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?
ok 12ax7 tube even if you blow on it can work as a microphone.

make sure and check thoroughly components arround your preamp and try to re-arrange component placements so that transformer is not on one axle with 12ax7 tube(s).

make sure that power amplifier(s) stay away with its powerful power transformers. you can also use tube dampers that will have on 12ax7 probably the largest effect among other different tubes.

The 12AX7's are on a seperate board vertical to the plane that the transformer is mounted on. Do I need to move the transformer somewhere else ? Where do I get the 12AX7 dampers?

I don't think that you should moove built-in transformer arround in the preamp. I meant different transformers that are in your other components ESPECIALLY in power amp(s).
Tube dampers you can get here on audiogon that are very often advertised for any tube.
Also make sure that your rig is not located close to the AC socket or power line. It is very essential for 12ax7.
You can also modify your unit to use different driving tubes that many tube-files do. I too will probably rework my poweramps to get rid of driving 12ax7 tubes.
Modifying the unit ? That sounds too technical for me as I'm only a beginner in electronics. Are there any literatures that teach ume how to do that? 12AX7 is cheap, using different types of tubes may cost too much ....
All small signal tubes are relatively cheap to the power ones and UNfortunately the power tubes have less life than small signal. I bet that replacing 12ax to the different kind of tube will not strike your budget too hard as you only need to change your tube I guess in 2...3 years.

I'm 100% sure that there are plenty of great books that step you thorugh complete understanding from basics of electronics to the complete components including amps, preamps, tuners and others, but I was studying electronics on different language and cannot recommend you a specific one to look arround.

All I used to do some time ago is to open the amp or preamp and study with open box to be well oriented with PC-board or elements v.s. circuit i.e. looked in the circuit like a map and than finding a proper "directions" through the real circuit elements.

Now I hope that you don't stack this preamp on ANY component and don't stack ANY component on your preamp as well.
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.
The other alternate solution is to increase the negative feedback that will decrease the sencitivity and the noise level. You can experiment with bread-board having different values of resistor and capacitor in parallel. try from 200K/150pf to go down the values.
Also you should check your PC board on how it's mounted and damp it with EAR special glue arround the mounting screws and arround the corners to the chasis.