#1
Hi basically what I'm asking is, is it safe to do this, like it won't harm the amp or anything.
#2
Apparently its safe if you remove them in a xoxo or oxox pattern then half the impedance selection on the amp.

But my output transformer still fried and cost me £100 to fix.

Frankly the difference in volume from halving the wattage like that just isnt even worth it.
#3
It wont sound good. Amps which are 100 watts are designed to operate with 4 powertubes and sounds best with 4 power tubes, even at low volume
#4
Quote by beckyjc
Apparently its safe if you remove them in a xoxo or oxox pattern then half the impedance selection on the amp.

But my output transformer still fried and cost me £100 to fix.

Frankly the difference in volume from halving the wattage like that just isnt even worth it.


This. You wont notice a difference unless you pooch your poor transformer like this unfortunate user.
Quote by zgr0826
My culture is worthless and absolutely inferior to the almighty Leaf.


Quote by JustRooster
I incurred the wrath of the Association of White Knights. Specifically the Parent's Basement branch of service.
#5
Quote by beckyjc
Apparently its safe if you remove them in a xoxo or oxox pattern then half the impedance selection on the amp.

But my output transformer still fried and cost me £100 to fix.

Frankly the difference in volume from halving the wattage like that just isnt even worth it.


+1 The volume difference between 20 watts and 40 watts isnt much different

What kind of amp do you have
#6
I thought you pulled the inner two or outer two...and I'm not sure if it works on all amps. I remember the Valveking being one you couldn't pull tubes on. I've pulled the outer two on my XXX head before...it made a difference, but it wasn't that noticable IMO. Really just amounted to my master volume knob being bumped up a tad
#7
I know 311zosojhvh did this, successfully, with help from Scott Splawn (who built his amp,) but I would want to hear it from the company first, as he did.
Quote by Cathbard
Quote by Raijouta
Unless its electronic drums.

BURN THE WITCH!!!!!
#8
Quote by eyebanez333
I thought you pulled the inner two or outer two...and I'm not sure if it works on all amps. I remember the Valveking being one you couldn't pull tubes on. I've pulled the outer two on my XXX head before...it made a difference, but it wasn't that noticable IMO. Really just amounted to my master volume knob being bumped up a tad

this - beckyjc your amp blew because you have to remove them in an oxxo or xoox formation, not an xoxo.
#9
Quote by SwampAshSpecial
this - beckyjc your amp blew because you have to remove them in an oxxo or xoox formation, not an xoxo.

+1 That's what I've always heard anyway.
Quote by Cathbard
Quote by Raijouta
Unless its electronic drums.

BURN THE WITCH!!!!!
#10
Quote by mcamp1230
+1 The volume difference between 20 watts and 40 watts isnt much different

What kind of amp do you have

I don't really think people pull tubes for a volume difference. They pull it trying to achieve higher gain tones. Some people have a misconception that you can get a more brown and saturated sound if you pull 2 power tubes from a Class AB or B valve amplifier. They say that your breakup starts earlier when you pull tubes.

Honestly, the differences I noticed when I tried it were mostly inaudible. You could still try, but hey if the amp has 4 power tubes, it wants 4 power tubes.
Quote by zgr0826
My culture is worthless and absolutely inferior to the almighty Leaf.


Quote by JustRooster
I incurred the wrath of the Association of White Knights. Specifically the Parent's Basement branch of service.
#11
get a thx hotplate or similar and save yourself the agro, or for the same money as a hotplate get a smaller practice amp
#12
Quote by SwampAshSpecial
this - beckyjc your amp blew because you have to remove them in an oxxo or xoox formation, not an xoxo.

Nope, there's no functional difference between pulling tubes like that. The tubes run in left/right pairs, so as long as you're not pulling just the two left ones or just the two right ones, the amp won't know the difference. Hell, with a decent transformer and a 4 ohm cab you can pull three tubes and run at 1/4 power. Of course, it doesn't sound good, but it can be done.
#13
Quote by SwampAshSpecial
this - beckyjc your amp blew because you have to remove them in an oxxo or xoox formation, not an xoxo.


I actually dont remember how i pulled them tbh, it was off somebody elses reccomendations (mrCarrot i think), so i probably did do it the right way since he knows his shit. As far as i know they run in pairs anyway sat next to each other, so as long as its not the first two or the last two you pull its fine.

Laney doesnt reccomend you do it anyway, some amps with better quality transformers may be more durable and better able to cope.

But i got this from another website anyway

The Laney VC30 is cathode biased and all 4 valves share a cathode resistor.
NEVER pull out output valves from cathode biased amps wired like this. Bias voltage is generated by the voltage drop across the cathode resistor. If you remove power valves then less current passes through the cathode resistor, hence there is less voltage drop across it, ie the remaining valves are biased hotter. As most EL84 amps bias the valves very hot to start with this will almost certainly bias your valves much hotter than their recommended dissipation, and the likelyhood is that they will eventually blow. If you are lucky, only the valves and fuse will need replacing, however you can also damage other components such as the screen grid resistors, cathode resistor/bypass cap and even the transformers.
Last edited by beckyjc at Aug 10, 2010,
#14
Quote by Roc8995
Nope, there's no functional difference between pulling tubes like that. The tubes run in left/right pairs, so as long as you're not pulling just the two left ones or just the two right ones, the amp won't know the difference.


Hmm...I didn't know that. Is there a reason why manufacturers recommend pulling a certain pair then? Does it have to do with the transformer the amp has more than anything else? When I emailed Peavey, the tech recommended pulling the outer two instead of the inner two
#15
+1 to what Colin said.

Quote by H4T3BR33D3R
I don't really think people pull tubes for a volume difference. They pull it trying to achieve higher gain tones. Some people have a misconception that you can get a more brown and saturated sound if you pull 2 power tubes from a Class AB or B valve amplifier. They say that your breakup starts earlier when you pull tubes.

Honestly, the differences I noticed when I tried it were mostly inaudible. You could still try, but hey if the amp has 4 power tubes, it wants 4 power tubes.


+1 to this too.

Also, I believe with Becky's she had a Laney and that was the way Laney recommended pulling tubes. Scott Splawn told me to pull the outer two in my Splawn (Marshall based amp). I've also heard the rec to pull the Inner 2 tubes but that was based on even a different amp.


TS - What amp do you have and what are you trying to achieve. My goal was to reduce the headroom somewhat but as mentioned people don't really do it to reduce the volume.
#16
Depends on the amp.
Some amps, like the Valveking, have the tube heaters connected in series. So pulling two tubes in the 100 watter is a no go.
MARSHALL JVM 210H
PEAVEY JSX
KRANK 412
MESA 412
FENDER STRATS
DIMARZIO
CELESTION
#17
Quote by Van Noord
Depends on the amp.
Some amps, like the Valveking, have the tube heaters connected in series. So pulling two tubes in the 100 watter is a no go.
Ah, I've always wondered exactly why you couldn't pull tubes in the VK. Weird Peavey decided to do the heaters that way. Should be a pretty simple mod though.

Anyway, the major advantage I see from using half the power tubes is the economical difference. The difference in volume is negligible, so why not do it?
Gear:
- Bugera 333
- VJ & VJ cab
- Jackson JS30
- TS9

Bugera Users Militia. We are horrible people. With a sprinkler fetish.
~ BUM: For all things extinguishing

Rackmount Tube Amp Project <<< Updates!
#18
Quote by eyebanez333
Hmm...I didn't know that. Is there a reason why manufacturers recommend pulling a certain pair then? Does it have to do with the transformer the amp has more than anything else? When I emailed Peavey, the tech recommended pulling the outer two instead of the inner two

Not sure why that would be. Usually you pull the inner two so they cool better. There really is no difference in which ones you pull electrically; they're all wired exactly the same, just two on each side of the PI.

As far as series heaters, yeah, the amp will just not work. That's not too common though, it's just Peavey cutting corners.

And yes, this should never be done on cathode bias amps.