Peavey kb100

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
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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

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! :p

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.

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Originally Posted by McCreed

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!

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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'.

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.

It's always wise to be nervous around electricity and circuits. Solid state amps are normally run at much lower voltages than valve amps, but with correspondingly higher internal currents (when running) to compensate for that. But if you don't have access to a schematic to check, and know how to read and interpret it,then play safe and for solid state amps allow a few hours for the caps to discharge after turning it off, and wait a day for valve amps (if you haven't got a capacitor discharge probe).

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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!

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My bad!!!

I'll just stick to stuff you plug into the amp...

Always better to be safe than sorry. And until you know for certain, always play safe.

First thing I usually do when I get a second-hand Peavey amp, is I replace all the input sockets with new ones, which reminds me, I did that to my Peavey Renown amp and that fixed the intermittent input sockets completely, I'd recommend buying a can of Electrical Clean & Lube from your local Jaycar Electronics shop, and give all the pots a spray with it, you'll need to put a bend in the end of the thin plastic straw that comes with the can of Electrical Clean & Lube so you can spray into the pot, then rotate the pot-knob back and forth through it's full range a few times, that usually fixes crackly/noisy pots.

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Originally Posted by DrNomis_44

First thing I usually do when I get a second-hand Peavey amp, is I replace all the input sockets with new ones, which reminds me, I did that to my Peavey Renown amp and that fixed the intermittent input sockets completely, I'd recommend buying a can of Electrical Clean & Lube from your local Jaycar Electronics shop, and give all the pots a spray with it, you'll need to put a bend in the end of the thin plastic straw that comes with the can of Electrical Clean & Lube so you can spray into the pot, then rotate the pot-knob back and forth through it's full range a few times, that usually fixes crackly/noisy pots.

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For pots, it's better if you can find lubricated contact cleaner. A little tougher to get than the regular stuff, but better for parts that move.

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Originally Posted by fender3x

1+

For pots, it's better if you can find lubricated contact cleaner. A little tougher to get than the regular stuff, but better for parts that move.

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Jaycar sell a can of Servisol Electrical Clean & Lube (Cat. No. NA-1012) it contains a lubricated contact cleaner, I think it costs about Au$16.00 or so per can, it is great for pots, Deoxit is good too.

Deoxit is the slightly better contact cleaner, so is great for jack contacts and other push connectors, but Servisol does have that lubricant, so is better for pots. Anything with a lubricant in it is going to accumulate dust so will require regular cleaning, but it's much better than living with scratchy pots.

This is a pic of my can of Servisol Clean & Lube, so far I've had very good results with it:

Attachment 40072

Went down to my local electronics shop this morning and grabbed an equivalent product and cleaned my scratchy as heck 20yo practice amp. It’s been bugging me for ages, now it sounds as good as new. Thanks guys 👍.

I have to see if I can get some of that brand. I have trouble finding the lubricated cleaner here.

I think there used to be an attachment you could get for pots so that you could lube them from the top without removing them, but it's been so long since I've seen this thing that I feel like I might be making it up.

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WD40 now do a proper 'fast drying contact cleaner' that works well (not the basic WD40), but it's not lubricated, so more like the straight Caig's DeoxIT. Though Caig also do a separate lube-only spray, CAIG DeoxIT Faderlube F5. It probably makes more sense to first clean out and then lube, rather than do both at the same time (although it is more convenient).

It's relatively easy to find the non-lubed contact cleaner, interesting that the WD-40 folks now have one. I didn't know you could get the lube-only. Looks like I can get it here, though it's pricy. But I see that the brand I usually use, CRC, has a silicone lube for electrical parts. Here you can get both for less than half the price of the Deoxit clearner+lube...for what it's worth.

In the photo of my can of Electrical Clean & Lube, that I posted, you'll notice that the end of the thin plastic pipe has a bend in it, I did that to make it easier to spray inside the metal pot-cover of the pots I was cleaning.

I do mine like doc...but the device I was thinking of is something like this:

Attachment 40119Attachment 40120

...I am, of course, too cheap to own one.

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Originally Posted by fender3x

I do mine like doc...but the device I was thinking of is something like this:

Attachment 40119Attachment 40120

...I am, of course, too cheap to own one.

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I think Stewmac stock something like that.

However that method may not get the cleaner/lubricant on the track, or be patchy at best. Better than nothing if you don't want to take pots out of a semi-acoustic to spray them, but not as good as being able to spray inside the slot.

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Originally Posted by Simon Barden

However that method may not get the cleaner/lubricant on the track, or be patchy at best. Better than nothing if you don't want to take pots out of a semi-acoustic to spray them, but not as good as being able to spray inside the slot.

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Yeah, I suspect that's right. I have been tempted for the semi accoustics where I don't have easy access. Then I see the price and begin wondering if it's even effective. a curved tube like Doc posted is probably better if you can get at the back easily.

Loosening the pot nuts slightly so you can rotate them if necessary, a flexible nozzle for the spray and a mirror should do it. Only if the wiring harness is very tight and doesn't allow the pots to turn enough to get the nozzle in might you need to think about dropping the whole harness down so you can pull it back nearer the F-holes.

Of course some of those Gretsch styles with knobs in the top and front horn could prove very difficult without removing pickups and almost fully removing and re-installing the harness again.

I found that simply putting a bend at the end of the thin plastic tubing you get with the cans of electrical cleaning sprays, worked well enough for me....hint, that idea is not patented, so free use of it is not only perfectly okay, I'm also encouraging it.

Where I think the bend-in-the-tubing idea really works and saves a lot of frustration, and, or, some unmentionable "colourful" words (I'm assuming you know very well what I mean by that), is in the situation where you have pots soldered to a circuit-board as found in the majority of most guitar amps that use printed circuit boards, I know only too well just how much of a pain it is to work on them, you usually end up taking the circuit board out of the amp at least half a dozen times in the process of servicing the amp, this is where old-style eyelet boards, such as those in Fender amps, have a big advantage, to replace a resistor, cap, etc, you simply desolder the faulty part and solder a new one in it's place.