My friend had a Marshall Valvestate head and it used to make a rumbling noise. He found out that a large percentage of them had a manufacturing problem. I'm pretty sure it was made in the mid nineties. Now, a coworker of mine wants to buy her kid a Valvestate 100 combo amp. I don't know how old the amp is.
Are any of you guys aware of problems with these Marshall Valvestate amps?
Quote from: Defnic on January 04, 2008, 09:57:00 AM
My friend had a Marshall Valvestate head and it used to make a rumbling noise. He found out that a large percentage of them had a manufacturing problem. I'm pretty sure it was made in the mid nineties. Now, a coworker of mine wants to buy her kid a Valvestate 100 combo amp. I don't know how old the amp is.
Are any of you guys aware of problems with these Marshall Valvestate amps?
I hadn't heard of any issues with them. Of course there is nothing more reliable than 100% solid state. My poor Dean Markley K-20X has gone through hell and back and still works like new.
thanks joecool.
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.
The Valvestats where made in the mid 90's 95 or 96 , they where not made long. I have 2 100watt heads , I have had no major problems with mine. not to rattle any chains , but Joe I work on amps everyday , and I see more Solid State than tube amps , on failures , most of the tube amps are mods.
Rock On
Quote from: Jack1962 on April 07, 2008, 09:00:52 PM
The Valvestats where made in the mid 90's 95 or 96 , they where not made long. I have 2 100watt heads , I have had no major problems with mine. not to rattle any chains , but Joe I work on amps everyday , and I see more Solid State than tube amps , on failures , most of the tube amps are mods.
Rock On
What's normally wrong with the SS amps? I'm no amp tech, but I've never seen an SS amp need more than a new pot or jack.
I'd guess blown output stages, loose solder joints in filter caps and cement resistors - and like you mentioned, various contact problems in jacks and pots. Sometimes input stages busted by "human errors", e.g. plugging another amp into the amp's input etc. Any older amp from 70's or 80's may also have problems with aged capacitors or other components.
But I still wouldn't call SS amps unreliable. I'm pretty sure that once these new "affordable" tube amps age a bit you guys will begin to see them serviced more and more frequently. I'm curious, the percent of SS amps is higher since most PA and keyboard amps are SS, so are most of bass amps and perhaps 50% of all guitar amps as well. It could be that this is "biasing" your opinion about their reliability. Is the percentage of SS guitar amps that come to service higher? There is also the issue that a tube amp that has one or several of its tubes blown is easier to fix than a SS amp in similar condition (having one or several active devices blown). I assume these cases do not most of the time enter service. Have you also considered the issue how profitable it is to service tube amps versus SS amps. Tube amps generally cost a lot more so servicing them might seem like a good alternative whereas taking a cheap SS amp to service may at worst double its price.
The Primary reason that I do more actual repairs on SS than tube , because the manufatures back in the early mid 80's started producing massive #'s of these amps , and pushing the the reliablity thing (any amp will last SS or Tube if not abused). The repairs I do the most are on blown preamp chips or transistors, or simply blown resistors in output stages, my favorite are the thermal sensors on the output Transistors. but it's basically because you can buy a SS amp a lot cheaper than a tube amp so there are more of them out there(right now ). However, I play thru SS amps as well, and I dig them too. It's all in what tone you want and with the amp modeling thing you don't really have to buy a $2000 amp to get that tone anymore.
Rock On
I often repair Valvestates (I have a VS100 on my bench right now) and Fenders, but to be precise, the problems are more mechanical than electronic. PCBs flex and develop invisible cracks just where the thin track (around 30 mils) joins the pot/jack/switch solder pad. Laneys, with a similar construction, are more reliable because they have fatter tracks (40/50 mils). Old Peaveys and most 70´s / 80´s amps, with their hand drawn PCBs, are most reliable in that respect.
Today I also have an Acoustic 118 with beautiful hand-drawn boards (and blown output transistors). Those cracked track problems are often mistaken as "cold solder joints", specially because they are repaired by resoldering, but truth is that resoldering just bridges both sides of the crack. I use a jeweler´s loupe to detect them. Sometimes I also find blown output transistors and very infrequently some blown TDA1514, very hard to find. I have made a replacement mini-board with an LM3886, which is cheap, available, and far stronger, and wire it to the corresponding pins (+-B, ground, etc.) on the original board.
Quote from: J M Fahey on June 05, 2008, 11:10:21 PM
Sometimes I also find blown output transistors and very infrequently some blown TDA1514, very hard to find. I have made a replacement mini-board with an LM3886, which is cheap, available, and far stronger, and wire it to the corresponding pins (+-B, ground, etc.) on the original board.
Neat, do you have any pics of retrofitting a LM3886 into something?
Dear Joecool: I´m up to my ears now with work, but next week I´ll convert my .pcb file into a .gif or .ps , take some pictures, and post them here. The 3886 is bolted to the original heatsink; upside down if necessary, (to avoid touching the original board) and a few short (no more than 10 cm) cables are wired to the original holes where the old chip used to live : +/-B, ground, etc. I often run speaker wires straight to the speaker itself, to minimize ground loop problems or instability. Basically i replace a "black box" (the original amp) with another.
I owned one of the 40w x 40w, stereo chorus Valvestate combos with two 12" speakers - made around 1994 in the UK. I had a number of problems with pots. First of all they got crackley really fast; and because they were mounted right on the board I also developed a number of cracked solder joints where the pots were mounted. I only owned it about 9 months before passing it on to my brother who kept it alive for another 5-6 years after eventually having all the pots replaced.
Yes , as JM said solder joints and pots can be a problem, not to cut myself out of work guy's , if your handy with a soldering iron , you can repair most of these prblems yourself, and save alot of cash, I charge $65 an hour to work on amps, and that's a competative rate here.
Rcok On
I think they-re quite reliable, and I love almost all of them, specially 8040 (80xx series are better than VS, but they do not use the 12ax7 in clean channel), but if you can buy an 8280, try it! Sounds amzing, with a mosfet clean preamp and power mosftes as output... plus stereo chorus!
They're reliable but if you have to change the tube - its a major pain.
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!
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.
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.
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. :'(