Solid state Guitar Amp - DEAD? yay or nay?

[graysonmillar]

So here's my situation..

I own this guitar amp that was made somewhere between the late 70's and the mid 80's. It's an "Acoustic" brand, don't know too much else about it other than it's a solid state and outputs 300 watts. It's a basic solid state amp that I have been using for the past 6 or 7 years to power my 4x12" cabs (only one at a time, never simultaneously).

So a few months ago I was playing guitar, and the thing just shut off. I checked the fuse, it was burnt out. This was pretty typical behavior for that amp when a fuse went out so I assumed that was my problem.

Well, I finally got around to buying new fuses recently, and me being inexperienced with electrical stuff I took the amp into radio shack to have the guy pick out the correct fuse for me.

I am assuming the fuses we're the right ones for the amp, but when I installed one (it uses one at a time), I could not get it to power on.

I can't figure out what would have damaged it, I haven't really moved the amp very much so I know something didn't get broken from being agetated. There was no sort of power surge that I am aware of when the amp 'blew the fuse', (nothing else in my bedroom was affected during the incident).

Like I said, I no very little about electrical stuff, so I am pretty clueless on this one. It's my only amp at this time, so I am freaking out from months without playing on my own gear.

Is there anything that would cause this sort of problem, from everyday, careful use?

Help

[tomg]

Is there anything that would cause this sort of problem, from everyday, careful use?

Help

Sounds like a shorted output transistor... Sometimes it just happens. If you know how to use a meter to check for shorts and the outputs are in sockets. Remove the transistors one at a time and see if one is shorted. Replace the bad guy and try again.

There is no guarantee that it didn't take out a driver transistor when it went but usually it's just output transistors on an Acoustic. They are build to take punishment.

Good Luck

[downfader]

Or just find yourself a good amp tech if you feel a little iffy about opening it up yourself (I know I personally would). He/she would also be able to tweak and sort out any other issues for you to make it more reliable in future.

A good guitar shop might be able to get you in touch with a good tech.

[john82]

i don't think there's much choice except for taking it to a professional,

if you don't have knowledge in electronics theres not much of a chance you'll be able to fix it by yourslef ah?

anyway i wouldn't expect too much from an amp that dates back to the late 70's

Johnny from guitars101

[Hink]

anyway i wouldn't expect too much from an amp that dates back to the late 70's

[amarule]

Could be anything from a broken/cold solder point, blown diodes in the power rectifier circuit, dried out caps, etc. No way anyone could diagnose it here without seeing it and putting it through some testing.

Is it worth fixing? Depends on the cost of the repair, but if it's SS then unless its the power transformer probably won't cost you much. While the tech is in there have him replace ALL the electrolytic capacitors.

[pandashake]

anyway i wouldn't expect too much from an amp that dates back to the late 70's

double that.

i was running a kustom 74 challenger with no problems until it was stolen. i would buy the same old amp again if i had the drive and the money.

[MitchK1989]

buy an evolver and use it as an effects box?

[Muzik 4 Machines]

acoustic is a good brand for transitor amps, get it fixed if you can

[C00kie]

acoustic is a good brand for transitor amps, get it fixed if you can

... if that's not already done. Notice this thread is now about a whole month old

[pinkjimiphoton]

So here's my situation..

I own this guitar amp that was made somewhere between the late 70's and the mid 80's. It's an "Acoustic" brand, don't know too much else about it other than it's a solid state and outputs 300 watts. It's a basic solid state amp that I have been using for the past 6 or 7 years to power my 4x12" cabs (only one at a time, never simultaneously).

So a few months ago I was playing guitar, and the thing just shut off. I checked the fuse, it was burnt out. This was pretty typical behavior for that amp when a fuse went out so I assumed that was my problem.

Well, I finally got around to buying new fuses recently, and me being inexperienced with electrical stuff I took the amp into radio shack to have the guy pick out the correct fuse for me.

I am assuming the fuses we're the right ones for the amp, but when I installed one (it uses one at a time), I could not get it to power on.

I can't figure out what would have damaged it, I haven't really moved the amp very much so I know something didn't get broken from being agetated. There was no sort of power surge that I am aware of when the amp 'blew the fuse', (nothing else in my bedroom was affected during the incident).

Like I said, I no very little about electrical stuff, so I am pretty clueless on this one. It's my only amp at this time, so I am freaking out from months without playing on my own gear.

Is there anything that would cause this sort of problem, from everyday, careful use?

Help

Hi,
having done some tube amp things over the years and having a bud that had one of them (he pumped bass thru it, you can definitely run two 4x12's with it with no damage once it's right again) heed the info on the output trannys...very common in accoustics..

but if you take it to a tech (and you should, these suckers get crazy after thirty years and changing one dumb component can throw the whole amp off and make it smoke....for real, my bassist had that happen 3 times in a row) make sure that he changes all the electrolytic caps in the power supply...
these amps use big caps, and ALL electrolytics get bad over time, even in solid state amps.
if the amp was humming, oor had a weird dissonant opposite-sounding bend to it faintly when doing bends on your guitar strings before the amp crapped out, it could very well be a filter cap gone south as well.

you may wanna search around, as you can usually find a replacement for around what you'd pay for repair...

BUT...then you're buying whatever problems the replacement has, too...and it's thirty years old.

IMHO, if you dig the amp, and it works for YOU, (and them accoustics are great amps when working, talk about EARBLEED PINYOUREARSBACKTOTHEFREEKINWALL) i'd get it fixed up...you gain an amp you like and are familiar with, and it should last for decades after being cleaned up.

good luck dude!
pjp