Both modification are as easy to reverse as they were to implement. The reason I'm sharing all of this is because I LIKE what I hear. Lowthers (I have the Medallion cabinets sporting PM2As)and Klipsch La Scalas are not often described as 'dull' or 'dark,' but I agree with you that if such were the case, the modifications I did to the amps could be a benefit for some.
I have installed volume controls on the Moondogs (250K stereo pots, one section paralleled with the other -- for a grand total of about 125K). Ron has indicated many-a-time that most modern digital sources with approx. 2 volt outputs can supply completely adequate work-power to drive the amps into clipping. I in fact used to use a passive preamp. (built from the cheapest Radio Shack parts I could find), which worked perfectly when I was using 2 feet of interconnect. I put volume controls on the amplifiers to enable increased flexibility of attenuation with active gain stages. I built a couple of designs from schematics published by Eric Barbour and Bruce Rozenblit....and was just about to embark on another (by Jack Eliano) when I purchased a non-working AES AE-1 6SN7 preamp from a friend. That was repaired, and it is now what I am using with the Moondogs. The fact is this: I don't really NEED it. With my amps as close to sources as they are, I can run straight from my (now tiring) CD player into the amplifiers, and use the onboard volume controls to control volume. However, I have become accustomed to the sound of an active gain stage, and I may once again move my sources further away from my amplifiers -- where active gain is more necessary.
Since I don't listen at overly loud levels, I find that turning volume down seems to have the subsequent effect of attenuating some of the high frequency information I perceive at higher listening levels. I'm pretty sure this has to do with the increased resistance imposed on the signal as the control is turned down -- and high frquencies are more invluenced by this than lower ones. Thus! installing the silver mica bypass caps between input and wiper allows some of those little 'sound guys' to get through to the other side.
It sounds marvelous to me.
BTW: Lowthers on open baffles sound absolutely stunning (to me). I'm in the planning stages of incorporating the PM2As on an open baffle that will be placed MTM fashion on top of the La Scalas. This will probably eventually be a biamped arrangement, with Moondogs on the Lowthers. Either that, or I may only use the La Scala bass bins with the PM2As. I thought this was a unique idea until I discovered that Dick Olsher is doing the same thing, and has plans available for his design.
Thanks for taking the time to respond.
Erik
