JJ 12ax7's whats the deal?

[Andy Le Blanc]

Just a a clients rig on the bench, with jj 12ax7 that crapped the bed.
took a plate resistor with it. I'm not too surprised at the resistor.
Fender has gotten cheap enough that their vendor's are getting dubious.

I've had good luck with the jj product so far, but I keep hearing more negative
experiences and now have had one with a jj 12ax7, no way that tube in that
application should have that short a usable life span.

[mumford]

I had a hot cat that would eat JJ tubes for breakfast, so I stopped using them--that was a couple of years back. I went through a couple of sets of power tubes in a year, and maybe 3 preamp tubes.

Granted, that amp was incredibly unreliable to begin with.

[dave g]

I had a hot cat that would eat JJ tubes for breakfast, so I stopped using them--that was a couple of years back. I went through a couple of sets of power tubes in a year, and maybe 3 preamp tubes.

Granted, that amp was incredibly unreliable to begin with.

Just out of curiosity, was it V1 that usually died? Because supposedly the high gain channel's input stage is grid leak biased with a really small bias resistance (1M). That's going to be really hard on the tube.

[dynaman]

Huh. I've always found them to be reliable.

[rfgordon]

I had a new JJ 12AX7 die in a new amp in February. It was in the cathode follower. It wasn't a violent failure, but it just got very weak and quiet.

I've had others get microphonic and noisy. All in all, my experience has been better with EH peanuts.

[neon333]

sorry for asking, but cathode follower meaning the tone stack?

[M Fowler]

I've had one JJ 12AX7 out of about 40 that went out on me.

[skyboltone]

Musta been a bad run. I have not had a failure with a JJ yet. But I do stick to the EH pre tubes pretty much. I got a gob of them when they were $8 apiece at one of the online sellers. On the other hand those 7189 equivalent Roosian jobs are a 50% unusable. They just seem to have one tube hog all the current. Even when you put two current hogs in at the same time one or the other will damn near shut it's partner down. And that's with fixed bias. They might work better with cathode bias. I dunno.

In the mean time, I'm going to get pretty serious with some English and Dutch tubes for a coming build. Because it's for me. But I'll be doing the break in with EH.

I've located a horde of metal based Tung-Sol 5881s. Kinda spendy but I'm getting some.

[Andy Le Blanc]

I had a good experience with JJ too, but I keep hearing a lot of negatives.

Eh seems good too but there is always a better tone.

I found a nice old amperex today, at the bottom of the bench spares basket,
to client been boning up on tube reviews and was very happy.

only thing worse than no clue, is half a clue. The demand for nos is going to get ridiculous at some point.

[Tonegeek]

Had 3 JJ EL-34's from tubesandmore.com go bad (running @ 460 v on the plates). This was all from one order where I returned the bad one and they sent another. Since then I pay extra and order them burned in for 24hrs. Still they only last about a year @ 6-8 hours a week useage. Never had a JJ pre go out, but had one EH go but it was in a cathode follower with pretty high plate voltage on it. I think the differential from plate to cathode was 260 volts. Also had a Sovtek LPS running in the PI go after about a year.

[Firestorm]

The demand for nos is going to get ridiculous at some point.

At SOME point???

I talked to a guy at CED awhile back and he confirmed that a lot of the most popular NOS tubes are already culls. Somebody finds a case of something, keeps the good ones and flips the rest. Eventually all that's available to buy is "rejects."

Consolidation on the new manufacture side doesn't help either. Say what you will about GT; I liked 'em a lot better before Aspen cashed out to Fender.

[mumford]

Just out of curiosity, was it V1 that usually died? Because supposedly the high gain channel's input stage is grid leak biased with a really small bias resistance (1M). That's going to be really hard on the tube.

Honestly, I don't remember. I sold it a couple of years ago.

[Andy Le Blanc]

Gt were alright, Fender as a brand umbrella is getting silly.

The NOS finally vanishing is a good thing, it will create a demand.

The tube audio presents much better than SS at similar price points.
Digital audio will always suck, analog has always had the magic. even with the noise floor.