MayDus, PCM2706/CS4398 USB DAC w Transformer output.

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More or less done.
Waiting for opinions from a few people who has helped before testing it.
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An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.
 
The first thing to say about the sound is that it's honest, crap in - crap out.
A bit on the bright, somewhat sharp side yet, but then it hasn't had time to settle.
Honest, dynamik, detailed...but no mercy for bad recordings what so ever.
The LF is very tight and dynamic, so is HF, but those are the areas I believe improve the most with time as the dac settles.
 
Happy to report it got the fiances stamp of approval, she could care less about DIY or what I tinker with...but she knows good soundquality :)
I let her listen before telling her what I've done and then she gives me a more or less objective opinion. Nice way to test that what I hear isn't wishfull thinking.
 
hey Mayday - how are you liking your DAC so far? is there an advantage to using the 2.5 watt rated Edcor vs their smaller models? Would the inexpensive Jensen transformer bring audible improvement?

I bought a similar DAC with what believe are the 1/4 watt rated Edcor and its very nice in ways. With cheap headphones listening on a CMOY, the transformer DAC reminds me more of tube analog sound - lighter in bass - less glare than the opamp output on some DACs in my pile.

does Edcor graph their transformers at a certain level relative to full rating?

is there significant DC from the DAC to partially saturate the core?

Edcor's graphs for two 10K->10K matching transformers


Half-watt rated WSM10K10K 11H primary inductance
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Two and a half watt XSM10K10K 25H primary inductance
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Edcors

Hi freddi, I'm sure Mayday will get back to you soon. I can share my insight if you'd like. My Cousin rebuilt using Edcor low wattage transformers in his CS4397 dac. He used the WSM 600/2.4K. There was no bass issue on that dac. It is a very detailed sound with excellent bass punch. In fact I feel it is more detailed then my Sheldon Stokes CS4398 dac with LL1690 Lundahls. The CS4398 is really very musical my only grip is that it doesn't seem to have all the details. :confused: My own experience with the Edcors is with XSM 600/600 transformers. I have 2 Analogmetric dacs. Well they started out as Analogmetric dacs. Highly moddified now. :eek: My Edcors are used with my second version of that dac. I dumped the reclocker and installed a DIR9001 adapter to CS8412 input receiver board. The digital filter is NPC SM5814 (no SAA7220 here). I run the DIR9001 in the "Sony" mode. Dac is the TDA1541 S1 Crown purchased back in the early 1990's. Long before the Chinese relabled stuff. Output is Pedja I/V using AD844 with offset current nulling and no negative feedback. Adapted a bit for 4X OS use. The AD844's drive the 2 1/2 Watt version of the XSM 600/600. Properly nulled TDA1541's and I have less then 1 mV idle on the transformers. Sound? Shockingly good. Bass is fine no problems in that area. I am very happy with it. :D No typical TDA sound. Whatever you feel about antique R2R dacs the transformers perform just fine. I agree that they sound better then opamps. My first version of the Analogmetric dac has a 7th order GIC gyrator Bessel filter with LME49713 I/V and output is OPA627. Very 3D like sound.... Still I prefer the Edcor version..... Might convert to Pedja driving the GIC. :rolleyes: DIY is never done. :p
 
Hi Torchwood421 - a lot of that description is over my head/unfamiliar (plus a sinus infection from reflux isn't helping) - is the lack of subjective detail from the CS4398 or from using a transformer?

what happens on 4398 when 10K/10K is used vs 600/600?

what tradeoffs might there be using the 2.5 watt model?

the 4398 on my table was done by Ed Padden - what might make a better headphone amp than a Banzai CMOY?
 
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Hi freddi, Yes I understand. The CS4398 in my opinion is not as detailed as the earlier CS4397. I think it is a CS4398 issue. I have had many Bluray players with the CS4398. CS4398 dacs have that lack of detail in all versions I have heard. It's worse with opamps then transformers. In my opinion. I have a CS4397 chip in my collection waiting for my next dac build. :) Only issue with the CS4397 is the output drive is lower then a CS4398. So with that one it helps to use a 1:2 transformer ratio just like my cousin did. A 4398 with a 10K/10K will see a lighter load. There is a big thread on DIYAUDIO about using transformers and many ratios have been tried. If the 600/600 is loading the 4398 to heavily that might explain what I hear (I don't believe that is the problem). An issue to keep in mind is that a 10K/10K will not drive long interconnects. I see no tradeoffs with the 2 1/2 Watt version. I presume they are physically larger. The higher wattage transformer will not saturate with a small idle currents. That old R2R dac I mentioned had a potential to have some current so that is why I used the 2 1/2 Watt version. For a headphone amp/preamp I designed a solid state solution using the AD8065/AD8066 with a Buff03 (obsolete) output buffer. It makes a very nice preamp when not driving headphones. I used the datasheets. I should have a schematic around here in my pile of DIY papers. :) You might try a AD8065/AD8066, one is a single the other is the dual opamp with a LT1010 or similar buffer amp. If you send me a PM I'll try to find the schematic and send it to you. Sorry I am not familiar with Mr. Ed Padden. I'll have to search Banzai CMOY. The old CMOY was a basic opamp headphone amplifier. Dave Hi Jonas, Let freddi know what you think about your 4398 dac with Edcors.....
 
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