Good Morning, I have a old Luxman D-355 that I like to restore / fresh up.

It have two Op-Amps after DAC chip ( analog out ). The units is NJM2100D ( dual ) from JRC, is it worth change them?

I also thinking of re-cap, the unit is from 1995 so 30 years old. But I like the way it present the music with the 1 bit DAC.

I think of good all around caps for the board except maybe some audio caps for the analog part.

Any thoughts ?

Frank

Hello, I have another taramps on my bench. 2 of the traces were burned away I had to repair them, crudely, the 2-10 ohm resistors in the +/- 5 volts circuit, they were reading in the kilo ohms.

I've managed to solder on the IRS 2093 IC, all the relevant voltages are there. VCC 1-2 is 14.2 volts, plus both +/-5 volts and 10.1 volts on the CSD pin.

But with all that the audio sounds distorted so a checked the drive voltages and they're are like 1 volt or .4 volts or even 2 volts.

NEW I'm selling 4 of the speakers in a lot for 60$ and shipping.
neodymium magnet , 55 hz to 5500 hz , spl 91 db , fs: 55hz ,vas: 0.58 cu.ft. , qms: 10.8 , qes: 0.58 , xmax: 3.9mm ..
vary nice mid drivers

SOLD SOLD These are new subwoofers. There in factory packing , so i can ship them.
45$ each I have four
thanks rick

Recently I installed Auva 50 footers under my speakers. Auva's are products from Stack Audio in UK and only sold dealer direct online. I installed these after a personal recommendation from an audio friend whose recommendations are always spot on. The Stack audio website is full of information on what the products supposedly do, along with numerous reviews and customer comments. Reviews and comments are always on the positive side, otherwise they would not be on the site. The product information is extensive. But then it is about selling a product. They do come with a 30-day money back, so it is a safe purchase. I made the purchase and installed the Auva's.
Once installed I did a slight speaker positioning adjustment, and I started listening.
It did not take too long a time to tell that something was vastly different in the music. And the vast difference is that the Auva's seemed to remove the electronic signature of the audio system. The music came alive and brought a "You are there" sound and feel to the music. This was across the board with every disc that I have played, no exceptions. Of course, the musicians are not there in the room with you quite obviously. But if you close your eyes to remove visual stimuli, the music does sound like the real natural sound of musical instruments and human voices, with nothing really added. I listen to classical and jazz, with some folk music at times. I tend to not listen to electronic popular music very much at all.

The Auva's are the real deal! They are highly recommended. I have found them to be the biggest sound improvement that I have ever made in all my many years of audio listening.

My speakers are in the pic below. They are DIY, designed in 2003 by the late Rick Craig of Selah Audio, and remade in 2018. They are simple DIY speakers nothing too fancy. They are a 2 1/2-way design with Seas W18E and Hiquphon OW,1. They are reasonably similar to Troel's CNO25, though my design predate Troel's by a long time. The spearkers are driven by a Starkrimson Ultra amplifier. All music is DSD64, DSD128 or DSD256 supplied by the Marantz SA KI-Ruby player.

I should add the following disclaimer:
I fully understand that my observations are worthless anecdotal observations and are completely unsupported by any graph, measurement, or any such thing. I only posted because perhaps there are a few odd individual listeners who might read this and investigate for themselves.

Working with a IRS2092S based amp and I want to modify it to accept non inverting signals. Pin 2 is marked as the + input and is normally grounded. Can I lift the ground with say a 100 ohm resister to ground and then use pin 2 as a non inverting input or am I missing something. It does state in the datasheet that the COMP and protect circuit reference the ground from pin 2.

A few days ago I suddenly noticed 'something' was humming noticeably in my set up and that something turned out to be my Sony MDS-JE480 Minidisc recorder which was in use at the time. Switch to standby and the noise vanished. Hmmm, well hummmm actually and from the transformer. Examination of the PSU shows that it uses two transformers, one for standby and one to power the main unit. Kind of unbelievable really for a budget model although it was and is ranked as one of the very best sounding of all due to its use of the very last generation of ATRAC which is the data compression system.

For curiosity I measured the mains and it is was high(ish) at 247 to 248 volt. Was that playing a part I wondered. The mains here is often in the 242 volt region but this was right at the top end. We also have something that is a kind of active voltage control system in this area where mains voltage is dynamically controlled and optimised in real time according to overall demand. It obviously has to keep within legal limits but the idea is to reduce voltage when demand is high to reduce loading on the grid which is sort of counter intuitive when you think of all the SMPS as lowering line voltage will increase current draw... however...

Back to the Minidisc. I wondered if doing the unthinkable would be possible... adding a series dropper resistor to the mains transformer.

The power supply is shown here. You can see the little standby supply at the top of the schematic and the larger (but in reality still pretty small) main transformer at the bottom. The PCB layout lends itself well to trying this as there are two wire links (arrowed) are fitted in the feed to the larger transformer primary. I removed these wire links and fitted two 56 ohm flameproof resistors in their place.



Results seem really good. Operation is now silent and the two resistors drop around 3 volts each and run essentially cold. The drop seems very constant and does not change under any operating conditions such as when the mech is loading. So regulation is essentially unaffected.

I wouldn't normally recommend anything like this but in this instance it seems to be a viable and workable solution. The PSU regulated supplies have a lot of headroom and even at lower mains voltage near the lower legal limit (not that we ever come close to that here) there should not be an issue.

Totally unrelated to this and something I only noticed with studying the PSU diagram is that the analogue opamp stages are fed from a 100% unregulated supply (arrowed). How audiophile is that? Perhaps very! because it certainly works extremely well on these budget machines and which as mentioned are reckoned to be one of the best sounding.



Also of interest is the 0.0022uF cap shown across the relay contacts in the PSU schematic. I measured an AC voltage of around 17 volts AC across the primary in standby, quite high really and due to the reactance of the cap. Is that of consequence? Maybe it plays a part in muting and silent power on and off as it means some voltage will be present on the rails (particularly the unregulated ones) even in standby. This is one of those times where you have to think that the designers really knew what they were doing.

The analogue stages fed from the unregulated supply:

im looking forward to learn new things and possibly help other learn new things about diy audio constructions ranging from building speakers to creating circuits

How might the midrange and HF band presentation change between these 1.4 and 2" models?


https://www.usspeaker.com/radian 745neoBepb-1.htm
https://www.usspeaker.com/radian 950Bepb-1.htm

Alternates https://www.usspeaker.com/radian 951Bepb-1.htm
https://www.usspeaker.com/radian 760neoBepb-1.htm


Which would you choose for what kind of two-way (only) speaker build and why?

Also, please recommend the best constant directivity horn you would suggest for any of those drivers.

Any experience with these?

https://alg-audiodesign.com/pavillons/
https://audiohorn.net/x-shape-horn/
https://audiohorn.net/next-gen-bi-radial-horn/
https://www.usspeaker.com/ciare pr614-1.htm

I want to add this tone control on this circuit.

Can I do it this way?( is the amplification rate too low?)
And I want to add direct function(don't pass the tone control circuit) i know it is unnecessary on this circuit( when the knob is on the middle, it works like direct function) it is for experimental reason, I want to know the effect of the capacitors of the tone control circuit on sound quality. So can I just add the switch on the input(like upper schematic) or should I add one more switch before the grid input(because i thought 12ax7 on the tone control could cause noise)(like lower schematic)
I am sorry for poor English.... can anyone help with these problem?

The School Amplifier from back in the day The School Amplifier

I am going to build an LM3886 chipamp on chipamp.com boards. About 30-34VDC on the rails (22vac tranny) with an 8 ohm speaker load.

I have 2 each of these heatsinks but no way to calculate if they are adequate. I will make the enclosure and can make it to fit.

The small heatsinks are 45mm x 50mm x 20mm. One LM3886 on each heatsink.
The large heatsinks are 270mm x 100mm x 50mm. Maybe put both chips on one heatsink?

Do you think the smaller heatsinks will work? If not would both chips on one large heatsink be sufficient?

I know this is somewhat of a guess without know the characteristics of the heatsinks but it is what I have.

Thanks

Small heatsinks:


Large

For a new topcabinet, I needed a MF/HF (or only HF) section, which is able to handle a crossover around 700Hz. The whole design revolves around maximum output for a given size. The dual 10" LF section is loaded by a short offset driver horn and ported rear chamber. For this to work, I knew from the beginning, that a relative low crossover was necessary (approximately 700-800Hz as an estimate). In total the following demands are set:

-Low XO possibility (700-800Hz)
-Maximum hight and width 29x29cm total
-+- 80 degrees horizontal dispersion
-50/60 degrees vertical dispersion
-Rotatable horn for possible horizontal arraying

This all could be solved by going for a coaxial CD or large 4" VC and for example a RCF HF950 horn. But there is no fun in that.
So I wanted to try a different (and unknown for me) path for this project. After some minor research I decided to just start with some design work and see what can or will come out.


This gave the following:



The MF drivers are two 4ND34-16 from B&C, and a new RCF NDX595.
The whole horn is for now printed out of 5 parts total due to the size of my current printer. In the end its the idea to bring it down to two and outsource the frontal part.

As I wanted to be flexible with some testing, I made the MF taps removable. This way i can test various placements, sizes and shapes.
By doing so, I am a bit limted in vertical placement eventually though, but priting that whole parts again takes a lot of time and money if I have to do that several times.

As I wanted to try it ASAP, I made some preliminary inside measurements with a calibrated UMIK-1. Its not ideaal, but gives a first impression.
Distance mic to SUT +- 40cm.

2x4NDF34-16 parallel, taps a close as possible with insert, two 22mm round holes (total area 7,6cm^2 per 4NDF34) + NDX595:

With this measurement, the back of both 4NDF34's was open.

I tried my best by closing the back of the 4NDF34's with gaffa tape and got the following results:

I will be printing some better parts for the drivers to get it better and neatly, I am quite sure its leaking currently.

The 1kHz dip of the NDX595 is due to the current tap design an placement. When covering with some pieces of tape:




To try and reduce the dip at 1kHz, I did a quick test with a MF tap inserts which has several small holes compared to the two 22mm diamter ones per driver.

Response evened out quite a bit, but less high end extension from the 4NDF34's:



Currently next things I want to do:
-New insert with angled taps (facing away from CD)
-Resolve some resonating parts I still have
-Make a turning table for some off-axis measurements
-Back covers for 4NDF34
-Measure NDX595 on the PH220 I have for some sort of reference
-Get my other measurement mic calibrated again to get some measurements with phase response. This will be crucial to eventually get a nice crossover and if going passive MF tap placement is key from the beginning.
-Do some impedance measurements
-Get a whole day to do various measurements and outside or larger room.
-In the end the HF exit integration can be smoothed out/be better

Its still a work in progress and the outcome could still be that its not viable in the end or does not meet the set criteria. But we will see 🙂

Hi all!
I need a service manual for Electrocompaniet Rena s-1. who can help?
sound disappears from the coaxial output. if you touch the case with your hand, it appears.
I contacted the dealer in my region, but they could not help me. A local service can help, but a service manual is needed.

Hello All,

I took the plunge,

Today I received from Madisound a pair of Purifi 6 – ½ inch Aluminum mid-woofers and a pair of Satori Textreme 29MM tweeters.

I also have on hand a pair of Satori Beryllium tweeters to audition.

See the attached links to the data sheets below.

This is planned to be two-way Bench-top speakers with a summed subwoofer tucked on the shelf below.

Look at the Purifi data sheet and you will notice that below ~ 125Hz that the Harmonic Distortion takes a steep climb. The crossover to the sub will remove the long excursion Low Frequencies from the Purify mid-bass driver. With the LF removed there is expected to be reduced intermodulation with the higher frequency voice content of the program material.

Purifi PTT6.5X04-NAA-08 6.5"

Satori TW29TXN-B-4 / TeXtreme Dome Tweeter

https://www.madisoundspeakerstore.c...tori-tw29txn-b-4/textreme-dome-tweeter-4-ohm/

https://www.madisoundspeakerstore.c...tw29bn-b-beryllium-dome-tweeter-black-flange/
https://purifi-audio.com/document/share/16/6b6d90f3-b9db-4eaa-9f36-9d424bd2adba

To start the crossover will be a active Rane Mojo MX23 that Is already on the shelf. There is a switchable factory summed sub-woofer output. The tweeters and mid-woofers will be driven by the XLR “HF” and “mid” outputs on the back side of the active crossover. The crossover frequencies are adjustable.

The Purifi site has a discussion about using series notch filters with the Purifi driver to notch out the 5kHz and ~ 9.5kHz resonate peaks from the Frequency Response. This is worth an effort. I think

A approximate 6 Liter sealed enclosure will used to start the Proto process.

Thanks DT

hello i am interested in learning more about more advanced speaker types such as planars and compression drivers

Bought a "Higher end" Sonance power amp and the chassis got wrecked in shipping. I am now selling the parts to make up the loss. ( I plan to keep the heatsinks and Toroid)

I have a few of these 50watt (8e) stereo power amplifier modules. All original parts (since all are working pullouts, all tested). They are Very conservatively rated.

At 8 ohms I measured clipping at 26.6vac RMS (That's over 80 watts) and at 4 ohms a little over 25vac RMS (over 150 watts) with its own power supply. To get to these numbers, you will need maximum rails of +/-45vdc. These are absolute max voltages per the uPC1225 predriver IC.

All you need is a transformer and a Bridge rectifier. The kit comes with the Power caps built in. I will explain hook-ups to the buyers once sale is done... very easy.

Uses the very robust Sanken 2sc3519/1860 pair.

Asking for $30 per Stereo module.

With +/-40V input it can output 2-34 Volt.
Power Supply Rejection Ratio is 70dB.

this is a self contained unit drove my zu omen defs
Power supply is at the bottom just connect to mains

Updated with USA made832A and mundorf zn .1mf coupling caps

https://www.ebay.com/itm/195251303531

$75 $10 shipping

Hi, i'm new on balanced audio and those hi-fi things, can anyone help me on verifying if this circuit would work for muting balanced audio? the XLR-Female receives a balanced low level signal from a XLR electret condenser MIC, the output of the circuit (XLR-Male) goes to the mixer that has phantom power, all 10uf caps are metal film, S1 and S2 are TS5A3359 analog switches that will be driven by a dedicated zero-crossing circuit, but that doesn't matter now, what i really need help is in knowing if the caps will pass through just the signal without any distortion or loss and if disconection will make any noise or pop, i also have the curiosity of knowing if this circuit is optimal for that purpose, thanks for the attention and sorry for the bad english, i'm brazillian.

Hello there, Here is the DIY reel to reel tape deck plans by Roger Sanders , article published in Audio Amateur Magazine No 2, 1972.

This has been in the works a while. At the request of friends (and a few critics) I've designed my own portable/desktop amp--The Objective2 (O2 for short). I just published the third and final main article to my blog.

It's a very objective approach (what would you expect from an electrical engineer?) at a low cost "one size fits all" headphone amp. The goal was to show how much performance is possible on a limited budget. It's designed to outperform even far more expensive desktop amps using solid engineering rather than audiophile designer parts or mythical topologies.

For now it's a DIY amp but it's a free open source design and a few commercial companies have already expressed an interest in offering it in various forms. Some have called it the spiritual successor to the Cmoy but the performance is in an entirely different league (sorry for not being more modest!). Some highlights:

* Enough output even for difficult headphones like the full size HiFiMan Planars and 600 ohm Beyers (7 V RMS and lots of current). It will drive nearly any headphone from 16 - 600 ohms to "live" levels.
* Completely silent even with the most sensitive BA IEMs (zero hiss with 131 dB S/N )
* Near zero ohm output impedance (0.5 ohms)
* Very low distortion of any kind--some tests push the lower limits of my dScope audio analyzer.
* ~8 hours battery life for the normal version & ~ 30 hours for the low power version
* Indistinguishable from Benchmark DAC1 in blind listening tests
* Switchable gain for use with different source/headphones
* Unique battery rundown protection
* DIY friendly, self contained on a single PC board, no surface mount parts
* Designed for a rugged inexpensive all aluminum case with a pre-made customizable front panel available.

And, perhaps the best part: You can build the fully functional self contained PC board for around $30 in parts with everything but the bare board available from Mouser.

The performance of this amp, as measured on professional instrumentation, genuinely rivals the well regarded headphone amp in the Benchmark DAC1 and is significantly quieter. It also beats every other amp, overall, I've ever had on my bench--especially its closest competitor the AMB Mini3.

I welcome feedback on the project and hope it develops into something worthwhile. I'm not looking to make any money from it in any way. Here's the link to the final article which has links to the earlier information as well:

http://nwavguy.blogspot.com/2011/08/o2-details.html





I have put together a fault finding guide on the O2 (post #3775) that gives step by step testing and checking procedures. Click HERE

I think it would be nice to learn about amplifier history (any type).

To start with a topic:

Does anyone know who built the first class D-type amp? Or who were the pioneers and how did the amps look like?

And when was it combined the first time with a weight sparing SMPS?

I enjoy so much small but efficient amplifiers because of their transportability.

I think I'm about 3 months into this project so far but I'm now going to start the build thread.

This build consists of 3 way nearfield monitors and a coffee table that is also a push-push bass reflex subwoofer.

This is in no way an "optimal" build. It was never supposed to be. It is meant to be an outlandish, exotic, fun build. I wanted to use different drivers, different configurations, different methods, different everything. I can build a two studio monitor and have it play back accurate. This is not that. That I could just buy. This is building something you cannot just buy. Something you'd have to make. Something you'd have to explain to even someone into audio.

OBJECTIVE:
Create an awesome 3 way setup with a sub that goes from 18 hz to 40K hz. Distorion under 2% for everything 200 hz and up. It needed it fit under my triple monitors and not take up too much office space. By making the coffee table for my office couch the sub I have succeeded for the sub. The 3 ways are pretty big but they tuck under the monitors which is dead space anyways. Budget was under $500. I think I might end up a little over with the crossover but we will see
Monitors:
Tweeter - GRS RT1.R - 5K hz and up $60 (on sale)
I hear good things about these ribbons. This is the first time I am using a ribbon tweeter. Hoping there isn't too steep of a learning curve. I took the measurements with a 45 uf cap. The sweep sounds insanely clean.

MID: - GRS 8" Mid Planar - 800-5k hz $55 (on sale)
This is another first, I have never used anything other than a cone driver for a mid so far. I did spent a ridiculous amount of time 3d printing horns. I learned a lot. I can get it go down to 500 hz cleanly but it requires a massive horn and that isn't the direction I wanted to go.

WOOFER: - Epique 5.5" MMAG Woofer $70 (on sale with coupon)
I was hesistant to go with this driver. It has measured out very well. With the port its hitting down into the 30s with ease. Impressive little thing. I got it on sale so not so bad. It has an incredible amount of XMAX. Interested to start working with this thing


Subwoofer: - GRS 12" High Excursion Paper Cone
Nothing special here. I have simulated these before and wondered how anyone could have a use for them since they require such a large box. Well, a coffee table is around 13000 inch square. So two of them work perfectly here.

ENCLOSURE:
This is a 3d printed enclosure. The filament used here is carbon fiber infused PETG. It is dense, heavy, and rings super low. I have so much bracing in this unit and the walls are so thick I'm pretty sure I could park my Acura RSX on it without it failing. I'll throw up some pictures for you to see. This part was printed on a very large 3d printer and it took 3 days to print. In total it is 6 pounds of filament. This isn't your friends 3d printing. This is industrial grade. I have a few of these at work and use them all the time. This required the largest one we have.

The Planar Mid is sandwiched inside the enclosure between the face and the body. Behind the mid planar is a diffusion array. I tested a bunch of these. This one works the best by a long shot. Not exactly sure why. The back cup is filled with polyfill. There is a sheet of microfiber cloth between the fill and the planar so the poly fill fibers do not end up inside of the driver.

The enclosure is exactly 0.38' cube. I forget how long the port is but it is exact to what I wanted. Do not underestimate the amount of time it took me to create this model to EXACTLY 0.38' cube volume AND have the port the exact length. The port is the stand. It still in prototype stage but with eventually be 3d printed in the same black filament as the body.


Coffee Table Subwoofer:

So this became of me just screwing around one night with WINISD. I needed a coffee table and didn't want a boring one. I run the fab shop of an engineering consulting company so I figured I might was well make the coffee table a sub and show off some fab skills. The volume is 13000" square. I forget the port length but there are two of them and they are 4" diameter. That is as wide of diameter as I could go without adding bends which I didn't want to do. They fire at the floor. The table will be 2" off of the floor. I won't get past the max port velocity until 200 watts so I think I am ok. I'll be powering it with a 200 watt RMS amplifier. I will run them in series for an 8 ohm impedence. This is an office so that should be sufficient. I'm not trying to shake the building down here.

The woofers will be sandwiched between the middle bracing and the outer walls. They are more than snug. I already fitted that up. They will not be screwed to the sides. There will be 8 M5 threaded rods running through the entirety of the cabinet to link the two woofers. There are also some reinforcing rings midway so that the threaded rod doesn't try to bow as they run a decent distance.

I think the bracing is sufficient if not a little overboard. Again, I can probably park my Acura on this without it breaking.

The big party trick here is the top will be clear Acrylic. It will be screwed on with gasket on all the bracing to seal it. No way am I doing all this crazy engineering and then hiding it. Nope, I want everyone to see what is going on.


Measurements:

These will be coming soon. I just took them today. I will get them into VituixCAD and start messing with the crossover. I'll probably go with a 3 way series crossover. I like the flexibility of the series crossover. Less need for a bunch of components in the form of notch filters. The Mid planar and the Ribbon will both require some notches. I can already tell from the measurements. They do all measure very clean. These are much lower distortion drivers than anything I have used before. Anyways, coming soon, I am running out of time before I have to head out to dinner.


Thanks for reading. I should be done with the sub next week and the crossover within the next 2 weeks.

This is going to be a bit of a dive into acoustic diffusion, so fasten your nerd spectacles with enough duct tape, Let's go to acoustic space!

I'd like to present diffusion from the point of product photography to give a visual reference point of what diffusion and reflections are, so it can be a bit easier to understand the concepts. Photos 1-4 are from the book Light - Science and magic, An introduction to photographic lighting, 4th edition, pages 35-37 (F. Hunter, S. Biver, P. Fuqua, published by Elsevier inc. 2012)


The Phase and amplitude balloon graphs of an acoustic diffuser (phase grating panel), measured with the proposed ASTM New Diffusion Standard @ 8.5kHz show the same effect as diffusing material (white paper/phase balloon) and specular reflection (plastic handles of the soldering iron & pliers, all metal parts/ amplitude balloon)



This is the measured panel on the balloon graphs above. Being a flat panel, it produces a specular reflection but the holes affect the phase change ie. light reflecting off of a white paper.

Several measured diffusers, the .GLL files and GLLViewer can be downloaded from NWAA Labs https://www.nwaalabs.com/Index Surface Reflectors (Diffusers).html

This article explains the flaws of measuring acoustic diffusion and trying to depict the phenomena with a scattering coefficient on a simple graph with the current standard:
October 9, 2022
The Misunderstanding of Acoustic Diffusion Test Data
Where we've been, where we are and where we're going
Richard L. Lenz, RealAcoustix LLC.
https://realacoustix.com/news/news-full-article/tmp-1

Matthew Poes of Poes Acoustics has a ~5min part in his video from this topic
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This mammoth of a video goes deeper into this topic, with explanations and measurements straight from physicist/acoustician Ron Sauro (NWAA Labs) and acoustic designer John Brandt, hosted by Karthik Ramanathan. Timestamp starts from the similar phase grating panel pictured above and continues to a show examples of diffraction modules.
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Didn't find much conversation about these topics so I hope this helps and opens up some discussion about the possibilities these new measuring methods can provide to modifying our acoustic spaces, but also how these may be utilised in speaker design. And please do correct me if I'm way off on something, I'm only a novice on acoustics and as english is not my native language there is a bit of a language barrier.

Up for offer are 2 pairs of NOS unmatched Yamaha 2SK76/2SJ26 V-FET's. I got these years ago from someone that Yamaha supplied samples to for an audio mag V-FET amp article they were writing back in the day. Since I haven't done anything with them yet it's time for someone else to hopefully make them do what they do best and enjoy them.

How about $180 US for the set + shipping and duties/tariffs for these sonic beauties.



Sorry but NA shipping only.

Hi all! So there is an old thread on this Chip. That it is very power hungry and noisy

And the thread poster wanted to have a dedicated PSU. Although I’m not sure why they talked about grounding it… if I understand it right. Isn’t the right way to do it is to have a PSU that have 5 volt to VDD and VSS ? And leave it grounded in the board.

The data sheet shows Pin 12 and 24 wouldn’t that solve the power issue ?

Is there someone out here that have experience in this!? 🙏

Hello, I am noob audio engineer from South Korea. My father was audio engineer and professor in 70s.and now I got his heritage(I used the word 'heritage' because he is too old to continue making amp because he can barely see. He is healthy) I have his 6v6 pp amp and other tr amps. Especially the 6v6 pp amp was his last work as he retired as a engineer and professor.(look at the pic) It had wonderful sound. But it is too old, it keeps causing problems. I don't want anyone to fix my father's work. So I want to study audio on my own and fix it(it is still not working)and also make my own amp too. Now I am making 6aq5 se amp for study. But I need advice from anyone here, so I joined the forum

Howdy. Wondering if anyone has considered a 4-driver PM90 with some of the new B&C coax drivers? I was thinking one could probably achieve a high-SPL box that's still pole-mounted. I was looking at B&C 8NDL64 drivers, which are less than 6lbs each. Add that to the B&C DCX-464 and either their ME464 horn or the RCF HF950 and you'd have a Loud full-range speaker.

I've been looking at the Meyer X40, Peter's PM90, and the Danley SM100B. Danley uses four less powerful drivers to keep up with the 5" coax mid/high. Peter has two horn-loaded drivers. Meyer just has two angled front-loaded drivers with a slotted port on the X40 and two slots on their larger X80.

I was thinking that Peter's design with the B&C horn would leave room for a pair of 8" drivers at top and bottom. Total component weight plus the horn comes out to less than 45lbs with crossover.

Thoughts? Anyone wanna throw this into some software and take a look? I'm an ideas guy - no idea how to run hornresp or any of the other fun toys.

Dual DC power supply from + 9 v to +18 v and - 9 v to -18 v, alternatively single power supply from +9 v to + 28 v DC (on customer request).
Input sensitivity 3 mv out 1470 mv gain 50 db, signal to noise ratio 105 db, impedance 47 Khom. frequency response 15 HZ 30 KHZ.

Hi,

Here's my Hantek 6022BE (2 channels, 20MHz) looking for a new home. Perfect condition.

£30 plus shipping.

fs FO L module in grade shape.
price 100€ plus PP fees.
Europe only

For sale 2 pcs smps HYPEX 1200A700.
Price 120€ each plus PP fees.
EUROPE ONLY

I would like to share my test and review on the new SB Audience ROSSO 65CDN-T 1.4” compression driver.
SB Audience ROSSO-65CDN-T + ES-600 Biradial Wood Horn
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Looking to Buy One or More Soekris DAC DAM1121

I’m looking for a good deal on one or more Soekris DAC DAM1121 units. I want to build a Raspberry Pi + Camilla DSP + Soekris DAC multi-channel setup.

I’m based in Brooklyn, NY 11211.

Thanks!

The ballast was pretty easy to bypass after some poking around with a multimeter.

***For those of you that are having trouble bypassing the ballast on any projector***

1 - Find the group of wires that come from the ballast to the main board.
2 - Power the projector on with NO lamp.
3 - Measure the voltages on all the wires connecting to the main board.
4 - Find the wire that is close to +3V
5 - Insert lamp (If you have one) and power on. Measure the voltage of this wire again. The voltage should be around 0V
6 - Connect the spot on the board where that wire connected to a ground on the main board.

This will bypass the lamps for 90% of projectors. It has worked for me on about 8 different models. All else fails just ground each wire and power on and see if the projector stays on. Remember that the wires coming from the board need to be grounded NOT the wires coming from the ballast.

This seems to be a frequent question/problem. Maybe this can be made into a sticky since commercial modding is getting popular.

Good morning.
I have a NAD C355bee amplifier, which actually works very well and sounds great.
However, just out of curiosity, since the amplifier is already 15 years old, I tried to measure the Idle current and isc circuit parameters.
In the service manual it refers to a value of 6mV for idle current, however, I measured a value of 8mV (after the amplifier had been on for 20 minutes), in both channels (to be precise 8mV L channel and 8.1mV R channel).
Can these values still be considered normal or do they need calibration as reported in the manual (6mV)?

For the calibration of the ISC circuit I did not understand well how to proceed.
The manual indicates "adjust the pot VR3 to make the DC voltage of the point of TP10 to the same as TP11".
If I measure TP10 (one tip on TP10 and one on ground) I get 56.5mV
If I measure TP11 (one tip on TP11 and one on ground) I get 19.5mV
If I measure TP10 + TP11 (one tip on TP10 and one on TP11) I get 34.7.




I have not touched any potentiometers yet, and before I do (if necessary), I would like to understand..

Thanks very much!

Hi guys, I have a new-to-me pair of HDI-3600 and would like to turn a great pair of speakers into a super pair of speakers. Having a look at the stock crossovers, lots of room for improvement, I think JBL could have done a better job frankly given the cost of these - no-name electrolytics (par for the course) and no-name film which appear entry level in the HF.
Question is, moving these caps and resistors to Mundorf options leave me with small variances in values.

I am not thinking these variances would make any significant difference, but interested in folks’ opinions. Would these small differences add up, what about the resistors?

Here is what I am looking at - replacement value + originating value for both caps and resistors:

Product+value_________________Original Value_________________Application

MCap Supreme
1.8uF(600V) _ _ ___________________ 1.8uF__________________________HF

MCap Supreme
3.9uF(600V) _______________________ 4uF___________________________HF

MCap EVO
22.0uF(450V)______________________ 24uF__________________________HF

MCap MKP (250V)
15.0uF(250V) ______________________15uF__________________________LF

MCap MKP (250V)
22.0uF(250V)_______________________23uF__________________________LF

MCap EVO
6.8uF(450V) ____________________6.2 & 6.8 uF___________________HF & LF

MCap EVO
15.0uF(450V )_______________________14uF_________________________HF

MR10 Metal-Oxide Film Resistor
2.2Ohm_________________________10W2R4J________________________HF

MR10 Metal-Oxide Film Resistor
3.9 ______________________________10W4R3J________________________HF

MRES20 MResist Supreme Resistor
10Ohm _________________________25W10RJ________________________ HF

Any thoughts or wisdom from experience? Notice I am considering vanilla MKP on LF and Supreme/EVOs on HF..

Thanks!

Hello, I have got this Fisher AM/FM Stereo Synthesizer tuner from around 1980 for many years now. At some point long ago it started to produce audible distortion with all Stereo stations, independent of signal strength. It works fine if switched to Mono mode and all functions are OK, like auto tuning, store, mute and LED's. Because of the slow increase in distortion over time I think it must be a (typical?) component loosing or changeing its value. I noticed an identical problem on other vintage tuners too.
The stereo containing frequency seems to be one or two digits away from the maximum strength frequency. Like I get a stereo light at 91.00 and maximum undistorted Mono at 90.20

Does anyone have an idea what to look for? I have found no service manual, so I did not open it yet. I dislike turning anything inside without a plan. I got a scope and all the usual stuff for electronics, but I'm kind of fixed on amps, my knowledge of tuners is very near to zero. Next I would mark the positions of the adjustable coils and watch for any change turning them a little, but that will be a last try before disposing it.
Would be great to get some hint what to look for and a pointer to a service manual.

Thank you.

I have designed couple current dumping amps. They have a common problem, too complicated. I never had the courage to actually build one.

I hope this my last attempt. I minimize all the unimportant parts and meanwhile retain the performance.

It has couple features that the original Quad 405 does not have.
1. Include the transistor Q2 in the opamp negative feedback. It creates a "super transistor" that has almost 0 impedance at the emitter.
2. I move all the gain to the output stage, The opamp works at unity gain. It simplifies the circuitry around the opamp. Also you can get most of performance out of the opamp. As you can see, I got 0.002% THD with LM358. It could be lower if switching to better one.

I leave the final stage 0 biased. I feel it isn't worth the effort to bias the final stage just to get the thd down to 0.001%.





Edit: 01/02/2025, overhaul the design.

I have an old Focal 11v7601db element, which I was thinking of building a box for, I found a program online to calculate the box size (42.92 liters Vent diameter 5cm lenght 16.97 ) can it be correct?

Novice here. Looking into 80s rack preamp GK 2000 CPL. It has a single input, 2 switchable channels, stereo outputs, and built in compressor, reverb & chorus. It sounds killer. I'm trying to answer the question: where in the circuit does this amplifier turn from mono into stereo, and what exactly is the stereo effect/content - i.e. how are the left & right channels different.

I attached a PDF with the amp's circuit. As far as I can tell, the whole guitar signal chain (first page), incl. the compressor, up to and not including the FX is all mono. The signal lead labelled "D" feeds into a four circuits (2nd page): dry-lo, dry-hi, chorus, and reverb that all end in a kind of stereo mixer. Signal lead "E" feeds the reverb gate circuit.

Observations/questions - correct me if I've misunderstood anything:

1. I can't figure out the difference between dry-lo and dry-hi. Really curious about that split. Is that a frequency split or a volume split?
2. Unless I'm missing something, the chorus seems to operate entirely in mono, which is different than i.e., the ADA MP1, a popular comparable preamp from the same era, where the original signal is split into 2, one gets mixed with the chorus signal, and the other as well but with its chorus component phase shifted by 180°. I couldn't tell if there's any phase shift on the L or R channels of the chorus on the 2000CPL.
3. The reverb seems to be the only circuit doing actually doing something in stereo. It seems that the 6 taps of the MN3011 BBD chip (each providing a different timing window) are divided between the left and right channels. I am not an expert but maybe that gives an expanded stereo reverb image.
4. But then later, in page 3, we can see both balanced and unbalanced sets of outputs have a mono/stereo switch each. I am not familiar with their symbol for switch, and can't really figure out what happens with either switch in mono mode.
5. Beyond that, it seems the output circuits of either L/R channel are identical in both balanced/unbalanced circuits. I couldn't identify if there's any kind of phase shifting or other shenanigans going on.

Any input is greatly appreciated!

Edit: Figured I attach the schematics here as images

I have an old Focal 11v7601db element, which I was thinking of building a box for, I found a program online to calculate the box size (42.92 liters Vent diameter 5cm lenght 16.97 ) can it be correct?

I recently purchased the JC-2 preamp kit that tubeshunter is selling on eBay. I made some changes to the stock component values to improve performance and reliablility. I also increased the gain to a little over 20 dB.

The kit I purchased did not have idss matched jfets. I had several of the JFETs on hand and selected idss matched parts. The differential pairs were matched to 0.1 mA, and the n and p channels were as close as possible. It will work without matching the fets, but the offset and distortion will be higher.

It is stable into 1000 pF capacitive loads, and has a THD of .001% in the audio band.

If you assemble this kit, be sure to test the bipolar transistors. The ones I received had their pin out reversed from the silk screen shown on the board. The picture on the eBay listing shows them inserted reversed as well.

I hope someone finds this of some use.

Hello friends!

Forgot my original sign in John, sorry, not sorry. This Maple Nut saved all our behinds with my knowledge of tech inventions and their history. You ALL have pattens pending on your designs and we are working to get the top tear DIY kits certified and into Vintage King and he new Canadian sister company Vintage Queen up and running that will become a part of L&M sometime in the future. VQ is being created in honour of the greatest Thermionic Valve Technicions in history Manley Laboratories Inc and Miss Manley.

Along with the Actual audio technicians in 1979 we banned the production of ALL tube, transistor, analog and solid state devices after a Earth Sound Research amp killed me on stage in 1978. We have been working for 46 years to eliminate the variant frequencies created by every mechanical device since the Patton of the first English tube was discredited and and infiltrate tube was patented creating 80:years of null harmonies that would have eventually killed us all. Miss Manley designed the MP with Dave imparting the math, but it is 100% her design with Dave as the LICENSED AUDIO ENGINEER who eventually signed off on her certification and MLI was born.

I created the math to help engineers create the first computer chip, ADDA, Apple, Logic, the Massive Passive, Unreal Enine, Wwise and Dolby Atmos to name a few. I’m broke lol, but never needed money but do need your help getting the Patten Corporation up and running.

As it stands POTUS and Parliment are 100% behind this initiative. If you don,t want to get sued add yourself to this list and we can open a line of dialogue and have some fun.

One Love
Dr. Black PHD, Kinetic Engineer (Wall)

You should thank Mr. Thompson Bell, Graf, Brian Roth and Doug.

I am building my first ever true DIY audio project, a soundbar for my bedroom tv, I am trying to source quality parts for it, and I'm feeling a bit lost in all the options, so I signed up to try and learn how to go about it, and eventually I will post the finished project.

Hi all!

Looking for either matched pairs or a large quantity of 550/560Cs. Thank you!

I am a long-term, semi-pro musician and a genuine music lover. Have a lot of records and cds. Love hi-fi. I am here mostly to ask questions on some hi-fi equipment that I have which needs to be repaired.
Thanks, Nikola

Hello,
You can find all revue l'Audiophile, in zip, here:
- Index of /revues/audiophile
or here:
- - Revue: L'Audiophile

Dear DIYers does anyone know how to open a Shanling CR60 CD transport?
I have a slightly modified Tempo ec1b CD player that sounds better fuller and cleaner.
I have tried to open the CR60 but did not succeed.
A different linear power supply makes a difference but not enough the Tempo
CD player when used as a transport still sounds better.
I hope to be able to upgrade the inner power supply and perhaps the clock.
Anyone tried with success?
Thanks

Nice to be here, and I'll be posting some questions. But I'll be also sure to post the solutions, if i can find any 🙂

Hi everyone.
I finished the basic preparation for converting my b77 from 4 tracks to 2 tracks.
The reproduce pcb was more or less similar, bought a used 2 track oscillator pcb and carefully made the needed changes for the transformation on the recording pcb ( quite harder than the reproduce one since there are some differences to the 4 track one).

I found some quite good prices for all 3 (play, rec, erase) 2 track heads (used ones) and i placed them on the headblock. Soldering and re wiring was a breeze. Used clear tape for initial allignment.
Monitor amp check (first step of the manual calibration process) went fine and it works perfectly well.

Then i started with the calibration of the playback head and i came across the first issue. I’m using a basic calibration tape that was very good for successful calibration of the 4 track playback head.
But now with the 2 track head when the switch is set to stereo there is no signal coming in the right channel. The mono section of the switch works perfectly well.
Tried to change the head cables (green where yellow goes) and then i only have left. So it’s not an issue of a faulty head or bad pcb connections, but rather something else either with the initial head adjustment (height or zenith - never done it before and there is no real guide on how to do it properly) or the calibration tape is not appropriate for 2 tracks.

Any advice would be much appreciated. I think i may need some more down thevroad. But this step,as you may know, is really important.
Thanks in advance

All,

I bought this turntable for $150, with the knowledge that it did not "turn on". It's a $2k turntable new and after research, I found the replacement parts for about $250. So, all in, I figure I'd have a roughly $2k turntable for about $400, after repair (so I thought!)

Anyway, I have now replaced all electronic parts of this turntable (Power PCB, Speed Control PCB, Motor, and new power supply 15V DC). After connecting all the new parts together, outside of the turn table casing, it still does not power on. Regardless of the turntable, these parts should at least power on, right? I am posting pics of the new parts connected and the 15v DC power supply and picture of the back of the turntable asking for DC power. Any thoughts of what else I could try with this thing?

Recently I bought a NOT working Meridian component amplifier. I found that there is a problem in the power module. Can someone provide me the circuit diagram?

Sun Kim from Seoul, South Korea

Hi all,
I am considering buying the Magnepan LRS speakers. Any critics about it, a power amp of 150w will be good enough to drive it? Any experience with these speakers from your guys? My room is about 24 sq. meters/260 sq. feet.
Best regards,
Williams

I am thinking of upgrading the mids on my 3-way horn system to a Volti FC260 tractrix, but am undecided on the driver. Many phenomenal systems have been built using the BMS 4592ND-MID (around $650 each), so that is a top contender. Much of what I read, and a little of what I have physically auditioned, however swears by Beryllium... which seem significantly absent from posts. Admittedly that was with Classic Audio Systems that had not only Beryllium but also field coil drivers Beryllium plus field coil is out of my price range - and it's impossible to separate variables. Looking at new Beryllium, Radian drivers look amazing... except for the prices: 760NEOBePB at $850 each, or the 950BePB at $1100. True, that is a big increase, but in the long run... in for a penny in for a pound. Three years from now I will have forgotten about the extra money. So... anyone out there have insights or experience on this? I am probably willing to spend the dough, but would rather not unless truly a significant step up. I tri-amp so efficiency is not an issue, and I am satisfied with all other specs.
Thanks.

I'm having a hard time figuring out how T2 gives a 16 ohm output but the amp is lm1875 which is 4 or 8 ohms out according to datasheet.

I'm picturing T2 as an autotransformer but considering the amp is well designed for a 8 ohm speaker and there's a tap for 8 but but coming off the main output is 16 ohm?

If I only use 8ohm speaker, I can't just remove T2 completely right?

More than anything I guess I'm tring to figure the role of T2.

Hello! I have seemed to end up on diyaudio more often than not when going down a rabbit hole; so I took the plunge and joined. Look forward to more deep dives.

The rumor is the digital recording of the 1812 Overture damaged speakers because of the new incredible dynamic range. Did this actually happen to anyone or has it grown to urban legend status? Your speakers had to have been on their last legs or the cheapest speakers in existence to fly apart from a loud passage. I say it was great marketing.

Hey everyone! Long time reader, first time poster! So much knowledge here it's awesome, not to mention Papa Pass!

I'm a big vintage audio fan and almost 100% vinyl. Have a few old Thorens kicking around in various states of restoration / hot rodding (TD150, 160 and 124). Got into tube gear a few years back and built a couple amps and a phonostage. Current set up is a 2A3 SET around 3.5W into some Altec 604Gs with hot rodded autotransformer crossovers. Really love getting into the DIY scene these past few years - always enjoyed fixing and lightly modifying my own gear but building from scratch has been awesome! IMO there's no better way to get this level of sound without spending 6 figures.

Decided to take a side step from my tube builds and built my first ACA last week. Loving it! This thing really has some heart - so sweet and transparent with a touch of that tubey goodness but a bit more oomph down low that I sometimes miss with the all tube gear. Looking forward to being a part of the group! Cheers everyone and happy building / listening 🙂

Hi! New to the forum, although not new to reading. Thank you to everyone contributing - it's truly an amazing resource. I am Henrik, writing from NY. Interested audio circuits in general.

For those of us using QA400 Audio spectrum analyser, some measures to facilitate building some proper x10 and x100 measurements probes…out of old scope probes.





#3Measuring QA400 Quantasylum Audio Analyser input impedance to do some 10x or 100x probes


This is part 1 , in this video , I show how to measure and make sure you get the proper results.

In part two I’ll show, how to actually build them and the results on screen with 103,5 db THD+N with the probe and no signal versus the 105,1 THD+N with no probe attached…and verus first try adding a simple resistor to the end of a probe results in part 2

Hi,
Trying to help a friend with his S/300. One channel went out. Looking for a repair tech. recommendation to send it to.

I'm rebuilding the power supply for an old solid state integrated stereo amplifier that has six radial electrolytic capacitors. They are as follows:

3000uF/35V
3000uF/65V
1500uF/30V
750uF/35V
500uF/30V
500uF/35V

I can find the exact values at Digikey but many are listed in the "Application" category as "Automotive".

I'm guessing for a power supply this doesn't matter but I just want to make sure before ordering.

The other categories such as "Audio" "General Purpose" "By-Pass, Decoupling", are any of these more appropriate for the preamp, phono preamp & driver boards?

I won't go into details, but I have a wiring issue. After changing out the two big PS Caps, I have 2 wires that I can't remember where they went. First, they are both small 16-18GA wires. One is red and one is black. They both have full eyelet terminals on the loose ends. I believe they are the red a black wires which lead to the front red power light... I know for sure the red one is. Can someone with an S/200 by willing to pop the top (4 screws) and help me with where these two wires need to connect back to? My email is svanos49@gmail.com Thanks, Steve

I'm looking for a small decent sounding single way or two way powered speaker that only has an aux input and volume control with no wireless connectivity of any kind, no battery and no remote control at a reasonable cost maybe around $100 or under.

I do not expect 20Hz bass, but I would like the bass response to be at least no more than -3dB down at 60Hz if not better than that.

Cabinet size should be no bigger than:

10" W
10" L
10" H

What single speaker would be recommended?

I can also install a pot in a box as a volume control if a recommended speaker does not have a built i control.

Hi, I'm Adrian, and I'm in the process of setting up some systems in a house that I've just moved into, last fall. This seems like a great forum, and I'm looking forward to learning, as well as sharing here. I'm basically a Martin Logan/Magnapan guy, but I also have many cone speakers. I'm into tubes as well as transistor gear.

I have the parts together for a quick and dirty 2 way open baffle system. One of the uses I have for them would be as studio monitors and the desk has the center of the 12" bass driver basically at ear level. I would be using a DSP amp so I can mess with delay and other parameters.... but I was thinking about mounting the full range driver coaxially. I don't think I've seen such a setup here outside of pre-made coaxial drivers.... am I missing something?

Almost any rock music fan likes long, interesting solos, but there are heaps of short, punchy licks and fills which aren't showy, but really set off the song. Like:

• Me Myself I, Joan Armatrading: solo by Chris Spedding;
• Gimme Some Truth, John Lennon: solo by George Harrison;
• Taxman, The Beatles, solo by Paul McCartney;
• I Won't Back Down, Tom Petty: solo by Mike Campbell;
• Fire, Jimi Hendrix (studio version - most of the live versions are longer)
• Baker Street, Gerry Rafferty: solo by Harvey Burns, I think?

Many more, of course: you could probably put in almost anything by The Beatles...

Your suggestions please!

Geoff

Hello,
I am a long time lurker and would like to interact a little more. I was a 12v installer in a previous lifetime and have a substantial collection of old amplifiers that I will be starting to restore. This site seems to be the place to get the best info.

Thanks
Mike

Heeelp!

Don't ask me why—it's a very long story—but I need a working Yamaha A760 amplifier. So far I've bought 3, and spent a fortune on refurb jobs by local techs that work on vintage gear. One of these techs has now passed away, and I want to avoid bringing things back to the other two shops because they've kept machines for over a year before!

I currently have one that works perfectly except for one thing: there's a hum/buzz on the speakers whenever any line level RCA input/output is plugged in to the machine.

I'm in North America, and the fundamental frequency of the hum seems to be 60Hz, with higher frequency noise harmonics, so this seems to be an AC grounding issue between the amp and other components. The noise is relatively quiet and stays the same volume regardless of where the volume control's at, but it seems to cause slight distortion in the audio signal.

When everything is unplugged from the line level input board, the hum disappears. There's no hum if just the speakers, turntable RCAs (and turntable ground wire) are connected. There is also no hum if the device plugged into the line level RCA board is not running on AC, like if it's an iPod running on battery. The RCA cables I have are decently shielded, and there is no hum problem on my other A760 amplifiers when I plug the same devices/cables in. (Those amps just have other problems I can't fix.)

While working on a prior A760 of mine with no hum issue, one tech told me there was a grounding problem with the chassis and he soldered a wire between the ground rail of the RCA inputs, the input switches and the chassis to correct it. So I used a multimeter to test continuity and resistance between the RCA ground and the chassis on this current unit. I assumed there may be oxidation in the chassis or a failing solder joint somewhere on a circuit board but there's good continuity for all RCA plugs to the chassis.

So I put this out to the community...what else could be going on here? Is there a specific component that may have begun to fail, and how can I test for that myself with a multimeter?

A few components have already been replaced, but I don't think the power supply in it has been touched. I know these machines have a weird "X" power supply, so maybe something's gone bad in that.

I tried testing the grounding of the two pairs of filter capacitors but finding the negative pin became confusing as they seem to be wired in series on the board and I'm not sure about discharging them etc.

(It may sound like I know what I'm doing but I've just done a lot of googling. I'm new to using a multimeter and not great at soldering so very simple instructions without abbreviated techy words would be best!)

I have been in audio and rock music for decades (don't ask). I have been very lucky to have met a lot of professional music-makers. Now, I am slowing down, playing a bit of music and finishing my stash of old VOX amplifiers and making guitars.

SOLD

NOS unused Scan Speak D2905/9000 and 18W/8545 My dad bought them years ago to build ACI Jaguars, and never did.

Let's get these to a home where they will be used. 🙂

$375 + shipping.

I am using a regulated power supply based on an LM317 to provide 6.3V DC for heating the filament of a 12AU7 tube.

Currently, I have wired it as follows:

• Pin 4 and Pin 5 together → +6.3V
• Pin 9 → GND (ground of the regulated power supply)

My question is: Is this the correct way to connect the filament in a 6.3V configuration?

I would appreciate any confirmation or suggestions to improve the connection. Additionally, should I consider anything else to minimize noise or extend tube life?

A pair of Fostex FT17H super tweeters for sale, one has a small chip in housing but still functions see pictures. Used with a pair BLH with full range speakers. Bracket is aluminum angle brackets machined for the tweeters and are solid. Has wire tie on back for wire tie down. Asking $95.00 Shipping paid by purchaser to lower 48 states

Hi all, I have an old Pioneer VSX-D1S receiver and am trying to hunt down the source of hiss.

When using any source input with playback on pause or disconnected, and using Direct Mode, there is no hiss until I crank the volume knob knob past 22. (I'm okay with that)
However, when using non-direct mode (again using any disconnected source input or playback paused), there is audible hiss when I turn the volume past 12. The hiss behavior is the same on Front, Rear, and Center speaker outputs, using none or any of the Dolby modes.

When I disconnect the DSP/DAC boards from the system, both Direct Mode and non-direct Mode have no hiss until I crank the volume past 22. I think this means the problem is in the DSP/DAC boards, or maybe these assemblies' upstream power supplies/regulators?
I re-capped most of the electrolytics on these two boards, and replaced the voltage regulators on these boards, but want to diagnose further before I buy other components.

The other thing I wonder is if the DSP/DAC needs to be adjusted (there are some variable resistors to adjust per the service manual), but I do not completely understand the equipment needs or what output to look for. Instructions in the service manual call for a noise meter, and an oscilliscope. I have an entry level oscilliscope; is that enough to try adjusting? It seems like these are the steps most closely related to minimizing hiss?


Schematics and service manual can be found at https://www.manualslib.com/manual/1123277/Pioneer-Vsx-D1s.html

Any help would be greatly appreciated!

Have been unable to use the website properly since trying to upload some files this weekend. It keeps flitting about and won't upload a file. Gets to the infamous 96% and stops.
Don't seem to be able to ask the online support either.
Anyone having any issues. This on an android phone. Have tried different browsers.
Get all these errors come up.
Cheers

Hello All !
I would like to build a 3 Ways with a 12" Bass driver for HiFi use. I see two options BMS 12N630 and SB ACOUSTICS SB34NRXL75-8. The crossover frequency should be 200/300Hz.
A lot of positive review about the SB Acoustics but nothing about the BMS 12N630.
On paper they have the same performance in a bass reflex enclosure.
Someone here have listened the two woofers ?

[Think I've got this in the right place, admins please move or delete if wrong.]

This is something ive been thinking about for a while now as my amp has no headphone socket. Then i rencently saw this video and thought maybe this could work:

Login to view embedded media
My problem is that i dont want to risk blowing my headphones up by forgetting to turn the volume down before plugging them in by using resistors but then didnt want resistors before the jack as that would affect the output to the speakers. So i came up with a practical solution (i think) where i use a 6PDT switch to go from speakers to headphones which lets me isolate the resistors to only the headphone jack.

Does this make sense? What resistors should i use and where would i place them? See dodgy diagram for what im thinking of doing.
Any feedback or help is greatly appreciated.
Amp is a Cambridge Audio A5, headphones are Bose Quietcomfort 15

hello, i just joined this forum for some advice on some stuff im building. i mostly just do budget builds so this is the first one im kind of willing to spend some money on