Dumb new tube question: do they "break in?"

[Jon Silberman]

What I mean is, do they change tone and/or volume characteristics in their initial use period due to any associated mechanical changes as does a speaker?

The reason I ask is I was at first a bit underwhelmed by the new quad of JJ 6V6s I threw in my TK Continental a few days back but I've been playing the amp heavily since then and they just seem to be blooming, for lack of a better word.

I don't know if this is due to the tubes breaking in in some way or perhaps I was just wiped by the end of the week when I first used 'em and by now, Sunday, I've completed my comeback and it's my fresh ears and rested self that's interpreting the sound as better rather than any change in the sound waves themselves.

[TheAmpNerd]

Originally posted by Jon Silberman
The reason I ask is I was at first a bit underwhelmed by the new quad of JJ 6V6s I threw in my TK Continental a few days back but I've been playing the amp heavily since then and they just seem to be blooming, for lack of a better word.


Jon,

How would you describe the tone when you first put them in new and were underwhelmed...


Versus


After they have broken in some, and bloomed, how would
you describe the tone now?

[Jon Silberman]

They seemed, at first, constricted for lack of a better word, like the highs and lows were being squashed. Now they seem fuller, not in the sense of more mids but as the opposite of what I described at first, more full-frequency. The difference is most noticeable in the bottom end. Everyone else who described the tubes called them "6L6-like" in how the bottom hung together relative to the flabbiness that is typical in a 6V6 amp when pushed. I just didn't hear that at first but I am now.

[Old Tele man]

...I don't know about "breaking in" but it MIGHT be that they're "drifting" into coincidence -- ie: their specs are converging ("drifting"?) towards being identical -- with use.

...Most people don't realize that identically "matched" tubes seldom stay that way! Their specs tend to "drift" (sometimes UP, sometimes DOWN) with usage and over time. Which means those "matched" tubes could either: (A) drift TOGETHER (get better); (B) drift SIMILARLY (stay same); (C) drift APART (get worse).

[scottl]

Maybe the wall voltage was way off on that first day. The bias of the tubes can be way out if the wall voltage is off. In my amps, I have measured from 34ma to 42ma with no other change but the wall current. Try it in the summer when the AC kicks on... The bias meter/multimeter will show it.

Scott

[Taller]

I first installed JJs in my PV Delta Blues. I expected some miraculous tonal difference based on hype that I"d read.

When I fired up my amp, I was underwhelmed...for the first 10 minutes or so.
I think when they came up to temperature and started 'cooking', that's when I heard them 'bloom' as you say.

Still happens to this day - I turn on the amp, play for a little while, and then they bloom! They sound more full once they warm up.
I'm talking EL84s BTW.

If you still have doubts Jon, maybe you could talk to Bob Pletka at Eurotubes - he sells JJ/Tesla tubes exclusively and loves to talk tubes, amps, and tone.

I've also had luck asking Myles [last name escapes me for the moment] of the Amplifier Blueprinting website.

[drbob1]

OTM, mismatched tubes are not necessarily "worse", in fact Kevin O'Connor (London Power) argues that you get more second order harmonics (sweetness) to notes with some mismatch. Anyway, as tubes drift it's possible that a quad may sound better or worse.

I think there's some evidence that all EL84s sound better when they get hot. I heard of a test using AC30s and installing fans (temperature is a problem with the vintage ones) where they felt the amps sounded better with the tubes hot. It takes about 30 min for tubes to temperature stabilize, so they ought to continue improving for that long...

[Old Tele man]

drbob1--I fully agree with you, matched-tubes are NOT an absolute necessity! In fact, I also believe that part of the "original" Leo Fender-era "sound" was due to the fact that the output tubes were NOT matched. In my opinion, "matching" in today's market has merely replaced the "quality control" of yesterday.

...and, I just stated the possible directions the tubes could drift..didn't say anything about how that drift might / might not affect sound.

[Lucidology]

Maybe the wall voltage was way off on that first day. The bias of the tubes can be way out if the wall voltage is off. In my amps, I have measured from 34ma to 42ma with no other change but the wall current. Try it in the summer when the AC kicks on... The bias meter/multimeter will show it.

Scott

Wow .. these kind of facts blow my mind ...
The tubes Bias can actually be off depending upon the wall voltage on a particular day ...

[scottl]

Yep...

Joe, the plates of the output tubes see a a voltage that is stepped up by the power tranny. Your wall AC is "multiplied" by the tranny. If the wall is higher or lower the plates see a change that can be about 4 times what the actaul wall chnage is. The bias voltage comes off of a seperate tranny tap. Because of the amount of windings, this voltage doesn't change to the same degree that the plates change. If the wall goes up, the following can occur. The output tubes run more voltage, ie hotter, and the bias doesn't change to accomodate the suddenly higher plates. Normally, you'd set a lower bias point if you have higher voltage plates, but the opposite happens. Like my other post, at 122V I get 500V plates and my bias is over 40ma. If I lower it to 35ma then it is too cool when the wall is 116V.

THis is why I gig with a voltage regulator! Fwiw, Robben Ford gigs his DUmble with a Variac to keep things constant. I hear a big improvement when I am in a 117V-120V window. THis is where I have the amp adjusted to sound its best.

Wow .. these kind of facts blow my mind ...
The tubes Bias can actually be off depending upon the wall voltage on a particular day ...

[bob-i]

Yep...
THis is why I gig with a voltage regulator! Fwiw, Robben Ford gigs his DUmble with a Variac to keep things constant.

Why did I not know this? Makes since.

Voltage regulation affects SS and tube equipment as well. I've had SS power amps on a PA sound like garbage when the voltage goes low.

[Blue Strat]

...I don't know about "breaking in" but it MIGHT be that they're "drifting" into coincidence -- ie: their specs are converging ("drifting"?) towards being identical -- with use.



...or drifting apart which could actually sound better to, at least, some people. ;)

[KeithC]

Yep...

Joe, the plates of the output tubes see a a voltage that is stepped up by the power tranny. Your wall AC is "multiplied" by the tranny. If the wall is higher or lower the plates see a change that can be about 4 times what the actaul wall chnage is. The bias voltage comes off of a seperate tranny tap. Because of the amount of windings, this voltage doesn't change to the same degree that the plates change. If the wall goes up, the following can occur. The output tubes run more voltage, ie hotter, and the bias doesn't change to accomodate the suddenly higher plates. Normally, you'd set a lower bias point if you have higher voltage plates, but the opposite happens. Like my other post, at 122V I get 500V plates and my bias is over 40ma. If I lower it to 35ma then it is too cool when the wall is 116V.

THis is why I gig with a voltage regulator! Fwiw, Robben Ford gigs his DUmble with a Variac to keep things constant. I hear a big improvement when I am in a 117V-120V window. THis is where I have the amp adjusted to sound its best.


Sorry to thread crap but can you recommend a good not to expensive voltage regulator?

Thanks!

[scottl]

Only two I know of that I would consider. The Furman AR1215II or ETA Sys.

Both pricey. The ETA seems to have a tighter spec but it is a little more dinero.

Sorry to thread crap but can you recommend a good not to expensive voltage regulator?

Thanks!

[tremolux]

Have some Tripplite LC-1800 floor units (non rack) that work very well purchased from a hospital surplus (or replacement) auction for around $30 each. I normally only run guitar gear on them so the recommended 15 amp ceiling is fine, there are 6 outlets with varing levels of filtering with regulation from 87 to 140. So far they've been great and lately Ive been running a small PA off one in certain places..

Pain in the rear to haul until I put handles on them and built small ply boxes for'em...but I concur, the Furman and ETA Sys are defintely the best way to go, high quality...not sure what the Tripplites run new, Mouser used to carry them.