#1
Hey,
On my peavey classic 50, I realized that it has quite alot of clean headroom. And, I wish to lower it.
Anyways, it's cathode biased, and it has 4 EL84's.
I've heard mixed opinions on if it's a good idea or not. Some people say that you pull the two outside tubes, and some people say not to touch anything. I just want to clear it up.
So, would pulling power tubes work out with my amp, or should I just leave it?

Thanks!
Call me Wes.
Gear:
Fender American Deluxe HSS Strat
Chicago Blues Box Roadhouse
Bad Cat Cougar 5
1957 Gibson GA-5
Ceriatone 18w TMB Combo
Hughes & Kettner Tube Factor
Various Ibanez TS9s
Weber MASS Attenuator
#3
There's a tutorial on the front page of the Laney thread for doing it, same principle applies.

Remember to halve your impedance switch to use the same load. Say it's set to 8 ohms normally for an 8 ohm load, at half power you would want 4 ohms for an 8 ohm load.
The Laney Thread are big and clever. No exceptions.
#4
Well, it's set to 16 ohms right now. If I pull the two outside tubes, should I just plug my speakers into the 8 ohm output?
Call me Wes.
Gear:
Fender American Deluxe HSS Strat
Chicago Blues Box Roadhouse
Bad Cat Cougar 5
1957 Gibson GA-5
Ceriatone 18w TMB Combo
Hughes & Kettner Tube Factor
Various Ibanez TS9s
Weber MASS Attenuator
#5
yeah, but use it as normal otherwise.
The Laney Thread are big and clever. No exceptions.
#6
Alright. I'll give it a shot.
I just want to confirm everything before I go pulling:

1. I pull the two outside power tubes (OXXO, shown in the laney thread)
2. I unplug my speakers from the 16 ohm output, and plug them into the 8 ohm output
3. Turn on, and play.

Alright, just confirm that and i'll go on my way.

Also, will it cut the wattage in half, or what is the math behind it?
Call me Wes.
Gear:
Fender American Deluxe HSS Strat
Chicago Blues Box Roadhouse
Bad Cat Cougar 5
1957 Gibson GA-5
Ceriatone 18w TMB Combo
Hughes & Kettner Tube Factor
Various Ibanez TS9s
Weber MASS Attenuator
#7
Saying you're halfing the power tubes you would half the wattage.

^ that should all work, go ahead.
#8
Quote by darkarbiter7
Alright. I'll give it a shot.
I just want to confirm everything before I go pulling:

1. I pull the two outside power tubes (OXXO, shown in the laney thread)
2. I unplug my speakers from the 16 ohm output, and plug them into the 8 ohm output
3. Turn on, and play.

Alright, just confirm that and i'll go on my way.

Also, will it cut the wattage in half, or what is the math behind it?

This is correct. I do the same thing w/ my SLO, no problems running it every day like that for 10 months so far.
Edit: Be sure the tubes/amp are fully cooled down before doing anything. Do not jar warm tubes.
As far as the wattage formula, just Google it!
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Last edited by riffhog at Apr 29, 2008,
#9
alright. I'm in the process of pulling them now.
I'll check back before I turn it on to see if anyone says I really shouldn't do it.

Thanks!
Call me Wes.
Gear:
Fender American Deluxe HSS Strat
Chicago Blues Box Roadhouse
Bad Cat Cougar 5
1957 Gibson GA-5
Ceriatone 18w TMB Combo
Hughes & Kettner Tube Factor
Various Ibanez TS9s
Weber MASS Attenuator
#10
I'm just going to check the schem to make sure that's right, is there like an online manual or whatever for it, do you know, showing tube positions?

I'm just making thoroughly sure for you. I've no doubt it'll work, but there's no harm in being absolutely certain.
The Laney Thread are big and clever. No exceptions.
#11
Quote by darkarbiter7
alright. I'm in the process of pulling them now.
I'll check back before I turn it on to see if anyone says I really shouldn't do it.

Thanks!

You have no idea how close I was to messing with you on this! It would be too easy!
Don't worry, though. It's totally safe. I wouldn't risk an expensive amp otherwise. I actually called Soldano before I did it, & the tech said no worries as long as you cut the impedance as stated.
To thayes93-The tube pulling should work on just about any tube amp with 4 output tubes & switchable output impedance.
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#12
Well, I pulled them.
I'm gonna turn it on now.
Call me Wes.
Gear:
Fender American Deluxe HSS Strat
Chicago Blues Box Roadhouse
Bad Cat Cougar 5
1957 Gibson GA-5
Ceriatone 18w TMB Combo
Hughes & Kettner Tube Factor
Various Ibanez TS9s
Weber MASS Attenuator
#13
Yeah, it definitely looks like it's safe, make sure you warm it up on standby first, and then if there is no sound as soon as you flick it off when there normally would be, just turn it off immediately and nothing will have been damaged.

I'm fairly confident it's very safe though.
The Laney Thread are big and clever. No exceptions.
#14
Quote by darkarbiter7
Well, I pulled them.
I'm gonna turn it on now.


I SMELL SMOKE!
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Riffhog for President


Quote by Cathbard
There's no point apologising for your feet smelling when there's a 300lb gorilla in the room taking a crap on the couch.


Recognised by the Official EG/GG&A Who To Listen To List 2011
#15
Oh the tension...Will Darkarbiter survive?!?

Will his tone sound like airborne rabies?!?

Will his OT simply give up and go to the place where all the calculators go when they die?

...
...
#16
Quote by darkarbiter7
Hey,
On my peavey classic 50, I realized that it has quite alot of clean headroom. And, I wish to lower it.
Anyways, it's cathode biased, and it has 4 EL84's.
I've heard mixed opinions on if it's a good idea or not. Some people say that you pull the two outside tubes, and some people say not to touch anything. I just want to clear it up.
So, would pulling power tubes work out with my amp, or should I just leave it?

Thanks!

Quote by darkarbiter7
Alright. I'll give it a shot.
I just want to confirm everything before I go pulling:

1. I pull the two outside power tubes (OXXO, shown in the laney thread)
2. I unplug my speakers from the 16 ohm output, and plug them into the 8 ohm output
3. Turn on, and play.

Alright, just confirm that and i'll go on my way.

Also, will it cut the wattage in half, or what is the math behind it?
You can't even read the schematic for your amp. What the hell are you gonna do with the math, genius?

1 - The output section of the Classic 50 is NOT cathode biased.

2 - If it was, and also used shared cathode resistors (as some 4 tube PP amps do) you wouldn't dare pull 2 tubes. The idle current in the remaining pair would double. Can you say 'redplate'?

3 - Reason out the effect of removing 2 tubes from the primary of the OT, and what that does to the impedance ratio. Then you'll know why you're doing it wrong.
Meadows
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#17
I did it, and it sounds great!
I get an incredibly satisfying chimey OD from the clean channel, and I get much less fizz when I switch over to the lead channel. All at very good volumes. It actually starts overdriving well at about 5 on my volume knob. Which is a very good volume where I live.
Very nice. I think i'll give one of my JJ EL84's to one of my friends who has an overly bright blackheart little giant. Hopefully that'll tame it.

But, thanks for all the help!
I think i'll leave it like this. I'll use my CBB for cleans, and my peavey classic for some overdrive.

^Dude, chill. I'm a total technical noob. I've just been told that it was cathode biased or something like that. That's why I went for help here.
Call me Wes.
Gear:
Fender American Deluxe HSS Strat
Chicago Blues Box Roadhouse
Bad Cat Cougar 5
1957 Gibson GA-5
Ceriatone 18w TMB Combo
Hughes & Kettner Tube Factor
Various Ibanez TS9s
Weber MASS Attenuator
Last edited by darkarbiter7 at Apr 29, 2008,
#18
2 - If it was, and also used shared cathode resistors (as some 4 tube PP amps do) you wouldn't dare pull 2 tubes. The idle current in the remaining pair would double. Can you say 'redplate'?That's the only reason you can do it with the VC30 safely, when I took it apart, reverse to what the schematic says, it has an individual cathode cap and resistor for each power tube.
The Laney Thread are big and clever. No exceptions.
#19
Quote by SomeoneYouKnew
You can't even read the schematic for your amp. What the hell are you gonna do with the math, genius?

1 - The output section of the Classic 50 is NOT cathode biased.

2 - If it was, and also used shared cathode resistors (as some 4 tube PP amps do) you wouldn't dare pull 2 tubes. The idle current in the remaining pair would double. Can you say 'redplate'?

3 - Reason out the effect of removing 2 tubes from the primary of the OT, and what that does to the impedance ratio. Then you'll know why you're doing it wrong.


I think it ironic that you are part of the group "Don't Chew the Newbies" and yet here you are being a condescending prat.
...
#20
I'm sorry to bump this thread, but would the same thing work with a Bugera 6260? The head is 120 watts and I only have a 60 watt cab. I know it would be possible to run the head through the cab unaltered and not turning the master volume past halfway, but I'd like to play it safe and get rid of the 60 watts I don't need anyway. The head has 4 x 6L6's in the power section.

http://www.thomann.de/nl/bugera_6260.htm
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#21
Pulling two tubes has little effect on an amp. The drop in volume is only approx. 3db's, very little to the human ear.
Also you're supposed to lower the amps impedance by one value, not plug into a lower ohm jack on the cabinet.
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#22
Quote by Green_Jelly
I'm sorry to bump this thread, but would the same thing work with a Bugera 6260? The head is 120 watts and I only have a 60 watt cab. I know it would be possible to run the head through the cab unaltered and not turning the master volume past halfway, but I'd like to play it safe and get rid of the 60 watts I don't need anyway. The head has 4 x 6L6's in the power section.

http://www.thomann.de/nl/bugera_6260.htm


It should make a noticeable difference. It did with my amp. I also did it because I have a couple 2X12 cabs that are only 60W, & I want to use them one at a time. Just make sure you pull either the 2 outer or 2 inner tubes while the amp is off & cold. Then make sure your speaker load is double the amp's output impedance. If you have a 16 ohm cab, use an 8 ohm output on the amp.
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Quote by Cathbard
There's no point apologising for your feet smelling when there's a 300lb gorilla in the room taking a crap on the couch.


Recognised by the Official EG/GG&A Who To Listen To List 2011