Question:
Alright because one of my preamp tubes is dying I thought might as well replace them all. I have a crate vintage series 50 watt.....so I need 4 pre amps tubes so for channel one I would like more headroom which tube do I want? The 12at7 or 12au7?
Answer:
beats me. but, since i'm interested in tube amps in general, how much would these tubes cost?
Answer:
Originally Posted by irtrogdor beats me. but, since i'm interested in tube amps in general, how much would these tubes cost? 12AX7 are around 10 and up depending on which brand. I think that goes the same for anything other types.
Answer:
10 like $10 usd? how many do you need to buy for a whole amp?
Answer:
You'll probably want the 12AT7, it should be noted that it has a bit more of a smoother distorted characteristic than the 12AX7s, IMO.
Tubes run $10-15, each, but preamp tubes should need to be replaced very often at all.
Answer:
I'd say go with whatever is already in it.
Answer:
for more headroom, I believe you'd want to stick with the 12AX7s. Lower gain tubes are going to lower your volume and decrease headroom.
I also recommend www.eurotubes.com for tube purchases...but that's just me. JJs are a very highly recommended tube, and Bob at Eurotubes sells them.
Answer:
Originally Posted by thesteve for more headroom, I believe you'd want to stick with the 12AX7s. Lower gain tubes are going to lower your volume and decrease headroom.
I also recommend www.eurotubes.com for tube purchases...but that's just me. JJs are a very highly recommended tube, and Bob at Eurotubes sells them. The big issue is his clean channel breaks up around 3. Wouldn't a lower gain tube decrease that problem when put in the V1 (clean channel) spot?
Answer:
I think lower gain tubes allow you to get more gain range out of your preamp without distortion, increasing headroom. A lower gain power amp tube would decrease headroom, but it's different in the preamp.
Answer:
Originally Posted by Ryan Freeland The big issue is his clean channel breaks up around 3. Wouldn't a lower gain tube decrease that problem when put in the V1 (clean channel) spot? Hmm...I think with a lower gain tube it wouldn't break up at three...so you'd have more flexible volume control, but an overall quieter sound...thus the volume of "3" would be maybe..."5" with a lower gain tube. Does that make sense?
btw, I'm pulling my info from www.thetubestore.com
Answer:
Originally Posted by thesteve Hmm...I think with a lower gain tube it wouldn't break up at three...so you'd have more flexible volume control, but an overall quieter sound...thus the volume of "3" would be maybe..."5" with a lower gain tube. Does that make sense?
btw, I'm pulling my info from www.thetubestore.com I think the more flexible volume control is what we're after. The power amp's volume is essentially set, so for more headroom like that, one would probably want a more efficient speaker.
Answer:
Originally Posted by Rainer. I think the more flexible volume control is what we're after. The power amp's volume is essentially set, so for more headroom like that, one would probably want a more efficient speaker. right...a lower gain tube would actually result in breakup at a lower volume, but it would occur more smoothly.
Answer:
Not enough info really. I'm not familiar with that amp, but I'd say it depends on where your breakup is occuring, which may or may not be in the preamp stage. If the amp is breaking up say, in the 3rd gain (tube) stage, then replacing that tube with a lower gain one would clean it up. Unfortunately, its not that easy to diagnose where breakup is occurring, at least not for me.
I'm assuming that's a 50 watt amp; if its a 1x12 and you have it cranked up a bit, it may well be that the speaker is what's breaking up.
The preamp stage may be saturating the PI (the phase inverter, which is the tube that "drives" the power tubes) ,with "clean" signal - in that case, maybe replacing it would help. It may be "worn out". In that position, current capability is more significant than in preamp stages; either a high current 12AX7 or maybe a 12AT7. The 12AT7 is lower gain than the 12AX, but it has like 8 times the current capability.
Your power tubes may be worn out and need replaced. They tend not to fail per se, but fade away. As they get worn, they can breakup at pretty low volumes.
What kind of signal are you sending the amp? What kind of guitar? signal chain? A strong signal, like from a MultiFX with the output up high, or high output pickups can saturate an amp. For my taste, with my amps, even "PAF" type humbuckers tend to be a bit too "hot". Try cutting the signal a bit in front of the amp, like with an eq pedal, or other active device with a volume control. Signal level is very important to the overall sound of an amp.
Your EQ controls on the amp (bass, mid, treble) do control the strength of signal between one preamp stage and another. You can lower overall gain by turning them all down an equal amount ( or boost gain by cranking them all up).
EQ - lower frequencies require more of an amp's power. A bottom heavy tone will cause an amp to distort more than a thinner tone at the same perceived volume. You can clean up an amp by simply cutting the bass eq a bit. Low freq's have the same effect at the speaker too - again, at the same perceived volume level, a bottom heavy tone will drive the speaker into more distortion than a thinner one.
Answer:
He isn't online right now, but I can answer some of the questions (we're in the same band).
It's a Crate VC5212. It's 50 watt, 2x12, 4 preamp tubes, 4 EL84 power tubes.
V1: Clean channel
V2: Dirty
V3: Dirty
V4: Phase inverter
Solid state driven reverb.
He bought the amp used and GC said they recently retubed the power section with JJ's. And there indeed are JJ's in the power section. The preamp section right now has a variety of tubes, 1 being a Groove Tube 12AX7 that seems to have gone microphonic. He switched it from V1 to V2 and there was crazy feedback on the dirty channel instead of the clean.
Answer:
Originally Posted by Ryan Freeland It's a Crate VC5212. It's 50 watt, 2x12, 4 preamp tubes, 4 EL84 power tubes.
V1: Clean channel
V2: Dirty
V3: Dirty
V4: Phase inverter I know the first part of the info is correct (amp and tube compliment), but how do you know what tubes correspond to what? The manual I read doesn't seem to be that clear about it.