I used to own a Lazarus preamp.I bought it in 95. It had 12AU7 tubes in it then. I still had bad noise problems, from hissing to a ringing, that I could never fix. I even sent it back to the factory twice, they would retube it and send it back saying that it speced just fine. I finally sold it off.I have had two preamps that use 12AX7 tubes and haven't had any noise issues. One was a Conrad Johnson PV4 and the other is my current preamp an Audio Expressions Symphonies. This preamp is totally quiet with the 12AX7 tubes. It has Ei tubes in it.
Lazarus tube preamp noise ....
Hi all,
After listening for a while on my new tube system I decided to complete the whole tube line by using the Lazarus pre-amp's phono as input to my aux of the Legend preamp. Knowing in advance from the seller that this preamp had some sort of "hiss" I still bought it to experiment. Whoa ... the hiss is higher than I expected kind of ... you know ... like the hiss from a cassette tape but even higher . Here are what I've tried:
1) Leave the preamp on for 3 days in a row . The hiss noise is less dominant but is still there.
2) Change the 12AX7 tubes from Tesla to military 5751 ... Still noisy .. even more .
The next thing I plan to do is to replace the 12AU7's pair but doubt if this' gonna work. My friend recommends to replace all the caps but doing this is a major thing and the last resort if I have to. Any ideas to do next?
After listening for a while on my new tube system I decided to complete the whole tube line by using the Lazarus pre-amp's phono as input to my aux of the Legend preamp. Knowing in advance from the seller that this preamp had some sort of "hiss" I still bought it to experiment. Whoa ... the hiss is higher than I expected kind of ... you know ... like the hiss from a cassette tape but even higher . Here are what I've tried:
1) Leave the preamp on for 3 days in a row . The hiss noise is less dominant but is still there.
2) Change the 12AX7 tubes from Tesla to military 5751 ... Still noisy .. even more .
The next thing I plan to do is to replace the 12AU7's pair but doubt if this' gonna work. My friend recommends to replace all the caps but doing this is a major thing and the last resort if I have to. Any ideas to do next?