unpleasant chaisaw distorsion on a fender

[nooneknows]

Hi,
I've noticed that one incarnation of my derivative od  from Booster 2.5 and Sweet Thing, on a Fender Twin gets really unpleasant, with a a ice cracking highs tone, a thing that doesn't happen  with my marshalls and my peavey.
I guess it's the broader band amplified by a clean fender, with a higher  cutoff frequency.
I've seen at RunoffGroove the thunderchief has a double lowpass filter at the end, sort like of (hope it can be seen):

 R1                 R2
^^^^----+---^^^^----+-----
              |                  |  
    C1   ===        C2 ===
              |                  |    
              |                  |


anyone know how to calculate the rolloff frequency?
thank you in advance.

M.

[nooneknows]

sorry the drawing sucks, please forgive me.... there are two RC cell to ground one after the other...

[jubjub]

I experience the same thing. For me the crodther audio hotcake is realy the best thing at getting that rock sound on a fender. Everything else just seems to harsh. Germanium transistor fuzzfaces can also sound good but not very flexible. I asked about this the other day and tried to find a simple mod to do to the bright switch on the amp but as yet have had no luck. Sorry I cant be much help to you, but at least I can do this.

--b-u-m-p-

[petemoore]

Not by the numbers, it certainly does the cleanly defined smooth [slightly] rolled off highs thing though.
 I'm looking for a Spst switch for the Thunderchief, to break the last caps conntection to ground. That should make a good bright switch, maybe an even smaller cap on the other side of the switch.

[niftydog]

sorry the drawing sucks, please forgive me

Get thyn ass to Andys site and downloadeth ye self yon copy of "ASCIIcircuit" lest ye ne'r beg forgiveness again.