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bmh1109
post Jun 5 2007, 09:35 PM
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I recently purchased a 1984 Carvin X-60 amp and the overdrive channel seems a bit odd. It doesn't sound right at all, way too much distortion, and not the good kind. I checked the cone and surrounds of the speaker to see if the excess noise was coming from there but they are both perfect. Im skeptical about the tubes in it now, it has 2 fender 6l6GC's and 3 12ax7 groove preamp tubes, which i imagine are over 6 or 7 years old. could it be the old tubes causing the poor distortion sound quality?

This post has been edited by bmh1109: Jun 5 2007, 09:36 PM


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MickeM
post Jun 5 2007, 11:02 PM
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QUOTE (bmh1109 @ Jun 5 2007, 10:35 PM) *
Im skeptical about the tubes in it now, it has 2 fender 6l6GC's and 3 12ax7 groove preamp tubes, which i imagine are over 6 or 7 years old. could it be the old tubes causing the poor distortion sound quality?

Sure could be, leave it in for service if you belive it's the bad egg so they can check it up for you.


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Rock
post Jun 6 2007, 12:11 AM
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QUOTE (bmh1109 @ Jun 5 2007, 09:35 PM) *
I recently purchased a 1984 Carvin X-60 amp and the overdrive channel seems a bit odd. It doesn't sound right at all, way too much distortion, and not the good kind. I checked the cone and surrounds of the speaker to see if the excess noise was coming from there but they are both perfect. Im skeptical about the tubes in it now, it has 2 fender 6l6GC's and 3 12ax7 groove preamp tubes, which i imagine are over 6 or 7 years old. could it be the old tubes causing the poor distortion sound quality?


I would upgrade the tubes anyway. Buy JJ tubes through the internet at Eurotubes.com. You can email the owner, Bob, he's extremely helpful and knowledgable. You will be amazed with the sound. About $70 total, and you will not believe the difference. Those are the exact same tubes I changed out in my Peavy ValveKing 112. I also changed out my stock speaker for a Weber Alnico Silver Bell. That was a bit more, I think another $180, but now it sounds even more incredible. It would have cost me more than double what I spent in total to get the sound quality I have now.
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bmh1109
post Jun 6 2007, 01:56 AM
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thanks for the suggestions guys, I would order the JJ tubes but i already have a set of Ruby tubes on order, but ill keep the JJ's in mind next time i wanna try some new tubes. I just really hope these new tubes clean up the distortion.


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MickeM
post Jun 7 2007, 09:55 AM
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QUOTE (bmh1109 @ Jun 6 2007, 02:56 AM) *
thanks for the suggestions guys, I would order the JJ tubes but i already have a set of Ruby tubes on order, but ill keep the JJ's in mind next time i wanna try some new tubes. I just really hope these new tubes clean up the distortion.

If you don't know already - Be VERY CAREFUL if you open your amp to do it yourself. Drain it before you start working on it or you might get a 700-Volts-through-yout-body kind of surprise.


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Rock
post Jun 8 2007, 12:47 AM
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QUOTE (bmh1109 @ Jun 6 2007, 01:56 AM) *
thanks for the suggestions guys, I would order the JJ tubes but i already have a set of Ruby tubes on order, but ill keep the JJ's in mind next time i wanna try some new tubes. I just really hope these new tubes clean up the distortion.


I wouldn't bother with the Ruby tubes, they are not very good or reliable. The problem is that there are too man variables and most of the companies do not do a very good job with testing and you can not buy them with tolerances.

Best bet is high gain preamp JJ tubes and JJ power amp tubes from Eurotubes. He individually tests each and everyone.
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fkalich
post Jun 8 2007, 03:43 AM
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QUOTE (MickeM @ Jun 7 2007, 03:55 AM) *
If you don't know already - Be VERY CAREFUL if you open your amp to do it yourself. Drain it before you start working on it or you might get a 700-Volts-through-yout-body kind of surprise.


when in doubt, use only one hand (and be wearing shoes). keep your other hand free.
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Rock
post Jun 8 2007, 04:20 AM
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QUOTE (fkalich @ Jun 8 2007, 03:43 AM) *
when in doubt, use only one hand (and be wearing shoes). keep your other hand free.


Here are the precautions. I definitely unplug but do not bother draining. Technically as long as you are not touching anything other than the tubes themselves you should be fine. But if you are very concerned, here are the proper steps before changing out tubes.

*** SAFETY WARNING *** READ THIS FIRST!!!!!

Working inside a tube amplifier can be dangerous if you don't know the basic safety practices for this kind of work. If you aren't prepared to take the time to learn and apply the right precautions to keep yourself safe, don't work on your own amp. You can seriously injure yourself or get yourself killed. This section is not intended to be a complete guide to safety in tube equipment, just to hit the high points as refresher for those of you who have some experience. The best way to learn the requirements and practices for safety in tube equipment is to find someone who will teach you one on one.

BASIC REQUIREMENTS

UNPLUG IT FIRST Pretty self explanatory. Do not, ever, ever, leave the equipment plugged in and start work on it unless you specifically intend to make some live-voltage measurement. Leaving it plugged in guarantees that you will have hazardous voltages inside the chassis where you are about to work. This is like setting a trap for yourself.
LET IT DRAIN If the amp has been turned on recently, the caps will still have some high voltage left in them after the switch is turned off. Let it sit for five minutes after you turn it off.
SUCK IT DRY When you open up an amp, you need to find a way to drain off any residual high voltage. A handy way to do this is to connect a shorting jumper between the plate of a preamp tube and ground. This jumper will drain any high voltage to ground through the 50k to 100K plate resistor on the tube. To do this successfully, you will need to know which pins are the plate pins. Look it up for the amp you're going to be working on. You'll need to know this for the work anyway. Leave the jumper in place while you do your work ( high voltage electrolytics caps can "regrow" voltage like a battery sometimes. Really. ) Remember to remove it when you finish your work.
TEST IT Take your multimeter and ground the (-) lead. Probe the high voltage caps and be sure the voltage across them is down, preferably to less than 10V.
BUTTON IT BACK UP FIRST Take the shorting jumper out. Put the chassis back in the cabinet, making sure all of your tools, stray bits of solder, wire, etc. are out of it. You don't have to actually put all the screws and so forth back in if you believe more work might be needed, but make sure that the chassis is sitting stably in the cabinet and won't fall out. At the end of a listening test, either continue buttoning up if you're done, or go back to UNPLUG IT FIRST.
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David OToole
post Jun 8 2007, 09:57 AM
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QUOTE (Rock @ Jun 8 2007, 05:20 AM) *
Here are the safety precautions ...


Great post Rock - yup those tube amps can sure pack a lethal wallop, even as you say, unplugged!

David


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bmh1109
post Jun 11 2007, 08:57 PM
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Well installed the new tubes today, taking the precautions you guys suggested and they installed with no issues. the ruby preamp tubes i installed are actually JJ tubes. I was suprized to see the JJ label on them when I popped them out of their little boxes. The old tubes were def. dead and the new tubes sound alot better, however the distortion channel still sucks. I think its just this particular amps distortion circuit that sucks. Any more ideas on how to clean up the distortion channel any?

This post has been edited by bmh1109: Jun 11 2007, 08:57 PM


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Ibanez Prestige RG2570E, Fender MIM Strat
Amps
Mesa Studio Preamp--->Mesa 50/50--->Line 6 M13 ---> into Avatar 2x12 Cab rewired for stereo operation
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Andrew Cockburn
post Jun 11 2007, 08:58 PM
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QUOTE (bmh1109 @ Jun 11 2007, 03:57 PM) *
Any more ideas on how to clean up the distortion channel any?


If you clean up the distortion channel, you'd end up with 2 clean channels ...

(Sorry, couldn't resist, I know what you meant!)


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Rock
post Jun 12 2007, 03:39 AM
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QUOTE (bmh1109 @ Jun 11 2007, 08:57 PM) *
Well installed the new tubes today, taking the precautions you guys suggested and they installed with no issues. the ruby preamp tubes i installed are actually JJ tubes. I was suprized to see the JJ label on them when I popped them out of their little boxes. The old tubes were def. dead and the new tubes sound alot better, however the distortion channel still sucks. I think its just this particular amps distortion circuit that sucks. Any more ideas on how to clean up the distortion channel any?


I would bring it in for service. Did you purchase from a reputable dealer?
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MickeM
post Jun 12 2007, 08:16 AM
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QUOTE (bmh1109 @ Jun 11 2007, 09:57 PM) *
Well installed the new tubes today, taking the precautions you guys suggested and they installed with no issues. the ruby preamp tubes i installed are actually JJ tubes. I was suprized to see the JJ label on them when I popped them out of their little boxes. The old tubes were def. dead and the new tubes sound alot better, however the distortion channel still sucks. I think its just this particular amps distortion circuit that sucks. Any more ideas on how to clean up the distortion channel any?

Yeah, bring it in for service. They might offer a couple of new tubes for a matching set.

I never work on my own amp, tubes have to be matched and biased. And when you buy a few from the store there's little chanse they will be matching. And after you plug em in to your amp they should be biased for best output, if the bias is off you got tubes that either don't run on their full potential or they run too hot.


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bmh1109
post Jun 12 2007, 10:07 AM
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I purchased the amp used from a local musician who didn't use it anymore. Ill have to ask around at the local guitar shops and see if any of them service tube amps, I feel sure at least one of them does. With alot of tweaking of eq and bright/lead switches some O.K. sounds can be coaxed out of it but it shouldn't be that difficult. However, the sounds i get out of the clean channel with my pedal setup are excellent, so the on board distortion isn't that big of a deal, it just kinda annoys me. So looks like there will be a trip to the guitar shop this week.


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Ibanez Prestige RG2570E, Fender MIM Strat
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Mesa Studio Preamp--->Mesa 50/50--->Line 6 M13 ---> into Avatar 2x12 Cab rewired for stereo operation
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