KB300 Starts Strong Then Fades

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Gramps9999
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Joined: Thu Dec 22, 2016 11:52 pm

KB300 Starts Strong Then Fades

Post by Gramps9999 » Thu Dec 22, 2016 11:59 pm

My KB300 starts strong when it has been off for a while, but them a few minutes in starts fading until you can barely hear it. Has anyone run into that, and if so, what might be causing it?

Dad Roadie
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Joined: Sat Aug 27, 2011 1:47 pm

Re: KB300 Starts Strong Then Fades

Post by Dad Roadie » Sat Feb 11, 2017 4:45 pm

Ive had this happen on my KB60 amp at different times. I believe your KB300 has some of the same features. Every time my amp has done this one of the items below has fixed the problem.

1# I turn the amp off off and using a guitar cord plug one of the cord ends into each input /output socket on the amp rapidly several times. (High/low/preamp out/power amp in/headphone) .These jacks get dirty and cause the signal to fade. This is very common on the Preamp out-power amp in jacks.

2#Ive also had this on my Peavey MP5+ . The issue on this was a dirty volume or tone pot on one of the channels. With the amp on when the amp fades gently turn each of the pots on the amp and see if it comes back on. If it does a little Deoxit on the pot in question should clear it up.


As these old Peaveys get 30 years plus on them this oxidation gremlin pops up more and more. Because a lot of the jacks are not easily obtainable any more the cleaning is about the only way to keep them up and running. I use my KB60 for our music clinic programs so it gets a lot of use. Ive found if I clean the jacks as described in part #1 and the pots as in #2 every 6 months or so the problem doesn't return.

Good luck and hope this helps!
Dad Roadie

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Enzo
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Location: Lansing, Michigan

Re: KB300 Starts Strong Then Fades

Post by Enzo » Sat Feb 11, 2017 6:27 pm

Dirty cutout contacts insert jacks and patch jack is common on any brand.

Spray some cleaner into the jack before poking a plug in and out a few times to spread it.

Rob22315
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Joined: Tue Jun 21, 2011 8:06 pm

Re: KB300 Starts Strong Then Fades

Post by Rob22315 » Wed Jul 26, 2017 8:31 pm

The KB300 I got for my church had a ridiculous amount of corrosion on the reverb tank terminals. I'm not sure why those terminals specifically would get so gunked up but the corrosion was thick and really tough to get off. You might take a look at the two RCA-like jacks connected to the reverb tank while you're in there poking around.

The other thing to check is the coil gap. It's common for the foam filter in the back of the BW to deteriorate and fall into the coil gap where it will gum up the coil eventually causing the whole thing to disintegrate and fail.
Peavey Transformer 112 (2) and 212.
Peavey Generation EXP

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