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previous: Lee M. My AX84 November (Marshall Plexi pr... -- 4/24/2000 11:10 PM view thread

Re: Taming icepick highs

4/25/2000 2:32 AM
Re: Taming icepick highs
Hi Lee,  
Just a couple of thoughts.  
The value of the bypass cap on the volume pot can make a big difference. You can try removing it and if that's too dark, then try using a smaller value. I've spent hours tweaking that one cap along with the cap in parallel with the 470K resistor (including the value of that resistor also). Those two caps can do all sorts of things to your tone. You might try increasing the .68uf bypass cap to around a 1uf. Go too high in value and to my ears it starts to muddy up.  
I've had problems with amps sounding too piercing also. However, rather than having extremely high frequencies and trying to shunt them to ground, I found to a certain degree, it's really an upper midrange that's piercing and not really the high end. So not sure, if that's the same as what you're talking about. That's why I've found bypass caps at the volume control and around series resistors can be tweaked to give a shine without the pierce. My tendency is to keep the cathode bypass cap as small as possible. (Larger values are fine to my ears at lower volumes)  
Lastly, when you say turning down your treble and presence you still have the piercing sound, it leads me to think it's more of the upper midrange, cause otherwise your highs should be about gone. Unless there's something else going on. I'd be interested to see how you make out with it.  
Good Luck, T. B.

Lee M. Thanks for the tips. I'll try thos... -- 4/25/2000 12:36 PM