[daveobuchanan]

I read in the past some threads about valve cassette decks. I have been working sporadically on a valve playback circuit. It uses a jfet input, but otherwise 3 valves for most of the gain and E.Q. I could use a step up transformer and or try lots of parallel valves for the low noise, but the jfet input buffer is very convenient, and the whole circuit is subjectively quiet. Ultimately for me this is about seeing how the tape sounds with a decent valve amp rather than all out principles.

I am feeling quite pleased with it at the moment, as my most recent round of tweaking has resulted in a very satisfying sound quality. In my investigations and researches I concluded that to get Dolby B to work properly the higher frequency performance is absolutely critical. Being in complete control of the design, which to be honest is a bit seat of the pants, has ended up with decent Dolby friendliness.

I am running it with a wireless world decoder at present. I have almost got a Dolby B decoder running, using valves for the audio path the "jfet" and transistors for the side-chain, but circumstances have halted the development of that. Now the deck is running pretty well I feel more inspired to pick it up again.