I talked to my Mom and Dad on the phone tonight, and Mom mentioned she was a little worried about me because I hadn't posted anything new at Jeff's Place for a while (I am blessed with the most terrific parents you can imagine!).

It turns out that I've been busier than usual, so I've been a little behind on posts, and I have a bunch of them that I want to put up for you, but this one is a special post for you, Mom, and all of you Leben CS660P power amplifier aficionados out there.

Many thanks to Ben for the comment he made recommending bypassing the Alps volume potentiometer on the CS660P's front panel. It's a great modification that pays significant sonic & musical dividends, and it's easy to do - you can't beat that!

The first step was to unhook everything from my CS660P and then pull out all the vacuum tubes and sit them aside. Then I flipped the CS660P over and removed the bottom cover to expose the Alps potentiometer.  I then used a hex wrench to remove the Alps' knob, used a crescent wrench to remove the nut that holds the Alps pot to the front panel, and then slipped it out so I could get a good look at it (below).

To be on the safe side I searched on the web for a wiring diagram for the Alps to make sure I didn't make a boneheaded mistake during the bypass procedure. I found a nice diagram (below, but with no attribution, so whoever went to the trouble to post the diagram - many thanks to you!).

I let my Hako 936 soldering station warm up to temperature, and then armed with the diagram above I then de-soldered the left channel input and output wires, then soldered them together with some silver solder (below). Be sure to leave the grounds in place on the Alps.

Then I did the same thing for the right channel (below).

Now that I had everything bypassed and re-soldered I used a little black electrical tape to cover the solder joints so nothing would short (below).

That's all there is to the bypass procedure for the Alps potentiometer! I reinstalled the bypassed Alps into the front panel of the CS660P, then put back on the bottom plate, put the tubes back in, and hooked everything back up.

I warmed the system back up and sat down for a little listening session before calling it a night. What a nice improvement! I heard greater transparency, better tone, better resolution, and a relaxed clarity that really benefited the music. This is a great mod with lots of benefit, so many thanks to Ben for letting us all know about it!