Connecting a single REL sub to a 440

[Bertie]

Yesterday I had a 220 and a REL S/812 sub. Today I have a 440 but what’s the best way to connect the sub? Allocate one of the master ports as a mono sub out or connect to both 220s via hi-level? Help

[audio_engr]

As its a REL, High Level is the way FWD.

[Bertie]

As it’s a REL, High Level is the way FWD.

But do I simply connect from the positives of both Devialets?

[Joe]

As it’s a REL, High Level is the way FWD.

But do I simply connect from the positives of both Devialets?

I would ask REL support as I did before i connected my REL to my single Expert 220 pro.

They gave detailed answer:

Hello Josef,

Thank you for contacting us, and for choosing a REL Acoustics subwoofer for your home audio system. While Devialet describes the 220 Expert Pro as being a "hybrid amplifier that offers the best of Class A and Class D technology", we recommend treating it as a Class D amplifier in terms of how to best connect the High Level cable for your new S/510 subwoofer. As such, the following instructions can be used when connecting High Level to this amplifier:
• Connect the red wire of the High Level cable to the right channel positive output terminal on the amplifier.
• Connect the yellow wire to the left channel positive output terminal.
• Connect the black wire to the ground thumb screw, located next to the "Line 2/Phono" inputs on the amplifier's back panel.

I hope that this helps, but feel free to let me know if you have any additional questions or concerns.
Regards,
Jacob Van Sickle
Customer Success Manager - REL Acoustics

[ray1234]

Normally REL works best with high level input. However, for Devialet 440 I would suggest to use low level input. Firstly if you use SAM the high level signal is SAM adjusted and would not be correct signal to feed the subwoofer. Secondly, I am not sure there is a common ground between the two 220.

I use D400 with SAM to main speaker and output to my SVS subwoofer using preout. I tried to configure mono sub-out but no output from the D400, I can never figure that out, stereo preout works though. Whether to use SAM or not with the subwoofer, you need to test. For my system, even with subwoofer it sounds better with SAM on.

[Delija]

I have used mono subs with 440 Pro.
(For some time I've also used stereo - but it made more sense to use mono, since I've calibrated them as a pair)

There was one bug, but only in bypass mode - in case when I didn't use subs anyway.
Sub (pre) out on companion didn't work.

[devianet]

I agree with ray1234 having tried both possibilities. Using the pre-out allows SAM on the mains, which makes the perceived bass even better and adds woofer protection.

I happen to use the pre-out socket on the companion, works fine for me. I have one (mono) sub connected to the 440.

The REL representative is worrying that the Expert has a constant offset voltage reference on the black speaker outs, which is indeed the case for B&O Ice. But the Expert does not; the voltage is 0.

So I can confirm that when using high-level subwoofer connections, choosing a negative (ground) speaker terminal on either Expert works just fine for the REL black wire. I also tried the ground thumbscrew, also fine.

[fraha]

As it’s a REL, High Level is the way FWD.

But do I simply connect from the positives of both Devialets?

I would ask REL support as I did before i connected my REL to my single Expert 220 pro.
They gave detailed answer:
Hello Josef,

Thank you for contacting us, and for choosing a REL Acoustics subwoofer for your home audio system. While Devialet describes the 220 Expert Pro as being a "hybrid amplifier that offers the best of Class A and Class D technology", we recommend treating it as a Class D amplifier in terms of how to best connect the High Level cable for your new S/510 subwoofer. As such, the following instructions can be used when connecting High Level to this amplifier:
• Connect the red wire of the High Level cable to the right channel positive output terminal on the amplifier.
• Connect the yellow wire to the left channel positive output terminal.
• Connect the black wire to the ground thumb screw, located next to the "Line 2/Phono" inputs on the amplifier's back panel.

I hope that this helps, but feel free to let me know if you have any additional questions or concerns.
Regards,
Jacob Van Sickle
Customer Success Manager - REL Acoustics

It's a good thing I looked into the forum   i was just about to write to REL and Devialet about the connection. I will get a Classic99 by mid september, and the connection thing is cleared in this case for me. Thanks.