Bad experience with new tested JJ6ca7's Buyers Beware!

[harddriver]

So I finally completed my 1969 Super Bass/Lead amp. I had purchased a new quad of JJ6ca7's from Doug's tubes as well as a set of JJEL34's. He had a hell of a time getting a quad of JJ EL34's to match and or not go into runaway bias when he was attempting to match a set as a result he delayed my order for quite some time. He told me he was having a bad time with JJ's power tube especially the EL34's. I didn't think much about it so finally my EL34's and 6ca7's came but I didn't install the 6ca7 for about a year or so because I wasn't done with the amp. I don't know the fate of the JJel34's as I installed them into an amp that I sold, they were fine when it left.

When I first fired the amp up it sounded great, then after some time I started hearing a slight low frequency rumble/pop when I would take the amp off of standby that would clear up after a couple of seconds but it was always there. When you would play it for an extended period of time say 30 minutes the bass would get loose, drop out and the distortion would get very harsh. These were biased pretty cold in the 50-60% of their 25 watt dissipation range @486DCV of plate voltage. I didn't want to think they were bad since the current draw was still good but after swapping 12ax7's the problem was always there sooooo....

As a last resort I installed a quad of low hour EH6ca7's that I have had for years and bam... the rumble off of standby went away and all my tight bass came back and the distortion characteristics of what a good superlead should be came back also.

Maybe they just could take the 486 DCV plate voltage I don't know, but the tube's current draw still showed(around 25-30 ma at 480DCV) them to be good and they didn't drift much from initial start up. I do know that I will have to eat the cost of a crap quad of power tubes. I remember Dave Friedman recently saying that JJ's quality had gotten really bad, I would have to agree. I know all tubes may have issues but I think I will refrain from JJ in the future unless I hear some better reports on quality going forward. I am mostly disappointed I thought the tube seemed to be well built physically and it sounded pretty good while it lasted.

 

[lowmantotempole]

1. I agree about the JJ 6ca7 tubes. I’ve had horrible luck with them and had the same thing happen a few times. Thank god I don’t use quads only pairs.

2. F Doug’s Tubes man... Maybe some have had decent luck but I’ve had nothing but problems ordering from that guy. Long waits, bad tubes, blah blah blah.

 

[Kapo_Polenton]

I've had no problem with the JJ 6ca7's I have and are still running them after a few years. I really like the sound of these as well. Good cheap great sounding tubes.

Get mine from the tubestore here in Canada though..

 

[napalmdeath]

I've had no problems with them either, and had them in my Triple XXX and now JSX. In fact, I've yet to have a JJ power tube problem from Eurotubes in over 10 years. Just because you had shit luck with your recent experience, I don't see the need to condemn them alltogether. Shit happens with tubes, I'd have to chalk it up to the vendor, not the tubes.

And, FWIW, they sound glorious!

Buy them from Eurotubes. If they don't cut the mustard, they go in the garbage, not in the mail to a customer. Get over it.

 

[scottosan]

Ruby EL34BHT, not the regular Rubys, perhaps not the best sounding but can handle more abuse than any new prod tube. I am hitting 545v with my CCV clone and ran them exclusively in the 5 XTCs I owned all of which were over 500V plate voltage. I had so many issues with various EL34's that I'll take the reliability over a little tone.

 

[harddriver]

1. I agree about the JJ 6ca7 tubes. I’ve had horrible luck with them and had the same thing happen a few times. Thank god I don’t use quads only pairs.

2. F Doug’s Tubes man... Maybe some have had decent luck but I’ve had nothing but problems ordering from that guy. Long waits, bad tubes, blah blah blah.

It may have been a luck of the draw thing but I still think I will stay away from them for now. Doug's tubes had been good for a long time with me but I hear Valve Queen really test the tubes more rigorously, it looks like she will burn them in at 300 400 or 500 DCV whatever you need. Most are 300 - 400 DCV. I think it will be Valve Queen for future purchases I know she is keeping Metro supplied with the Mullard EL34 reissues for his amps.

I want to try the Mullard reissue 12ax7's long and short plate but for those prices I can buy NOS but I still would like to hear them and pick up a spare set of EH6ca7's from her.

The EH6ca7 sound way nicer than I remembered so far I'm really pleased with them nice and tight without being too 6l6'ish.

 

[scottosan]

1. I agree about the JJ 6ca7 tubes. I’ve had horrible luck with them and had the same thing happen a few times. Thank god I don’t use quads only pairs.

2. F Doug’s Tubes man... Maybe some have had decent luck but I’ve had nothing but problems ordering from that guy. Long waits, bad tubes, blah blah blah.

It may have been a luck of the draw thing but I still think I will stay away from them for now. Doug's tubes had been good for a long time with me but I hear Valve Queen really test the tubes more rigorously, it looks like she will burn them in at 300 400 or 500 DCV whatever you need. Most are 300 - 400 DCV. I think it will be Valve Queen for future purchases I know she is keeping Metro supplied with the Mullard EL34 reissues for his amps.

I want to try the Mullard reissue 12ax7's long and short plate but for those prices I can buy NOS but I still would like to hear them and pick up a spare set of EH6ca7's from her.

The EH6ca7 sound way nicer than I remembered so far I'm really pleased with them nice and tight without being too 6l6'ish.

Doug is a standup guy, simply most tubes are shit regardless of testing or who sells them. As for Valve Queen, I talked to here once and was turned off when she told me that there are no longer reliability issues with JJ's

 

[harddriver]

Ruby EL34BHT, not the regular Rubys, perhaps not the best sounding but can handle more abuse than any new prod tube. I am hitting 545v with my CCV clone and ran them exclusively in the 5 XTCs I owned all of which were over 500V plate voltage. I had so many issues with various EL34's that I'll take the reliability over a little tone.

That's good info to hear. I didn't think 486DCV was crazy high but I know anything above 450 pushes new production tubes kind of hard. We'll see how the EH6ca7 hold up but so far so good. I'm kind of a 6550 KT88 6ca7 guy when compared to EL34's. I had a set of real Gold Lion KT77's for my 2203 in the early 90's those tube rocked I really liked them I know I'll never find those NOS again I went back to SED 6550C's in that amp after the KT77's.

I think if I go EL34's in this amp it will be those EL34BHT or the Mullard reissue's.

 

[harddriver]

.Doug is a standup guy, simply most tubes are shit regardless of testing or who sells them. As for Valve Queen, I talked to here once and was turned off when she told me that there are no longer reliability issues with JJ's

The email I got from Doug he sounded like he wanted to drop them altogether because of reliability issues he was having that much trouble with them. Not to long ago Dave Friedman posted here and was saying they were having big time issues with them and he used them all the time and used to speak highly of them. Like I said it's too bad they failed, they looked like they were really built well, nice internals and heavy thick glass envelope. Maybe Dave can comment on what he is seeing recently since they go through alot of tubes for his amp line , he would know the current state of things amongst the new production tubes.

 

[guitarbilly74]

I stopped reading it at Doug's Tubes. Had a real bad experience with that guy once. Never again.

 

[Phil M]

Yeah, I won’t use that vendor ever again. F ‘em indeed.

 

[scottosan]

.Doug is a standup guy, simply most tubes are shit regardless of testing or who sells them. As for Valve Queen, I talked to here once and was turned off when she told me that there are no longer reliability issues with JJ's

The email I got from Doug he sounded like he wanted to drop them altogether because of reliability issues he was having that much trouble with them. Not to long ago Dave Friedman posted here and was saying they were having big time issues with them and he used them all the time and used to speak highly of them. Like I said it's too bad they failed, they looked like they were really built well, nice internals and heavy thick glass envelope. Maybe Dave can comment on what he is seeing recently since they go through alot of tubes for his amp line , he would know the current state of things amongst the new production tubes.

At one point, I bought 9 quads of JJ's from CEDIST back when I was doing repairs. Out of the 36 tubes I think 2 quads lasted 6 months, had a tube go bad almost instantly in the other 7 quads, so basically ended up with 7 duets and 2 quads for the price of 9 quads

 

[napalmdeath]

.Doug is a standup guy, simply most tubes are shit regardless of testing or who sells them. As for Valve Queen, I talked to here once and was turned off when she told me that there are no longer reliability issues with JJ's

The email I got from Doug he sounded like he wanted to drop them altogether because of reliability issues he was having that much trouble with them. Not to long ago Dave Friedman posted here and was saying they were having big time issues with them and he used them all the time and used to speak highly of them. Like I said it's too bad they failed, they looked like they were really built well, nice internals and heavy thick glass envelope. Maybe Dave can comment on what he is seeing recently since they go through alot of tubes for his amp line , he would know the current state of things amongst the new production tubes.

At one point, I bought 9 quads of JJ's from CEDIST back when I was doing repairs. Out of the 36 tubes I think 2 quads lasted 6 months, had a tube go bad almost instantly in the other 7 quads, so basically ended up with 7 duets and 2 quads for the price of 9 quads

That sucks. I've probably placed over 100 orders with Eurotubes. The only problem I had was a shipment to the wrong address. The only JJ power tube problem I had was with Tube Depot and that was a KT77.. I had more issues with SED's than I did JJ's.

 

[RACKSYSTEMS]

JJ tubes are total crap these days.. Wont even go into how many of them failed in the field.. I would say all of the recent ones.. If a amp comes in for service we just replace them no mater once because they will fail.. Old a few years ago this was not a issue.

 

[harddriver]

JJ tubes are total crap these days.. Wont even go into how many of them failed in the field.. I would say all of the recent ones.. If a amp comes in for service we just replace them no mater once because they will fail.. Old a few years ago this was not a issue.

Dave can I ask what new production tubes seem to be the most reliable these days and what you like preamp/power tube wise? Sovtek, EH, Chinese EL34B's? I know you may not want to comment but I thought I would ask.

 

[CrazyNutz]

Sucks about the curent JJ power tube problems. Luckily I have a few quads of JJ el34's and e34l's from years ago that have been rock solid.

As for the EH 6ca7's they sound great.

 

[MetalHeadMike]

Guess I've been lucky. Every amp I've owned over the last 11 years has had JJ power tubes of one flavor or another, and I've yet to have an issue. Everything from 6550, 6l6GC, EL34, KT77, and E34L and they've been fine Not loyal to them by any stretch it just so happens every amp I've acquired has had JJ in it and I've not minded the tone so I've never tried anything else.

 

[Braciola]

I stopped reading it at Doug's Tubes. Had a real bad experience with that guy once. Never again.

Amen brother.
I've had a few bad experiences with that guy.
Besides that, I can't stand JJ tubes.
I now use Laura at Valve Queen

 

[napalmdeath]

Guess I've been lucky. Every amp I've owned over the last 11 years has had JJ power tubes of one flavor or another, and I've yet to have an issue. Everything from 6550, 6l6GC, EL34, KT77, and E34L and they've been fine Not loyal to them by any stretch it just so happens every amp I've acquired has had JJ in it and I've not minded the tone so I've never tried anything else.

I've not had any issues either. E34L, KT77, 6CA7. I'd have to go back nearly 10 years when I got a bad KT77 from Tube Depot.

 

[psychodave]

I’ve had issues with JJ tubes. The pins used on the tubes are quite thin and sometimes don’t make contact. I have a brand new quad of 6CA7’s I got a few years ago that I had to add solder to each pin to make them work with ANY amp.

As for tone, they are okay. I like the 6CA7 the most, then EL34, EL34II then E34L. The E34L’s I have are like 18 years old and I mainly use them as a test quad since I know they work. They might have 3 hours of use on them. I do know they seem to be a lot better than what’s made today.