It is currently Mon Mar 16, 2020 6:42 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 17 posts ]  Go to page Previous  1, 2
Go to page Previous  1, 2
Author Message
Post subject: Re: 1967 Fender Bassman AB165 blowing fuses
Posted: Sun Mar 20, 2011 4:44 pm
Offline
Aspiring Musician
Aspiring Musician

Joined: Fri Dec 12, 2008 5:32 pm
Posts: 329
Well if you changed the resistors on the power tubes it will probably change the bias, that is probably you are getting the same sound with both tubes. The output tubes are probably a little on the cold side with the low power you seem to be talking about


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: 1967 Fender Bassman AB165 blowing fuses
Posted: Mon Mar 21, 2011 1:11 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
You know, I usually don't have "too little volume" as an issue, even if the bias pot is turned too cold, into into Class B settings. The amp sounds horrible, but usually you still have good volume with new, strong testing tubes.

However, if your amp popped fuses before... you may have also damaged the screen resistor(s) (470-ohm, 1 watt) or the grid stopper resistor(s) (1500ohm, 1/2 watt) that are connected to the power tube. If either or both are damaged, the amount of current/signal that passes through the power tube maybe severely limited.

Both resistors sit on the power tube sockets. Might be a good idea to check them out, to be sure they are ok.

http://www.kbapps.com/audio/schematics/ ... ab165.html

Edit: I now realize this topic has been posted on this very thread! Must remember to read first and take my "brain meds." Anyhow, in this vein... check to be sure the sockets are not damaged. Sometimes they crack when too much juice passes through a tube. Also, look for any carbon tracking left behind by popped resistors. These could short out some of the signal. Check for good contact between pins and socket.

And that the grounding strap from pin 8 (cathode) to ground is good, for each 6L6GC.

Good luck!


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 17 posts ]  Go to page Previous  1, 2
Go to page Previous  1, 2

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: