A4 Hiss and Hum [message #12555] |
Mon, 28 December 2009 18:47 |
Shaun_Musings
Messages: 323 Registered: April 2009 Location: Reading, MA
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Senior Member |
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Okay, the hum is noticable and annoying. The hiss is loud when the trem/vibe is activated. Could this just be that it needs a better cleaning? The Reverb tank hisses a little until it is turned up...
Shaun
Born on the Baaaaayou (Ok, in Massachusetts)
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Re: A4 Hiss and Hum [message #12596 is a reply to message #12595] |
Thu, 31 December 2009 08:37 |
pleat
Messages: 1454 Registered: June 2004 Location: Belding, Mi
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Senior Member |
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Shaun,
I don't have many of the schematics you need, I have PC105 and PC803. I did have at one time 5 full Kustom notebooks with all their schematics. I sold them last year to a collector in NV.
One huge problem Kustom had with the A series amps with the white mallory caps. The gals soldering the boards would solder the cap and then try and wiggle it to make sure it was secure on the board. Problem was, the leads were solid on the board, but from the heat in soldering, the leads would pull loose inside the cap, and kustom had a lot of failures in the field with bad caps. Once Kustom saw what was happening, they instructed the girls not to try and move the caps until it had time to cool down inside the cap. Problem solved, and when the B series amps came out, kustom stopped using the white caps.
Don
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Re: A4 Hiss and Hum [message #12608 is a reply to message #12597] |
Thu, 31 December 2009 17:10 |
pleat
Messages: 1454 Registered: June 2004 Location: Belding, Mi
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Senior Member |
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Shaun, you can send me a email at djt@chartermi.net and I'll send you what I have. Given the history of the white mallory caps, I'd replace them as long as your changing transistors. I'm not a tech, but I do know you should use a heat sink when replacing transistors. Too much heat soldering them in can cook them. I assume that your trying to get excessive hiss and hum out. I'd take the advice of stevenm and replace the caps as well.
I know I've always had reservations on buying any of the A series heads, knowing that I don't want to replace all those mallory caps, knowing the early problems kustom had with them, and adding 40+ years in the mix, I stick with with the B series heads.
Don
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