With a lot of pleasure I have been using my DIY DAC with I/V transformer and output tube section for years now, BUT I was thinking of rebuilding the DAC with an output transformer output-section in combination with tubes.
Anyone ever made a DAC with an input AND an output transformer?
Anyone ever made a DAC with an input AND an output transformer?
Yes if by 'input transformer' you mean one between the DAC and analog stage : Grossly parallel multibit DAC adventures
It doesn't have valves though.
It doesn't have valves though.
Sure it does - if you look at the picture the output transformers are top right, they're RM10 ferrite cores. They're needed not for impedance transformation (they're 1:1) rather balanced to single-ended conversion.
Don't the ferrites make the sound dry & constrain Richard ? I never have good experience even when using ferrite beats for PS.
Cheers
Cheers
Ferrite beads are a rather different application for ferrite than as a transformer core. Probably a quite different mix - optimized for high losses at HF. The sound of the transformer-based DAC is ironically completely the opposite of 'dry'.
Thanks Richard, I use transformers for my dac too but have never experimented with Ferrite types. I don't use it for I/V application anymore as they tend to sound too polite for me on the 1541 dac.
Cheers
Cheers
I use ferrite because its easily available, fairly easy to DIY and its cheap. Its far from ideal as its flux limit is very low (as core materials go) but for signal transformers that's not too much of an issue. I'm not using my trafos for I/V (still using a resistor for that) but to enable me to use a much bigger resistor (for line level output directly) but present it to the DAC as a very small one.
Sure, see:
Valve DAC from Linear Audio volume 13
Linear Audio | your tech audio resource
https://linearaudio.net/sites/linearaudio.net/files/ThevalveDAC_PCB_FPGA_files for web posting.zip
https://linearaudio.net/sites/linearaudio.net/files/additionaldatavalveDACversion2p1.zip
The article costs 2.99 euro, but the design databases can be downloaded for free. Mind you, the fact that I used an input transformer for each S/PDIF input is not documented.