Re-capping the McIntosh MC30's
A couple years ago, I switched my main monitors from Mackie HR824’s to a pair of B&W DM-602’s, each powered by a McIntosh MC30 amp. The improvement in sound is just stunning. The sound stage is very 3-dimensional, you really get depth of field information that you can’t hear with lesser speakers/amp combos. By the way, the B&W’s are probably the best bargain in speakers around. Probably the only fault of this system as monitors is they might sound too good sometimes.
Actually, there are other faults. With seven tubes each, each amp acts as a mini space heater. In the winter I have to keep the windows open, and in the summertime, I hardly even turn them on. Also, each amp came with the original set of capacitors from the 1960’s, which are prone to deterioration and failure. I recapped the first MC30 about 2 years ago. I’ve been putting off doing the second until recently when I noticed a considerable drop in treble. Now, some purists say the magic is in the original caps. All I have to say that is, the magic is in not having a cap burn out, make all the tubes explode in your face and burn your house down. Purists are stupid.
My second MC30 is actually a “MacKIT” which were sold as kits for a brief time in the 60’s. There is a sticker on it which reads “McIntosh Clinic Performance certified 7-10-73”.
Tracking down schematics for these, especially the MacKIT, can be a real pain, so as a public service, here are some schematics.
MC30 early gif
MC30 pdf
MacKIT pdf (thanks Ben Hall)
Here are some pictures from the recap job.
