K200-1 head [message #24116] |
Mon, 02 November 2015 10:54 |
Breakersbass
Messages: 13 Registered: August 2015 Location: Summerville,sc
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Junior Member |
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Guys,
I have a k200-1 Bass head only that has alot of white noise. The caps appear to be Mylar.What can I do to lower this hiss at idle?
Thanks
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Re: K200-1 head [message #24118 is a reply to message #24116] |
Mon, 02 November 2015 13:00 |
chicagobill
Messages: 2006 Registered: April 2003
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Senior Member |
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Start by trying to locate the source of the noise. Turn down all of the controls and turn them up one at a time, making note of which ones if any, makes the noise better or worse.
Try using a high value cap to ground out the audio signal coming from the two preamp boards going in to the power amp. Or you could just unsolder the two blue wires from the pre amps to the power amp input. That would isolate the power amp circuit to see if the noise is being generated there or in the pre amps.
The actual noise can be generated by transistors, resistors and sometimes caps. Finding the actual source is sometimes difficult. Once you have found the general area of the circuit, you can use a capacitor to shunt the audio signal to ground and listen to hear if the noise is shut off. Then you will know that the noise is being generated somewhere in the circuit ahead of where you grounded out the signal.
Some people will just rebuild the entire circuit hoping to cure it. This will work to a point, but requires a lot of parts and a lot of organization to not install the wrong part in the wrong place.
Let us know what you find out.
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Re: K200-1 head [message #24120 is a reply to message #24116] |
Mon, 02 November 2015 16:49 |
chicagobill
Messages: 2006 Registered: April 2003
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Senior Member |
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Unless you have a Lot-A-Tone head, there are no Germanium transistors in there.
Pleat does ask a good question though, is it an A or a B series head?
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