Metropoulos Forum

anyone cut out C48 (.001 cap on preamp board) It's just sending a lot of highs to ground? I clipped it and the amp sounds a lot better on both channels IMHO. Wondering if anyone has done this ? Is this like the clarity mod that FJA does? will this hurt my amp? One last question, what does the .1 cap (C15) do? it's right where you plug your guitar in and the signal has to go thru this cap before getting to V1 (thinking of bypassing this too). thanks for any info on this stuff.

Can you post a link to the schematic?
Thanks.

jamme61 wrote:anyone cut out C48 (.001 cap on preamp board) It's just sending a lot of highs to ground? I clipped it and the amp sounds a lot better on both channels IMHO. Wondering if anyone has done this ? Is this like the clarity mod that FJA does? will this hurt my amp? One last question, what does the .1 cap (C15) do? it's right where you plug your guitar in and the signal has to go thru this cap before getting to V1 (thinking of bypassing this too). thanks for any info on this stuff.

C48 does essentially the same thing the 1n cap across the cold clipper stage of the SLO does, shunting upper harmonic frequencies to ground. It will not hurt your amp to remove it. C15 serves two functions, 1) to block DC from getting to or from the grid of the first tube and 2) it forms a high pass filter with R25.

thanks for the help. I think I'll leave the input cap alone but, the other (C48 ) sounds a lot better off IMHO. I see what your talking about on the slo 100 and I also see this on my Mesa Tremoverb schematic. I'll have to play the amp out to check it out. here's a link for the schematic if anyone is interested http://www.blueguitar.org/new/schem/peavey/5150evh.pdf" onclick="window.open(this.href);return false;

[[/quote]
C48 does essentially the same thing the 1n cap across the cold clipper stage of the SLO does, shunting upper harmonic frequencies to ground. It will not hurt your amp to remove it. C15 serves two functions, 1) to block DC from getting to or from the grid of the first tube and 2) it forms a high pass filter with R25.[/quote]


Why do they do this in amps? is it just to make them stable because of all the gain?

jamme61 wrote: Why do they do this in amps? is it just to make them stable because of all the gain?

Sometimes for stability against oscillation sometimes for filtering most of the time both.