|Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only.|
|8th Apr 2009, 4:42 pm||#1|
Join Date: May 2006
Location: Arlesey, Bedfordshire.
KB Minuet distortion
My KB OB10 Minuet (Trader sheet 1345) sounds good for the first 15 minutes or so after switching on and then becomes distorted. R3 gets too hot to touch, but the voltages on the pins of V1 (6BE6) & V2 (6AT6) don't seem to alter from those specified. I have changed C17 and C20.
Am I barking up the wrong tree in assuming that either V1 or V2 is taking too much screen current and causing the distortion, or does R3 usually run hot? In which case I should be looking elsewhere.....
I don't have any spare valves for this set, so substitution is not an option at this stage.
Thanks in anticipation
|8th Apr 2009, 4:50 pm||#2|
Join Date: Sep 2003
Re: KB Minuet distortion
Well it sounds to me like the O/P valve may be going into grid current. You could check C4, R4, R11 and R13.
Try another speaker (does not have to match, just for a test) but I would suspect V4.
Might be worth checking C15 and C16.
If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?