01-28-2013 08:24 AM
Hey guys.
I accidentally ran my head (100-watt Marshall Superlead) for about 30 minutes without it being plugged into the cabinet. It ended up killing one of the power tubes (#4) and the High test fuse. I pulled the one and four power tubes, replaced the high test fuse and halfed the ohms to run the amp at half power.
Is it better for me to repleace one and four with new tubes without biasing the amp, or run it at half power?
My band is on the road right now, so replacing all four and having the amp biased is not an option.
Thanks in advance.
01-28-2013 08:34 AM
I'd run at half power....whatever damage may have occured around 1 and 4 may make running them unbiased even worse than normal.
...then again, the resulting skraw could be the exact toan yer after........j/k
01-28-2013 08:55 AM
01-28-2013 09:00 AM
01-28-2013 09:15 AM
goodhonk wrote:
the second one is just for looks.
:lol:
Sucks about your amp man. I think you'll be ok running it like you are but I would pick up a matched set of tubes and put them back. As long as they are matched you shouldn't need to bias the amp again.
01-28-2013 09:39 AM - edited 01-28-2013 09:40 AM
conky wrote:
goodhonk wrote:
the second one is just for looks.:lol:
Sucks about your amp man. I think you'll be ok running it like you are but I would pick up a matched set of tubes and put them back. As long as they are matched you shouldn't need to bias the amp again.
unless it's a matched set of the same spec (like a #'d Groovetube set), you'd still have to bias the amp.
01-28-2013 10:30 AM
You can go without rebiasing but it "could" wear the tubes out quicker. So it is what it is, you'll rebias when you can and keep an extra on hand for emergencies.
01-28-2013 01:04 PM



01-28-2013 01:47 PM
alien wrote:
Shoulda got a Peavey Rage 158. ! Facepalmed
Fix'd
Those things never die...the CL's full of 'em. You can make your own 3x3 MayStack of'em for less than the cost of one Boogie.
:WINK:
01-28-2013 02:20 PM
01-28-2013 03:22 PM - edited 01-28-2013 03:23 PM
:robotembarrassed: stupid forum.
BALLS
01-28-2013 03:29 PM
You're lucky you didn't fry your output tranny!
01-28-2013 04:50 PM
You probably should get the transformer checked. They can still work and be damaged. They will just be quieter and you might not notice the difference with it running at half power since you're already expecting it to be quieter.
01-28-2013 05:29 PM
This. Just get a matched quartet and get it biased and be glad it wasn't worse.
blueboxer wrote:You're lucky you didn't fry your output tranny!
christianatl wrote:
Fuck off. SAL is a good dude, and we're actually friends in the real world.
01-28-2013 07:51 PM
do a kickstarter, we could all chip in.
01-29-2013 04:20 AM
01-29-2013 07:21 AM
Maybe we should ask the experts in the amp forum! ![]()
01-30-2013 07:02 PM
I don't think you guys get what I'm saying. I'm well aware that I should replace the quartet and get the amp biased. That is not am option while we're on tour.
In leiu of getting the amp biased and replacing all four tubes, is it better to run at half power with the remaining two and three (or one and four) positions, or is it better (less worse? hahahaha) to replace a pair and run at half power or replace all four and run at full power without biasing?
Phil? Someone who knows what they are talking about?
01-30-2013 07:14 PM
christianatl wrote:I don't think you guys get what I'm saying. I'm well aware that I should replace the quartet and get the amp biased. That is not am option while we're on tour.
In leiu of getting the amp biased and replacing all four tubes, is it better to run at half power with the remaining two and three (or one and four) positions, or is it better (less worse? hahahaha) to replace a pair and run at half power or replace all four and run at full power without biasing?
Phil? Someone who knows what they are talking about?
run a pair in the two middle posiions, or two outer positions (don't run three tubes). some peope say that you should half your impedence, other techs say don't bother and leave your impedence selector to suit the cab.
01-30-2013 07:24 PM - edited 01-30-2013 07:33 PM
christianatl wrote:I don't think you guys get what I'm saying. I'm well aware that I should replace the quartet and get the amp biased. That is not am option while we're on tour.
In leiu of getting the amp biased and replacing all four tubes, is it better to run at half power with the remaining two and three (or one and four) positions, or is it better (less worse? hahahaha) to replace a pair and run at half power or replace all four and run at full power without biasing?
Phil? Someone who knows what they are talking about?
I would run at half power with two tubes as you mentioned. Obviously equipment failure is a huge bummer when you're on tour.
If you run with a new set or even a new half set with the old ones they could be too hot or cold for how your amp is biased right now and sound like shit.
If you're happy with your amp at half power and the tone is half way decent I'd ride this out until you can get your amp biased with a new set of tubes.
If someone has heard any ill effects from running a particular amp at half power (I'm not sure what you're running) please chime in.
Yes, and if your amp is anything like my Silverface Bassman 100 you can have one spot open on either side as if there's a line down the middle of the four power tube sockets.
Also wether or not you want to run at a different impedance seems to be somewhat of a matter of opinion, though I've found most people that say you should, say to go up. So if your amp runs at 8 ohms go to 16, if your amp runs at 4 ohms go to 8. Wether or not you want to risk a mismatch would really depend on how bitchin your output transformer is.
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