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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
2,021 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. 

calvinj
2,319 posts
 
How is it sounding 
ricred1 OP
2,021 posts
 
calvinj,

I received the upgraded Signal cable for high-level connection yesterday and connected it last night. My initial thoughts are I prefer the sound via the low-level connection. To my ears the bass is more defined and it integrates just as well. The subs disappear no matter what connection method is used. I’ll compare the sound of the different connection methods over the weekend and let my ears determine what sounds best. I know what REL thinks about the high-level vs low-level input, but how many REL owners have actually compared the sound of the high-level vs low-level in their system?
daveyf's avatar
daveyf
2,871 posts
 
@ricred1 Thanks for the update. How do you like the new Signal cables vs. the stock REL cable?
You make an interesting point about the high level vs. the low level input. I would suspect that the high level should always sound better, just as REL states, simply because the signal to the sub is exactly the same as what the main speaker sees from the amp. Question is, whether the REL’s active amp is modifying the signal in such a way as to somehow interfere with the signal...and as such you ( or anyone) prefer the sound from the preamp via a ic (low level) vs. from the amp via the Signal cable(high level)...could be. I will be interested to hear your thoughts.
Have to admit, that I have NOT actually compared the two ( high vs.low) BUT once again, I do see REL’s logic.
almarg's avatar
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almarg
9,670 posts
 
Regarding line-level vs. speaker-level, in the specific case of speaker-level connections to Richard’s amp it seems to me to be possible that the less than ideal nature of the ground path/signal return path between the subs and the amp (with the AC safety ground wiring being part of that path, as I had explained earlier) might be a factor contributing to his findings.

Generally speaking I would not expect comparisons of line-level vs. speaker-level involving amps whose outputs are not balanced or bridged to necessarily have much correlation with comparisons involving amps whose outputs are balanced or bridged.

Also, as I had mentioned earlier in the thread it would seem logical that the more transparent and accurate the sonics of the amplifier are, the less likely REL’s rationale for speaker-level connection is to be applicable.

Best regards,
-- Al

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