New member needing some help.

[Slaughtered]

Hey everyone, I just skimmed over your forum a little but I'm really in need of some help.

Sad to say my tube amp knowledge isn't much, and I'm sure my problem is an easy fix! But I'm looking for advice to make sure.

I own a Dual Recto Solo Head (3 channel), I run it at half power with 2 6L6's (mesa) and 1 5U4G. Now when I was playing yesterday I was turning up and the volume increased slightly not as its usual increase. It sounded muffled, this was on Channel 3 (it happened all others though too) ok so my Channel Volume is about 12:00, and my output is now at about 11:00 and still a slight increase till it seems for some reason it Jump in volume, as it realize where the dial was and BOOM. Mesa goodness.

I really need to fix this , I'm sure its powertubes, I have a couple sitting here to switch them out. So I'm going to do that later today. But there can always be the chance I'm wrong here and maybe something else is up.

If you've experienced this first lack of volume, and then a sudden JUMP in volume. Please help!

Thanks.

 

[Boogiebabies]

A dirty volume, or failing volume pot will give you the same effect. The dirt or missing resitance layer will cause issues with volume.
Also, if the pot has been banged in, the tabs on the back fail to hold the pot fully together and you end up with bad sweeps or volume drop out during vibrations.

 

[jbird]

With your limited wealth of tube amp knowledge, I'd have to ask: Why are you pulling two tubes to obtain your supposed 1/2 power? It's not "really" becoming a 50 watt amp, it's not intended to operate that way, and lastly, you did'nt mention where your operating your speaker load? I would suggest re-installing all fresh tubes and using the volume control judiciously, with Mesa's designed pre-amps, there's really no need to push the power section so hard for nice gain! Why is it you desire the two tubes pulled, anyways?

 

[Platypus]

With your limited wealth of tube amp knowledge, I'd have to ask: Why are you pulling two tubes to obtain your supposed 1/2 power? It's not "really" becoming a 50 watt amp, it's not intended to operate that way, and lastly, you did'nt mention where your operating your speaker load? I would suggest re-installing all fresh tubes and using the volume control judiciously, with Mesa's designed pre-amps, there's really no need to push the power section so hard for nice gain! Why is it you desire the two tubes pulled, anyways?

+1

 

[Shep]

i find the mesa dual rec three channel's sound like puss unless the power amp isn't at 2:00 ... i then have my channel master at 9:00 or even less so it isn't unbeleively loud...i also run it at 100watt's..

i would say pot problem's so yeah I agree with BB...he know's his stuff

 

[Slaughtered]

With your limited wealth of tube amp knowledge, I'd have to ask: Why are you pulling two tubes to obtain your supposed 1/2 power? It's not "really" becoming a 50 watt amp, it's not intended to operate that way, and lastly, you did'nt mention where your operating your speaker load? I would suggest re-installing all fresh tubes and using the volume control judiciously, with Mesa's designed pre-amps, there's really no need to push the power section so hard for nice gain! Why is it you desire the two tubes pulled, anyways?

I had read in the manual about it, after reading it I figured I would try it. And I noticed a tone difference (of course).

I was just powering up and had the probelm earlier in the day, I know when you crank it up it gets better and better. But I didn't want to send shockwaves of feedback with a noise jump, and also scare the **** out of me when it finally did recongnize it.

A dirty volume, or failing volume pot will give you the same effect. The dirt or missing resitance layer will cause issues with volume.
Also, if the pot has been banged in, the tabs on the back fail to hold the pot fully together and you end up with bad sweeps or volume drop out during vibrations.

Sounds like you know whats up, any sure way to determine a solution? I'm taking it its something I can't fix either. So should I go let the local guitar shop enjoy my company and my $$?

Thanks!

 

[nemesys]

Before you take it to a repair shop, I'd spray some contact cleaner into the volume pot in question. Unplug your amp, remove the knob, spray the cleaner into the ring where the part that turns meets the part that doesn't turn, work the pot back and forth through its full sweep several times, wipe away any excess cleaner, wait a couple of minutes for it to dry, and go. Quick and easy.

This doesn't sound like a power tube problem, but there's nothing wrong with swapping them out to verify that. It's also pretty quick. Just for the hell of it, see if the same thing happens if you switch to silicon diode rectification on the back of your amp, to see if there's a problem with your rectifier tube (the 5U4G). It's unlikely that this is the problem, but it only takes a second to check.

Just some quick things to try before you pay to have it repaired...

 

[JOEY B.]

I would clean the volume pot as described and also the input jack, and effects loop jacks if you are running anything through them. I had an odd experience with signal loss that turned out to be a dirty contact on the input jack. Spray some contact cleaner on the tip and ring terminals of your guitar cord, insert quickly into the jack, and turn it back and forth. I agree that there is no need to pull tubes for a supposed volume decrease. If you've ever heard a Simul-class Mark series at 15 watts, you know what I mean. The decibel level does not decrease that much. You just lose bass response and headroom. It is the same result when I switch to 60 watts on my MkI.

 

[jbird]

Anyways, before you decide to take it to a tech, I would return the amp to "normal" operating specs, meaning all the tubes in place, and known good tubes at that! The 1st thing a tech will suspect, and usually the most common problem with tube amps, is the tubes! At least taking those elements out of the question, along with a can of contact cleaner, you'll be able to save yourself some money and a tech some time!

 

[Slaughtered]

I'm going to be out of state for a while so I'm really not going to be able to do any of this anytime soon. But please suggest a contact cleaner, and these pots that you speak of, I basically only know what the manual has told me. How would I go about clean them, would I just remove the knob and see some sort of an exposure. Because it seems like I would have to get into the rig somehow? So please go into more detail somebody.

Yea new tubes, I was wanting to try some EL34's instead of the 6L6's anyway. Luckily a place down here real close is a Mesa dealer, so I can get the hook up when I return.

Oh and another question! The pulling of tubes, nobody else does this? I guess because your pushing them harder, wa la they wear sooner. Hmm, when I get back from my trip I'll do a totally retube of them all.

Maybe I should mention that I swapped out the rectifier tubes (remember I was running 1 rectifier, and 2 6l6's). I did this because when I was playing one day it was just making noise like a humming sound. I replaced the rectifier tube with another and it quit. But then later I get the problem that I had mentioned first.

Could they be linked together, or is it just not my week before I leave? If thats the case maybe I should stick my unlucky *** home!

 

[Platypus]

http://store.caig.com/s.nl/sc.2/category.188/.f

Deoxit is great^ (you can find it at any good electronic store)

As far as the rectifier thing, can you explain that in more detail? What exactly did you do step by step? What rectifier tubes did you replace them with?

 

[Slaughtered]

http://store.caig.com/s.nl/sc.2/category.188/.f

Deoxit is great^ (you can find it at any good electronic store)

As far as the rectifier thing, can you explain that in more detail? What exactly did you do step by step? What rectifier tubes did you replace them with?

Thank you for the recommendation, but is it just as simple as taking off the knob with the allen wrench (as it appears to be) and squirt some in there?

Since I was running 2 6l6's and a 1 rectifer tube, the other 2 (including the other rectifier tube making it '3') to me were the "backups". So when I heard the hum, I removed the rectifier tube, replaced it with the exact same model 5U4G that came with the amp.

That problem ceased. Then when I was turning on my amp the next day or so, I began to turn up the volume with a different increase (mind I didn't change any settings of volume) and I kept turning it up on the Output (master volume) till eventually it seemed to catch up with itself and blasted sound through the speakers.

So thats when I stopped, read my manual trying to find anything about that, no luck. I searched google and found this place.

Do you think they are linked? Or were you curious about a certain thing about what I did, because all I did was swap out the tubes of the exact same thing.

Or is it because I ran the amp at a half-power, but as jbird mentioned its truly not half power. And yeah I was operating on a proper load, the Mesa 2x12 rectifer cab (V30's) I have 8 ohms.

 

[Platypus]

What you did was technically 'safe' to do according to Mesa, but anytime you are troubleshooting an issue as dubious as this, it makes for sound advice to replace the amp to its original configuration and start the troubleshooting process from there.

Furthermore, I think you'll find that you're not really gaining anything by operating your amp in the fashion you currently are and you are really better off running the amp as it was intended to be run. That's another issue so we can talk about that later. I would restore all the tubes to their proper places and begin troubleshooting from there.

How old is the amplifier/tube set? Are you the original owner?

 

[Slaughtered]

Yup all me, bought it last year brand new about this time of year I believe. The tubes that are in it are what came with it.

 

[Platypus]

Yup all me, bought it last year brand new about this time of year I believe. The tubes that are in it are what came with it.

Ok so that narrows some things down a bit. Can you post your settings for every knob on the front? I'm curious where you are running your volumes mostly but other things in the EQ affect that so just indulge us if you don't mind. The volume pot seems to be the best working theory as of now because of the symptoms.

Has the amp taken any jolts or bumps or knocks to the front panel at all? Even if by accident?

 

[Slaughtered]

Mind you that the amp is eq'd for a Jackson SL1 JB bridge, Cool Rails neck.

Channel 3:

Modern

Presence: 9:00
Master Volume: 11:00
Gain: 3:00
Bass: 8:00
Mid: 11:00
Treble: 8:00

Channel 2:

Vintage

Presence: 11:00
Master Volume: 12:00
Gain: 2:30
Bass: 8:00
Mid: 10:30
Treble: 9:45

Channel 1:

Clean

Presence: 10:45
Master: Volume here is all the way (maxed out)
Gain: 11:00
Bass: 9:00
Mid: 7:00 (add some for I guess a little more grit, it seems adding mids, add volume.)
Treble: 9:00

There ya go, I've never told anybody my settings because its always in constant limbo. Although I know little about amps, I sure enjoy tweaking guitars. So if any of that seems odd, I'm welcome to any recommendations. But then again your not playing my guitar with my pickup height, pole pieces and playing style as me.

But then again its just an indulgence, so enjoy! I should add I ususally try to compensate with the Channel 1 vs the other 2 because of the volume difference. And since I'm such the tweaker its not unusual for those setting to change all the time. Although pleased with the amp, I do enjoy searching.

 

[Platypus]

Ok cool, nothing looks like it'd cause an issue for you.

Do all of the channels act the same way? Where is your 'output' volume if you're using it?

 

[Slaughtered]

Well that depends on the neighbors last time I spoke with one she said she could hear it clearly while she pulled in the parking lot.

Badass yes! But sadly I feel that maybe my location dosen't permit this amp anymore. I moved into the city from the country. My intention was to start playing in bands, and still is! But it dosen't seem to be going that way as of now, just not my luck at finding the right people.

So volume has been set pretty low, since I want to be a good neighbor and all but when it seems nobody is home I'll crank it up on the master close to noon. Thats when it was working properly.

And also in the setup that I have now, at the non 50 watt setup I'll be sure to change this by the way! With El34's! But I did it to see if I could get the tubes to saturate at a lower volume, and it did change the tone, but you guys recommend otherwise. So I'll adhear to your advice for sure!

I do remember going from Channel 3 to Channel 2 and getting the same thing. So I guess its the Master Output. So the process would be new tubes, proper operation settings, play. Problem persists, clean Volume pot on Master Output (which I still will need some 'detailed' instruction on). Can I pick up that product at wal-mart? Or find something similar?

Oh and no this amp since its been in my possesion has been played around at some places, and banged up on a few walls. But nothing on the face plate.

Carrying a head and 2x12 up and down steps before jamming and after is just the worst!

 

[jbird]

And yeah I was operating on a proper load, the Mesa 2x12 rectifer cab (V30's) I have 8 ohms.

Wrong! Are'nt you suppose to half the ohmage when pulling tubes? So it should be out of the 4 ohm jack?

 

[disassembled]

And yeah I was operating on a proper load, the Mesa 2x12 rectifer cab (V30's) I have 8 ohms.

Wrong! Are'nt you suppose to half the ohmage when pulling tubes? So it should be out of the 4 ohm jack?

AHHHH it's the AMP NAZI!!! No amp for you! 1 year!

Relax....an impedance mismatch isn't going to hurt the amp as people do it all the time. It's ok to go one notch out of match (16ohm cab to 8 ohm input 8 ohm cab to 4 ohm input) you will just lose a little volume and some characteristics will change a bit but there's nothing to worry about.

To the original poster:

You can't clean the pots unless you take the amp apart. Seeing as how you did not know this I do know recommend that you take your amp apart and wait for a friend or repair person that is qualified to do this to step in. If your pot has been damaged due to abuse, movement, or whatever could have happened it may have to be refabbed or replaced.

What you can do to try to loosen up any dirt is while the amp is off or in standby turn whatever ones are giving you a problem back and forth kind of fast to see if that helps you out.

Greg