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K200 Hiss Only On Bright Channel? [message #3861] Thu, 11 March 2004 09:31 Anonymous My K200B-1 has fairly loud hiss on Bright side and is perfectly quiet on Normal side. Why do used Kustoms always seem to have problems on the left (Bright) side? You have to stay plugged into Normal side to survive. Report message to a moderator

Re: K200 Hiss Only On Bright Channel? [message #3874 is a reply to message #3861] Wed, 17 March 2004 07:33   stevem Messages: 4733 Registered: June 2004 Location: NY Senior Member HI, Does the bright channel have more gain or volume than the normal channel or just more treble and hiss? Does the bright switch work? Report message to a moderator

Re: K200 Hiss Only On Bright Channel? [message #3908 is a reply to message #3874] Sat, 20 March 2004 12:48 Anonymous Everything seems to function on Bright Channel. The Bright switch works, and the hiss is noticably altered by the Treble, Bass & Volume pots & Bright switch. The hiss begins the moment the volume is turned and gets louder as the volume is raised - whether or not a guitar is plugged in. When I plug my bass into the channel, the notes are produced, but with the loud hiss in the background. I have already replaced cord w/3prong, output transistors w/NTE181MPs, and Mallory CGS50V25000 caps, just to recondition. All contacts, blade connectors & pots cleaned, PC Boards checked for anything obvious. I thought that maybe, this would cure the hiss in the process, but no change. The Normal side works fine and is silent at idle. Report message to a moderator

Re: K200 Hiss Only On Bright Channel? [message #4194 is a reply to message #3908] Fri, 14 May 2004 11:42 Anonymous I'm not sure how much hiss is normal but they all have some. Do you have a grounded plug replacement? Report message to a moderator

Re: K200 Hiss Only On Bright Channel? [message #4195 is a reply to message #4194] Fri, 14 May 2004 13:43 C4ster Messages: 686 Registered: June 2001 Location: Mukwonago, WI (Milwaukee... Senior Member A grounded plug will have no effect. The resason the hiss is more pronounced in the bright channel is that channel has a higher treble frequency than the normal channel. The hiss comes from the very high gain of the channel. Kustom uses a volume that runs the output of the channel back into the input inverted from the original signal. The two signals cancel each other in varying degrees depending on the volume setting. If you noticed, you cannot completely turn the volume down to 0. There is always some signal getting through. That high gain amplifies the noise in the transistors, resistors and diodes and that is the hissing you hear. I have heard that replacing all of the resistors with metal film resistors and better grade transistors will substantially reduce the hiss. Most of the times though, we just live with the hiss as a badge of Kustom honor. Conrad Report message to a moderator

Re: K200 Hiss Only On Bright Channel? [message #4293 is a reply to message #4195] Wed, 02 June 2004 13:39 Anonymous I replaced all of the transistors and all of the capacitors and I still have the same amount of hiss. Argh! So, I guess it's time to replace the resistors then. It will be all brand new parts by the time I am done. Oh well. Report message to a moderator

Re: K200 Hiss Only On Bright Channel? [message #10512 is a reply to message #3861] Sun, 22 February 2009 10:28   77Pbass Messages: 18 Registered: February 2009 Junior Member I just purchased a 1970 KB200B-1 with the same problem. Sounds like I should replace the resistors first and see if the hiss is reduced. Are there any schematics available? The sticky post gives alternate method to get schematics but they don't work. I don't want to attempt the work without a schematic and knowing the proper wattage. Report message to a moderator

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