ljm_ljm)

Thank you a lot.

I am new to all posting of any kind. This site is my first, but could not resist.
Please forgive any clumbsyness in my posting process.

I am a EE nearing retirement, and beginning to have time to contribute and learn about audio.

My background is in low power a analog IC design for medical devices. I also have some experience in high voltage a d power conversion.

If someone has one available and is willing to send to Switzerland!

It is this unit OpenDRC : OpenDRC-DA8

If you have something similar available, please let me know!

Wish you all a nice weekend,
Erik

Looking for a pair of the 4 ohm version, but would consider 8 ohm version.

Hey diy Community,

Got an Adam P11a active studio monitor which is none responsive when switched on; no "amp power" noise, nothing.

Swapped the fuse out, and plug.

Swapped over transformer and main capacitors which still didn't work.

Wondering if this is a common or known issue with p11a's?

Any ideas would be greatly appreciated!

Hello everyone, it has been awhile since I have posted here. I have two pair of Pinnacle Arctic 1's and a pair of Pinnacle Arctic 2's.

Arctic 1



Arctic 2



I also have enough extra woofers and tweeters to make an extra MTM Arctic 2 giving me enough to make a 7.1 channel home theater. I cannot find anything about these on the web at all. I called Pinnacle and talked to a tech who has been there quite awhile that gave me a little info. The Arctics were built in 1993 and were considered a premier speaker but were short lived due to the fact that the cabinets cost too much to manufacture. They were hand painted and had too many hours into them. They do have a beautiful gloss finish. The 1's were $375 and 2's were $475 I believe. They use 1 inch aluminum dome tweeters and 5-1/4" poly cone mids, both made by peerless











These have to be one of the cleanest, best sounding speakers I have heard. They do everything very well with the exception of bass, but I believe almost all bookshelves need subwoofers. I have heard many speakers and these have always trumped when it comes to treble, midrange, midbass, especially vocals and strings.

My father and I were talking and thought it would be fun to do a tower, a small line array, possibly open baffle. Problem is I don't know the T/S parameters. The crossovers for the Arctic 1's seem simple using electrolytic caps, here is a schematic. (my first time drawing one so please point out anything that looks wrong)



So what would you do?

1. Build the extra MTM for home theater and leave it alone

2. Build the MTM and replace all of the caps with better ones (about $50 a pair for crosscaps)

3. Build a pair of towers using four woofers per side

4. Find two more woofers and build small line arrays (maybe open baffle)

hmmm.

Also, if I were to send someone trustworthy a woofer would they be able to measure it for me so that I can find out the best app for it?

Thanks for your time,
Dan

I have made a 3d model of a tapped horn / tapped pipe where the different variables for throat / mouth and length can be changed and it will redraw itself to the new parameters automatically. This is a part of a set of subs that I plan to build, but I think that the idea of it, the 3d model that you can plug numbers into is a good idea for the community to have, and would like to have some people try it out to see if it's something worth doing more of.

Link to model





DISCLAIMERS: (please read)

The model is made in Onshape. You need to signup for a free account to edit the model, but there is not software to install it's all in browser, unless you plan to use a mobile device. Then there are apps for that (mobile is a better UX actually, I used my phone to make the model.)

The length variable is NOT accurate, however if you view "Sketch2" there is a dashed line running down the center of the horn, select all of it's segments then tap the calipers icon on the top and it will give you a very close approximation of the actual length, then you can adjust the variable up or down and remeasure. I'm not sure how to fix that. I tried using a correction algorithm that got it closer, but it still wasn't right.



If you select part4 and press the scales icon it will tell you the total volume of the horn.



If you select all of the parts (except part4) it will give you an estimated weight (for plywood and polycarbonate and an as of now imaginary driver)



The model is meant for stacked cnc cut plywood with polycarbonate sides, if enough people think it's a useful idea then I will make a few for more affordable, less wasteful construction, and more flexible fold styles.

it's constant flare only, I haven't tried compound flares yet, not sure how that would behave.

If you go too high or low with the variables the model will twist itself into a knot, just hit undo and it will go back together. This isn't the most flexible folding style, but it looks really nice with clear sides and it keeps the mouth on the floor.

The driver in the model is one I'm designing custom for this sub, it's not done, and is just there to give a size reference.

Hello guys. I have built a dc coupled two stage DAC output like from the schematic. In the original version I had 10H 120ohm choke, and the last two capacitors were 330uf electrolytics and resistors 470 ohm.
It played really well, but I thought I can make an improvement.

I was suggested by a friend to replace the last elcos with 20uF foils.
I also replaced 470ohms for 1k2 for better filtraton and time constant with the smaller capacitors.
I fired it up and.... everything cleared up a bit, highs were better, the usual improvement when you replace electrolytic with foil. But the energetic deep bass that I was proud of are not here so good.
I thought why?
First reason will be that the B+ voltage for 6N2P will be slightly lower, but I dont trust that 1 volt difference can be so big in sound.
Than I replaced the chokes. (every time I added bigger choke to a power supply, sound was again more dynamic and energetic). This didnt improve the energy.
The other reason can be simple:
simply that the new caps can not store so much energy as the big elcos....
But Im still confused.
In my power amp, I have driver stage which draws 5mA. And totally doesnt matter if the filtration paper in oil here is 5uF or 10uF or 15uF. Even if I increase the dropping resistor a bit, no difference in sound.


I simply dont trust that Ive moved the operating point too far from the original, by having a 5 volt loss for the 6N6Ps and 1 volt difference on 6N2P. Or do you think it can be the case?

They are schematics.









Thank you very much for help. Best regards, Michal

My ongoing clear out of amplifiers:- I have a set of these F5t boards which as you can see I have cannibalised for other later projects. The Mosfets and jfets removed, everything else is in place as was when last used working perfectly...All the resistors are dale even the 5 watt and the caps are Muse Gold.





I have a set of matched quad jfets 170/74 GR's which where used in this amp before I went to quads in both for 100watts per channel.

They all measure good and OK.





£100 the lot + P&P at cost

PM please

Commes with a schema.Small pcb for Bias.

25$ + shipping.

In near mint condition and perfect working order.
Serviced.
Supplied with nos Tesla tubes
Original outboard power supply
Excellent phonostage
£650 + p&p
Only selling because I need a passive preamp to go with my Quad 909 .

Hi folks,

This is Vincent from Hong Kong and it is my first post in DIY Audio. Nice meeting you guys here.

Recently I'm working on adjusting OTK 6J1 biasing voltage. The 6J1 is triode connected and self-biased. I found that the cathode voltage is not stable with certain combination of anode resistors and cathode resistors. By "unstable" I meant the voltage is varying up and down.

In addition, as the 6J1 is triode connected, the anode current should be the same as cathode current, right? However if Ia-Ik, the result is not always zero. What did I do wrong? Please see the schematic and data below. Thanks guys!

I'm laying out the chassis for a 7591a amp using the iron (both power and output) from a Fisher 500B receiver. I have a quad of EH 7591a that I'll be using for initial playing around. Are the JJs worth the trouble of comparison or should I just not bother, given the bad luck people have reported with JJ octals? The EH tubes are the coin base style.

cdm4 mechanical problem - disc rubs, not spinning freely (solved, mods report)

Hi,
I did a thorough search on diyaudio but couldn't find anything concrete, so I'm asking for a little help or suggestions:

Just got a well looking Grundig CD3000 (cdm4 with tda1543, planning some nice mods here when I get it working), which doesn't read discs for a low price. Tested it and turns out that the laser appears to be fine, fortunately, but it rather seems to have a mechanical problem: the disc starts to spin but seems to rub against the base of the transport or the platter, I'm not sure, so it gives up with ERR. I decided to test further by inserting a piece of paper underneath the cd onto the disc platter - now, disc would rub less and start to spin up to right speed, making less rubbing noise, but still not reading. I figured the focus distance would not be perfect due to the paper, so I slightly pressed on top of the clamp and now the player was able to read TOC and started to read a track with heavy skipping. Still some rubbing sound, which would explain the skipping.

So, does anyone have an idea what might be the problem? If it was a CDM1 I'd say that the disc platter had lowered on the shaft due to wear, but I don't think this can happen to cdm4, also the paper test seems to prove the opposite, as it only starts reading when pressed down (so it can't be lower than original, as I haven't touched any trimpots).

Could it be damaged or worn clamp? I've heard about some bearing but I can't seem to find it. Could the transport base not get low enough when loading the disc and be rubbing against the cd? a very well working tray loading mechanism (often these infamous gear breaks) speaks against this, but I don't know.

I have two other working cdm4 based players here, so I might start to compare them bit by bit to the defective cdm4 and try to find out what's going on, but I though maybe this is a common problem and someone could give me some hints, sparing me some time.
Thanks in advance.

P.S.: I've repaired a couple of CDM2 transports so I've got general knowledge about repairing philips swing arm mechanism, but didn't repair any cdm4 yet.

hi!
I have heard that the dac in the very first playstation
was of very good quality.
So I wondered if it would be possible to mod the ps1
to accept external digital signal ?

Could someone look at my circuit if there is something not right about it?
It's a stereo preamp (one channel shown) which also serves as a low gain mic preamp. I've build it years ego but did some minor changes and also changed the output from anode to cathode so I can connect it to heavier loads like solid state mixer without worrying about over loading the output. Thanks for any info.
Also, I thought about implementing NFB but didn't bother because it would lower the all ready fairly low gain for mic, but would it be worth the trouble anyway?

I have just received my Audio Aero Capitole mk2 after a Signature Edition upgrade and a transport change by Audio Aero factory in france. The player is 7 yrs old, but never had any major problems.

It now has a big problem which I am unable to solve. It remains muted. On very rare occasion, the sound comes back after re-powering up and once it starts play, it continues to play flawlessly for weeks until I stop it. The moment it is stopped, it mutes itself and is extremely difficult to get it to play again.

I disassembled the transport, reseated all the internal cables, changed /tried different software chips, but everything works fine except the muting problem. Currently it has a 5.6 chip.

The disc spins, the player recognises the cd tracks, displays the track and time (of the playing disc), volume control works, etc.. but no sound.

When fed with an external transport through a digital input, the muting problem very much remains.

I just can't get it to play!! Checked the Integrated circuits, they all seem fine: no cracks at all etc. The two output miniature tubes glow and power is passing through nicely.

I am presently in a dispute with Audio Aero over this very problem and the player is not going back to the factory. Where I live, there is no Audio Aero dealers, but I do have a qualified electronics engineer/technician who services pioneer and technics CD players.

My amp works fine with a different source. My interconnects are not faulty.

Would really appreciate any idea on what could be wrong and how to go about getting it to play. It's crazy.
Many thanks.
lall

Pascal Pharmacon posted an interesting article yesterday, so I thought I'd find out how they perform:

https://phys.org/news/2017-06-diffuser-ten-thinner.html

From what I can tell, this is a conventional quadratic diffuser, but the "wells" in the diffuser have been squashed so that the sound radiates radially.

So let's find out!



First off, here's a sim of how sound radiates in a room. The dimensions of the sim are 200cm x 200cm (6.5' x 6.5')

The speaker on the left is 20cm in diameter (8")

The frequency is 1000Hz

I am looking in to building new floor speakers, currently I have three way conventional bass reflex with bi-amping and active crossover.

They will be used for both TV/movie and music (no disco or metal, mostly jazz and folk). No subwoofer will be used.

How would fullrange 8" satisfy this? Seas FA22RCZ in a vented (sealable) enclosure, (in Finnish) Audiokit Aw-F22 rakennussarja - Hifitalo ?

Or the same driver in a horn enclosure, Mauhorn IV – D a r k L a n t e r n ? How do they sound, are they very directional and difficult to place in an apartment?

I have access to a full fledged carpentry workshop but no competence in designing enclosures.

after 10 years I try to build it

As per thread tittle i want to buy a few pcs of LME49810.
the part is obsolete few years now.i found a reliable source but requires a minimum of 50 pcs.the cost for 1 Ic is 18 GBP....
Feel free and post your interested here.

BR
Vasilis

Too many DAC's therefore selling this setup, inlcuded is :

- Beaglebone Black with working Botic image
- Placid Supply
- Hermes
- Cronus
- Buffalo IIISE including Crystek Clocks and local Powersuppy Regs
- Legato I/V output stage

all of course in fully working condition ...

Asking 450,- Euro for the setup + shipping which of course depends on the destination

thx

I have a Sure/Wondom AA-AB35281 amplifier board.

The specs PDF states:
"Gain: Min 28.5, Typical 30.5, Max 32.5"

This leads be to believe the gain setting is adjustable.
But the PDF doesn't state whether it can be adjusted or how if so.
Does anyone know if it can be adjusted and if so, how?

PE Specs sheet:
https://www.parts-express.com/pedoc...200w-fanless-audio-amplifier-board-manual.pdf

Hi everyone¡¡

Today comes to me an eclipse xa1200 ice amp.

I dont test any amp, before i check the inside. In this one i find a rarely and 100% sure bad conection on the irf1010 ps mosfet, see the image.

So i take off all the ps mosfets and test it. No power, no 12v on the tl494 so replace the remote signal transistor. 12v on vcc and c1 and c2 of the tl. Now i have around 4-5v on the tl outputs, but im sure the ps mosfets drivers are grone. Anyone here have the shematic or the corrct part nunber for q919 and q921?

Thanks!

Hi
I intend to put a 12” AE Dipole woofer on an OB which will be about 56cm wide by say 50 cm tall. I will also put some short wings on the baffle. I will run the woofer up to 600hz. I have read what Linkwitz has to say about diffraction and I want to just check I’ve understood correctly. The wavelength at 600hz is 57cm, so I’ve concluded that edge diffraction should not be an issue. Have I got that right?

For those who didn't find "Monolithic SuperSymmetry" interesting
enough, I present a concept schematic which uses power chips
such as the LM3875 or 3886 (or anything else, for that matter).

Hi All,

I have inherited two massive LIFE PO4 batteries in nice alloy cases (30Kg each and approx £1,100 RRP each!) they are 48 volt / 150 Amp Hours rated and would like to use them as the power supplies and physical bases for a pair of floor standing active monitors.

Each 3 way monitor stack has three separate monoblock 500 watt class D amps and 3 channels of DAC per speaker, so 6 channels amps and dacs in total.
The 6 Ohm bass section is 95dB per watt @ 1 meter.
The 8 Ohm mids are 100dB and the TPL tweeter is 100dB sensitivity.
DAC's and A to D are built into the amps and the only input is an optical Toslink (no electrical connection with the music server / DSP)

I want to run the whole system from the batteries and use DC to DC voltage/current reduction for the amplifier boards and DAC's.

Questions:
What is the best approach or technique to achieve DC to DC reduction in this situation and any company or product component recommendations would be much appreciated!
Highest audio quality is my goal and I don't want to waste these super expensive batteries by scrimping on the DC reduction.
Thanks in advance
Alex.

Does this board use the IR21844S ?

The part number starts with IR just wanna confirm

I have dismantled a Thomasina? organ and have the Leslie pedal to sell.
$20.00 plus shipping to Canada only.

Hi fellow social distancers, Got two Skar RP 2000.1D in for repair. Both in protect. Power supply runs. No shorted outputs. Pulled all the outputs to see if it made a difference. No change. The protect circuit is controlled by a 393 comparator chip. Just to be sure I changed the 393 chip. No change. Can anyone shed some light on the protect circuit in these amps? Thanks



LM393

Pin 1: +5.2V
Pin 2: +5V
Pin 3: +8.5V
Pin 4: Gnd
Pin 5: +2.5V
Pin 6: +2.2V
Pin 7: +5.2V
Pin 8: +14V

This would solve my diy AC line connection nicely using one panel hole.
Ya not for the EU probably but North America we still using line cords.
I have one of the surplus experts looking for a NOS stock.
The IEC panel entry is a pain if fabricating enclosures, and the switch/lamp/fuse system is fragile.

hi all
has anyone ever tried using Digital design z18 subwoofer for spl purpose in here???
if yes,i need your help...

During my clean out I found these which may be of some use to someone. I'll give it a week before I throw them out. I'll cover postage and ship in Australia only.

TDA1543 DAC new
TDA1543A DAC used in a NOS DAC
TDA1545A DAC new
4 x K170 used (was in a B1 buffer) and were originally matched but can't say they are now

Hi all
I have a pair of 5-1/4" KEF passive radiators to sell. They were from some KEF Cantor 111 Speakers whose woofers died by teenage hands. The outer frame dimensions are 8-1/4" x 8-1/4".

They are in very nice condition - no sign of surround deterioration.
$40.00 for the pair. Buyer pays shipping. Shipping weight 275 grm each plus packaging.
Regards John L.

does anyone has its service manual ?

Does this speaker build idea using these two drivers in a ported cabinet ala cheap DeVore Orangatun O/96 style, a bad idea?

Dayton Audio PA310-8 12" Pro Woofer

Peerless by Tymphany BC25SC08-08 1" Fabric Dome Tweeter 8 Ohm

If I could get 45hz out of it, I would be happy, yet if I could get 40hz even happier.

Looking for a high efficiency build for my Sony V-Fet and Music Reference RM-10.

Thanks

Stumbled upon this photo and don't recall any explanation as to it's purpose. Anybody have an idea what this is called and its purpose?
Thanks

Hello! I have a Musical Fidelity V2 DAC and trying to understand the power supply plan.
It uses unipolar power supply 12V and for the opamps creates the negative rail using two DCDC charge pumps LMC7660 from TI.

When measuring the two rails that feeds opmaps i measure a difference of minimum 1.5V and i want to try and correct this issue if possible.
As can be seen on the picture the positve rail goes almost unchanged from power supply to opamps.
The input on pin 8 of charge pumps is 8,9V and on pin 5 I measure 7,8V. I was expecting to have Vout equal -Vinput.
The group formed by C21,C44, D3, D4 also confuses me because in the end I have -12,6V on opamp negative rail.
What is the role of C21,C44, D3, D4?
What can I do to have equal voltages on opamps rails?
I attached the complete schematic of DAc and also a screenshot with measured voltages.
Thanks! Adrian

Hi
Recently I got few complaints about the amps that uses these driver boards as shown in the attachment. The amp trips when they drive 1ohm into it. Other wise with 2ohms or 4ohms they will play good. But when they get some heavy load they will trip. I want to know where to investigate the problem. Thank you.

A donut for the first one who find the title's reference... 😀

ok so, while testing (torturing) the PA woofer-mid, It started to smell burnt voice coil. A lot.

Now, I'm not used to smell that a lot since usually, when I torture drivers, it's JL audio's subwoofers, and they don't have that kind of heating v.c. problems...

so I have a question: is it the driver that goes into his first heat cycle (so it's somewhat normal) OR the driver may be damaged or lost some of his original properties in a permanent way?

In other words: HOW BAD are the consequences of a voice coil that got very hot, but still working apparently normally...?

Hi,

How would you rate chip amps amplifiers you built in past?

Maybe this information will help others decide which amps to build.

Anyone in knowing of standalone AAC (raw AAC primarily, m4a optional) SD card decoder-player pre programmed chip or module or kit, just as there are plenty of mp3 decoders available? Or any suggestion to make one by programming ATTINY85 etc? Thanks in advance.

I'll post photos and descriptions soon.

here's a small list of stuff

F5 Amp
B1 buffer
dcb1 buffer
ezdac

some audio cable (ie thick power cables)

+even selling my plateau stereo stand
----------
Ok, here's the asking price for what you see...

dbc1 buffer +transformer - $200
b1 buffer - $225
F5 Amp - $700
dynaco st-35 $800
----
rack - $225 (pick up only)

* shipping extra

I'm trying to go from digital filters to analog since I havent found a good solutions with good enough converters for the digital part!
I'm building a three way system and so far my plan was to use MiniDSP for the bass because it's gonna be extremely expensive with a good passive filter- but then I thought that maybe I could make a active filter for the bass, just like on my old sub amps.

My question:
How can I make a 24db LR filter for the bass at 300hz, or even better with a trimable frequence?

The amps are TPA3255 1x480W 1Ch Class D Audio Amplifier | eBay

Is better use 8 Ohms OPT with 8 Ohms speakers, to 4 Ohms tap with 4 Ohms speakers ?

Or are different performances.