Help needed mono use of stereo Amp.


2010-12-29 10:39 pm
Hello folks,
i have to set up the old music system for my father.
it consist of
2x Musical Fidelity P-170 Stereo Power Amp

The stereo amps should work as mono amp, but i dont have the knowlege of bridging stereo amps. and i couldn't find some manual or schematics for the Stereo Amp.

as far as i know does the pre amp have normal and an inverted output, but i am also not certan how to connect them with the Power Amp.

if the pre has normal and inverted outputs....all you need to do is connect one channel to the normal output and the other channel to the inverted input AND, did I say AND, and connect the positve lead of your speaker to the + side of the normal amp AND the negative lead of your speaker to the positive side of the inverted channel. You MUST ensure that the ohms of the speaker is double the rating of the amp. SO if your speakers are 8 ohms and your amp can handle 4 ohms you are OK, BUT if your speakers are 4 ohms and your amp can only handle 4 ohms, you CAN NOT bridge your amp. This is CRITICAL, do not take any short cuts on the impedeance. Damage to your amp may result.


2010-12-29 10:39 pm
thanks speakerfritz

now i know the name of the preamp
Musical Fidelity MVT
i am not sure if i understand you right,
as i understand you it have to be:
non invert output left channel, invert output right channel.
but how do i connect the Loudspeakers correctly.
thanks for your help

You need 4 power amp leads.

Connect normal left and inverted left to L and R of one power amp.
Connect normal right and inverted right to L and R of other power amp.

Connect each speaker across the L+ and R+ of each stereo power amp.
Make sure you maintain the correct phasing, be consistent, e.g. normal
always goes into Rin and speaker + always goes to R+out.

You will now have bridged stereo Left and Right mono amplifiers.

rgds, sreten.