Saturday 17 July 2021

Telefunken Echomixer "Kanal A" Pre Amp

 A cool little pre amp circuit from an old german reverb unit. It is fairly clean on its own, it adds some volume, lows and sparkles to your sound. When being puched hard, it clips in a very pleasant way. It also works great for pushing a tube amp. And of course it can be used as a studio tool for drums and keys.

The stock transistors were TFK OC603s. After some experimitation I found out that low leakage transistors wih Hfe between 70 and 120 sounded best (....at least to my damaged eardrums) so transistors spec'd for Rangemasters or USSR germaniums works really good.

 

 
Layout with onboard voltage inverter. (Still unverified)