when I switched to my EMT chain I thought I was prepared reducing a little noise of the EMT 139a phono pre. You may only hear a very light breeze between the different music songs in the pause between the songs.I tried some Nos matched tubes I had bought for this improvement – but failed.
All units in this chain work pretty efficiently, the EMT R 80, Ortofon arm and A 90 cart, the Western Electric 618B, the EMT139a phono pre and at least the EMT JPA in the MM function.
So what am I doing? Believing one of my technical advisors that one should select 100 tubes using only the matched 8 ones for the two Mono EMT 139a?
I was pretty in dispair of quite a difficult way ahead of me. In the end I precisely built it back to my old matched tubes and took care that the tubes stood firm in their sockets.
When connected to the chain and the WAVAC amps I suddenly realized that the breeze was nearly gone. Wow! Maybe the two 139a units needed a special treatment or just a good stand for the tubes after having driven 20 km with the set from my technican who implemented these fabulous boxes…
AudioCirc.com 
Eckart,
So is there an advantage to using two 139a preamps for stereo? Isn’t that the same as the 139st?
Norman
LikeLike
Norman,
139a was before 139st. As it is the Mono version you need two of the units to produce a wonderful Stereo sound. In effect it is the same Stereo sound than the 139st, maybe a little more elaborated.
The units are pre 60ies but all important electronic parts are improved, you see it under vintage phono – part I, II,III.
Btw. The R 80 is still a good machine 🤣
Best
E.
LikeLike