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Are Marshall Valvestates reliable?

Started by Defnic, January 04, 2008, 09:57:00 AM

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slideman82

It's not a pain in the *ss changing that tube, in fact, is the most simple thing you can do inside one of these! Major problems are pots, changing them will take a few minutes, but taking off the PCB from the chassis needs some patience!

DIYmastermind

Quote from: THChrist on February 12, 2008, 08:41:45 PM
ever tried one of the MG series? they r solid state (100%) but sounds so full of life you'll think you're playin' thru a valve-amp or hybrid. sounds good to me. try before you buy, but first, press the FDD switch.

I have a Marshall MG15CDR combo amp. Well, had. I converted it into an 8 ohm head. Even before i did the conversion, the amp had an irritating hum on the od channel, no matter what guitar was running through it. It still hums and i'm trying to sell it for parts bacause i was never really impressed with the tone. However when i run it through my WGS vet 30 loaded Luke 2x12C (Orange 2x12 closed back cab clone) the clean channel sounds full and focused. Then again, what wouldn't through that cab? Idk, maybe i got a dud? I did buy it used from a pawn shop. And for the first year i had it the od channel was fine. One day it just started humming badly. It didn't get dropped or anything. In fact, it sat on the floor in my room that whole year. 

Enzo

When someone tells you that so and so model of such and such brand had a "large percentage" of them fail in some way, ask yourself this:  how would he know what percentage of them had that problem?   Answer is, he wouldn;t.   That is all internet talk.   People visit an amp forum and see several people having trouble with some amp, and assume it must be because there is some inherent flaw.   But in reality, it is more likely that the offending amp is a more popular model so there are a lot more of them out there.

I bet if you watch a Chevrolet dealer service department you will see a lot more Impala models than you do Corvettes.  Is that because Corvettes are more reliable?   Probably not.   It is more about the fact they sell thousands more Impalas than they do 'Vettes.

All these amps are made with the same materials and based on the same circuits, I have no reason to think any one is more or less reliable than another.   As someone said, the main problems are mechanical.  Big filter caps crack their solder, jacks come loose and crack their solder, pots fail or are broken.

Roly

Quote from: joecool85What's normally wrong with the SS amps?

By far and away blown output stages (which frequently tracks back to speaker connectors and leads), together with all the other normal stuff for all stage audio gear, broken connectors, drink spills, dirty pots and connectors, things inside damaged by heat or vibration.

Most PCB laminate doesn't like prolonged heating, you tend to see a lot of browned to charred PCB and associated power resistors and zeners.

In older amps lifting tracks on PCB's are often a problem, particularly after a previous repair or two.

You see sundry design problems such as PCB laminate that is too thin, components that are too large to mount on a PCB, cooling problems.

And just when we all thought we were out of a job, the beancounters arrived...

Then;
Pots and sockets were securely mounted on solid steel front and back panels, and had flying leads to the rest of the circuitry, point-to-point or central PCB - and the input sockets were all metal.

Now;
All controls and sockets are generally mounted on an all-in-one PCB.  Often their entire physical support is through their soldered connections, itself a bad practice, all fastenings to the front panel having been eliminated for economy of materials and production.

One thing that hasn't changed is that people trip over guitar leads, and amps get deep-sixed doing a faceplant on the floor.  This sort of accident is much more traumatic with this economised construction style than it was with an earlier generation of amps that had very substantial steel chassis to carry the heavy transformers, and incidentally all the controls and sockets.

Repairing amps and synths that really aren't worth repairing is pretty standard bread-and-butter these days.    :'(
If you say theory and practice don't agree you haven't applied enough theory.