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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
ricred1 OP
1,988 posts
 
So I decided to start playing around with my subs. REL says the high-level connection is "superior " to the low level connection method. I think all systems are different, so I decided to compare the sound of the high-level connection to the low-level connection. Initial thoughts on high-level connection using stock REL speakon cable vs low-level connection using Audioquest RCA Boxer subwoofer cable. The low-level connection has more bass output and you can feel it more. Not night and day, but it’s easily discernible. I think with the low-level connection you loose a little detail and resolution. I had to turn my amp and preamp off to disconnect the speakon cables and connect the RCA cables, so that may account for a slight loss of detail and resolution. It usually takes 30 minutes for everything to sound normal again. The other issue may simply be the AQ cable is better than the cheap cable that comes with REL subs.
I've already ordered a REL speakon cable from Signal Cables. I should have it bye Thursday, so I'll see how much difference it makes.
daveyf's avatar
daveyf
2,835 posts
 
Richard, you ordered one cable or two from Signal? If you are running two subs, I would think you need two cables ( one per sub). Your post above seems to indicate that you ordered a single cable.
oem-wheels
196 posts
 
I read the 1st 12 replies or so a few day ago and popped in today without reading the rest. So sorry if I repeat this or someone found a fix.. I just came across this "post" about how REL subs shouldn't be driven by a true balanced amp like the Rowland.. Not only won't work right but its dangerous.. Use unbalanced amp with REL.. 
ricred1 OP
1,988 posts
 
daveyf,

I ordered two 7’ cables with spades from Signal(one per side). 
ricred1 OP
1,988 posts
 
oem-wheels,

"I just came across this "post" about how REL subs shouldn't be driven by a true balanced amp like the Rowland.. Not only won't work right but its dangerous." That's true if it isn't connected the correct way. I talked to Jeff Rowland and one of the Chief Engineers of REL that told me how to connect everything. As a matter of a fact a friend that owns Rowland 925 mono-amps uses REL subs and told me how to connect my RELs. I believe he's had his setup for a couple years and has never had problems. 

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