wideband transformers suggestion for output stage for dac or cd players?

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Hello,

Can anyone suggest some brands of transformers for the output stages of either a dac or cd player?

Wide band ones seem to be the choice but can anyone with experience with them explain why?

What's good; transformers with copper wire vs silver wire or both silver and copper wire?

What's the difference in performance between a transformer and a toroidal one?

What's the best material for the core?

Thanks
 
Hi ,

I am curious to hear your experience about those DACs ( in general)
with I/V conversion made using only a transformer.
What is in your opinion the difference in sound respect using only a little resistor followed by a triode ?
And what is the difference from both respect a active I/V conversion made with a transistor ? :angel:
I'm a newbie on those circuits and I'm searching to learn .........

thanks,
Paolo
 
Actually best audio note dacs use passive I/V conversion instead a resistor conversion, than they use tube output amplification, that tells a lot about that kind of configuration.
I didn t use any buffer, just a LL 1626, with 1:20 ratio in my Denon cd player and a pcm 1702 dac, which improved sound of cd player. After that I used it with a ad1865 nonos AN clone dac, just to try how it sounds. I used 220R AN tantalum resistor for a I/V conversion, than I put same Lundahls for passive output. In both situations I could say that passive buffering gived a very balanced sound, with no extremas in lows & highs, very neutral, but a little thin sound for my taste. Removing transformer and putting 5687 as a tube output, gived "muscles" in sound, but I think that the any active component on that place cannot make that airy, natural and neutral sound like passive output devices. Probably combination of transformer and tube could make a great sound, but I never tried it, and I m planing some day to made I/V conversion (R2R dac with current output is neccesary) with a nice transformer...
 
Other options

Good Luck on your project!

First off, you can get a quick education on transformers by reading the white paper by Whitlock on the Jensen transformer site. It is worth reading if you need a general background.

Second, you will quickly discover that transformers can vary widely in price. The Lundhals and Sowters that have been recommended are expensive. Alternatives that are easier to find in the USA are Jensen, Cinemag (less expensive) and Edcor (even less expensive).

I have personally used the Edcors for a similar project. Although they are not the ultimate in performance, they are considerably less expensive then the others that have been mentioned. It is the response in the low frequency range that will be the most impacted.

If you give us a better idea of what your price-point is, then the suggestions can be more meaningful. It is always easy to recommend the most expensive product....
 
Thanks robot and WithTarragon :)

I am studing various options and planning the future mine personal DAC.
For mine work with loudspeakers I need the better source as possible.
Some points are firm:
- find a used Denon cd with alpha processing ( now AL24) and output current
- jump all the crappy ICs after the DAC chip and restart with "........"
- I have heard opposite opinions about passive I/V conversion.
I need the more datas to make a "statistic" than I 'll take a decision.
I think a transformer has to be very good to be "trasparent".
Maybe for differential DAC output it can be very very "appropriate", like pushpull amps;
not sure if the same can be for normal SE DAC chip, as like monotriodes type.
But OTL has his reason too!!! :D
At this moment I am very confused, have to learn more on the subject:cannotbe:

Listening about one Audio Note ( big model , do not remember the number) was not of help/clarification but IMO it is related to the NOS principle that I do not like:(

Cheers,
Paolo
 
Hi guys,

Just purchased a pair of Denon DCD1450AR used.
They use one 1702 for channel.
I was looking on the Sowters page wher he has a transformer 8347
specific for 1702.

I am worried from that frequency graphs, do not seem to my inexpert eyes the best thing one can expect:rolleyes:
It is slightly rising with frequencies...:bawling: ( ok vertical division is expanded).
One more, I do not have understood if using a more little value for resistor , performances on the bass are improved ?:confused:
What is maximum value that I can use ? 100 ohm or more?

Thanks,
Paolo
 
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