I think this is the right place for this...
I realise that this is made as a keyboard amp but a couple reviews I have looked at say good for bass and acoustic electrics. The best part is that my parents neighbour gave it to me and said if u don’t want it then throw it out because if u don’t take it then I will. One input is not working but everything else seems fine.
Does anyone have any experience with these? Is it worth cleaning up and getting everything going again? Cheers
Last edited by Rossco381; 04-04-2021 at 02:53 PM.
Hey, a free amp is always a welcome item in my book.
A bad input could be as simple as resoldering. I think that will have closed jacks pcb mounted jacks, but I'm not an expert when it comes to amp repair. However there are a few members here that really know their stuff with these things!
Hopefully they'll come to the rescue...
One thing I can can tell you for certain, is that will have deadly electrolytic capacitors in it. Be sure to discharge them properly before you go poking around in there!
BTW, if you haven't got it already, I found this:
https://www.audioservicemanuals.com/...2-89-schematic
Last edited by McCreed; 04-04-2021 at 03:30 PM.
Making the world a better place; one guitar at a time...
It should be great for bass or acoustic electrics. KB amps have to handle all the highs to the lows on a keyboard which goes lower than a bass and as high as the highest notes on an acoustic guitar.
I agree with McCreed that there is probably deadly voltage inside in the big caps. Best not to open it if you can avoid it.
You could just not use the non-working channel. You still have two, so you might not even miss it. McCreed may be right that a solder connection may have come loose. Before opening it or taking it to a repair shop I would be inclined to try to clean up the jack a little with some contact cleaner on a Q-tip. It may not have an effect, but there is enough visible rust on the jacks to at least give it a shot....
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Was thinking that. Is only 2 of us at any one time playing anyway. I have gotten by up till now with a single small amp, so i think we should be right. Apparently has not been used for quite a while, so might just tidy it up as much as I can without opening the case up. Thanks for the quick replies. Might be a job for a rainy day ..... hang on a minute......
Success. Little bit of electrical contact cleaner soaked on a piece of dowel slightly smaller than 1/4". Measured the length and shape of input jack and worked in and out a couple times. Little bit of crud came out and tried some sound on all inputs and works a treat. Thanks for the tips.
I am guessing you'll be pretty happy with it for bass. It's a 1x15 right? It should be built like a tank. Plenty of amp to play bass in a practice session or even small gigs. Nice get!
Bingo! That was too easy!
Making the world a better place; one guitar at a time...
Yep. 15inch. According to Dr google it is a 15" eminence made 8ohm 100w speaker made in the 43 week of 1987. Well over 20 kg i am thinking and bloody solid.
It's a transistor, not a valve amp. On the 220/240v model of this amp, the only caps are on the secondary side of the mains transformer, and the main voltage rails are at ±25v dc. Whilst care should always be taken around electronic circuits with a mains input, in this case, with the power just off, even 25v isn't going to cause any harm or even a mild shock unless you've got really wet sweaty fingers, and a few minutes wait will see the voltage drop even further. Even bridging between +25v and -25v points on the circuit is still within the 0-60v DC range of 'extra low voltage' and deemed to be 'low risk'.Originally Posted by McCreed
In a valve amp, the secondary circuit electrolytic caps will typically be charged to between 300v and 500v DC, which definitely is very dangerous to play with until the caps have been discharged, either quickly using a proper discharge probe or naturally over time (I always allow 24 hours).
Thanks Simon. I shouldn’t have been so nervous about removing anything to have a look. It turned out I didn’t need to remove anything anyway and it seems to all be in working order.
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