Musical Concepts amplifier modifications upgrades

John (Hillig) is a great tech and a really good guy.  I've known him for many years.  He did a couple of Hafler and B&K amp upgrades for me back in the day.

Wonderful work and well worth the money back then.  Not sure what the charge is now for your amps, but there are many decent amps now on the market that may be better than putting more money into what you have?  Just sayin'.

If you do have John do the mods/upgrades, you won't be disappointed.

we sent many Hafler customers to him to wring out better performance, none were ever disappointed 

Every one seems to be sastified with his work.

Rather than upgrading the existing design of the amplifier, Mr. Hillig specializes in a redesign of the amplifier. He chooses certain amplifiers as the "bones" on which he builds his own design.
He generally uses the transformer and portions of the power supply, pots and switches while most of the existing circuitry is replaced with his own circuit boards.
I have a couple pieces which he has redone; a Hafler DH-101 preamp and a DH-500 power amp which are significantly better sounding than the originals. I am also currently using a Musical Design D-140 which is his own brand.

I highly recommend his work.