Valve / Tube DAC with transformers

Arno Pf

Member
2008-01-20 6:53 pm
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?
 
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.
 
So it does have an output transformer? If so, got a topic link of schematic?

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.