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
How long have you had the NOS/NIB Siemens tubes in your CJ LP-140Ms? Did you just install them and they started going bad a few days after you installed them? Did you follow CJ's tube bias directions to make sure you installed the tubes with the right bias setting? I hope you installed them without touching the tubes with your naked hand (should always use a cloth or gloves etc) as the oil on your hands when in contact with the tube glass can make them "pop" and go bad. I would call CJ for proper tube installation and bias settings for your mono blocks. With some of your tubes going bad you may have also blown some resistors in the circuit boards, so if your dealer has a technician who is familiar with CJ gear check your amps out to make sure it is only the tubes that need replacement that would be your best path forward. Good luck.
Cmalak, I have them about 4 months in my LP-140M. and all the tubes is very very good when tested with TV7 tube tester.

CJ tech (Ed Deitemeier) told me: do NOT substitute any 6922s for the factory supplied tubes (that is Electro-Harmonix) ... it's suck since I do NOT like Electro-Harmonix at all.

They do have 4 screwdriver to adjusting 6550 output tube bias, but NOT for the input driver tube (which is 6922). Is there anyway to bias/setting these driver/input tube?

Thanks
Sorry..I misunderstood. It's the input/driver tubes that went bad not your power output tubes. So the answer is there is no bias adjustment for input/driver tubes. The bias setting is for the output tubes. Then replacing the 6922s is relatively simple and is a matter of trying out different variants to see what you like best. Good luck.
Does this happen for both monoblocks or only one?
is your tv7 a tested and verified 100% operational tester?
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.
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.
Samhar, I did but seem like C-J design their powerAmp to used with Electro Harmonix.
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.

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.

Noh, it's impossible because CJ is very conservative and my dealer told me that they will NOT going to do any modification on my amp.
Well, I'm giving up and looking for the other PowerAmp!
Vinhuse if you really like those amps I would give bob bracket of rhb designs a call to see if he can modify them to use the tube you reaaly want to roll into those amps;here is his website address,also he gets very positive customer comments on his work.

http://www.rhbsounddezign.com.
Give it a shot might work out well for you
Vinhusc...have you heard the amps with the stock CJ 6922s? If not, I would at the very least do that before deciding to switch your amps and see whether you like them or not.
I hear your frustration I also dislike the EH sound!!! I also don't care much for the 6H30 so you might be carful as you also may not like this tube!!!
Just curious what speakers are you using?
I saw someone post about the dreaded "hand oil". Sorry to say but this is a load of crapola. I have tubes ranging from WE212E that will remove you finger prints if you touch them hot to a gazillion 6550s in the CJ and jadis JA-500. In no case have I lost a tube due to touching it. Old wives tales from the audio crypt.

Peter
Sr. Writer
The Absolute Sound
http://www.avguide.com/forums/peter-breuningers-reviewer-background
If there is something sticky on the tube or I just want to clean them up I use lighter fluid it doesn't damage the lettering.
Thank you so much for all of you guy info.

Personally I do NOT like anything make in Russia or China. However, CJ designer do believed: There is NO better tubes available to improve the sonic performance for the CJ LP140M !!!????!!! I do NOT agreed with them about this and I have to switch the others gear.

My system: Sonus Faber Guarneri Memento spk with REL B2 Sub, MBL 5011 PreAmp, Weiss Medea DAC, Esoteric P-05 CD Transport.
Thank you so much for all of you guy info.

Personally I do NOT like anything make in Russia or China. However, CJ designer do believed: There is NO better tubes available to improve the sonic performance for the CJ LP140M !!!????!!! I do NOT agreed with them about this and I have to switch the others gear.

My system: Sonus Faber Guarneri Memento spk with REL B2 Sub, MBL 5011 PreAmp, Weiss Medea DAC, Esoteric P-05 CD Transport. and IsoTek Sigma GII Power Conditioner.

Believe me, I've already spend so much money on my stereo system and I can NOT let any junk stuffs degrade the system.
look up andy at vintage tube service
Good news! Conrad Johnson just call me and ask the sent my LP-140M for them to update the circuitry for the driver input... so I be able to run any kind of 6922 tubes in my PowerAmp.

They claim that their design was optimized for the used of Electro-Harmonix! ... sound silly to me.
Great news!!!!

"They claim that their design was optimized for the used of Electro-Harmonix! ... sound silly to me."

Not really!! They set the amps up to run tubes they knew would be readily available. I also dislike the lack of harmonics in the current Russian 6922's, they just don't have a good quality sound.

If you decide to try another tube give the Amperex 7308 a try, warm with detail another great tube!! Don't forget 6DJ8's can't always be substituted for 6922 because of higher heater current.

Enjoy,
Sam
Not liking Anything from Russia or China? You probably have a short term memory, these are exactely the countries that continued to develop and improve tubes when few did after the 70s. shungang is among the best current productions.