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

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

You don't want a forgiving speaker with McIntosh IMO. The new DALIs I heard were not all that forgiving (ribbon tweeter) but if your's are, then it is time for a change.

You don't mention your budget so I will guess. If I were you, I would look into using Triangles like the Celius ESw or Altea ESw (the latter is 2.5 way if you like that). These speakers are pace and imaging champs which will compliment the 2155 very well - and can be really sweet deals on Agon.

Other options are JM Labs, which is what I use with my McIntoshes. The older Electra series can be had cheap these days and they sound fantastic. The Chorus lines are cheaper still but shouldn't be overlooked cause their tweeter is best in class IMO. The JM Labs tend to have more bass and bigger soundstaging than the Triangles at the expense of some imaging precision.

Personal preference and taste must play a role for you to be satisfied so do some homework before buying. There are many great options. Anything from Thiel, B&W, Revel, and Paradigm Reference will also work great with your Mc. (I have first-hand experience with all of my recommendations.)

Be sure to post your thoughts about the sensitivity change.

Arthur