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Old 16th July 2021, 07:14 AM
Richard Richard is offline
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Join Date: Dec 2005
Location: Notts
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Default Re: KEL34 making safe to work on

Quote:
Originally Posted by willslenco View Post
OK guys, looks like I have couple more problems:

1. It only affects the right channel and displays itself as intermittent low level crackle through speaker. It is worse on start up and slowly settles down over the course of about half an hour, it is much less frequent and obtrusive after this and only really noticeable with no music playing (I have left amp on with no music for a prolonged period to ascertain this). After an hour it's pretty much silent.

2. Getting a crazy buzz, and other weird noises, through the speakers at about 1/2 to 3/4 volume, both channels, with or without inputs connected, on all sources. It's not hum but a definite buzz which appears around that volume and disappears again after it. I don't normally play above 1/2 volume so it may have been there a little while. I've tried different speakers but same result. Also swapped a couple of EL34s in/out and fitted new 6AU6s and ECC82s but no change.

Where should I look next?

Hi Will, yes as Bob says, and my thoughts are,


1. go to http://www.world-designs.co.uk/forum...read.php?t=135 and scroll down to the ECC82 anode resistors. I had KEL34 and Kit88 amps and wrote up that FAQ from first hand experience.


2. can you outline your chain of connections; source>pre>amp>speakers and if there is any other attenuation before KEL34 vol pot. Sometimes what you describe can be an impedance mis-match from 2 pots on the input for example. Otherwise as Bob says check for joints and connectors and swap out what may simply be a noisy pot, it may have been used a lot around that setting by the previous owner.
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