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bisesik 26th September 2020 08:30 AM

Quote:

Originally Posted by Flikoman (https://www.diyaudio.com/forums/vendor-s-bazaar/327794-output-transformers-dacs-post6353083.html#post6353083)
0.3Vrms? That is pretty low. ...

I would like to point one conceptual addition. I have addressed it a few times earlier. Again. The lower will be the i/v resistor seen by any (pure) current-type DAC, like AD1862/65, PCM63/1702/04 the better sound you will get as their output switches works worse when the voltage, converted from output current on the i/v resistor (impedance) is applied to them. Thus anybody should decide what is the sensetivity threshold in his own audiosystem is after DAC?.. I hear that in my system, the values upper than 20 Ohm of the seen impedance become affects on SQ much. It doesn't mean that this value is suitable for any other system (even <10 Ohm are known), but 20 Ohm is a quite common point of practice. Further, 1 mA*20 Ohm= 0.02V. To get 2V it is needed to use turns ratio of 1000! Just unreal to do within the needed FR. Moreover the input impedance of the next stage should be 2MOhms BTW for that. Going down to earth for trying with the widely existing practice of 47kOhm input impedance. The turns ratio for the targeted 20 Ohm impedance seen by DAC, should be ~1:50. The voltage (without internal losses) should be 1 V in this case. I am still trying to make such a ratio, but 22 is achieved for now.

The OpAmp approach is another story, DAC see around zero voltage across its output, but the targeted signal through its feedbacks... Meat grinder...

potstip 27th September 2020 11:33 PM

1 Attachment(s)
Hello Ivan;

In 4493 there are couple of output voltage/gain options. Is it matters?

Note 14. The analog output voltage with 0dBFS input signal when GC[2:0] bits = “000” is calculated by the following formula:
AOUTL/R (typ. @0dB) = (AOUT+) - (AOUT-) = 2.8Vpp * (VREFHL/R - VREFLL/R)/5.
This expression is equivalent to 5.6Vpp and is differential and irrespective of ground reference or the Vcom bias voltage.
Note 15. The analog output voltage with 0dBFS input signal when GC[2:0] bits = “100” is calculated by the following formula:
AOUTL/R (typ. @0dB) = (AOUT+) - (AOUT-) = 3.75Vpp * (VREFHL/R - VREFLL/R)/5.
This expression is equivalent to 7.5Vpp and is differential and irrespective of ground reference or the Vcom bias voltage.

bisesik 28th September 2020 08:26 AM

Hello Erkan. In terms of 4493 SQ itself I don't know, I am not use AK4493 and can not comment. In terms of transformer parameters - it doesn't matter, you will get the same signal level after transformer as before it.

clay-speakers 28th September 2020 09:46 PM

I use the AK4493 in a few different DAC's I manufacture & it works very well with a 1:1 transformer which Ivan can supply. For the record his transformers sound excellent.
Using the AK4493 in hardware mode a 0dB signal will give you 2v rms out - perfect!
With the chip in software mode you also have higher output level option which gives 2.65v rms out.

tubo 4th October 2020 08:14 AM

Hi Ivan,

I would like to order a pair for my D3 tda1541 dac.. pm sent

Thanks

bisesik 4th October 2020 01:47 PM

Hi tubo,
The most funny (on the edge of hysteria) is that Ryan still waiting when his pair of transformers will come to him. Unexpectedly huge delays with Australia airmail/customs/politic rules/etc. More than 2 months on the way :clock: :confused:

tubo 4th October 2020 02:11 PM

Hi Ivan,

Thst is very unfortunate. Will it be possible to ship to great britain? Or fedex to usa if thats an option?

Thanks

Patjr 17th October 2020 07:59 AM

Hi Ivan,
FedEx package arrived yesterday.

So it left you on the 9th and was delivered here in South Australia on the 16th.
Expensive but quick.
Haven't had time for a good sit down listen with a glass of wine yet, but first impressions have put a smile on my face. Thank you for your efforts.

tubo 21st October 2020 06:21 PM

Hi Ivan,

I received my package today.. thank you very much

chromenuts 12th December 2020 05:52 PM

3 Attachment(s)
Hi Ivan

I finally have my D3 TDA1541A DAC up and running in my system.

I have two D3 boards with TDA1541A running in dual/mono configuration using only some Caddock MK132 of about 110 Ohms as IV resistors.

It sounds very good, but I was wanting for the possibility of some more gain as one of my efficient horn speakers was recently knocked over and damaged. I have temporarily resorted to using a less sensitive open baffle speaker which I feel might benefit from some more gain.

As I contemplated a build of the CEN IV stage or ordering transformers I noticed Tubo had put his entire D3 project up for sale. I now own the transformers that you made for him.

I have been trying to figure out how to configure the transformers to use with my DAC.

I saw your schematic and related information in post #430.

To be honest, it is over my head. There are some electrical schematics that make sense to me, but I am not an electrical engineer and I simply donít understand how things should be oriented for my application.

You mentioned that these transformers could be wired in a single ended application like mine to take advantage of differential output without having to worry about nulling the offset from the TDA1541A?

I really need an illustration of some sort showing how the jumpers, connections and any resistors (iv or otherwise) should be installed.

I have attached a picture of the transformers and board as I received them.

Iíve also attached a picture of my DAC so you can see how I currently have the outputs wired.

I was considering wiring the inputs to the transformer board to some RCA plug pigtails so I could just plug the transformers into the RCA output sockets on the back of my DAC as a test.

My IV resistors are mounted in dip sockets which allows me to change them out or even bridge the sockets so that they could be placed before or after the transformers. I was going to experiment with making some of my own wire wound IV resistors.

I am open to your suggestions as to what would be the simplest/best way to arrange things.

Any help you could offer would be greatly appreciated.

Regards
Kevin


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