JJ Tubes 12AX7/ECC83S Hum Problems Anyone?

[Rob's Radio-Active]

I have had a lot of JJ Tubes 12AX7/ECC83S preamp tubes that seem to pick up hum from the heater supply--definitely 60Hz and very non-linear on the scope.

In the amp I built, I ended up having to replace the first gain stage tube with a Russian Tung Sol after swapping in several JJs with not a lot of improvement. Changing to the Tung Sol solved the problem, but I have a lot of JJs on hand. I have read a lot about these JJs humming on a Google search. I may be done buying/using them for preamps.

One of the JJs I tried was, in fact, badly defective in this regard. Putting it on my test jig with headphones, it is very loud compared to all the others. I can't find any cold leakage from heater to cathode with 100VDC between them, but it does hum loudly enough to drown out and distort the signal when hot and in the amp. But all of the JJs in socket 1 hum much worse than the Tung Sols I tried.

Anyone had consistent problems with JJ preamp hum?

Cheers
Rob

[Leo_Gnardo]

Anyone had consistent problems with JJ preamp hum?

Nope, only inconsistent. Occasionally I run across one that's too hummy for preamp use, the next one OK.

Early 2000's I tried their 12AX7 - every one in the batch ticked like a Geiger counter. By 2008 or so that became a rarer problem and now nearly nonexistent. I like 'em because they don't have the annoying "jingle" common in Shuguangs; when the note ends, audio fades to black. And I've found too many problems of allsorts in the tubes from Russia sold by New Sensor, no matter what paint design is on the glass.

Where do you source your JJ 12AX7's? If they're consistently hummy, maybe they separate the prime tubes & sell the culls as the "regular run".

[Jazz P Bass]

email: info@jj-electronic.com

Contact Jan Jorgo (JJ) & bitch.

[Jammin'John]

JJ's

No issues with them. I think that they are dark sounding though and I don't use them in MY amps.

JJ

[Rob's Radio-Active]

Thanks guys.
Leo, I buy them wholesale. Parts retail and a little restoration work for locals is my business.

Cheers,
Rob

[TimmyP1955]

So far, I've had this problem with JJ 12AX7s only in JCM900s, which seem to be very picky about this.

[tedmich]

5 X JJ ECC83S (plus one Sovtek 12AX7LPS in the PI) and my 6505+ has no appreciable hum

[Chuck H]

Thanks guys.
Leo, I buy them wholesale. Parts retail and a little restoration work for locals is my business.

Cheers,
Rob

Well there's your problem. Tube vendors are supposed to cull the grossly hummy and microphonic tubes as a service for the premium they charge. Lately I've been thinking that this isn't the case anymore. But maybe they actually still do, but what they have to pull from is just awful. So that's what you're getting when you buy wholesale. The tubes that vendors do sell, plus the ones they don't.

The way I hear it the big MFG's like Fender, Berringer, Crate (loud?), Peavey, etc. command a certain performance level and don't get questioned. These are where most of the tubes used in guitar amps go after all. You take care of your best clients, right? So let's say Fender (now Groove Tubes?) gets a select crate of 12ax7 tubes. They reject half of them. Because they need to sell amps that actually work. Those were already selected tubes and half get returned (this is all speculation based on hearsay). What happens to those tubes, and all the other lesser tubes that weren't in the "selected" tube lots? Do you suppose the Rusky tube manufacturers just melt 'em down and call it quality control? Nope! Those get boxed up and sent to vendors that now must choose the best of the worst. And when you buy wholesale that is what you can expect. Not one tube in a batch that you buy will be as good as what Crate, Berringer or Fender is putting in their amps. Which is a real problem for we little folk that build custom amps because we can't even get tubes for them that are as good as what the run of the mill amps have in them from the factory! And that's if you buy from a vendor, at a premium, who is culling everything that isn't technically "useful" at least. IMHO buying tubes wholesale is so much more trouble than savings. But you're learning that first hand. So I'm just preaching at the choir now.

[The Dude]

FWIW/take it or leave it. I was buying wholesale until a couple years ago. It got so bad that I told them to shove it after the vendor would no longer accept returns. I now have a dealer account with Mojotone. I haven't had a single bad tube in 2+ years. I pay more, but it's worth it. I used to have to run every tube on the tester (with the wholesale vendor) when I got them because they only had a 30 day return policy. If I didn't, I'd be stuck with a boatload of useless glass. Now, I don't bother. It's worth the extra $ to have tubes that work. If one considers testing time, time wasted shipping tubes back + cost of shipping, time wasted putting defective tubes into a repair, torqued off customers because the amp you just fixed is back already, etc., etc., it actually cheaper paying the higher cost.

[Rob's Radio-Active]

Thanks for the insight, guys. Most of the tubes I get wholesale work well, and I am trying different brands that are supposedly better screened, although still wholesale.
The problem is if I can't sell just the tubes--not a repair job--for what anyone can buy them for, I have to offer something extra like my own screening process.
It's a work in progress, I guess.

Cheers,
Rob

[Chuck H]

To speak directly to your question then, I recently bought some JJ 12ax7's just to try them. Half are too noisy to use as anything but function tubes (tremolo oscillator, reverb driver, etc.). And these were purchased from a vendor. A bad one which shall remain nameless (but rhymes with The Stube Tore)

And I've been buying unacceptably hummy Russian tubes from Sovtek for many years

[Leo_Gnardo]

Thanks for the insight, guys. Most of the tubes I get wholesale work well, and I am trying different brands that are supposedly better screened, although still wholesale.
The problem is if I can't sell just the tubes--not a repair job--for what anyone can buy them for, I have to offer something extra like my own screening process.
It's a work in progress, I guess.

Cheers,
Rob

What Chuck H & The Dude had to say ^^^. (And tedmich, if I'm not mistook, pre tubes in those big Peaveys are run on DC filaments, so hummy tubes go silent. A good place to install pre tubes with troublesome hums.)

Robs, this is the reason I avoid selling "just tubes." Heck I just tested a set for Vibrolux Reverb, ran 'em in an amp for a day as a final check, then get an email from the orderer: "My better half is giving me hell, can't spend money now, please cancel order." Things like that.... I got things that can make me money, I should spend my time on them.

We had a big go-round about JJ's a couple years ago, went beyond a hundred posts. Some people were getting failing output tubes, hummy pre tubes, all the regular stuff. If there were any conclusions to make, Mojo came out as a good seller that apparently culled out noisy pre tubes & dodgy outputs (YAY!) but by far not the cheapest source. Similar for the first outfit that brought JJ to North America, Eurotube in Portland OR.

The wholesale situation makes it difficult for a small outfit - that's doing other things - to compete. OTOH there are some good 1-person shops that specialize in only tubes and do an excellent job. I point people who want to buy just tubes to a good local place so shipping won't take long, Doug's Tubes on Long Island. Haven't seen any baddies come outta Doug's. Another place with a good rep so far Valve Queen near Columbus Ohio. Out Chicago way Jim McShane has an excellent rep, deals mostly with hi fi stuff, but don't ask him for any JJ tubes, he hates 'em, had a bad run-in earlier in the millennium. I'm sure there's more scattered around the USA. What I'd like to avoid is having some weenie customer take up my time & postage over some tube they consider bad, where it may well be a problem with their amp instead, as it often is. Or some limitation of the amp, like cascaded gain stages (what's in your JCM 900's & similar) that re-amplify any small noises a tube might make, which become bothersome at volume. For those you have to make a special test jig, cascade stages, listen, time consuming, and by the time you add your time & technology in, you have to charge as much or more than the customer will pay other outfits. I say "Let it be THEIR problem not mine."

I'll sell tubes I stock, as part of a repair, because then I can de-select any problems before the customer picks up the amp. And if a customer brings me tubes they acquire somewhere else, any problems THEY have to sort out with their vendor. I can tell you about an enthusiastic young guitarist who picked up one quad after another of EL34 from the local store, where one tube out of 4 was clearly bad from the get-go, bad pre tubes too. I hope he learned where NOT to shop for tubes.

[Rob's Radio-Active]

Well I don't just sell tubes, but as a part of my business, I want to build a rep for good customer service and the best stuff I can find, even if I charge a buck or three more. I haven't had issues with JJ power tubes or rectifiers so far. I'm going to keep trying different brands and suppliers and do a second check out on my test jig.

I don't use "The Stube Tore" since they unexpectedy back ordered a few tubes in 2013. I never got my tubes or my money back. They could not be reached and never responded to my emails. By the time I figured out the back order was never going to be filled, it was too late to file a complaint with PayPal. The only response I ever got was when I told them I was going to make sure everyone on the various forums would know how they screwed up. I guess some outfits don't get that a good reputation is earned.

Cheers,
Rob

[Leo_Gnardo]

I don't use "The Stube Tore" since they unexpectedy back ordered a few tubes in 2013. I never got my tubes or my money back. They could not be reached and never responded to my emails. By the time I figured out the back order was never going to be filled, it was too late to file a complaint with PayPal. The only response I ever got was when I told them I was going to make sure everyone on the various forums would know how they screwed up. I guess some outfits don't get that a good reputation is earned.

Cheers,
Rob

Yes it's a shame they got shoddy, they put up enough ads everywhere. Long time ago it was a decent outfit, last couple years been hearing complaints. Caveat emptor, too bad people have to find out the hard way.

FWIW I source tubes mostly thru Ruby & CE, typically $500+ orders. They don't cater to individuals just businesses. Still no guarantee of hubert hum free preamp tubes. For hi gain circuits where low hum/buzz is critical, I gotta roll one after the other in the amp or preamp to find ones quiet enough for the gig. Whatta PIA.

[ThermionicScott]

email: info@jj-electronic.com

Contact Jan Jorgo (JJ) & bitch.

I've got some bad news for you about Mr JJ...