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#1 Help required to finish a valve project - please

Posted: Fri Feb 02, 2018 5:08 pm
by Blues45
Hi, Friend of mine had a go at building a Headphone Amplifier. He lives in London and I live in Oldham, Lancs - the amp is currently with me. It is built but has a couple of issues - one being MONO when it should be Stereo, and the other issue being HUM.

Any kind soul out there who might be able to assist????


Thanks.

#2 Re: Help required to finish a valve project - please

Posted: Fri Feb 23, 2018 9:44 am
by RhythMick
Is there a circuit diagram ?

How far did the build get ? Does the one channel work ?

#3 Re: Help required to finish a valve project - please

Posted: Mon Apr 30, 2018 6:16 pm
by Firebottle
Does the amplifier have floating heaters, i.e. no connection to the signal ground at all? This can cause hum issues.

If the output is in the form of a cathode follower then a raised bias voltage is probably necessary to avoid excess heater cathode voltages on all the valves.