JCM601 - diode already clipped?

[LouieTM]

Hello,

I just picked up a JCM601 combo almost for free and, when I opened it to change the valves, I also checked the infamous diode that a lot of JCM600 owners have clipped.
Now, I'm a chemical engineer by trade, so I know nothing about the inner workings of an amp, but when looking at the schematics, it seems like there has been some sort of modification done to the C105 already.
Even with the old valves, I didn't find the amp's overdrive to sound too harsh, on the contrary. This was also the reason why I checked the diode, since I didn't want it to be to gainy.
Could a knowledgeable someone take a look at these photos and tell me what is the situation there?

Thanks!







For reference, here's the schematic I was referring to: http://www.drtube.com/schematics/marsha ... -61-02.pdf

-- Tue Feb 15, 2011 11:50 pm --

I meant "diode already bypassed", obviously, not "clipped". Sorry! :)

[KevinOConnor]

Hi Guys

Is the 10k resistor replacing C105? If so, it is there to add compliance to the clipping. This softens the sound as TUT explains.

Oddly, on the schematic, beside the designation for R104 is written 1nF-50V. This cap - were it in the R104 position, would also soften the distortion a bit.

Have fun
Kevin O'Connor