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[Defnic]

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?

[joecool85]

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.

[Defnic]

thanks joecool.

[THChrist]

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.

[Jack1962]

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

[joecool85]

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.

[teemuk]

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.

[Jack1962]

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

[J M Fahey]

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.

[joecool85]

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?

[J M Fahey]

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.

[wildschwein]

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.

[Jack1962]

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

[slideman82]

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!

[4by12]

They're reliable but if you have to change the tube - its a major pain.