Bridging the Mcintosh 402 amp


I'm going to get another Mc402 2 channel amp as I have one and bridge them to run my Piega C10 Ltds. Before I brought them out of storage, the Piegas were powered with just one of the 402's and it wasn't enough. They are ahungry speaker, so the best economical and pairing option to my Mc2200 tube pre is another 402 but it I'll need to bridge them. I've never done that. What's bridging the 402 entail? Thanks
128x128knollbrent
Take a look inside the manual for your amp, it's in there. I bridge a MC252 for the center channel in my HT/Music room. You will simply be connecting a couple of jumper cables between the speaker terminals on your amp. Which ones will depend upon your speaker, there are two ways it can go. The manual lays out both ways but again, which way will depend upon your speakers. Hope that helps.
Mike
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Look at pgs 12 and 13 of your manual. This explains in detail how to change it to Mono operation.
As a point of information, the MC402’s mono mode doesn’t bridge the two channels, it puts them in parallel. Which is actually better, as bridged amplifiers often don’t do well sonically when driving 4 ohm speakers such as yours.

Although I don’t have the user manual to look at, in looking at the rear panel diagram in the service manual (at hifiengine.com), and assuming the 4 ohm impedance spec of your speaker is reasonably accurate (as opposed to being significantly lower than that at many frequencies), I believe you would use the amp’s 8 ohm taps, and as Mike indicated you would connect jumpers between those taps. You would also set a switch on the rear of the amp to "mono parallel" mode rather than stereo mode, and you would connect the preamp to the amp’s right channel input, balanced or unbalanced as you prefer (setting the input mode switch correspondingly).

Good luck. Regards,
-- Al