tonight I run first version of tubed dolby decoder

[intell]

Hi guys!
Last year I spend a lot of time thinking about how to built tubed dolby decoder,
and today I finish soldering, and it works!

Sound pretty good compared to IC based decoder, but I'm still not finished a calibration of this tube unit.

After calibration I can record some demo files, unfortunately I don't have a BC tapes, but I have some Mo-Fi cassette tapes.

Sorry for my poor english.

Anton.

[ironbut]

Congratulations Anton!

I'm sure that wasn't an easy project.
You should try an get a couple of the better BC's for testing and final voicing.
I'd like to suggest the Vanguard BC of Gould/Gottschalk  "Latin American Symphony" and "Night in the Tropics".

[xcortes]

Hi Anton and Congratulations!

Can you share more details with us? Did you base your project on some Dolby boards or did you start from scratch?

[intell]

Hi ironbut, thank you. I try to find these tapes.

Hi xcortes, I took first original transistor version of decoder, and replace all amplification stages in audio path with vacuum triodes, first I try it in microcap simulation, and it help me so much, to choose tubes and voltages.
But in schematic still present transistors, one FET in variable filter, diodes in limiter (indefeasible part of dolby circuit), and one bipolar in FET control signal amplifier.

Anton.