#1
My band mate just picked up a 5150 from a pawn shop yesterday, we plugged it in and it started having some post gain issues. He would play it and the volume would decrease, and the overall bass response/punch would diminish. It comes back and goes out again. In order for him to keep up with my 6505+ post gain on 3 his has to be pushing 8 or so. Tube problems?
#3
Sounds like some power tubes on their last leg to me, but it could be other things too. That would be my first guess though
I'm just a kickin' and a gougin' in the mud and the blood and the beer.
#4
Well it's like the volume flickers basically. The EQ on the amp works fine. I don't know if you guys know who Billy Ingram (Molly Hatchet) is but it was one of his stage left 5150's. Which tubes should we replace?
#5
Quote by xbreakx6505x
Well it's like the volume flickers basically. The EQ on the amp works fine. I don't know if you guys know who Billy Ingram (Molly Hatchet) is but it was one of his stage left 5150's. Which tubes should we replace?


Power tubes, and all of them. They are the larger ones. I would recommend getting them matched.
I'm just a kickin' and a gougin' in the mud and the blood and the beer.
#7
Quote by xbreakx6505x
No need to change out the preamp tubes or anything?


Well, if you don't like the tone, then yeah, change them. But from what you have said this sounds like an issue with the power. If you could record it, it would be helpful. While I believe it is the power tubes, it could be something else, and I am not a tech. We have some very knowledgeable people on here, I would wait until later in the day at the least before making any decisions. To elaborate on your original question, preamp tubes generally won't cause issue with volume. I suppose there are exceptions to every rule but still. When preamp tubes fail, or become microphonic, they cause alot of feedback, and when I say a lot, I mean it. You would know if you had a failed preamp tube, the feedback would make the amp almost unplayable at louder volumes once it got good and toasted, and the feedback would be noticed even at lower volumes.
I'm just a kickin' and a gougin' in the mud and the blood and the beer.
#8
Well lets go off topic for a second. How would I know what preamp tube would give me the sound I want? and is it a big difference? We play metal/hardcore.
#10
There are tons of options. Generally, JJ is the best buy for the money. 12ax7 tubes are the standard, there are lower gain versions such as the 12au7 and 12at7, and then there is the 5751, which is no longer in production but can be bought at most online tube retailers. I like jj tubes, they sound good and are cheap. some people say it sounds dark, I would kinda agree.
Most stuff you get at guitar center and places like are rebrands of other tubes, some of them are quality stuff, some of them aren't. Again, I'm not the best person to ask, I pretty much go with JJ because they are highly regarded and I'm not made of money. The options go on for days, as putting certain valves in certain positions yields different results. It takes a lot of experimenting, which I am not willing to do. I think we have a ultimate tube thread or something to that extent, I would search for it, see what you get out of that.

EDIT: I have been beaten to the draw! that's the thread I mentioned.
I'm just a kickin' and a gougin' in the mud and the blood and the beer.
#11
Odd, I don't see Ruby's tubes listed. But okay, sounds fair. I just hope it's not a indepth schematic problem. Thanks guys!
#12
One question before I go. I have some Ruby 6l6gcs in a Valveking Head. Should I switch them out with the 5150? and since this head was operated by Billy Ingram do you think he had it biased differently?
#13
If they are in good shape, then it should be fine to at minimum test the 5150 with them, but I would still get some more soon. The 5150 is a fixed bias amp, which means you are pretty much stuck with its bias settings unless you get it modded to run at a different bias. This means biasing is a non issue.
I'm just a kickin' and a gougin' in the mud and the blood and the beer.
#14
Ha I bought this same 5150 from a pawn shop in Jacksonville, actually I bought 6 of them Took it apart It had a screw from the chasis floating around in the preamp section. Haa its a small world.
Last edited by RisenfallMusic at May 9, 2012,