Sub Query...

[Mr.Ian]

I think it would apply to anything connected between the sub and the the amp speaker terminals.

[icehockeyboy]

I think it would apply to anything connected between the sub and the the amp speaker terminals.

But what would it do?
Would it damage the sub, or amp?

As I said nothing was humming, or behaving oddly, the only thing, which might have been purely coincidental, was that my iPad would not pair with the amp via Bluetooth.
To make sure I disconnected the sub, re booted everything, and when I powered it all up again, they paired, like I say, that may be purely coincidental.

[Mr.Ian]

This is what rel say on the subject

Here’s where Class D amps get weird (not all, but about 90% exhibit the anomaly I will describe next). The Black speaker terminals on the rear of your amp traditionally, and by electrical convention, mean Earth Ground. Zero ohms, zero Hz. Ground. But with most Class D amps, that Black-colored speaker terminal* is no longer ground. Worse, it actually references to a positive voltage that is significant. We consistently measure 10-15 volts ABOVE ground. In practical terms, if your REL were mistakenly connected to a Class D amp or receiver the input of the REL would eventually be burned out because it would be pulling 15 volts through a circuit designed to see zero voltage. Over some period of time—months or a few years, this unwelcome voltage will burn out the front end of your REL.

[icehockeyboy]

Hi Ian,
I’ve been on the phone to REL numerous times this week, and I gleaned from day 1 that If I’m using the hi level input, the black wire should not be attached in the normal way, however if an earth hum was present, to attach it to the amp chassis, so I’ve been through this scenario, and at this stage it was where I got no audio output from the sub.

But inputting via what they term the PC input, which is a 3.5 mm mini jack, I got audio, with no earth hum at all.

But despite everything sounding great, am I likely to encounter problems?

[icehockeyboy]

No one seems to be able to sort this problem, even REL say they’d have to talk to their place in the USA.

[Lawrence001]

I went through a very similar experience to you with a Rel Quake and Tripath amp, followed the instructions to no avail. I think I used a ground from somewhere into the RCA and the speaker red outputs to the high level inputs. Can't remember if I got no sound or a bad hum but I called it a day before I risked blowing the amp.

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