RA280 high level connection to subwoofer - Black wire

User Tips
#1

I want to connect my subwoofer using its High-Level connection with a Speakon cable, but I’m unsure whether the black wire should go to the RA280’s ground or to the negative terminal of one of the speakers.

I’ve heard that many Class D amplifiers don’t share a common ground on their negative terminals; instead, both terminals (positive and negative) carry active voltage with respect to chassis ground. Connecting the subwoofer’s black ground wire to a live negative terminal will cause a short circuit that could damage the Rose RA280’s GaN FET amplifier modules.

#2

It sounds like you have a REL subwoofer.

You put the black wire on the Ground screw.
REL has some documentation on this.

#3

I have a Sonus Faber subwoofer Gravis II.
Thanks so much!

#4

Ok,
I have the REL which has Black, Yellow and Red wires to a Speakon connector.

Per REL the red to the right positive, Yellow to the Left positive then black to the ground.

However… you should check w your manufacturer’s information as it could be different.

#5

Thanks. Rel and Sonus Faber share the same technology.

#6

@arodrij

Thank you for your inquiry.

When connecting the Sonus Faber Gravis II to the RA280 using the High-Level (SpeakON) connection, please do not connect the subwoofer’s black (Ground) wire to either of the RA280’s negative (-) speaker terminals without confirming the correct connection method.

Depending on the amplifier’s output circuit design, the negative (-) speaker terminals may not be the same as chassis ground, and an incorrect connection could potentially affect or damage the amplifier or subwoofer.

Therefore, rather than applying the connection method recommended for another manufacturer’s subwoofer, we recommend following Sonus Faber’s official High-Level connection instructions for the Gravis II.

Thank you.

#7

Hi,
I believe we’ve already gone past that and recommended to use the chassis ground.

This is how I connected my REL to RS520 and it appears that the Sonus Faber uses a similar approach.

I agree that connecting it to the black speaker connection is not a good option.
Again, its best to talk w the Subwoofer company on how to connect their products.

HTH

#8

@Smegel

Thank you for sharing your experience and additional information.

As you mentioned, we also recommend confirming the correct High-Level connection method with the subwoofer manufacturer before making the connection.

Thank you.

#9

I have 2 REL subs hooked to my RS520 and do not have the black ground hooked up I just taped the end up and I get no hum.

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#10

@Jimmy_B

Thank you for sharing your experience.

If your REL subwoofers are operating normally without the black ground wire connected and you are not experiencing any hum or noise, there is no need to change your current setup.

However, connection methods may vary depending on the subwoofer model and its design. We recommend following the connection instructions provided by the subwoofer manufacturer for the safest and most appropriate setup.

Thank you for sharing this information with the community.

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#11

There is a simple trick to check if your amp is bridged or not. Requires a multimeter. Turn the amp off completely and disconnect it from the mains. Measure resistance between L & R NEGATIVE (black) terminals using the multimeter. If it shows 0 (zero) the amp is not bridged. If there is no electrical connection between the negative terminals the amp is bridged.
As always proceed with caution, exceptions to the rules happen

#12

Here’s a useful diagram from Chord Company which shows regular type high level connection for NON-BRIDGED amp

high-level-1
high-level-11024×1024 24.7 KB

#13

@Jimmy_B IIRC that’s a ‘floating ground’ which means the Sub isn’t grounded.
You may want to test having the two black wires going to the ground. I haven’t checked on the REL site about two subs… Since I’m in a near field setup one sub under my desk works. In a larger environment… I agree that two subs is better than one!

@Serge
YMMV depending on the sub and the amp. The Hifi Rose amps are not the same and I would be wary of doing what works for Chord.

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#14

@Smegel Yeah I got the connection info from a Crutchfield video and he said for Class D you can float the ground but you can also attach it to the chassis ground or run a RCA from an input to the LFE for grounding.
Yeah that diagram from CHORD may not be correct for REL and Class D I would be wary.

#15

Yes, the diagram is for NON-BRIDGED AMP so it excludes Hi-Fi Rose RA280 and most of Class D amps. Sorry for confusion

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