#1
my friend just gave me one of his old amps tonight. it's a Crate Vitage Club. it's got space for 8 tubes. but it's only got 4 in it right now. there's spaces for 4 "12AX7" tubes. is it bad to play it without those 4 tubes? and also when i first played it, i put it on standby for about 3 mins and smelled a slight burning/hot smell after i turned it off (played for about 5 mins, just wanted to test it really quick). is this normal? how do you tell if a tube is bad? and when i put it on stand by, do i need to turn the power on too?
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#2
Are you sure they are preamp tubes(12AX7)? The power tubes are the large ones, and the 12AX7 tubes are the small preamp tubes. You should be running it with all the preamp tubes I would imagine, I've never seen people running without all the preamp tubes. If they are power tubes, people sometimes take out pairs to cut the power output. Did you try it on all the channels?

Standby is used to heat up the tubes to operating temp before you send a signal thru them. Make sure the amp is in the "standby" position when you turn the power switch on. After a minute or 2, after the tubes have heated, you take the standby switch off so the signal is running through the tubes and you hear sound. You probably shouldn't be smelling anything burning, unless they are brand new tubes or something, which I doubt. When you turn it off, it's good practice to put it back into standby before you shut the power off. It's a good way to assure it's in standby when you power it back up.

Take it to a local amp tech to give it a good once over, and maybe have it retubed if they are old tubes. It can make a big difference in tone.
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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#3
i tried both channels, they both work. but every now ad then the sound glitches, i think it's most likely because of the missing tubes.

the tubes are set up in 2 rows of 4. the top row has all 4 tubes (not sure what size exactly, didn't check) and the bottom row has the tubes missing and say 12AX7 on the thingy you put the tube in.
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#4
also, when i have the power on, and standby on too to warm the tubes, when i turn the standby swithch of after warming them no sound comes through. but if i turn the stand by swith back on, i get sound. is this normal?
word to your mother
#5
Quote by realitysux
also, when i have the power on, and standby on too to warm the tubes, when i turn the standby swithch of after warming them no sound comes through. but if i turn the stand by swith back on, i get sound. is this normal?

ok, what positions do you have labeled on the switch. There will be no sound when it's in standby, that's why it's called standby, it's standing by waiting.

If it has "Standby" and "On", the one labeled "Standby" is the standby position, the "On" position means the amp is on and functioning.

Odd that it's functional, I wonder what the other set of 12AX7 tubes do. Those are definitely preamp tubes if they are labeled 12AX7 in the sockets. I would definitely get some for it, they aren't expensive, like $8.00 a piece for the 12AX7. You can get tubes at places like thetubestore.com and eurotubes.com.

I would take it in to a tech though, you really have nothing to lose if you were given the amp. It may have a lot of potential if it's running like it was designed, and they would be able to tell you of any maintenance items that need attention. Things like electrolytic caps dry up after many years, and it will create that 60hz hum that's common in old amplifiers. I know my Mark IV had over 10 yr old preamp tubes when I got it, since they last longer than power tubes. It sounded like a completely different amp when I replaced them, it made it sound new again.
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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Last edited by Erock503 at Aug 12, 2006,
#6
it's got an on and a standby switch. the standby switch only lights up when the power is on too. but if i turn the stand by switch off with the power on, there's no sound.
word to your mother
#8
yeah, that's great man, good to have friends like that.

Ok, so we're clear then? Make sure the standby switch is the "Standby" position before you turn the power on. Turn the power to "On", wait a couple minutes(there should be no sound during this couple minutes as the tubes heat up), then flip the standby switch to the "On" position, and you should hear sound.
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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#9
When you turn the amp on, the standby switch should be off, meaning that when you turn on the power, the light under the standby switch should be off. There should be no sound when you turn the amp on with the standby switch and light off. You need to do this to let the amp warm up. After about 2 minutes, turn the standby switch on, which will light up the standby switch. You should hear sound coming out of the amp now.

After reading the manual, the tube guide states that this amp should have 4 EL34 tubes (power tubes) and 4 12AX7 tubes (preamp tubes). I wouldn't operate this amp without all of the tubes in the amp. It's possible that you can play some channels without all of the preamp tubes since this amp seems to have 5 gain stages (gain stages 4 and 5 share the final preamp tube in the chain).

Take the amp to a tech and have him install matched preamp tubes in all 4 positions. If the amp is missing all 4 preamp tubes, then you have to be plugging in to the effects return for there to be any sound coming out of it, if this amp will even turn on without the preamp tubes that is. Hopefully the guy that gave it to you didn't mod it to remove the preamp tubes.
#10
^you mean matched power tubes. You don't need to match preamp tubes. You use a balanced preamp tube for the driver position. Get 4 matched power tubes(EL-34), and 4 preamp tubes(12ax7), with one of them being balanced for the driver/phase inverter position. Also have it biased by the tech you take it to.
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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Last edited by Erock503 at Aug 12, 2006,
#11
Quote by Erock503
^you mean matched power tubes. You don't need to match preamp tubes. You use a balanced preamp tube for the driver position. Get 4 matched power tubes(EL-34), and 4 preamp tubes(12ax7), with one of them being balanced for the driver/phase inverter position. Also have it biased by the tech you take it to.


Yeah...that...sorry, I'm pretty tired, been building an effects rig and pedalboard/case all day.
#12
nice!!! what do you have on it, and any pics?


oh, and realitysux, I was wrong about the switch positions, but the principle is still the same. Different amps just label them different. So regardless of what positions are labeled what, if you turn on the amp, there should be no sound while it's in standby.
The amp will have power and the light on, but there won't be a signal passed to the power tubes, just the heater elements will be active. When you take it out of standby(or if it's labeled to turn off standby or whatever), that's when the power is on, and you are hearing sound.
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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Last edited by Erock503 at Aug 12, 2006,
#13
https://www.ultimate-guitar.com/forum/showthread.php?t=406789

I'll have more pics up soon. Spent all day cutting and gluing tolex and making patch cables. Hopefully I'll finish the tolex tomorrow.
#14
Very Nice! That's going to look great man. What box is that in the middle, with the one dial that everything is plugged into? Also, is that light blue cable a midi cable, and if so, what is that controlling? I'll be psyched to see the finished pics.
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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