Dual Rectifier Problem - Noise (From Head - NOT Feedback)

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CjGuitarist82

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Dec 8, 2010
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Nashville, TN
Hello, all... 1st post here and I need help. I got a used dual recto (three channel) back in Feb. It worked amazingly until a couple of weeks ago. First, my (current) setup.

PRS SE Custom 24 - VHT Valvulator I - Boss TU2 - Dunlop 535Q - Boss CS3 (NEED to upgrade this) - ISP Decimator - 808 (still trying to choose between Ibanez & Maxon, I have both) - Boss NS2 - DUAL RECTIFIER [Then in the loop] - Ibanez DE7 Delay - EH Holy Grail Nano Reverb [All into] - Marshall 1960a

Yes, this amp has spawned a terrible case of GAS, haha. On to the problem.
A couple weeks ago I noticed it was much more noisy than it should be (as it should be Silent with the guitar's volume down & 2 different noise suppressors), so I started troubleshooting. Now, before anyone says anything about the 2 noise suppressors, the ISP quiets extra guitar noise / NS2 cuts the pedal noise... trust me, it works great. The noise I'm getting is kind of static-y and louder when the amp is louder. I can't hear it so much on the clean channel, but I assume that's because it's the Clean channel, and whatever the problem is isn't being pushed enough to really come out. The noise is the same on Channel 2 & 3.

My first step in troubleshooting was checking for ground loop hum, Not It. Next I tried taking individual things out of the chain (pedals, cables, etc.), No Change. I bought a new preamp tube (12ax7, like the rest) and tried it in each position with no noticeable change in the noise or tone (good or bad). I tried taking out 2 power tubes & a recto tube (to make it 50watts) and it still had the same noise. I tried it with the opposite tubes and in the opposite slots with both... same noise. I tried two different guitars, both with the same noise, so it's not the guitar. I JUST got done playing with the guitar plugged Straight into the head with No pedals and Nothing hooked into the FX loop (and the loop turned off), so it's Definitely not anything to do with the chain.

One time while I was playing and getting the noise, I tapped the power tubes and the 3rd one from the left made the noise worse & made all the sound cut out (for less than a second, aka. while I was actually tapping it). I couldn't get it to do it again, though (until tonight, when the same one did the same thing Once when tapped). My initial thought is to replace the tubes, but money's pretty tight so I don't want to drop the cash if there's a chance that's not even the problem. I'm thinking since it wouldn't cause the noise more often when tapped it could actually be a problem with the spot it plugs into instead of the tube itself? I could see the rest of the tubes dimming/lighting up crazy with it when it had the problem while tapped.
I've also (the last few days) had a noticeable volume drop / rise very randomly when playing. Maybe once every 3-5 minutes it'll get half as loud (or twice as loud) over the course of half a second or less.
I had suspicions that it could be a problem with the cab back when it was just noise, but given the volume roller coaster & the noise from the tapped tube, I'm pretty sure it's the head itself. I've looked all over online for someone else with a similar problem (with advice already given) and seen nothing quite like this.
Any advice will be Greatly appreciated.

p.s. I tried playing with it turned up louder (have to keep it quiet in my apartment) but I didn't hook anything up to any of the outputs and I could still (VERY Faintly) hear my signal in the head... is that normal with tubes or could that be connected to my problem somehow. (Probably a stupid question)
 
Well, as you already guessed, it sounds like a bad power tube. You never know what abuse they went through when you buy a head used. Noise in any form is - of course - much worse in Channel 2 & 3 where it gets amplified 'til kingdom come ...

Before you buy a new pair of power tubes, you can pull out the middle pair, double your impedance rating on the cabinet (I think) and see if the problem stays. Running your amp on 50 Watt for testing isn't a problem, although I have never done this (owning a DR2010) and someone with more experience might comment on that. Or try searching the board, I'm sure you'll find some information.

If the noise gets much less, it looks like a tube. If it stays, something else is wrong ...
 
Like I said, I tried pulling the tubes (to make it 50w) and it still had the noise. I haven't tried it since the volume drop / popping started though. It's hard to test for because it does it so randomly. I pretty much just have to play until it does it... sometimes it'll do it after 2-3 minutes, sometimes I'll play 10-15 and it won't do it at all (the general noise problem is constant though). :?
 
If I were you I'd retube the whole thing. You are trying to trouble shoot a set of tubes that are who knows how old. Some people play on tubes for 5-10 years if the amp doesn't show any signs of probs (eventhough It is recommended that you change tubes once a year>> depending on how often you play). Having said that, I bought a used DSL50 about 6 monthes ago and immediately took it in for a retube. It turns out that the head had the original factory Marshall EL34s (2005 model DSL Head). I'm willing to bet your problem is a mixture of all the tubes in your amp and that it simply needs fresh tubes. I'd imagine troubleshooting with one preamp tube isn't gonna make much difference if all the rest of the tubes in the amp are toast.
 
Yes, a full retube is essential before thinking it might be something else. The tubes can share the same noisy characteristics if they all have the same amount of wear.
 
CjGuitarist82 said:
p.s. I tried playing with it turned up louder (have to keep it quiet in my apartment) but I didn't hook anything up to any of the outputs and I could still (VERY Faintly) hear my signal in the head... is that normal with tubes or could that be connected to my problem somehow. (Probably a stupid question)

Hmm, are you saying you played the amp with no speaker hooked up?

Do not do that with a tube amp. The output transformer needs a speaker load at all times. You will risk blowing powertubes or worse, the output tranny. If you did it for just a minute I'm sure that everything is OK, Mesa's are pretty tough.

If you are getting volume swells, read this: http://www.forum.grailtone.com/viewtopic.php?f=4&t=25102&start=19

With the noise and sound cutout you described I would immediatly change the powertubes. A blown powertube can take out other components in the amp, not all the time, but it can happen.

Dom
 
domct203 said:
Hmm, are you saying you played the amp with no speaker hooked up?

Do not do that with a tube amp. The output transformer needs a speaker load at all times. You will risk blowing powertubes or worse, the output tranny. If you did it for just a minute I'm sure that everything is OK, Mesa's are pretty tough.


I kind of figured that was the case. I only did it for a minute.

Thanks for the advice (everyone). I guess I'll try some new power tubes for starters. Can't afford all new Power & Preamp tubes at the moment. I'll just leave him alone til I get him fixed up :( ... which means I have to play through my other guitarist's Vetta II combo for practice. :evil: What really sucks is the Guitar Center here only has Groove Tubes (and they're over priced), so I'm going to have to order some... unless Sam Ash has some (I hate that place).

Any other insight?
 
First, NO, do not ever play your amp again with no speaker load. You will fry your output transformer. Second, stay away from places like Guitar Center or Sam Ash or Musician's Friend or Music 123 or anywhere else like them for tubes. They do not properly "match" their power tubes like claimed. Buy from a real tube vendor that knows tubes and takes the proper time to test and match. Some examples would be Bob At Eurotubes, Doug at Doug's Tubes or The Tube Store. All are excellent vendors. I do not like Groove Tubes myself, Groove Tubes does not make tubes...they take other brands of tubes, "test & match" (not well) and re-label them as Groove Tubes as if they made them. I prefer JJ's or SED's for power tubes.

As far as the noise goes, you most likely have a bad power tube. Just because you took them out two at at time, doesn't mean you don't have more than one bad tube. If they are all an original set with each other, and they're old, chances are good the others are hurting as well and giving you problems all the same. If money is an issue, and excellent deal is JJ 6L6GC's at Eurotubes for around 70 bucks. Can't beat them at that price, they sound great IMHO.

I have dealt with tube amps for a long time, and always change and bias my own tubes. I just got rid of a Soldano which was bias adjustable so I could get a new 2010 Dual Rec. It is not adjustable...yet. It goes into the amp shop here in Chicago tomorrow for a bias trim pot mod. Power tubes can give big problems, especially if old. They're like light bulbs and even new ones can go. Preamp tubes not so much...they last much longer, if not forever.

Hope this helps,
Ryan
 
CjGuitarist82 said:
domct203 said:
I kind of figured that was the case. I only did it for a minute.

Thanks for the advice (everyone). I guess I'll try some new power tubes for starters. Can't afford all new Power & Preamp tubes at the moment. I'll just leave him alone til I get him fixed up :( ... which means I have to play through my other guitarist's Vetta II combo for practice. :evil: What really sucks is the Guitar Center here only has Groove Tubes (and they're over priced), so I'm going to have to order some... unless Sam Ash has some (I hate that place).

Any other insight?

No insult to you, and everyone has to learn, but I'm still amazed at the number of people that kill their tube amps by unplugging the speakers ...
 
UnderJollyRoger said:
I'm still amazed at the number of people that kill their tube amps by unplugging the speakers ...

I am amazed at why you would even bother to do this when you can clearly hear all the noise is coming from the speakers.

And no matter what you are running, tubes amps make noise, they will never be silent. (unless on standby!) :lol:


Does the amp sound fine on all channels while actually playing?
 
UnderJollyRoger said:
No insult to you, and everyone has to learn, but I'm still amazed at the number of people that kill their tube amps by unplugging the speakers ...

Haha, yea I didn't see that in the Tube Amp handbook when I bought it. It won't happen again. Someone needs to put up a PSA of little stuff like that for newcomers.
 
volatileNoise said:
And no matter what you are running, tubes amps make noise, they will never be silent. (unless on standby!) :lol:

I understand what you're saying, but I've had this amp for 10 months now, so I know how it SHOULD sound. When it's working right it's actually pretty **** quiet when I'm not playing. (Other than pedal noise, which the NS-2 cuts Completely in this setup. I'm using the ISP to cut the signal for tighter stops... not for "noise" issues).

The new "noise" is only Noticeable when I'm Not playing (when it would Usually be more or less silent). That's not to say it isn't there While I'm playing... I probably just can't hear it over a half cranked Mesa :wink: . It does Not sound fine when I'm playing though, due to the volume drop / swell I mentioned.

I hate Guitar Center, too (and Sam Ash & the others even worse), just kind of stuck when it comes to smaller stuff and I need something fast. I definitely did Not want anything from GrooveTubes, but that's literally All they sold at this particular GC and I was somewhat desperate to see if a new preamp tube would do the trick. I don't mind ordering to get the right thing except that I have to record in about a week for a comp. we're doing that's going out to 3 other countries. Would kind of like it to sound decent, haha. My other guitarist plays through a Roadster, so I could record with that... but I like my setup better.

Anyway, new power tubes are definitely the next step. Feel free to keep more advice rolling in, though.
 
CjGuitarist82 said:
UnderJollyRoger said:
No insult to you, and everyone has to learn, but I'm still amazed at the number of people that kill their tube amps by unplugging the speakers ...

Haha, yea I didn't see that in the Tube Amp handbook when I bought it. It won't happen again. Someone needs to put up a PSA of little stuff like that for newcomers.

It is mentioned in the manual, hidden on the "Precautions and Warnings" page in the beginning of the manual:

"WARNING: Always make certian proper load is connected before operating the amplifier. Failure to do so could pose a shock hazard and may result in damage to the amplifier."

I agree, it needs to be spelled out clearly and maybe included in the speaker hookup section, instead of just cryptically mentioned in the warnings.

Dom
 
domct203 said:
It is mentioned in the manual, hidden on the "Precautions and Warnings" page in the beginning of the manual:

And I even read the manual! Shame on me. I bet some people don't even bother to read it though.
 
So, I'm on Eurotubes and I think I'm just going to get one of the full re-tube kits. Has anyone tried any of the various options they offer?

I'm thinking:
*Mesa Dual Rec Standard retube kit with 6L6GC's
Price: $119.75
Description: A matched quad of the JJ 6L6GC's for a very fat and full sound along with 5 JJ ECC83S's one of them being balanced for the phase inverter in V5.

*Mesa Dual Rec - High Gain Option with 6L6GC's
Price: $134.00
Description: A quad of JJ 6L6GC's for a deeper tone from the power section. For the front end 3 hand picked high gain JJ ECC83S's for V1, V2, V3, a standard ECC83S for V4 and a balanced ECC83S for V5. Lots of depth and a scorching lead tone.

*Mesa Dual Rec GZ34 Rectifier Upgrade
Price: $32.00
Description: If you like the Rectifier tube sound but you find the stock 5U4's too mushy then here is the answer! A pair of the JJ GZ34's which are plug and play. These will maintain the Rectifier tone but put the mush on hold.


Can anyone offer some insight on the difference between 5U4's & GZ34's? Is the "High Gain Option" worth the extra $15?
 
I read this post (http://www.grailtone.com/forum/viewtopic.php?f=4&t=6784&start=0) about GZ34's being safe in the Dual Rec., but that doesn't entirely answer my question about them. (Other than just getting people's opinions on them) I was wondering if I need to worry about any bias adjustment if I would switch to GZ34's? Yes, I know the Rec's have a fixed bias, that's the point of my question... would switching fit within the parameters set for the fixed bias? Do the Rectifier tubes even have anything to do with that?

Sorry for all the new guy questions... this is my first time having an amp worth learning about.
 
The JJ 6L6's are awesome, the preamp tubes are ok except v1,v2 IMHO. I use a tung-sol reissue in v1, and a Sylvania NOS in v2, JJ's in the rest. That tung-sol is AWESOME. It's a magic little tube for v1. v2 sounds good using a multitude of different tubes, but the JJ ECC83's aren't for me in that position...too dark sounding. The GZ34's will give less sag and compression that the 5U4GB's, which I don't like. The whole reason for having tube rectifiers in an amp is to get sag and compression, something I love. So I use 5U4's. Bob Pletka is a smart guy, but sometimes I don't agree with him in the tone department.
 
I just got a great deal on tubes (on Craigslist... hear me out, haha). I talked to the guy ahead of time, then about 30 minutes in person about random gear stuff. Point being, I trust him.

ANYWAY:
*4 Matched MESA EL34's - Used less than an hour.
*4 Matched MESA 6L6's - Used a few months.
*3 MESA 12AX7's - UnUsed
*2 MESA 12AX7's - Used

$100

I'll probably try the EL34's while I have them, just to check them out, but from what I've read I doubt they're for me, so I'll probably sell them. The 6L6's Were used a few months, but I've used mine longer and there's no telling how long they were used Before I bought the head. The used 12AX7's weren't even in the ad, so even if they're no good it's no skin off my back. He said he's pretty sure one's fine and the other might be.

NOW, The Results:

I played the amp for 2-3 minutes before I swapped the tubes to get a feel for the problem again. I was plugged Straight into the amp, so no pedals (and only a couple cables) involved. Still had the noise problem And it did the cut out / slight volume drop thing. I even heard the cut out noise when the guitar was turned all the way down.
I put in the new tubes. I've only been able to play 5-6 minutes (got a phone call), but between me playing and leaving it On (aka. not on standby, just On with the guitar turned all the way down) while I was on the phone, I didn't hear the cut out thing anymore. Like I said before, though... it's Really random. The noise, however, is still there. I haven't swapped any of the preamp tubes yet, and I'm thinking there's even a chance it (the noise) could be cab related. I'm going to try to get a hold of my buddy's cab tonight to see if I can eliminate that possibility.

I'll update when I figure... anything... out.
 
I just played for 20-30 minutes straight. No more dropout / Extra noise problem, but the general noise (which Wasn't there before) is still there. Cab swap is next, then preamp tubes.
 
owned my recto going on a year now. dont remember ever turning it on and not hearing *some* kind of noise, especially on red. i would try connecting your amp to different power outlets. the power outlets at my rehearsal studio are horrid - they have neon lights on the same circuit as the outlets :? At home i know there are a couple of dodgey outlets i never plug into. But yeah point being, i think there will always be some kind of unwanted noise when you sit with the amp cranked and guitar volume down. I just got into the habit of switching to green when im sitting with the volume down.
 
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