Beautifully Restored McIntosh MC2105 Power Amplifier and Walnut Case
Fully Restored, Beautiful Condition, and Operating Flawlessly
Bob the Tech Audio (www.bobthetechaudio.com) has restored this MC2105 from top to bottom to give it a fresh start on another 50 years of life.
We started with the power supply, installing a new fuse holder, replacing the main filter capacitors with fresh Cornell Dubilier parts, and replacing the high voltage power supply multi-capacitor with a model built to match the original specifications. While the heatsinks and main filter capacitors were out we gave the chassis a good polishing.
We removed and replaced the original electrolytic capacitors on the input board, meter board, and the driver boards. We also replaced the input board’s worn and cracked “tropical fish” film capacitors. Finally, we upgraded the driver boards per the McIntosh service bulletin, which mitigates the risk of thermal runaway in these units.
We verified diodes, transistors, and other key parts on the input, meter, driver boards, and the heatsinks.
Electrically the unit operates flawlessly. All power supply voltages are correct. Heatsink bias is verified to be as specified. Distortion is measured at well under 0.1% from 20Hz - 20kHz at specified output power 105 Watts per channel, and gets as low as 0.027% in places. The unit runs to ~120 Watts per channel (2kHz, 120VAC line) before distortion reaches ~1%. The unit sounds great.
We touched up front panel paint in areas where it had flaked off a bit. The new paint looks great and the front panel looks pristine. One minor flaw that we didn't catch remains in the front panel paint. New light barrier foam keeps the white front panel lighting from leaking into the blue light of the meters. There are two shallow scratches in the front panel glass near the knobs. The paint flaw and scratches are not noticeable from just a foot or two away, but I have close up pictures for your awareness.
We've installed a new set of 5/8" tall feet on the chassis, which we can replace with 1" feet if desired. The unit is equipped with the panloc rods and springs (not installed when I took the picture). The panloc cups and retaining features on the rear of the panloc rods are missing, but we've installed a pair of speed nuts to retain the panloc rods in the chassis. When installed, the panlocs look and feel like the originals from the front of the unit. There is the slightest amount of rust in the area immediately surrounding the fuse holder, but the rest of the chassis is rust-free.
The unit comes with a walnut case, which is also equipped with panloc features. The panlocs in the rear do not operate because of the missing features on the unit (mentioned above), however the retaining features on the side of the unit operate properly in the case. We removed the worn felt on the feet of the walnut case and replaced it with fresh felt. The case now looks like new. We will entertain a sale at a lower price without the walnut case, if desired.
Shipping Container and Manual
The unit will ship in a brand new factory double box system.
Please contact me through a PM here on the site, or at [email protected], for additional pictures and to discuss pricing, shipping, etc.