Subs AC plugged separately or together?

Which is the best way to plug 2 REL subs to AC?

All my system (TT-SPP-BHK Preamp=PST-DS DAC-M1200s) is plugged to 2 P12s and both of them are plugged to the same AC dedicated line. Due to the number of HC sockets available, P12 EU version has only one HC each (used to plug the M1200s ampli) I must plug separately the 2 REL subs to a different, NON dedicated, AC line. Directly to 2 receptacles on the wall of the same AC line, in common with other devices in my house (restricted in the same room as computer, Degritter, monitor screen, Philips hue lights and nothing else). The Subs go to M1200s with high level connection.

Would it be so impactful if I plugged the subs together with the rest of system? If so, for what reason (ground in common, less interference/noise from a dedicated AC line, use of a regenerator vs direct wall)?

The only way would be to buy 2 P15s (I’m a symmetrical guy! One would not be good for me) to substitute the 2 P12s, not a cheap step, so I would like to invest the money for a good reason.

Any suggestion, as always, will be very appreciated.

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They don’t have to run off the HC port. If you’re running high inputs, I’d try to keep the subwoofers as close to the amplifier’s power source as possible to avoid ground loop resonances.

Also, never unplug the REL power cords right after power down or they’ll drain their stored energy right down the negative terminal of your amp. They didn’t include that one in the manual. :man_facepalming:

Otherwise, try it either way and choose the one that sounds best.


Thank you @vee.

Actually I can only plug the RELs to a different wall AC line (both of them to the same line but a different one from the 2 P12s).
Then I will study with my electrician to add 2 more receptacles to the wall on the same dedicated line, in order to plug the RELs to the same home AC line of the P12s (and therefore keeping all the components of the system - amps included - and the RELs all together), if better than plugging them separately.

As for correct unplugging the power cords of the RELs… good suggestion, thank you!
So, if I understand well, I need FIRST to turn off and unplug the M1200s power cords, SECOND I can turn off and unplug the RELs too, is it right?

For best sonics, in my experience, powering my REL sub via my P12 is the way to go. Initially, during the REL break-in period, I connected it directly to the wall outlet, which is a dedicated circuit for the P12. I took my time with the REL break-in and optimization of setup (power cords, placement, levels, bass trap, etc) then finally connected it to the P12. The improvement was easy to hear.
I have noticed that the REL sub (S/510) creates a great deal of power supply noise (500w class D) that goes back into the AC feed. On power up of the sub, my audio system sounds awful, so I’ve found that the sub has to be powered for a few hours before critical listening. REL recommend that the sub is “on” all the time - and the reason is very obvious to me.
What has been your experience with your subs with respect to optimizing setup?

I had my dual s812s plugged into a P12. Did not seem to make any difference at all. I now have both plugged into a AQ1200 with various other devices etc. The main amp plugged into dedicated 20a circuit. This seems to work well. I have never had a hum or ground loop issue with a REL but I’m sure they happen depending upon set up.

Unfortunately my P12s have only 1 HC socket each (EU version schuko). So they can feed only the M1200s amps and nothing else HC.
I have 2 RELs T/7i since last spring. A good balance was found with right cables speak-on, power cords (AQ Tornado, all the rest of the system Dragon), set up with so many changes and room treatments. Especially investigating in phase on wall outlets (schuko is always a challenge) I almost avoided any audible hum.

I put into the system also 2 CAD ground control GC1 (BHK Preamp+DS DAC and SPP Phono) and the sound became more clean, soft and pleasant - with good results also for basses in general and transients impact.

Last tweak was a SR Purple fuse into the BHK Preamp, it let the sound open more than before. New fuses are on the way for SPP and PST (unfortunately the P12 EU version needs 3A and SR Purple of this value doesn’t exist!)

So I was wondering if investing in new outlets on the wall (to add to the dedicated line, the same of the rest of the system) would improve the RELs work in general balance and SQ. A few guys on forum prefer to keep subs apart on a different AC line, this is the reason why I’m asking your opinions here.

If you’re going to plug/unplug power cords, disconnect the high level input Speakon connector first, power down everything, wait a minute for caps to discharge, then unplug power cord. Disconnecting the Speakon will ensure any ground differentials won’t flow between the amp and the subs.

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