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Need help C-J monoblock LP-140M with Siemens CCa

I am new to the tubes world and this is the first time ever I have tubes power amp in my audio gear.

I have been used 3 different sets of NOS/NIB Siemens CCa tubes in my Conrad Johnson LP-140M amplifier, and all have started to fizzle, crackle and/or pop within a few days.

Just curious if others have had this problem? My dilemma is that I like the sound of these CCa tubes, and don't like any junk tubes (Electro-Harmonix was supply with the Amp from C-J factory) in this amp. I don't believed they sound nearly as good as Western European make tubes.

I have hear about Ediswan CV2492 from UpscaleAudio.com, is it really equivalent or better than (Siemens, Telefunken or Valvo) CCa?

Thank you so much for all your feedback and/or suggestions for alternative tubes.
vinhusc
vinhusc OP
11 posts
 
Rleff, both of them but after few months now only 1 side!

They not happen all the time. Sometime I power ON about 2-5 minutes you should hear big crackle/pop and after that is good!
Yes, my friend TV7 tube tester is good.
samhar
1,048 posts
 
Exchange the tubes one at a time to the other amp, this should show which tube is making noise or if the noise is something else.
vinhusc OP
11 posts
 
Samhar, I did but seem like C-J design their powerAmp to used with Electro Harmonix.
myles_b_astor's avatar
myles_b_astor
134 posts
 
Vinhusc is right. Got the same dirt straight from the top. For some reason, the 140M amplifier is more sensitive to the choice of driver/input tube than is the 275M. In fact, Lew said use of other tubes could damage the 140M. And in fact, they carefully match all three tubes and tell you to only use them in the positions indicated.

So caveat emptor.
samhar
1,048 posts
 

Ask CJ if it's possible to have a tec modify the bias in the amps to work with the Siemans. I know with my amp I have to re-bias my 6DJ8 or 6922 even when using another set of the same model tubes.

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