SPDIF Transformers

Status
Not open for further replies.
Jump to Latest
#4
Transformers

No(MF) and No(H)

I looked at the specs for dozens of thse and they were really not very suitable. The best sounding commerical ones are in the Monarchy DIP. This was a few years ago and they may have changed types for all I know.

With a few mods the DIP was the best sounding device of its type and blew the DTI Pro and Ultra Jitterbug digital interface devices away. Even stock it was better than either of those two. I have not heard the new one though.


http://www.monarchyaudio.com/
 
#8
Been there, done that

" I just said it was spec'd by Cirrus as a recommended transformer"

Yes an I have talked with John Marshall at Schott who designed it. I have done enough measurements to tell you the shortcomings of these and sevral of the designs from Scientific Conversion. There are real measured and sonic differences is pulse transformers. I spent a year refining my design and have measured and listened to over a dozen other designs.
Most pulse transformers are designed for the absolute minimum capacitance between windings to the detrement of every other parameter. SPDIF transformer design is an art and one of the most difficult designs I have ever done.
 

Attachments

  • at_pic2.jpg
    at_pic2.jpg
    47.3 KB · Views: 2,265
#9
This is usually the part where I get booed off the stage, but in a digital system you need to get the bits from one end to the other without errors and with a specified average rate. If your architecture relies on decreasing the standard deviation of edge-to-edge arrival times, your architecture is broken.

The scientific conversion and schott transformers are good enough because they get the bits into the receiver without degrading the signal. Anything else is overkill. If you can get the interface up and running without any pulse transformer, that is even better.

Synchronize the clocks in the transport and the DAC, buffer the signal in the DAC to reject jitter, and make sure your word clock (bit clock for ΣΔ designs) is low-jitter. Case closed.

-jwb
 
#10
Most pulse transformers are designed for the absolute minimum capacitance between windings to the detrement of every other parameter. SPDIF transformer design is an art and one of the most difficult designs I have ever done.
Click to expand...
Fred, which are the important parameters ?.
What sort of sonic differences do you find ?.
I could not find an Audient page - have they evaporated ?.

Eric.
 
#13
Oh really?

"The scientific conversion and schott transformers are good enough because they get the bits into the receiver without degrading the signal. Anything else is overkill. If you can get the interface up and running without any pulse transformer, that is even better."

I guess things like impedance matching as a function of frequency, bandwidth, and distortion have no effect on jitter or edge rates. The isolation noise between source and receiver that transformers are used for is not important either. And the fact that they sound different is not worth worrying about either. I wish I had known all this before I spent a year designing a pulse transformer and impedance matching network and sold a few hundred of them to unwitting customer with this mistaken belief that they sound better than no transformer or any of the off the shelf units.

Disillusioned transformer designer,

Fred
 
#17
@ Eric

hi, i'm using old transformers of 10MBit cards. they work fine. But there are some differnt ones. only transformers with one primary and one secondary winding works. to receive even spdif and aes/ebu signals with the same configuration, i also use a rs485 digital receiver behind the transformer to reconstruct a propper ttl level.

achim
 
Status
Not open for further replies.
Top Bottom