Tubes...

[GreySeraph]

Hey guys Haven't been on here in a long while! I wanted to ask you thoughtful fellows what you think about different tubes and how you bias them, whether you go hot or cold and what brands/types of tubes you guys use. Right now I just changed out the tubes in my amp to 2 EL34s and 4 6L6s and I'm running them pretty down the middle, mainly because it's the first time I've ever biased an amplifier before by myself.

[Rampdog]

Myles has a couple good threads running concerning this... Plus check out his 'Feel Free To Ask Myles'......

[The Geoff]

http://www.guitaramplifierblueprinting.com/Tubeprimerandselection320-2.pdf

 

 

 

[Caevan O’Shite]

Hey, Grey'! I'd wondered about you recently... how are you? Gettin' a bit more tube-y, huh?

 

To a degree, it depends on the amp and what sounds and feels right and best to YOU. That is, within reasonable limits for the given tubes.

 

Generally, I would probably prefer the bias to be running slightly "hot", or "under-biased", but not by a lot; and again, it would vary with the given tubes an amp. "YMMV", as they say- you might want a little more or less than the next player.

 

I have installed 1 ohm, tight tolerance, 2 watt wirewound resistors at the cathodes of output-tubes before, to measure the current-draw at "idle" with a DMM; but the various devices made for this, that plug into the tube-sockets with the tubes in turn plugged in to the device, look like a GREAT idea...

 

Some amps, like the "red-knob" Fender Twin I used to have, include built-in external test-points and trim-pots to set the bias (and sometimes "balance") with a DMM. Super convenient!!

[Electric Biscuit]

considering Mesas don't have bias adjustment, I use stock Mesa tubes biased (I assume) somewhere in the middle

[Caevan O’Shite]

considering Mesas don't have bias adjustment, I use stock Mesa tubes biased (I assume) somewhere in the middle

 

A good tube-vendor, like Doug's Tubes or KCA NOS Tubes, should be able to provide you with various tubes that will "fit" the bias-requirements of your Mesa amps.

[GreySeraph]

I started checking out some of myles' threads theyre pretty cool!

 

To answer all the stuff here, I'm running a Diezel Herbert 180watt with 6 power tubes and 6 preamp. I put in 2 EL34s and 4 6L6s and 6 12AX7s and biased the EL34s and 6L6s at 60mA each. I believe theyre all JJs.

 

Two questions I have:

1)Is running the tube "hot/under-biased" supposed to mean less mA? My amplifier has an external bias, so i dont know if that changes anything; I was instructed by a friend in using a multimeter with changing the tubes, and the amp now sounds pretty bitchin'.

2)Do brands of tubes significantly alter the sound?

 

@Caevan: Hey man long time no talk! Yeah dude I'm really excited about getting back into electric play. I'm still very much doing the whole classical thing, just I've done nothing but classical for almost two years now. I just did Joaquin Rodrigo's Concierto de Aranjuez, a guitar concerto with the Orange County Symphony Orchestra in September and that was the reason for me not popping my head in here (I had been working on that piece for about a year and a half).

[GreySeraph]

http://www.guitaramplifierblueprinting.com/Tubeprimerandselection320-2.pdf

 

 

 

Dude this is awesome! Thanks!

 

edit: dude, now im just full of questions of all of the random things this article doesn't answer. BAH!

[Electric Biscuit]

considering Mesas don't have bias adjustment, I use stock Mesa tubes biased (I assume) somewhere in the middle

 

A good tube-vendor, like Doug's Tubes or KCA NOS Tubes, should be able to provide you with various tubes that will "fit" the bias-requirements of your Mesa amps.

 

doesn't matter, I'm trying to sell my F-50 right now anyway

[Caevan O’Shite]

I started checking out some of myles' threads theyre pretty cool!

 

Yes, they are!

 

To answer all the stuff here, I'm running a Diezel Herbert 180watt with 6 power tubes and 6 preamp. I put in 2 EL34s and 4 6L6s and 6 12AX7s and biased the EL34s and 6L6s at 60mA each. I believe theyre all JJs.

 

 

What a wicked cool amp... !!

 

I've long thought that I'd really like a Diezel VH4, though I've yet to try one...

 

Is such a powerful high-watt amp a bit of overkill for you, or do you find its volume usable and useful?

 

Two questions I have:

1)Is running the tube "hot/under-biased" supposed to mean less mA? My amplifier has an external bias, so i dont know if that changes anything; I was instructed by a friend in using a multimeter with changing the tubes, and the amp now sounds pretty bitchin'.

 

"Under biased" means lesser negative-voltage is applied to the grid, ie a lower (but negative) figure, resulting in a greater current (mA) being drawn, and the tube running "hot".

 

"Over biased" is just the opposite, wherein too great a negative-voltage is applied to the grid, resulting in a lower current (mA) being drawn, and the tube running "cold".

 

There is a little room here for preference in-between. If your amp "now sounds pretty bitchin'", it's probably right where you want it. Optimum specs and tube-life are not necessarily the same as optimum tone and performance; some trade-off here is virtually inevitable. Plate voltage is a factor here. See Myles for harder and more reliable specific info here, though!

 

 

2)Do brands of tubes significantly alter the sound?

 

They can and will; design specs and physical differences can vary quite widely. And in general, old NOS are at a premium for good reason! That being said, I've mainly used recent production tubes of good (by current standards) quality, as I'm either playing at home, or at penny-ante gigs of little significance, and wouldn't want to use up NOS tubes on such, let alone pay the cost for 'em. (In fact, at home I largely use digital-modeling and sometimes a pedal with one tube in it, partly for those reasons.) If I were playing "real" gigs and/or seriously recording, I'd likely pop more high-quality NOS tubes in place, and stockpile what I could, as well!

 

 

I'll tell you what, in many (perhaps most) amps, having a "balanced" or "matched" Driver/Phase-Inverter tube can make as much difference as a set of matched output-tubes, even WITH a matched set of output-tubes. An MPI is one that has been tested and found to have very similar qualities between its two internal triodes.

 

It's a real bottle-neck in the amp if a poorly balanced 12AX7 or 12AT7, etc., is driving the output-tubes, resulting in phase-cancelations and resonances at various frequencies which yield perceived "dead-spots" on the fretboard and generally poor tone ad weakened response.

 

Also, the driver/phase-inverter tube works and wears out along with the output-tubes, and as such should always be replaced when the output-tubes are. The old PI may or may not still be OK for use in another, less critical socket in that or another amp.

 

Caevan: Hey man long time no talk! Yeah dude I'm really excited about getting back into electric play.

 

Cool, cool...

 

I'm still very much doing the whole classical thing, just I've done nothing but classical for almost two years now. I just did Joaquin Rodrigo's Concierto de Aranjuez, a guitar concerto with the Orange County Symphony Orchestra in September and that was the reason for me not popping my head in here (I had been working on that piece for about a year and a half).

 

To say that I'm mightily impressed would be an understatement, Grey'!

[GreySeraph]

I've long thought that I'd really like a Diezel VH4, though I've yet to try one...

 

Is such a powerful high-watt amp a bit of overkill for you, or do you find its volume usable and useful?

 

I really enjoy the amplifier, and I don't really have to play it that loud either. It gets good clean sounds as well as distortion and what not. I read a lot of myles' thing that the one guy posted up on this thread and he had this deal about high watt amps being overkill and equaling a probable poor performance, depending on genres and w/e. Personally, I really enjoy all the sounds my amp has to offer, although it doesn't do everything that I would like.

 

 

There is a little room here for preference in-between. If your amp "now sounds pretty bitchin'", it's probably right where you want it. Optimum specs and tube-life are not necessarily the same as optimum tone and performance; some trade-off here is virtually inevitable. Plate voltage is a factor here. See Myles for harder and more reliable specific info here, though!

 

I'll definitely keep this in mind. I'm not sure of exactly what I want, as I'm still new to the whole biasing-it-myself thing. Gimme a few years and I'll feel a bit more comfortable with it

 

 

Thanks dude for the info on tubes and what not. Again, yeah I'm really trying to get more knowledgeable with my electric stuff.

 

And thanks for the nice words RE the concerto! I'll try to have a video of it up here soon

[Larryz]

I have a guy bias my 6L6's (matched set) whenever I change them for about $20...as I'm not a DIY'er anymore...