I believe this is the best bargain in audio you can have I but this amplifier I run to few problems I did recap it this amplifier it can compete with every amplifier cost 10 times the price I pair it with dunlavy Athena the sound was incredible the amplifier running hot but this is not problem if you read the manual they mention that I believe the first 10 vatts class A

I have the audio research A not the B

The Audio Research D100b is an old amplifier built from 1977-1980. Built like a tank in every way from the internal parts to the outer casing. It is rack mountable and has handles on the front. Now to the sound. Fantastic for starters. The D100b is so transparent and smooth sounding. You hear every detail in the music, and this amp makes you listen deeper and hear things you have never heard before. No grain, just pure sound. It is a typical Audio Research amp. Very defined sound. I have owned many, and this one sounds as good as all of them, with the exception of the bottom end of my former D300. The bass is extended, the highs are smooth. And it is simply amazes me that a amp that is this old, STILL sounds this good. It has a nicer all around sound than my former Krells, except for the legendary bass that Krells are known for, and when paired with a Audio Research preamp, it is pure magic. I am running a Audio Research Sp6b tube preamp, and the combination is fantastic. If you can find one, I would recommend you jump on this amp, it is that good!