Adjust resistance & capacitance to

Hopefully, pretty straightforward. Vinyl sounds GREAT with one amp I have. With another that has a more extended high end, I notice some harshness on certain LPs. Was wondering if anyone had experience adjusting capacitance and/or resistance to smooth overly bright treble. My phono-pre has switches to accommodate different cartridges - both MM & MC. If yes, any advice on the direction to move things? Thanks in advance.
Soften treble: lower impedance.
I find under 300 ohm for MC best.
If your MC cart is running in a 47Kohm setting, that makes the treble shrill.
Most MM are designed for 47Kohm.

I have never really played around with capacitance so not comment on that.
Elizabeth, Thanks. That gives me the direction I needed.
Need a little more info.
Same cartridge, same turntable, same phono preamp, same line stage but different power amps? Or is it
Same cartridge, same turntable, same phono preamp, different integrated amps?

I'm asking this because I had a situation in which a new power amp revealed that my cartridge was actually mis-aligned, the previous amp wasn't clear enough for me to hear the problem. It took me forever to track the problem down to the alignment because I was making incorrect assumptions and applying "corrections" to the wrong components.

The key factors that made me realize it was the cartridge alignment was that the harshness usually occurred towards the end of an album side and was exacerbated by loud passages. I also compared albums to CDs to see if it was simply a bad mastering job.
A cartridge is adjusted or fine tuned to the system integration. Thus, with each amp, you may have to adjust the tracking angle or your loading as this can have profound impacts on the top end and other aspects of the sound. Jallen
Folks - thanks for the input. Discovered the reason for the poor sound quality when switching back to tubes (tube pre & monoblocks) was that the solid state integrated I had been using for the last 1/2 yr or so required the Heed's hi output RCAs. Forgot I'd made that change. Changed connection of the tube preamp to the low out RCAs from the Heed and things went back to sounding really great. Useful to have confirmed both load and impedence settings can be useful for "tone adjustment".