Any luck with JJ 6CA7's?

[steve_k]

Anybody having good luck with JJ 6CA7's here as far as reliability? I was rolling some tubes yesterday in my Cameron Jose and thought I would give the quad a go. They do sound good, a little smoother and less sterile than the SED's. At 450PV, I had them biased up around 32mA and let them settle in for an hour or so. With the chassis out, and the amp at an "oh shit" volume, I could see the tubes pulsating light with every deep note and palm mute. They handle the gain well and have decent head room, but I have never really thought of tubes as "throbbing members" and prefer not to see them reacting to every stroke on the strings. Makes me think they are near to shitting themselves and just won't last. I haven't seen tubes respond this dramatically and will probably go back to the trusty SED's today and button it back up. I just don't trust JJ's in some amps, no matter how hard I try to like them tonally. I would hate for one of them to let go and get tube jizz all over my Cameron....

Steve

 

[Loudness250]

Yeah, I don't think you should be able to see the tubes react, that does not seem right.

 

[gtr31]

My Baron had them in it
And they blew after 4weeks

No other tube has gone on me
JJ do consistently

 

[rokket2005]

I have a quad in my rivera, have been in there for maybe a month and a half. I had regular maintenance and biasing done right after I put them in though, so.... No problems so far.

 

[Erock]

I've had mixed results with them. I really like their sound in the right amp. I've had them in my Uber TJ for almost a year with no issues, which is surprising considering the plate voltage. They sound the best to me out of the tubes I've tried in that particular amp for my tastes. I had a set in a Wizard that would crackle a bit when they were first turned on, but then they would sound fine after they warmed up. They stopped doing it after a while, but I never felt quite safe with them. They didn't really do much for me sound-wise in the Wizard anyway though, so they got yanked. JJ in general kind of piss me off, the slightly smaller pins have already caused me issues where I needed the sockets re-tensioned to fit them properly.

 

[steve_k]

I've had mixed results with them. I really like their sound in the right amp. I've had them in my Uber TJ for almost a year with no issues, which is surprising considering the plate voltage. They sound the best to me out of the tubes I've tried in that particular amp for my tastes. I had a set in a Wizard that would crackle a bit when they were first turned on, but then they would sound fine after they warmed up. They stopped doing it after a while, but I never felt quite safe with them. They didn't really do much for me sound-wise in the Wizard anyway though, so they got yanked. JJ in general kind of piss me off, the slightly smaller pins have already caused me issues where I needed the sockets re-tensioned to fit them properly.

I am with you there Eric. They sound good, but I just don't feel safe with them. They are coming out soon as I get another cup of coffee in me...

It's weird with the high PV's and JJ's. A JJ will run forever in a Bogner. I use them in Ubers and 101B's with 500+ PV without problem and they keep on churning. Put them in something else with PV's in the 450-500 range and the snap, crackle and pop starts.

I've just never really noticed the elements pulsating that significantly in a tube. Biased any cooler, I think the headroom will disappear. Never thought about the small pins though. On the opposite end of the spectrum are Ruby's. You have to ram and cram them in sometime.

Steve

 

[Erock]

I've had mixed results with them. I really like their sound in the right amp. I've had them in my Uber TJ for almost a year with no issues, which is surprising considering the plate voltage. They sound the best to me out of the tubes I've tried in that particular amp for my tastes. I had a set in a Wizard that would crackle a bit when they were first turned on, but then they would sound fine after they warmed up. They stopped doing it after a while, but I never felt quite safe with them. They didn't really do much for me sound-wise in the Wizard anyway though, so they got yanked. JJ in general kind of piss me off, the slightly smaller pins have already caused me issues where I needed the sockets re-tensioned to fit them properly.

I am with you there Eric. They sound good, but I just don't feel safe with them. They are coming out soon as I get another cup of coffee in me...

It's weird with the high PV's and JJ's. A JJ will run forever in a Bogner. I use them in Ubers and 101B's with 500+ PV without problem and they keep on churning. Put them in something else with PV's in the 450-500 range and the snap, crackle and pop starts.

I've just never really noticed the elements pulsating that significantly in a tube. Biased any cooler, I think the headroom will disappear. Never thought about the small pins though. On the opposite end of the spectrum are Ruby's. You have to ram and cram them in sometime.

Steve

yeah, it is weird how they work so well with Bogner, I've had no issues with any of the JJ's I've tried in those amps. I never had them pulsating though, that would concern me too. The pins can definitely be an issue, especially if you've had something like Ruby in there for a long time that's stretched the pin sockets over time. When you put the smaller JJ's in, the intermittent contact can cause the snap crackle pop noises, intermittent volume drops, odd noises, etc...

 

[steve_k]

I've had mixed results with them. I really like their sound in the right amp. I've had them in my Uber TJ for almost a year with no issues, which is surprising considering the plate voltage. They sound the best to me out of the tubes I've tried in that particular amp for my tastes. I had a set in a Wizard that would crackle a bit when they were first turned on, but then they would sound fine after they warmed up. They stopped doing it after a while, but I never felt quite safe with them. They didn't really do much for me sound-wise in the Wizard anyway though, so they got yanked. JJ in general kind of piss me off, the slightly smaller pins have already caused me issues where I needed the sockets re-tensioned to fit them properly.

I am with you there Eric. They sound good, but I just don't feel safe with them. They are coming out soon as I get another cup of coffee in me...

It's weird with the high PV's and JJ's. A JJ will run forever in a Bogner. I use them in Ubers and 101B's with 500+ PV without problem and they keep on churning. Put them in something else with PV's in the 450-500 range and the snap, crackle and pop starts.

I've just never really noticed the elements pulsating that significantly in a tube. Biased any cooler, I think the headroom will disappear. Never thought about the small pins though. On the opposite end of the spectrum are Ruby's. You have to ram and cram them in sometime.

Steve

yeah, it is weird how they work so well with Bogner, I've had no issues with any of the JJ's I've tried in those amps. I never had them pulsating though, that would concern me too. The pins can definitely be an issue, especially if you've had something like Ruby in there for a long time that's stretched the pin sockets over time. When you put the smaller JJ's in, the intermittent contact can cause the snap crackle pop noises, intermittent volume drops, odd noises, etc...

Now that you mention that, this could be some of the trouble people are having with JJ's. Maybe the ground making intermittent contact and blowing. Good point

I am still tossing the fuckers though

 

[Erock]

I've had mixed results with them. I really like their sound in the right amp. I've had them in my Uber TJ for almost a year with no issues, which is surprising considering the plate voltage. They sound the best to me out of the tubes I've tried in that particular amp for my tastes. I had a set in a Wizard that would crackle a bit when they were first turned on, but then they would sound fine after they warmed up. They stopped doing it after a while, but I never felt quite safe with them. They didn't really do much for me sound-wise in the Wizard anyway though, so they got yanked. JJ in general kind of piss me off, the slightly smaller pins have already caused me issues where I needed the sockets re-tensioned to fit them properly.

I am with you there Eric. They sound good, but I just don't feel safe with them. They are coming out soon as I get another cup of coffee in me...

It's weird with the high PV's and JJ's. A JJ will run forever in a Bogner. I use them in Ubers and 101B's with 500+ PV without problem and they keep on churning. Put them in something else with PV's in the 450-500 range and the snap, crackle and pop starts.

I've just never really noticed the elements pulsating that significantly in a tube. Biased any cooler, I think the headroom will disappear. Never thought about the small pins though. On the opposite end of the spectrum are Ruby's. You have to ram and cram them in sometime.

Steve

yeah, it is weird how they work so well with Bogner, I've had no issues with any of the JJ's I've tried in those amps. I never had them pulsating though, that would concern me too. The pins can definitely be an issue, especially if you've had something like Ruby in there for a long time that's stretched the pin sockets over time. When you put the smaller JJ's in, the intermittent contact can cause the snap crackle pop noises, intermittent volume drops, odd noises, etc...

Now that you mention that, this could be some of the trouble people are having with JJ's. Maybe the ground making intermittent contact and blowing. Good point

I am still tossing the fuckers though

haha, can't say I blame you, I'd toss em too if I saw pulsating. Almost forgot, I had them in the Cam Atomica, and they sounded good in that too. No issues, but it also was new, so they fit nice and tight. I'm going to have to keep a close eye on them now that you mentioned this, I don't normally have the heads out of the headshells when I'm cranking them, and all my amps have solid grills.

 

[steve_k]

I've had mixed results with them. I really like their sound in the right amp. I've had them in my Uber TJ for almost a year with no issues, which is surprising considering the plate voltage. They sound the best to me out of the tubes I've tried in that particular amp for my tastes. I had a set in a Wizard that would crackle a bit when they were first turned on, but then they would sound fine after they warmed up. They stopped doing it after a while, but I never felt quite safe with them. They didn't really do much for me sound-wise in the Wizard anyway though, so they got yanked. JJ in general kind of piss me off, the slightly smaller pins have already caused me issues where I needed the sockets re-tensioned to fit them properly.

I am with you there Eric. They sound good, but I just don't feel safe with them. They are coming out soon as I get another cup of coffee in me...

It's weird with the high PV's and JJ's. A JJ will run forever in a Bogner. I use them in Ubers and 101B's with 500+ PV without problem and they keep on churning. Put them in something else with PV's in the 450-500 range and the snap, crackle and pop starts.

I've just never really noticed the elements pulsating that significantly in a tube. Biased any cooler, I think the headroom will disappear. Never thought about the small pins though. On the opposite end of the spectrum are Ruby's. You have to ram and cram them in sometime.

Steve

yeah, it is weird how they work so well with Bogner, I've had no issues with any of the JJ's I've tried in those amps. I never had them pulsating though, that would concern me too. The pins can definitely be an issue, especially if you've had something like Ruby in there for a long time that's stretched the pin sockets over time. When you put the smaller JJ's in, the intermittent contact can cause the snap crackle pop noises, intermittent volume drops, odd noises, etc...

Now that you mention that, this could be some of the trouble people are having with JJ's. Maybe the ground making intermittent contact and blowing. Good point

I am still tossing the fuckers though

haha, can't say I blame you, I'd toss em too if I saw pulsating. Almost forgot, I had them in the Cam Atomica, and they sounded good in that too. No issues, but it also was new, so they fit nice and tight. I'm going to have to keep a close eye on them now that you mentioned this, I don't normally have the heads out of the headshells when I'm cranking them, and all my amps have solid grills.

Just something else to worry about......

Sorry!

 

[steve_k]

Brand new 6CA7's have been sent to the circular file.

Found a new home for Gold Lion KT77's. Great for a Jose style amp with the added headroom. Hint....hint. Also, rolled some preamp tubes. Those JAN-Phillips 5751's are great for V1. Allows you to run the gain at volume to get the grunt with clarity and without the excess feedback with the Jose master engaged. V2 is a GT 8th Gen Chinese and an NOS EI Yugi in V3. The Yugi's in the PI really let these particular style amps breathe.

 

[Heritage Softail]

Brand new 6CA7's have been sent to the circular file.

Found a new home for Gold Lion KT77's. Great for a Jose style amp with the added headroom. Hint....hint. Also, rolled some preamp tubes. Those JAN-Phillips 5751's are great for V1. Allows you to run the gain at volume to get the grunt with clarity and without the excess feedback with the Jose master engaged. V2 is a GT 8th Gen Chinese and an NOS EI Yugi in V3. The Yugi's in the PI really let these particular style amps breathe.

I have a handful of Yugi Ei. The PI is the best place? I tried it in a few amps in V1 and it was gritty. Right now the IIC is sitting out ona table rolling tubes. I have blasted it last night and no pulsating tubes Sovteks and Mesa tubes in the power section. I need to learn how to bias tubes.

As a IIC guy, what worked good in them for you? I bought a coffee can full of tubes from Dave on his NOS tube sale so I finally have a few options

 

[fek]

I have had JJ 6CA7's mixed with =C= 34's in a RM100 for a few months now and have not had any issues. I haven't watched them when playing to see if they are reacting in any way though. Will try that tonight.

I do have a set of EH 6CA7's as also but have not popped them in yet.

 

[steve_k]

I have had JJ 6CA7's mixed with =C= 34's in a RM100 for a few months now and have not had any issues. I haven't watched them when playing to see if they are reacting in any way though. Will try that tonight.

I do have a set of EH 6CA7's as also but have not popped them in yet.

I am sure it was just a shit quad. Had them about a year but haven't used them in an amp yet. Nothing to do with them being JJ's or the 6CA7. I just have really bad luck with JJ's for some reason. I like the tone of the tubes though. May give the EH's a shot when I order next time.

Steve

 

[hthomas]

Hey Steve, see if you can get your hands on a EH 6CA7 quad. They are reliable. At Port City we tried out the JJ's vs EH in our a new amp and we preferred the EHs. Just my .02

 

[rupe]

I've never found an amp that's harder on power tubes than my Matchless Chieftain. The only tube that seems to last more than a few months is the JJ E34L...SEDs sound like garbage after about 10 gigs (sound great before that though). I never tried the JJ 6CA7s but the EH ones seem pretty rugged in that amp as well (although they have too much low end for the Chieftain).

 

[steve_k]

I've never found an amp that's harder on power tubes than my Matchless Chieftain. The only tube that seems to last more than a few months is the JJ E34L...SEDs sound like garbage after about 10 gigs (sound great before that though). I never tried the JJ 6CA7s but the EH ones seem pretty rugged in that amp as well (although they have too much low end for the Chieftain).

True.....and that's the strange thing about JJ's of any tube family. Those Matchless amps are Class A and they can be brutal. SED's aren't the optimal for every amp for sure. Of course, one's a triode and the other a pentode. I guess it is all in the QA/QC from cradle to grave. I just don't trust the fuckers.

 

[50MkII]

I was talking with a friend who builds boutique amps recently about tubes. They really like the JJ's for power tubes, but stated they have run into a bad batch. After which he called them up and they performed maintenance on the tube making equipment (say over the weekend) whereas other companies will not due to the down time. He has found that JJ's equipment need the retooling about every 6 months or so to keep their tubes reliable. If they do that, he considers them to be very reliable. I do own a quad of the ones you mentioned from a previous but have not tried them in that type of amp. I have tried the EH 6CA7 in my '72 Marshall 1987 (non-modded) with the PV in that amp hovering in around 474-480 with bias set around 32-34. Tried too many power tubes in that amp almost to list here (including the JJ 6CA&'s), but the EH 6CA7 did make it through to the final round in that amp but I ended up with another one in that amp. Might be worth a try. Based on your musical interests, sounds like you may prefer the KT's though. Did you have to change any resistors to go with the different tubes? Have you tried the Sevtlana EL34's non-winged C's in your Cameron Jose? HTH

 

[baron55]

JJ's are all over the place as far as quality goes. Make sure that they are burned in for at least 24-48 hours from the tube vendor. Usually the ones that get through rugged testing do okay. Testing is not enough, testing plus burn in is good

Valve Queen and Doug's Tubes do burn in the tubes they sell.

As for tubes SED are the only ones I know that can handle 500 volts on the screens. The Ruby tubes say they can (Chinese Shuguang).

In most tube amps at idle, the screen voltage is pretty much the same as the plates. The idea is to have the screen resistors under load and heavy load drop the voltage and current to prevent screen meltdown.

So in some amps that have high plate voltages, usually the designers will beef up the values of the screen resistors to 1.5K to 2.0K to help with dropping the screen.
voltage under load.

In amps with lower plate voltage the screen resistor values may be less and causing the screens to pull more current causing them to glow (bad).

So that might explain why you see the tubes glow in the lower plate voltage amp.