#1
Some of you may have seen my previous thread about speaker ohms and know I burned out one of my power tubes yesterday. Since I am band-new to tube amps I want to make sure I don't screw up ordering my new ones and that what I know about them is actually correct.

1) The Valveking has 6L6's, as long as I order 6L6's again I don't have to worry about biasing correct? (I'm planning on going with the E-H's)

2) The tube I burned out is the first from the left. Since it will take a few days for the new ones to be delivered, in the meantime can I still use the amp if a remove the third tube as well? (Only for bedroom levels.)

3) Should I just buy 4 and replace all the power tubes while I'm at it, or would it be ok to just swap out the 1st and 3rd tubes?

Thanks for the help.
And maybe we can fly away from here, surf on the debris of a broken scene...
#2
1) The Valveking has 6L6's, as long as I order 6L6's again I don't have to worry about biasing correct? (I'm planning on going with the E-H's)
a different tube most likely wouldn't fit (except for an el34 and the like) but if you're switching who makes the tubes, yes you should have it rebiased.

2) The tube I burned out is the first from the left. Since it will take a few days for the new ones to be delivered, in the meantime can I still use the amp if a remove the third tube as well? (Only for bedroom levels.)
no, tubes are part of the circuit... so if you played without the one tube, it might just not work at all, or something terrible may happen, i don't know.

3) Should I just buy 4 and replace all the power tubes while I'm at it, or would it be ok to just swap out the 1st and 3rd tubes?
it'd be better to just buy a matched quad and keep the ones in there as spares. i'm a bit iffy on mixing power tube brands though...

you could get a lot more help if you put this in the tube sticky at the top of the page.
Gibson SG Standard + 18volt EMG-81 & 85
Mesa/Boogie Mark IV + Recto 2x12
Keeley Modded BD-2
Vox V847a
Quote by one vision
Bureaucrats gonna crat.

Recognised by the Official EG/GG&A Who To Listen To List 2008
#4
1) Have your amp rebiased. Unless otherwise stated in your manual, 6L6's are all you can use, with the exception of something like Yellow Jackets.

2) Ditto^ tubes run in series. The only time you can do this is on an amp with 4 tubes that allows you to run one pair at a time. You can probably make some kind of noise with a burnt tube still installed, but if you take it out and run the, disaster will strike.

3) If you buy 4 tubes, then when you install the second pair you DONT need to rebias the amp because they already matched. You should change tubes in pairs BTW. Just like batteries, you don't want to mix old and new. Its better not to mix brands.
Suhr Custom, Flaxwood Rautia or Grosh Tele thru
HBE Medicine Bawl Wah
Analogman BiComp
Texas Two Step OD
Fulltone Ultimate Octave/Fuzz
Boss CE-2
TC Nova Delay
SLO-100, 65 London or Bogner Shiva
Ask me about any of this stuff!
#5
NVM, I didn't realize that valvekings ran 4 power tubes
Suhr Custom, Flaxwood Rautia or Grosh Tele thru
HBE Medicine Bawl Wah
Analogman BiComp
Texas Two Step OD
Fulltone Ultimate Octave/Fuzz
Boss CE-2
TC Nova Delay
SLO-100, 65 London or Bogner Shiva
Ask me about any of this stuff!
#6
Bahhhh. I really don't have the money for this **** right now :-/

$60 for new tubes and then however much the re-baising will cost me at a shop.

Looks like I'll be putting in some OT this week.
And maybe we can fly away from here, surf on the debris of a broken scene...
#7
If you've got 4 power tubes, and the 1st one broke, you can go ahead and pull the 3rd one. The amp will only put out 50 watts, but it should work unless something else is wrong. Make sure to set the impedance for the next lowest setting (if you're running an 8 ohm cab, put the selector on 4).
#8
Quote by Roc8995
If you've got 4 power tubes, and the 1st one broke, you can go ahead and pull the 3rd one. The amp will only put out 50 watts, but it should work unless something else is wrong. Make sure to set the impedance for the next lowest setting (if you're running an 8 ohm cab, put the selector on 4).


Not a situation anymore, my roomate is bringing it down a shop for me to be re-tubed and biased as I type this.

$150 gone and I'm getting cheapie EHX tubes.

I would have upgraded to some nice ones but rent and loan bills are due this week.
And maybe we can fly away from here, surf on the debris of a broken scene...
#9
Quote by gald
1) The Valveking has 6L6's, as long as I order 6L6's again I don't have to worry about biasing correct? (I'm planning on going with the E-H's)

There's some misinformation in this thread already regarding which tubes will work and which tubes will not. Any octal base power tube (6l6, 6550, 5881, kt66, kt88, kt90, new production el509, etc) will fit in the VK, but heater current draw and plate voltage will determine which ones the amp can actually use. I'm assuming your VK has 6l6gc's as opposed to actual 6l6's (which used a metal casing instead of glass). If that's the case you may want to try some kt66's or some 5881's. Regardless, rebias the amp.

Quote by gald
2) The tube I burned out is the first from the left. Since it will take a few days for the new ones to be delivered, in the meantime can I still use the amp if a remove the third tube as well? (Only for bedroom levels.)

It's generally fine to run a 100w amp as a 50w with only two tubes operating, however the output impedance change. I believe it doubles, but I'm not 100% sure on that. Depending on the specific design of the amp, you might want to install half power switches on each of the two sets of tubes so that you can always get by when a tube goes down.

EDIT: I looked it up and the output impedance does indeed go down as stated a couple of posts above this one.

Quote by gald
3) Should I just buy 4 and replace all the power tubes while I'm at it, or would it be ok to just swap out the 1st and 3rd tubes?

Again, technically you'll be fine replacing two (and technically you can get by if you replace only one), but if one has already gone down I personally would go ahead and replace all 4 of them.
ESP LTD EC-256 and a Fender Deluxe VM
Last edited by Kendall at Jan 28, 2008,