My first attempt for a serious preamplifier, yikes! I promised some people I would put this info up so you can all see where I started.
I found the schematic in some magazine (Klang & Ton??), around 1992 I think; Nothing original. It was intended to be used with an ECC82 or 6SN7. I had no knowledge of tubes or where to get them. Looking around I ended up with a source for all kinds of electronics junk. The tube business was not in it's hay-day as it is right now, and internet had yet to go public (yes, I'm THAT old!).
I found some cheap ECC32's made by some weird company named Mullard, I had never heard of anything but Philips and RCA. They specced like a 6SN7 but the heater was a bit different. Heck, why not use these, they should do. I also got hold of a pair of Mullard GZ37 somewhere else. It looked like it could do more than just drive my tiny ECC32 tubes. All the parts were hidden in a 19" housing. Boy was I naive then!
A Mullard line-up; ECC32 and GZ37.
Compared to the other preamps I have built in the meantime, the ECC32 amp does not rate among the top. I've found that the SRPP topology destroys the sound too much and that directly heated triodes give a much more open and musical sound. Come to think of it, the ECC32 is just an indirectly heated 26 :)))
I still have a pair of Mullard ECC32 (brown base, original box, wow!), just for nostalgia sake :)