Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: jerryjg on June 24, 2010, 01:12:39 pm

Title: One tube pulsing in a quad
Post by: jerryjg on June 24, 2010, 01:12:39 pm

I have a amp, a Bogen amp that one tube in the quad of 4 7868's is pulsing al ot brighter than the others. Doesnt matter which tube I put in that position. Also, once it arced- hadn't been fired up in awhile.  The two front tubes make a very high pitched squealing  noise when pressed down sometimes- not all the time. Any ideas whats going on here.
I played the amp for a good long while and it does seem to run cool and no issues besides that one flare up of the tube and the bright pulsing of it. Loose tube pins?

Title: Re: One tube pulsing in a quad
Post by: John on June 24, 2010, 01:39:02 pm

One of the guys will probably tell you to make sure there's not a "channel" burnt between 2 of the terminals on the pot, and to make sure you don't have any bad solder joints.