Tube Questions

  • Thread starter Thread starter chamelious
  • Start date Start date
chamelious said:
Its only a year or two old, and i play metal/hardcore stuff. Without a gate, especially at gig/practise volumes you always get some kinda shitty noise when you dont want it betbeen muted stabs and whatnot, which is unacceptable. Unless maybe you have perfect gear. But even Trivium/as i lay dying/etc use boss ns-2's and stuff.
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*shrugs* I have used a ton of gain, really dense sound, never a problem. Like I said, if your signal volume is 100dB+, what difference does it make if you have 70dB of noise? If yo have the gate up high enough to get rid of all that, it will chop off the notes when they get down into that buzz, which is far worse (IMO) than the noise could ever be. If the noise gets unacceptable, something is wrong, and I fix it.

A year or two is plenty of time to croak a set of power tubes. I retube more or less annually. Definitely check for microphonic preamp tubes (it sounds like you've got one or more), you can swap them yourself. Then recheck your gain-staging like I suggested in my first response. You'll probably still want a retube.

Oh, and cheap preamp tubes are notoriously noisy, you may solve that problem right away.
 
Cool first thing i will do is check the gain staging as you say. (Currently guitar is plugged into the amp with a good cable, no pedals or anything).

Will check for a bad tube too. Hmm preamp tubes are 12ax7's, i thought those were ok ones but this is my first tube amp!
 
Ahhh yes that makes a lot more sense. Is there a good brand to go for, with a bias on a good high gain/metal sound.
 
If you're in the US, email dougstubes or thetubestore. Those guys will know better than I about your amp's preferences.
 
Outlaws said:
Because they don't all use them.
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Is AC/DC a metal band? Saw them live couple months ago. Two ancient looking Marshall heads front and center, probably old 200 watters, driving a total of 32 (I think) Marshall cabs stacked 2-high, 16 on each side of the drummer. One mic hanging in front of one cab on each side. No changing guitars between songs, and not a pedal to be seen. Guitars sounded great!
 
Most of those 32 will be there for visual effect, there was probably 1 maybe 2 cabs actually being driven. They could have had rack gear set up out of sight too. And nah AC/DC's not metal, its classic rock.
 
Oancient1 said:
Is AC/DC a metal band? Saw them live couple months ago. Two ancient looking Marshall heads front and center, probably old 200 watters, driving a total of 32 (I think) Marshall cabs stacked 2-high, 16 on each side of the drummer. One mic hanging in front of one cab on each side. No changing guitars between songs, and not a pedal to be seen. Guitars sounded great!
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i have a buddy that roadied for blue oyster cult... he used to laugh about the satge amps... they had something like what you describe but only one cab was loaded...
 
dementedchord said:
i have a buddy that roadied for blue oyster cult... he used to laugh about the satge amps... they had something like what you describe but only one cab was loaded...
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I worked the stage for a Metallica show many years ago. Out of 27 Marshall cabs on stage, only three were real. The rest were just empty boxes with the Marshall logo on them. All nine of the Marshall Majors visible were fakes; the real amps were 2 50 watt and 1 100w (for bass) heads behind the stacks. The PA did the heavy lifting.
 
Haha its mad.

Had a quick play with the amp (couldn't play it loud, neighbors) and amongst not being able to find a tone i liked (theres no treble, all i can get out of it is thick bass) i noticed that the feedback pitch that i was getting last week, comes even without the guitars volume on. Channel gains on full (still not nearly enough) and that squeel comes out when master gets past about halfway.
 
chamelious said:
Channel gains on full (still not nearly enough) and that squeel comes out when master gets past about halfway.
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You are going to probably need a 20' cord and stand 20' away from your amp.

Nothing new here.
 
It could be either, but I've only ever had preamp tubes do that. There's no saving the tube - you should throw it away. Do you have a spare "known-good" 12AX7 (not necessarily good sounding, just not microphonic)? If so, you could cycle through replacing each one and see if/when the problem goes away. If none of them are the problem, then look at the power tubes. I guess from your description, it sounds like it's a power tube (since it seems to be tied to the master gain), but that's speculation -- it's still worth checking the preamp ones.
 
Dont have any spares this is my first foray into the world of tube amps. Dont know if it helps but theres also a LOT of hiss at high volumes with high gain, something ive not heard from solidstate amps. Like enough to make conversation diffcult.
 
chamelious said:
Dont have any spares this is my first foray into the world of tube amps. Dont know if it helps but theres also a LOT of hiss at high volumes with high gain, something ive not heard from solidstate amps. Like enough to make conversation diffcult.
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That could be a lot of things - it could be a[nother] bad tube, but it's as likely to be anything else.

Not that I'm suggesting anything here, but I use a Marshall half stack (had it for >20 year) and it always had a big hiss at high gain (but was rarely up that loud), but recently I followed Tone Lizard instructions and removed a capacitor that was there to brighten the signal in the preamp circuit, and the hiss decreased considerably -- now it's deceptively quiet until you do so much as brush the muted strings, and then it rips your head off. Not much value to telling that story now, except to say that the hiss could be from a lot of things (or a combination of several).
 
Try swapping all the preamp tubes, they're probably not doing you any good. 90% likely to fix the squeal, 50% to fix or mitigate the hiss. After that, take it in for service. They do need check-ups, just like cars.
 
ermghoti said:
Try swapping all the preamp tubes, they're probably not doing you any good. 90% likely to fix the squeal, 50% to fix or mitigate the hiss. After that, take it in for service. They do need check-ups, just like cars.
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Cool thanks i'll do that, any suggestions on brand?
 
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