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REL subs with Rowland Amplifiers

I'm having issues connecting my REL Carbon limited subwoofer to my Jeff Rowland 625 S2 amplifier via the high-level input. 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. When I use the low level input, the output is sufficient and the sub sounds great. Per my conversation with Jeff Rowland I need to ground the black wire by loosening a screw on the amplifier and connecting the black wire, but if it isn't properly grounded I may damage my amplifier. Is there anyone that owns a REL with Jeff Rowland 625 S2 amplifier or other balanced differential amplifier? If so, how do you connect your REL via the high-level input. Is there an easier way to ground the wire than unscrewing the screw on my amplifier. I just don't want to unscrew the screw and prefer another method of grounding the sub.   
ricred1
almarg's avatar
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almarg
9,670 posts
 
Hi Lalit,

Given that the amps you referred to are SETs they do not have balanced or bridged outputs, so connecting your subs as you have described is perfectly fine.

My statement about counting their blessings referred to what I had said just before that, meaning that those who have connected the black wire to the negative output terminal of a fully balanced (or bridged) amp should feel lucky that (a) it worked ok, and (b) damage didn’t result. As I said, which of those eventualities occurs, in the case of an amp having balanced or bridged outputs, will depend on the internal grounding configurations of the particular sub and amp.

Best regards,
-- Al

lalitk's avatar
lalitk
5,456 posts
 
Hi Al,

Now that makes perfect sense 😊

I also experimented (skeptics at first) with non-grounded power cords for all of my components except preamp to eliminate any ground loop or hum issues. The results were shockingly good, my system is dead quite now...the interconnects from preamp provides static dissipation through the secondary ground connection & neutral thus eliminating any ground loop caused by interconnection of electrical equipments having multiple paths to the ground.
ricred1 OP
2,021 posts
 
daveyf,
"If you are not connecting the black wire, I would be concerned that you are not grounding the sub." If it wasn't properly grounded I'm assuming I would hear a hum? I assume REL's Chief Engineer wouldn't tell me to do something that would damage my amp or sub.
ricred1 OP
2,021 posts
 
Al,
 I initially connected the red wire to the right positive channel and the yellow to the left positive channel, with the black wire floated. Now I have it connected to the right positive channel, but the black is still floated. I was told that if I don't hear a hum, the amp and sub are properly grounded and I won't have any issues. 
daveyf's avatar
daveyf
2,871 posts
 
@ricred1 Al’s comment above about the balanced aspect of your amp is correct. I use both a balanced output amp ( the Rowland) and a non-balanced mono amp ( Jadis), The points that Al brought up are 100% correct with the balanced design. Nonetheless, I think you are not hearing the sub in a way that would be beneficial with the set up you now describe. The sub is only receiving the mono signal from the left ( or right, depending on which mono block you use) channel.
Quick question for Al, if I were to hook up my two (2) subs to my Rowland stereo amp, would I actually utilize the summed red and yellow cables for each left and right connector and the black cable ( now two) for the ground connector ( that Jeff installed)....or leave those disconnected entirely? ( like what ricred 1 is doing).

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