• Disclaimer: This Vendor's Forum is a paid-for commercial area. Unlike the rest of diyAudio, the Vendor has complete control of what may or may not be posted in this forum. If you wish to discuss technical matters outside the bounds of what is permitted by the Vendor, please use the non-commercial areas of diyAudio to do so.

Pushing the limits of TDA1543 NOS DAC

The transformer will also lower the impedance seen by the chips. Being Iout, they really want to see 0 ohms.

In the balanced config with transformer, the Iout of each chip will see the parallel between the resistor and 1/2 of the reflected impedance on the primary. It´s quite easy to see they will be happier that way than if they were seeing the usual 1K or more.

And then there´s the filtering effect of the transformer which comes in handy with non oversampling.

Best,
Alex
 
Last edited:
I want it to make it look a bit more fancy, so I added those LEDs; they indicate sources and phase.

Hi, so you can indicate wether you´re in- or out-of-phase ? I guess
you´re using the 74atc86 chip for that. With relay?
And what circuit do you use for changing the source? I think the impedance
of the switch is important cause it affects 75ohm imp.

Greetings Ulf
 
I use TOCO toggle switch for source selecting, didn't observe any problems.

As to polarity switch, this is how it's implemented (to match my reversed XLR output wiring, for unbalanced signal, it will be the other way)
 

Attachments

  • pol.jpg
    pol.jpg
    68 KB · Views: 4,431
Last edited:
The DAC has been voiced and finalized in my friend's reference system which is highly optimized vinyl rig with 3 way active speakers. In a recent test, the system owner had hard time distinguishing vinyl from digital; the analog front end consisted of modified Versa Dynamics with double Forsell platter, custom air compressors, ZYX Universe silver cartridge and AR PH7/AS phono stages. The digital sources were either modified TL1 and TL0, plus this NOS DAC. His previous AR CD8 was later replaced by TL1/ NOS DAC combo (there was simply no doubts what sounded better).

Quite by accident I came across pictures of this system today, while browsing local audiophile club meetings: http://stereopal.com/HomeVisit/Marlen.htm
This is the older setup, from last October. You can still see there the TVC line stage I've built for him. The most recent picture in attachment. It's sort of a spy pic, that's why the quality isn't to my usual standards ;)

This is the system when we (me, Marlen and George from Audio Oasis) do all the critical listening comparisons. While all technical aspects of the design come from me, those two other guys always contribute to the final voicing of the device.
 

Attachments

  • iphone 075.jpg
    iphone 075.jpg
    537.8 KB · Views: 3,495
Last edited:
And what do I use? My main DAC does not feature such fancy enclosure, I actually tried to avoid enclosure completely and ended up with a board mounted to a piece of spruce block with two small panels to secure connectors and another one on top, holding everything together. I quite like it this way. We compared fully enclosed DAC to this one, and didn't observe any major differences.
 

Attachments

  • D10.jpg
    D10.jpg
    165.1 KB · Views: 3,311
  • D20.jpg
    D20.jpg
    158.6 KB · Views: 3,133
  • D30.jpg
    D30.jpg
    196.4 KB · Views: 3,012
  • D50.jpg
    D50.jpg
    197.4 KB · Views: 1,381
  • D40.jpg
    D40.jpg
    183.6 KB · Views: 1,410
My main transport is still TL0. Normally Shigaclone stands right beside (to play discs TL0 can't), but recently I was also using ML31.5 (testing before upcoming sale). The line stage is S&B TX102 (fully balanced), amps are F3 (mids/highs, passive crossover) and A75 (bass, crossed actively). The speakers were built in 1996 and I still find them attractive. The DAC sits in a back. All cables come from: BLUEBERRY HILL AUDIO-Manufacturer of high-end cables
 

Attachments

  • sys.jpg
    sys.jpg
    195 KB · Views: 1,952
  • sys2.jpg
    sys2.jpg
    199.2 KB · Views: 1,688
Peter, Having listened to a recently purchased Maganvox CDB 482 CD player with TDA1541 chip, I find myself interested i what this DAC is capable of. I have CS4398 OS DAC and find that it can sound digital at times with artifacts apparent in places. While it is not optimized, this seems likes a reasonable and simple implementation of a NOS DAC that would give me a pretty good idea of what to expect from this type of setup. I have two questions for you concerning the build. How do you match the chips? Would there be any advantage to adding I/V stage like D1? My current setup is Borberly balanced line-stage and Pass AJ's. I am also in process of gathering parts for F3 and noticed you use this amp. I have chosen it because i hope it pairs well with my MA 10.2 drivers. DO yo have any comments on the F3 sound?
 
I match the chips in a circuit; just swap them in and out until I get desired offset level, usually below 10mV.

I can't imagine any advantage in adding active I/V stage, unless of course your line stage can't work with passive I/V.

I like the sound of F3 very much, however, I'm not using any coupling caps at the output, those are replace by speaker's crossover capacitors. That also means that F3 works only as mids/highs amps in a biamp system.
 
HI Peter
I am using your Nos dac about 2 years now and I am very satisfied with the excelled sound
As all I think that it will be interesting to try your mods to go to the next level...
My Dac is fed by a Optima Red Top battery 12v/50Ah.
Do you think that I will need the Psu with the transformers or only the Regulators?
Your thoughts always count a lot!;)
Thank you Emmanouil
 
Thank you Peter
I would go with the Battery and the regulators. I will need 2 or 3 of them?
(Some photos from my Nos dac and the Singaclone feeding from the Battery)
 

Attachments

  • DAC.jpg
    DAC.jpg
    27.7 KB · Views: 2,812
  • TRANSPORT.jpg
    TRANSPORT.jpg
    28.5 KB · Views: 2,777
  • OPTIMA BATTERY.jpg
    OPTIMA BATTERY.jpg
    28.4 KB · Views: 2,751