TDA1543 NOS DAC experiment

[Igla]

Here is my TDA1543 NOS DAC.It started as experiment to play with.I must say that I was impressed with the sound.TDA1543 is running from 5V (7805), another 7805 is for CS8412.I/V resistors are 2k metalfilm;reference resistor is 2k in parallel with trimpot.
With 1kHz input signal and 10kohm resistors at the output I was watching the signal on the scope turning the pot till I got no clipping (1k5 was the final value for Rref if I racall it right).The DAC gives just a little less than 2V P-P at the output on 10kohm load.
I've made some changes since this picture was taken.
Another 7805 was added for CS8412....couldn't hear some significant changes in sound.Then I removed both 47uF caps from CS8412 power pins and 100uF cap from TDA regulator output pin.This made quite a difference.The last but not the final version has no caps on CS and 100uF cap on TDA regulator output.
Power suply diods are MUR160.

[Igla]

No comment at all?
I was hoping to get some tips...perhaps about regs or something.
Would it be better to use LM317 to feed TDA1543; or maybe passive regulation with Mosfet?
Did someone experiment with caps on CS power pins and discovered something interesting?
How about input 10nF caps?Which sounds good?

I'm must say I was hoping to get some information about I/V resistors.Would be better to use lower values - like 1k ohm.
What is the difference if I/V resistors are bigger or smaller?
How this affect sound?
Regards;

[Igla]

I have just realized, that I was making terrible mistake.
When I was measuring DAC output with my CRO, I accidentaly put in player test CD with -6dB sinewaves (I made thic CD with CoolEdit).By the way...the TDA1543 is running on 5V.Everything looked allright with 2k I/V resistors and 1k5 Rref.The sound was good except a little harsh from time to time - I would suspect the sound became harsh, when music reached 0dB.

Then I realized mistake and put in the player original test CD with 0dB sinewaves.On 10kohm load the DAC was clipping badly.
I had to lower 2k resistors to 1k and trim Rref to 1k.
Now things looks good on CRO.

This sweet spot is very narrow; for Rref I have 2k resistor in paralel with 20kohm multiturn pot.If I turn the pot for less than one turn left or right from the sweet spot, the DAC starts clipping one or the other half of the wave.I guess I'm on the edge with 1k resistors for 5V supply.I suppose I could lower I/V resistors or go on 6V supply.
Any suggestions?


Regards;

[dsavitsk]

I use 8V on the TDA1543 (using an AN8008 regulator per peter daniels suggestion which is a good one) and 2K7 I/V with 1K4 Vref and it works well. Also, with 8V, 1K and 1K works well but gives a different, though not less pleasing, sound. http://www.ecp.cc/NOS-USB-DAC.html

[Igla]

Thanks for reply.
I would try AN regulator but unfortunately not one store in whole country stock them.
I guess I'm quite limited with 5V supply - 1kohm I/V resistors are apparently upper limit before clipping.
Still, at the moment i guess I'm happy with LM317.It gives smooth and less fuzzy sound compare to 78xx.
The same thing happened when I removed electrolitics from CS8412 supply pins.Sound became more smooth and liquid.
I still have to try ragulation with mosfet.I had at home my friends TDA1543 DAC with IRF520 regulation but I didn't like the sound much; could be supply or two TDA1543 in parallel.He also applied a lot of R-C filters all arround the board.

Here are my latest modifications.

Regards;

[Gasho]

Where did you get CS8412 in Slovenia?

Try LT1086 variable regulators. You can try voltages from 5-8,5V with TDA1543.

Regards

[Igla]

Hy Gasho!
Thangs for repply.
I got CS8412 from a forum member, who was kind enough to send me one CS8412 and two TDA1543 from Germany.
I started with 5V supply because I don't need a lot of gain and
the lowest supply fits in my concept of minimalistic design.
I will try higher voltages and LT1086 regulator...still waiting to see, what else do I need before I place an order.
What about CS8412 regulators?Do they affects sound?

Regards;

[Igla]

Gasho...I forgot to ask you where did you got CS8412.
Is there some store in Croatia stock them?
I would like to get another piece of CS8412; and a few pieces of TDA1543 also.

By the way; I have two pieces of TDA1543A I don't know how to use them.
Anybody wants them?

Regards;

[Zoran]

TDA1543A is for the another type of input datas
and it could not be used in Your recent dac design
with Philips I2S input data...
Also You have to do little compensation on output
because dac have lacking in highs starting from 5-6KHz -0.3db
to 20KHz -4db... Also can be a peek at around 44KHz that should be attenuated
...

[Igla]

Hi Zoran !
Yes; I know about TDA1543A.It works with Japanese input format
so it can't be used with CS8412.
I got them from my local shop listed as TDA1543.But when I got the order they were TDA1543A.
It would be blessing to see a schematic on the net using TDA1543A for NOS DAC.I would try it.It's just a matter of right receiver, I would say.

What compensation do you have in mind?
I know for a rolloff but when listening to music I never had a feeling something is missing at the top.

And offtopic...my I ask you where did you get CS8412.I assume you have DAC with this receiver.
From some local shop?

Regards