Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Mr. Mojo on March 24, 2020, 12:48:55 pm

Title: 5f6a - 4 Filter Caps vs. Hoffman’s 5?
Post by: Mr. Mojo on March 24, 2020, 12:48:55 pm
The original 5f6a had 4 filter caps in the dog house - but Hoffman’s design uses 5 - I searched, but could not find an explanation for this - can anyone tell me why?
Title: Re: 5f6a - 4 Filter Caps vs. Hoffman’s 5?
Post by: sluckey on March 24, 2020, 01:36:19 pm
Quote from: Mr. Mojo on March 24, 2020, 12:48:55 pm
The original 5f6a had 4 filter caps in the dog house - but Hoffman’s design uses 5 - I searched, but could not find an explanation for this - can anyone tell me why?
Both amps have 5 filter caps. The original has 4 in the doghouse and 1 on the main board.
Title: Re: 5f6a - 4 Filter Caps vs. Hoffman’s 5?
Post by: Mr. Mojo on March 24, 2020, 02:31:51 pm
Gotcha!  I see what is going on -- the 5th Cap (#4) replaces the 8uF cap in the PreAmp Ground bus section on the Fender schematic.  That makes sense now.  Thank you!

Other question - - what does raising this value to 20uF do?
Title: Re: 5f6a - 4 Filter Caps vs. Hoffman’s 5?
Post by: 66Strat on March 24, 2020, 02:56:18 pm
Quote from: Mr. Mojo on March 24, 2020, 02:31:51 pm
Other question - - what does raising this value to 20uF do?

It shunts to ground all of the magic mojo that make the 5F6-A Bassman the king of guitar amps and turns it into a lifeless tone turd. :laugh:

I seriously doubt that you could nhear any noticeable difference. It may help a little bit in filtering and reduce the potential for 120 hz hum.