Vintage/ Older Solid State Amp Maintenance?

FF71

Silver Supporting Member
Messages
5,511
We all know that vintage tubes amps needs to be serviced.

How about SS amps? I really LOVE my recent acquisition, a Marshall 5210.

What are the signs that it needs to be serviced?

So far, I've noticed that sometimes it pops, and a bit of hum when the volume is really high..I'm not sure if a brand new one will do the same, or maybe it's just a power issue?

I really love it, that I barely play my '65 DR and Boogie Mark 1 right now..and a plus..I don't use my pedalboard anymore!


 
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J M Fahey

Member
Messages
2,436
Yes, killer amp, don't overthink.

Tube amps wear a little every hour they are on, because cathode material has only so many electrons available to boil off and pass current, that's why tubes gradually weaken.

In fact some datasheets give you how many *hours* of good service they can give, and since a 10000 hour tube is a *premium* one, I guess regular ones must be way below that.

Of course, power tubes wear fast, preamp tubes last decades, but the fact is all wear, sooner or later.
That's why tubes are plug-in ;)

Now transistors being solid and not needing to boil anything, will either work forever same as the first day or die a violent death, so don't overthink it: if your amp works, enjoy it; if you have a problem, repair it.

What will eventually give you problems is what I call "mechanical parts": pots/jacks/switches/connectors but again, you'll notice that when it happens.

Being a combo is also good; a typical problem with heads is that users connect them to the wildest loads ("hey ... I found this odd speaker in the attic, let's connect it to see how it sounds") or use plain broken/shorted cables.
 

FF71

Silver Supporting Member
Messages
5,511
Really if it's working fine, have it recapped every 20 years.

If it has a large amount of hum while idle, that will let you know it's time.


Hope that helps.

Really? Cool exactly why I'm asking. I didn't know that SS amps needs a recap. Thanks!
 

Laurence

Gold Supporting Member
Messages
8,444
I feel as though getting decent maintenance on older SS is now more difficult than on all tube system; but my experience is limited to an old Rosac and a Lab Series L4. The Rosac is pretty simple, but the Lab Series is a bit more complex...Good techs willing to work on those types of items, IMHO, are rare.
 
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1,657
I don't work on SS amps often, but the few vintage ones I've done showed zero symptoms of the nasty bulging / exploded caps inside.

Maybe it's something about the high voltages of tube amps, but they're definitely prone to "showing you" when something is wrong.

If I hadn't inspected the guts, I would've never known my SS amps were struggling. How much abuse a given transistor will take until it fails is entirely unknown to me.
 
Messages
1,657
I feel as though getting decent maintenance on older SS is now more difficult than on all tube system; but my experience is limited to an old Rosac and a Lab Series L4. The Rosac is pretty simple, but the Lab Series is a bit more complex...Good techs willing to work on those types of items, IMHO, are rare.
Having restored SS amps, I'd say that techs-for-hire don't restore these because there is much more circuitry involved. More circuitry = more hours = higher bill for the customer. There aren't many SS amps worth a $300 service charge.

Considering the stagnancy of the SS market, most of these amps are not worth the high cost of restoring.
 

Tone_Terrific

Silver Supporting Member
Messages
33,083
Caps, dried up heat sink paste, oxidized pots, jacks, ribbon connectors, broken cooling fans, piles of dust and debris clogging the airflow...everything breaks.
E v e r y t h i n g. Your finest booteeky masterpiece will crap out at some point.
 

slybird

Member
Messages
6,465
I dad is a big am radio listener. Has several transistor radios. They all work. I don't think any of them have ever been serviced.
 

zenas

Member
Messages
8,769
Last SS amp I got roped into looking at was a Peavey TNT bass amp. I told the guy I'm not a SS guy by any stretch but he's a friend.
Thing was unusable due to noise but messing with one of the pots affected the noise. At that point I figured bad solder joints or bad pot.
So I pull the chassis and everything looked pretty good. (no obviously bad joints) Shot some Radio Shack tuner cleaner in the pots and that did the trick.
Been a few years and the darned thing is still working.

Moral of that story is.
Sometimes you just get lucky. :)
 
Messages
1,187
Just had my Marshall 5275 serviced. It is from about 1984, and I've had her since 1992. She definitely showed me she needed work. Popping, static in the knobs, and volume drops and jumps at unexpected times after a long period of not being played.

Mine needed jacks cleaned, a couple cold solder joints redone, and a resistor replaced, as well as every pot cleaned. Luckily, our repair tech was very reasonable on the labor. $30.00.

Here's the only pic I have right now. She is lower right corner.

 




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