REL subs with Rowland Amplifiers

daveyf,

The black wire is floated and not connected to anything. I'll have dual subs and will receive the 2nd sub on Tuesday. That's why I was advised to connect my single sub this way.

@ricred1 If you are not connecting the black wire, I would be concerned that you are not grounding the sub. I connect my subs with the red and yellow summed to the red output per amp and the black to the black output per amp. This is with dual subs and mono blocks. I’m pretty sure that way they are each getting a mono signal....left to the left sub and right to the right sub. The way you are describing your connection would indicate that you are only getting the mono signal from one of your amps to the sub...and not the summed stereo signal.

Ricred 9-22-2019
Al,
"So are you saying, then, that the only difference between what worked and what previously didn’t work was twisting the red and yellow wires together, while having exactly the same connections in both cases?" YES

I believe the answer to this question is actually "No," since when you initially reported the problem you were connecting the two wires to different channels, while in the case of the good results you have just obtained both wires are connected to the same channel. So the connections were different when you had the problem vs. when you did not have the problem. From your OP:

Ricred 9-17-2019
I connected my sub according to REL’s instructions...yellow lead to positive on one channel, red lead to positive on the other channel, and floating the black wire(ground). I get minimum output when connected according to the instructions.

Regarding grounding, the ground path/signal return path between the sub and the amp that presently exists, which is providing the good results you have obtained, is as follows:

From the circuit ground within the sub via some unknown but presumably low impedance within the sub that connects its circuit ground to its AC safety ground, then via the safety ground wire in the sub’s power cord to the AC outlet, then from the AC outlet via the safety ground wire in the amp’s power cord to the amp’s chassis, then via some unknown but presumably low impedance with the amp that connects the amp’s chassis to its circuit ground.

As I alluded to earlier, that path may serve as an adequate ground/signal return path with some and perhaps most designs, depending on the internal grounding configurations of the particular amp and sub. And given that REL recommended doing that, and that the results are good, I would leave well enough alone. Just don’t ever put a cheater plug on the power cord of either the sub or the amp, which would interrupt that path!!

So as things stand now I believe the mystery that remains is why with that same ground path you had the problem in the first place, when connecting the red and yellow wires to different channels. The only explanations I can think of, both of which appear to be very unlikely, are:

(a)You inadvertently connected one of the two wires to a negative output terminal of one channel of the amp, while connecting the other wire to the positive output terminal of the other channel. That would cause the signals from the two channels to be subtracted from each other, rather than added.

(b)Something is wrong with a component or cable.

As I say, both explanations seem very unlikely, so I’m at a loss to explain why you had the problem in the first place.

Best regards,
-- Al

Daveyf 9-22-2019
I connect my subs with the red and yellow summed to the red output per amp and the black to the black output per amp. This is with dual subs and mono blocks.

In the case of an amp having balanced outputs, such as Ricred’s, the black wire from the sub should absolutely not be connected to a negative output terminal of the amp. Doing so would cause the full amplitude signal that is present on that output terminal of the amp to be connected to the sub’s ground. Depending on the internal grounding configurations of the amp and the sub (and more specifically on the impedance through which their circuit grounds are internally connected to their chassis/AC safety grounds) doing so might work, but is very poor practice at best and could very conceivably cause damage at worst. If the outputs of your 8T are balanced (or bridged) that would presumably be the reason Mr. Rowland recommended installing a ground terminal on it.

Over the years I’ve seen a number of members here mention that they connect the black wire of a REL sub to the negative output terminal of a fully balanced amp, and the results seem good. To that I say they should count their blessings :-)

Best regards,
-- Al

“Over the years I’ve seen a number of members here mention that they connect the black wire of a REL sub to the negative output terminal of a fully balanced amp, and the results seem good. To that I say they should count their blessings :-)”

@almarg,

Not sure what do mean when you say ‘count their blessings’...is it a cautionary smiley at the end?

I own dual mono SET amps and after consulting with REL and amp manufacturer, I also connected red/yellow wire to positive output and black wire to negative output of the terminal. Like Daveyf, I am also using dual subs. The Input Impedance of each mono is 100 kOhm.