Why is my Mcintosh MC-2155 slow?

The mid-eighties McIntosh amps are like that generally speaking. They have so much microdynamics that the tempo gets a little lost. You can speed it up a bit by replacing the capacitors since they are 25 years old at this point.

Also part of it is probably due to your speakers. Those older amps don't have much damping factor so they are fairly sensitive to the speaker load when it comes to bass reproduction. What you are hearing is actually slow bass. Back in the day, speakers didn't have the bass they do today - nor did they have such wacky and terrible loads. You could improve the speaker/matching to get even better results.

There are several Agon guys that use those vintage McIntosh amps. Maybe they will chime in here but if not, find them in the member system pages and ask their thoughts on speaker matching.

Everything is a tradeoff. The sonics you love so much about it are partly due to this slower tempo. You like the wealth of microdynamic information but the price you pay for that is the appearance of slower speed. It's all a compromise.

Arthur

Sorry for being dense, but I'm really sure what you mean by "slow". Your amp sounds great but it sounds slow?

I'm now "house sitting" a semi-inherited McIntosh. It kinda appeared out of the blue, and I had such high expectations for it that I stopped acquiring an Anthem that same day. Got it hooked up and it sounded just fine - and in a way that was a little disappointing but probably because I'd had such unattainable expectations. It took a little while to come back to earth and realize that it was doing exactly what it was supposed to - cleanly amplifying the signal and nothing else. It didn't have any extra edge or boost or pizazz or anything that would make it seem more special and stand out in an audition room.

Maybe that's what you're hearing elsewhere and missing w/ yours? Or maybe there's a better way to define or describe how to hear speed?

McIntosh amplifiers normally sound slower than other solid state amplifiers so there is nothing wrong with your 2155. However, there is way that you can change the way it sounded. The MC 2155 has an input sensitivity switch of 0.75V/2.5V. Set it at 0.75V will reduce the negative feedback and increase the gain of the MC 2155. With higher gain, it will sound more dynamic and forward. You can then use the volume control on the front panel to fine tune the best balance between the smoothness and the transient speed.

Hsindao's advice is excellent. I didn't think of it before but I too have found that amps sound more dynamic when they are running at high gain (i.e. low input sensitivity). I run my MC240 at high gain by using "twin amp" instead of "stereo" - definitely an improvement across the board.

Try 0.75V and let us know what happens! Just be sure you have the volume control down all the way before powering the amp back up.

Arthur