Marshall 2061x head lost volume - Help Troubleshoot

[King Guitar]

Hey Guys,

I was running my Marshall 2061x head last night through a fully optioned 200 watt max Ultimate Attenuator into a Marshall Hand wired 4x12 cabinet.

note: The Marshall head has the upgraded Mercury Magnetics Transformer installed.

Volume and tone where dimed on the 20 watt head and the UA was attenuating the signal. Head set to 16 ohms and cab is 16 ohms.

Sounded killer, then is just kinda downshifted to a very weak signal almost inaudible. I immediately shut it down. No strange smells or anything.

I unhooked the UA and just plugged the head into the cabinet straight and plugged my Les Paul in, very very weak distorted output with everything cranked.

I took the back panel off and the tubes which are new Groove Tubes are heating up fine and glowing normally (Orange).

I hope to hell the newly replaced Mercury Magnetics OT didn't crap out on me.

I am going to get some replacement Power tubes today and see if that helps.

Any ideas?

 

[nbarts]

Did you check fuses?
Checking tubes would be the first thing to do anyway.

 

[JerryP]

Definately has the symptoms of a shorted outpt transformer. Power tubes would be a good first step. Cranking an amp into an attenuator is bad news.
Jerry

 

[Anonymous]

Cranking an amp into an attenuator is bad news.

Isn't that the whole point of an attenuator?

Steve

 

[King Guitar]

Put new power tubes in with no change. Taking to my amp tech now.

 

[druckpig]

Put new power tubes in with no change. Taking to my amp tech now.

over the years Ive had quite a few mains transformers cook as opposed to output transformers as a result of using attenuators, I stopped using attenuators as a result...

hope its nothing too major wrong with it

 

[JerryP]

Cranking an amp into an attenuator is bad news.

Isn't that the whole point of an attenuator?

Steve

IMO that's not the way to use them unless you enjoy damaging your amp. I find attenuators work best if you dial in a good tone with the amp and then use the attenuator as needed to knock the level down to something more usable. Running an amp wide open leads to high voltage damage with arcing of tube sockets, shorted output transformers, burnt circuit boards, and all sorts of other ugly shit. Older amps that weren't designed for distortion handle them up to higher level and it allows them to get to the sweet spot, but I would never go to 10. Modern amps designed for gain will let loose sooner. Pushing a square wave into a saturated output transformer leads to flyback voltage and high voltage damage.

You wouldn't jack your car tires off the ground and put it to the floor would you?

Jerry

 

[RoidRage]

Cranking an amp into an attenuator is bad news.

Isn't that the whole point of an attenuator?

Steve

IMO that's not the way to use them unless you enjoy damaging your amp. I find attenuators work best if you dial in a good tone with the amp and then use the attenuator as needed to knock the level down to something more usable. Running an amp wide open leads to high voltage damage with arcing of tube sockets, shorted output transformers, burnt circuit boards, and all sorts of other ugly shit. Older amps that weren't designed for distortion handle them up to higher level and it allows them to get to the sweet spot, but I would never go to 10. Modern amps designed for gain will let loose sooner. Pushing a square wave into a saturated output transformer leads to flyback voltage and high voltage damage.

You wouldn't jack your car tires off the ground and put it to the floor would you?

Jerry

Listen up guys... Cause Jerry know's his Stuff!

Best,

Roid RAGE

 

[Anonymous]

Cranking an amp into an attenuator is bad news.

Isn't that the whole point of an attenuator?

Steve

IMO that's not the way to use them unless you enjoy damaging your amp. I find attenuators work best if you dial in a good tone with the amp and then use the attenuator as needed to knock the level down to something more usable. Running an amp wide open leads to high voltage damage with arcing of tube sockets, shorted output transformers, burnt circuit boards, and all sorts of other ugly shit. Older amps that weren't designed for distortion handle them up to higher level and it allows them to get to the sweet spot, but I would never go to 10. Modern amps designed for gain will let loose sooner. Pushing a square wave into a saturated output transformer leads to flyback voltage and high voltage damage.

You wouldn't jack your car tires off the ground and put it to the floor would you?

Jerry

Well... with the PeaceMaker amp I used to play through, the only way to dial in a good tone was to crank the thing to 10, which had the unfortunate side effect of being beyond the realms of all that is holy loud. It was either an attenuator or a PPIMV. I used a HotPlate with the thing cranked wide open for many years with no damage whatsoever to the amp. Eventually I went with the PPIMV which worked well too...

Perhaps attenuators are bad for amps (although I personally haven't experienced any bad effects), but with a NMV Marshall type amp, you have no choice besides a PPIMV and to get the goods ya gotta crank 'em to high heaven... With most modern amps you have a regular master to use so I wouldn't see the need for an attenuator...

Steve

 

[King Guitar]

Cranking an amp into an attenuator is bad news.

Isn't that the whole point of an attenuator?

Steve

IMO that's not the way to use them unless you enjoy damaging your amp. I find attenuators work best if you dial in a good tone with the amp and then use the attenuator as needed to knock the level down to something more usable. Running an amp wide open leads to high voltage damage with arcing of tube sockets, shorted output transformers, burnt circuit boards, and all sorts of other ugly shit. Older amps that weren't designed for distortion handle them up to higher level and it allows them to get to the sweet spot, but I would never go to 10. Modern amps designed for gain will let loose sooner. Pushing a square wave into a saturated output transformer leads to flyback voltage and high voltage damage.

You wouldn't jack your car tires off the ground and put it to the floor would you?

Jerry

Well... with the PeaceMaker amp I used to play through, the only way to dial in a good tone was to crank the thing to 10, which had the unfortunate side effect of being beyond the realms of all that is holy loud. It was either an attenuator or a PPIMV. I used a HotPlate with the thing cranked wide open for many years with no damage whatsoever to the amp. Eventually I went with the PPIMV which worked well too...

Perhaps attenuators are bad for amps (although I personally haven't experienced any bad effects), but with a NMV Marshall type amp, you have no choice besides a PPIMV and to get the goods ya gotta crank 'em to high heaven... With most modern amps you have a regular master to use so I wouldn't see the need for an attenuator...

Steve

+1

 

[kasperjensen]

A few years back I had a Marshall head (quite old... don't remember the model now ) which did the exact same thing.
I have never been much of a tech-savvy guy, so I sent it off to Marshall HQ in Milton Keynes (UK).
During the week it was away, I sold it to a friend of mine. I delivered it to him, and it still didn't work despite Marshall claiming it was in perfect working order after I had paid the £250 (app. US$500 at the time).

I had seriously expected more from such a well established company...

 

[JerryP]

Well... with the PeaceMaker amp I used to play through, the only way to dial in a good tone was to crank the thing to 10, which had the unfortunate side effect of being beyond the realms of all that is holy loud. It was either an attenuator or a PPIMV. I used a HotPlate with the thing cranked wide open for many years with no damage whatsoever to the amp. Eventually I went with the PPIMV which worked well too...

Perhaps attenuators are bad for amps (although I personally haven't experienced any bad effects), but with a NMV Marshall type amp, you have no choice besides a PPIMV and to get the goods ya gotta crank 'em to high heaven... With most modern amps you have a regular master to use so I wouldn't see the need for an attenuator...

Steve

Many modern amps don't have "the tone" till they're too loud. A 5150 doesn't hit the sweet spot till 3 or 4 on the master, that's loud as fuck! Some players can benefit from an attenuator used to knock the volume down a little bit. My point above was to use it to control the volume, not to make the amp distort. As I said above the older amps like a plexi/NMV Marshall that weren't designed for distortion work OK with them, to a point. Pushing anything to the limit is going to strain things. Sure some amps will handle it better than others. There are a lot of vintage Marshalls out there with replacement OT's that didn't.
There's a reason Mercury Magnetics voids the warranty on any transformer used with an attenuator.
Jerry

 

[King Guitar]

not for nothing but I have run Marshall heads wide open for years as that is where you need to be to get the tone usually and I have never had these issues. This head sounds great but it was only maxed for 15 minutes total before it checked out, that is pretty weak for a 20 watt head that was designed to be cranked and advertised as a 20 watt plexi you could get the full on 10 tone at a lower volume.

 

[glip22]

Could just be a PI tube. Sometimes one of the triodes die. Happened to me a couple of times. Whenever I lose output I go right to the powertubes and PI tube. The tube can still glow and have no transconductane. Hope it's as simple as that.

 

[JTyson]

I would think that little beast would be made to run dimed, I've used a Marshall attenuator(SE100) for years, but dont run the amp dimed, I just used it to knock down the vol a bit

 

[stratotone]

Regarding attenuators - how is running an attenuator with an amp on 10 any different than running that amp on 10? So what you're really saying is to never crank your amp wide open?

Pete

 

[Anonymous]

Regarding attenuators - how is running an attenuator with an amp on 10 any different than running that amp on 10? So what you're really saying is to never crank your amp wide open?

Pete

The only difference I can see is the nature of the load. Speakers have a more varying inductive load than most attenuators, although some comapnies who make them claim to have solved that issue to an extent.

Steve

 

[Anonymous]

Many modern amps don't have "the tone" till they're too loud. A 5150 doesn't hit the sweet spot till 3 or 4 on the master, that's loud as fuck! Some players can benefit from an attenuator used to knock the volume down a little bit.

Yeah, it's loud, but it isn't even in the same ballpark as a cranked PeaceMaker or SuperLead... In that situation, you have no choice but to figure out some way to attenuate.

My point above was to use it to control the volume, not to make the amp distort.

What I don't get is why are you making that point since the amp in question is a NMV Marshall which has to be cranked to get the tone the user wants. Whether he went with or without an attenuator, he's gotta crank it to get the tone. Short of modding the amp with some sort of master or power scaling, he's gotta use an attenuator. He's not using the attenuator to make the amp distort (don't understand how this would happen anyway), he's using it to reduce the volume of his distorting amp...

As I said above the older amps like a plexi/NMV Marshall that weren't designed for distortion work OK with them, to a point. Pushing anything to the limit is going to strain things. Sure some amps will handle it better than others. There are a lot of vintage Marshalls out there with replacement OT's that didn't.

But the bottom line is that cranking any NMV Marshall not designed for distortion in order to achieve distortion is already putting the strain you are talking about on the amp, attenuator or not. If you are using a quality attenuator of the right rating that uses an inductive (not pure resistive) load, it shouldn't be THAT different than the same cranked amp into a 4x12... NMV Marshalls may not have been designed for distortion, but that is how we all use them and they sure sound sweet doing it. Most of us would just like that tone without going deaf... Seems a proper attenuator would be a sensible approach...

Steve

 

[stratotone]

We need Ed D in here to give us the straight dope on attenuators. Where are ya, Ed?

 

[Anonymous]

We need Ed D in here to give us the straight dope on attenuators. Where are ya, Ed?

I don't think he's gonna touch this discussion with a ten foot pole at this point!

Don't worry big guy! I'm carrying the attenuator torch!

Steve