Differential Monoblocks with twin REL subs


Hi, I would appreciate any advice to avoid damaging my amps. I have a pair of Magneplanar MG 2.6R speakers which I use with a Primare 928 pre and a couple of Primare 928 Monoblock power amps. I am now looking for a little more bass depth and so have bought a pair of 2nd hand REL Q50 subwoofers. I now realise that I am not sure how to connect them without risking damage to the monoblocks.

The issue is, I think that the monoblocks are fully balanced (differential) amps, and so unlike most amps, the
-ve terminal is likely to be live, and connecting the REL Neutrick black ground lead as normal to the -ve terminal would short the amp.

So my questions are:

1. Would my best bet be to connect both yellow & red Neutrik leads from my left sub to teh +ve terminal on my left monoblock, nothing attached to the -ve terminal, and teh black ground wire attached to a ground point on the amp's chassis? Same for the right sub & monoblock. Would this be safe?

OR because the amp is deifferential would I be losing out on some of the signal by not using the -ve terminal?

2. In which case should I connect the yellow live Neutrik lead to +ve, the red live Neutrik lead of -ve on the same monoblock, and the black ground lead to a ground point on the chassis? Would this be safe?

3. And finally, if the amp isn't really differential (I don't have the manual, would either of the above options be likely to cause any damage?

I hadn't really thought this through properly before buying the subs, so any help greatly appreciated before I take the plunge and set them up.

mackh
mackh

Showing 2 responses by atmasphere

You might check with the manufacturer. Just because the amplifier is fully differential does not mean that the output connection is floating.
Heck I would just hook it up and see if it works. If it seems OK when you power up the subs, maybe it is. If there is a problem it will tell you right away and you turn it off and see what you can do.

Most subs that I have dealt with run right off the amplifier output terminals and don't interfere even if the output of the amplifier is floating (which ours are- we make fully differential amps).

I would thus not worry about the ground wire unless you encounter a hum.