First gig with MTS....amp died 10 minutes in.

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mrtatemyballs

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How frustrating! I have been rehearsing and playing with my RM50 for months and have had no issues. First gig and the darn thing dies during the 2nd song.

Sound starts cutting in and out then gets real quiet, and my weber mass attenuator starts smoking out the back.

I wrap everything up and take it home in a huff. Plug in just guitar into amp and the strangest things are happening.

It's like the master is on 10 all the time. When it is on zero it is still ear splitting loud, but cutting in and out. Turning the master does nothing at all.

I take it to a local tech, and after sitting in his shop for 5 days it works fine the first time he fires it up. He runs it for a good 3 or 4 hours, and can find no problem.

It's back at home now working fine. I have a gig friday and I am so nervous.

Any ideas guys?

i just put in a NOS phase inverter tube, could that tube be the culprit?
 
I had a rm50 combo myself...I used it alot at rehearsals and I was never quite confident that it was gig worthy. It did seem to have issues..just like yours..no volume..then Id wack it with my hand and the amp would be on 10...really inconsistant stuff. I sold it at a low cost to a guy who felt ok buying it with some known issues.
Some people get the whole repair-thingy.
Anyway, advice??? Id use a different amp.Sorry to say..maybe others have had better succes with rm50 combos..but I only had one and over 8 months I never felt it was gig worthy.
I love Randall MTS..but I think Bruce Egnater and the gang at Randall lost interest in the middle of getting the rmn50 out. Just my guess.
GtrGeorge
PS: My rm4 and rt 2/50 has never failed me...they've fallen from 5 feet and kept on rockin.
GtrGeorge
 
PS: I dont know if all or most rm50s have issues..do a search here,maybe.
But whatever ya do..don't blame yourself. Things happen. Playing gigs is like an epic battle..things happen...its very tough on people and gear.
There is a reason why pros use certain gear again and again and again. It always performs.
Its the gear makers who are supoosed to make sure the stuff works right,not us. (unless its routine maintenence)...
so dont get crazy...
just keep rockin
GtrGeorge
 
What's the history of the amp? New? Used?
If the Weber Attenuator "starts smoking" something is wrong. At least, open it up and see what smoked.
If a volume pot doesn't work, check the pot itself, the volume boost jack, solder connections...did the pot knob get hit? Is the metal cover of the pot loose? Detached? etc.
Check the ohms switch. Does it slide and click into the 3 positions positively?
Is it pushed in? Loose? etc.
Pull the amp chassis. Any black "soot" around the output tube sockets?
Any evidence of arching on the board? Anything smell burnt?
If your tech didn't check for that, what are they waiting for?
 
It sounds like the attenuator might be the cause of the failure. Not sure, of course, since I can't check out the amp. But in general, attenuators have a terrible record of destroying amps. I'm surprised anyone uses them anymore, esp with the good MV circuits that are available. Randall Aiken and other boutique builders have tons of stories of all the amp repair jobs they got from people gigging with attenuators and blowing up their amps.
 
How loud did you have the amp's master? May be unrelated, but my RM100 turns out to be 140W, not 100, so could have something similar and done weird things to the attenuator...
 
Thanks for the advice guys. However, I'm pretty familiar with electronic circuits and how attenuators work, so I feel confident using them. My weber mass has lasted with me through 4 rigs now, and I consider it the best investment I have ever made in my tone. I run my master on 6 so it's not like I am blowing it out.....I just tend to play on quieter stages with in ears, but I still want cranked amp tones. Not using it is not an option.....well, until it gets fixed I guess I have no choice.

Anyways. Here is my best guess as to what happened:

I switched over to my clean channel and something obviously was not right.

On a dark stage I couldn't do much troubleshooting, but during the song everything got weak and started cutting out, even though the signal was very hot and more gainy than usual. This was my first gig with a new compressor pedal so I was checking that thinking it was the problem. I unplugged all effects from the chain and the effects loop and it was still effed up.

After I got the amp down I saw that someone had taken my clean module and turned all the knobs up to 10....so when I switched to clean...BOOOM twice as loud as on my drive channel.

I think that blew the attenuator, which then messed up the amp in some way until it had a chance to cool down.


Anyways, the tech checked the chassis, and he is pretty familiar with egnater designs. Everything looks fine, nothing burned, no bad connections, but just to be safe he resoldered the master volume pot connections.

I have a rehearsal thursday and a gig friday, so we will see how she does.

I love this amp so hard, I just hope it can hold up.

EDIT: amp is still working fine, and sounds wonderful. Best tone I've had in years.
 
Slashpepper said:
How loud did you have the amp's master? May be unrelated, but my RM100 turns out to be 140W, not 100, so could have something similar and done weird things to the attenuator...

What makes you believe it really be 140w? The amp was originally set up with four 30w power tubes but most legit amp manufacturers derate that to 100w since you will never run that power section at 100%, not for long anyway.

I wouldn't be surprised if the problem that some combos have is that boost circuit. That's an accident waiting to happen. I think the safe thing to do is permanently mod the combo with a slotted pot like Bruce uses in the bias section so it won't accidentally get turned up to 11 or else bypass that circuit altogether.
 
"After I got the amp down I saw that someone had taken my clean module and turned all the knobs up to 10....so when I switched to clean...BOOOM twice as loud as on my drive channel."

That's why...NOBODY TOUCHES MY EQUIPMENT!!!!! EVER!!!!!

OK, you may now resume whatever you were doing.
 
OK GUYS.

Further updates.


When I play the amp for more than 30 minutes or so, the volume keeps cutting in and out. Starts to seem like a phase inverter or power tube problem.....but here is where it gets WIERD.

A few minutes after that, the master volume knob stops working and the amp locks in on 10!!! It is all the way up all the time and turning the master does nothing. No more cutting in and out, just stuck on 10.

It gets wierder.

I built a BOOST footswitch for the amp with a pot so I can control the amount of boost. In effect, it switches the master control of the amp to the pot in the footswitch.

When I plug in and activate the boost, all the problems stop. I can control the volume of the amp just fine via the pot on the footswitch. The knob on the amp still does nothing, but the amp seems to perform fine so long as I leave the boost engaged.


Thinking I have a bad solder joint or something in the master control section.

Any ideas?
 
You probably have something as simple as a bad volume pot and/or solder connections, OR, the jack you plug the boost switch into is not switching
back into the circuit when you pull the plug out of it, SO, get some DeOxit5
and clean all the jacks and pots, ESPECIALLY, the series effects jacks.
 
Totenkampf said:
What makes you believe it really be 140w? The amp was originally set up with four 30w power tubes but most legit amp manufacturers derate that to 100w since you will never run that power section at 100%, not for long anyway.
.

I've blown two sets of speakers (though unrelated to the power, I think...) so in general trying to find out what's wrong the thing the amp tech did some sort of power test on it.
 
This is one of the most misunderstood topics regarding amps out there. Wattage is a measure of electrical power. Most people NEVER approach using the quantities of horsepower under the hood of any amp, certainly not for a sustained period of time.

If you blew speakers, it's typically the result of a MASSIVE transient peak forcing over excursion and not at all related to the wattage of your amp. My suspect is a fracture in you Master Volume pot based on all the info you posted below. Until it's replaced, you are subject to experiencing it again.

True story to illustrate the above point:

In 2010 my band was heading a Friday night gig at The Stone Pony in Asbury Park. The Stage Manager thought he was lending me a hand at load in by rolling in my Mesa Vert 2x12 for me. My pedal board was on top and took a dive right next to the stage. I didn't notice one of the patch cables had come slightly unplugged, neither visually or sonically.

About 50 minutes into our hour set, there was a thunderous crackle emitted from my cab. Sure enough, the subwoofers under the stage were directly under my pedals and it had shaken the patch cable out. The transient spike it caused forced my 50 watt head (only on about 11:00, which might be around 25 watts of output) to blow one of the to Celestion G12-K100's in my cab.

There you have an amp putting out around 25 watts blowing a 100 watt speaker in a cab that had 2 inside. It's the only blown speaker I have ever experienced in 17 years of active gigging.
 
Thanks for the responses guys. Rob, I will check the master volume POT. I re-soldered it already, will go ahead and replace it and see what happens.
 
UPDATE:

The volume pot was not the culprit. I ordered a foglifter board from Rob since I wanted one anyway. I had to call him on the install because my original board had the pinout in a different order. i got it installed and it really made a nice difference in the overall clarity of the amp and the useable low end.

Unfortunately, it did not fix the problem.....so it's safe to say the volume pot is not the issue.

Here is what I have found:

When I play the amp WITHOUT anything plugged in to the "boost" jack, the amp acts up by jumping back and forth from whatever volume I have set to 10 sporadically.

When I plug a cable into that jack, the problem magically goes away. It doesn't even matter if I have the boost engaged or not, just putting a cable in the jack fixes the problem. I have had several 3 hour plus rehearsals lately, and as long as I keep something plugged in the boost jack....no problems. As soon as I remove it....problems.

Pretty sure my boost jack either has a bad solder joint, or is just failing mechanically and needs to be replaced.

Any thoughts anyone?


Also having a problem with my effects loop, but I will start a new thread to keep this one localized to this problem only.
 
kc2eeb said:
"After I got the amp down I saw that someone had taken my clean module and turned all the knobs up to 10....so when I switched to clean...BOOOM twice as loud as on my drive channel."

That's why...NOBODY TOUCHES MY EQUIPMENT!!!!! EVER!!!!!

OK, you may now resume whatever you were doing.

So true. People tend to have this attitude "hey I know what I'm doing and what are you afraid of?" .. well, you don't and this.

It does sound like the combination of maxed clean + broken master vol did the trick. I'm not really surprised that killed the Weber ;) Although on the other hand I'm surprised the Weber doesn't have some kind of safeguard.
 
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