yamaha m-2 amp c-4 preamp set up

I recently hooked up a new pair of kef xq40 speakers to a vintage yamaha m2 amp (240 wpc) and matched c4 preamp. Bass and mids out of this world clarity. Truly remarkable. The high end clarity is razor sharp... however with this razor sharpness I am hearing some raspiness... and suggestions ... thanks.

I don't know as much about the sound of the preamp, but to my eye, the M2 and M4 are some of the most beautiful and well made Japanese components from that era.

I have an M2 in my collection which I have not used very often but puts up a surprisingly good fight vs my Levinson 23.5 through my Magneplanars.

Others might want to learn more about your source and cables before trying to diagnose "raspiness".

Good luck.
The raspiness occurs with both hd audio cd and rca from my droid phone. I have system biwired with 14 g flat monster cable ... 10 foot runs.

Have you ... or is there such thing as amp tine up?
That's interesting, I was just gifted the same amp/preamp combination, but I haven't had the opportunity to connect everything up. I'm rolling with anticipation!

As an aside for this series of Yamaha amplifiers, would anyone please know if there is a source to repair / replace the beautifully back lit switches?

I searched forever to find an M2 with working lights, but recently lost the back lighting on the power switch.
In all the searching I did for this amplifier, I seem to remember someone saying that it is difficult to change these lamps if they burn out. From what I can tell, there are at least three Yamaha products that use these lamps: C4 preamp, M2 amp, and M4 amp.

I thought someone had mentioned an LED "work around".

The back lit, translucent switches on these amps are drop dead gorgeous as is the anodized, high quality casework on these Yamaha products.

There was also a class A integrated amp, the A1 (?) as I recall but more rare than the others.

My understanding is that the original switches used a normal incandescent bulb, which was then wrapped in a colored, rubber (?) cover to give them their one of a kind beauty......but I may be wrong.

In any case, given the growing list of fans and no shortage of the C4 and M4, perhaps someone will sell a repair kit.....