Blonde Bassman 6G6-A

Janglin_Jack · Post by **Janglin_Jack** » Thu May 12, 2011 1:53 pm

I picked up a Blonde Bassman 6G6-A through a friend and it appears all original with the exception of the filter caps being replaced and a resistor in the bias network. The Normal channel seems a little underpowered. There is no output until you get the volume knob up to around 3. I know on some of my other amps, there is a cutoff usually below like 1 where the amp sort of shuts off, but on this amp, that is at around 3. I would expect on 3, the amp would be LOUD. What should I check?? I replaced all the preamp tubes so far.

I am going to check some of the voltages, etc, but not really sure where to start with this one.

Mike

sgv · Post by **sgv** » Fri May 13, 2011 3:14 pm

I have a blonde Bassman from late '61 early '62. It has a SS rectifier with oxblood.

I've had cap work done on mine over the years, as I used to play 80-90 shows a year with it. My volume did have that "shut off" limit...yet it was under 1. The original volume pot is very sensitive and the amp is ripping at 4. I'm not sure what would cause your issue...yet it doesn't sound normal.

Good luck with it!

Janglin_Jack · Post by **Janglin_Jack** » Fri May 13, 2011 5:33 pm

Thanks for your confirmation. I have had other amps with that cutoff, but usually around 1. I got the schematic and noted all the voltages. I will pull the tubes and start testing the amp to be sure all the voltages match up. I'll let you know what I find.

Mike

sgv · Post by **sgv** » Sat May 14, 2011 9:19 am

If I have some time today...maybe I'll snap a few pictures of my Bassman chasis.

Janglin_Jack · Post by **Janglin_Jack** » Sat May 14, 2011 2:47 pm

I opened the chassis and checked all the resistor values against the schematic and tested each one with my meter. Everything checked out. I put my meter on the Normal volume pot and it was giving me strange readings. As I turned the knob, it didn't move the needle at all on the meter and then it sort of jumped to 1M at the very end. I took the pot out and tested it and it is failing. The wiper must be losing contact or something. I noticed it was a 1M Linear pot too, instead of Audio taper. I put in a 1M Audio taper pot and the amp comes one between 1/2 and is LOUD at 3/4.

I also spent the evening checking all the voltages and everything tested great. So all seems great!

Thanks
Mike

Metropoulos Forum

Blonde Bassman 6G6-A

Blonde Bassman 6G6-A

Re: Blonde Bassman 6G6-A

Re: Blonde Bassman 6G6-A

Re: Blonde Bassman 6G6-A

Re: Blonde Bassman 6G6-A