MC150s as mono blocks... bridged or parallel?


I'm planning on adding a second MC150 to my system (w/C712 control center) to each drive a Magnepan MG3.6 (4 ohm)... my MC150 owner's manual is not clear on why bridged would be used versus parallel operation... I'd appreciate any advice, thanks!
mike95120
What's an MC150*? Solidstate or tubed? If SS, does it have a switch for bridging?

Generally, tubed-amp channels are paralleled when one 'monos' the amp. The power combines, into half the individually rated impedance. IOW, a tubed 100wpc-into-8-ohms amp will deliver 200 watts into 4 Ohms (from those same 8-Ohm taps). A SS amp does that too when its channels are paralleled, so you just add the power outputs of the 2 channels. IOW, if one has a very-high-current SS stereo amp that's rated at 100wpc/8, 200wpc/4, and 400/2 (which is rare among audio amplifiers), it'll deliver 200 watts into 8 Ohms, 400 watts into 4, and 800 into 2. This is a great way to obtain a high amount of power (and current capability for low-impedance speakers) from otherwise-more-modest and affordable amps.

However, when a SS amp is bridged, its total power theoretically quadruples one channel's output (because the voltage swing doubles), but each channel 'looks' into only half the apparent impedance, so we often run into the amp's current limitations before it gets to the 4-times power output.

It's all sort of complicated, but the best way to resolve it is to listen to the combinations you have available and see how they sound.

I think the Mag 3.6s are relatively insensitive and at 4 Ohms are relatively current-hungry, so paralleling probably makes more sense than bridging, at least to start with.

* Not all of us know everything!
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