O/T: Calling Mark Hammer-'59 Bassman tone stack question

[Russ]

Hi Mark (or anyone else who might help),
My question is about the 5F6-A Fender Tweed Bassman tone circuit, which includes a 56K slope resistor and two .022 caps (bass and mid caps).

What would be accomplished by changing the tone circuit to a 100K slope resistor and a .1 bass cap, such as Fender's Reissue '59 Bassman has?
Does this serve to shift the lower-end frequencies up somewhat, or am I totally confused here?

Thanks in advance,
Russ

[aron]

Russ,

The answer lies here:

http://duncanamps.com/tsc/index.html

Now go and design a killer tone stack!  

[Russ]

Sorry, Aron, I have an iMac computer, and I can't get download that software. Can anyone just give me a layman's explanation of what this would change?
Thanks,
Russ

[aron]

Virtual PC will run it or probably one of the free emulators:

[Russ]

Sorry again, Aron, I greatly appreciate your help with this, but I don't quite understand how to interpret the graphs (and in the second graph I believe the bass cap should be 100nf and the mid cap 22nf).
That's really why I just want to get a simple explanation of what will occur when the slope resistor is changed to 100K and the bass cap to .1uf
Thanks, Russ

[Mark Hammer]

Russ,
I'm assuming Aron has addressed your query?

[Doug_H]

;lkj

[cd]

Yes, the bass turnover frequency is shifted down slightly, as is the midrange.  The treble is not really affected.  The overall result is that you'll hear less bass and mids.

[Russ]

Thanks guys, that's what I was wondering about. I have a Tweed Bassman clone and I'm hoping that changing to the RI Bassman tone stack will serve to tighten up the low end a little bit and cause it to be a little less flabby.
Thanks,
Russ

[WorkBench]

What rectifier tube are you using?

[cd]

Thanks guys, that's what I was wondering about. I have a Tweed Bassman clone and I'm hoping that changing to the RI Bassman tone stack will serve to tighten up the low end a little bit and cause it to be a little less flabby.
Thanks,
Russ

I can't say for sure but the OPPOSITE might happen - the bass will become even more flabby.  Changing to the original values pumps more bass & mids through the rest of the amp = more flab.

[Russ]

The amp has a 5AR4 rectifier tube.
Thanks,
Russ