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REL subwoofer using only red cable not yellow per REL technical dept

Hi,

I am using a pair of REL 5/SHO subwoofers for 2 channel application and find it mates well with my pass monoblocks and harbeth 40.2 speakers.

I called REL recently because only using minimum setting( 10 clicks ) for gain and crossover and whether newer 812 faster sub would allow me use higher crossover and gain. 

REL suggested first unplug yellow wire from speaker terminal and turn up sub gain as that might improve the bass integration ..

So far sounds promising....just wanted to let others know about this possibility although YMMV....




128x128karmapolice

Showing 6 responses by golfnutz

golfnutz
231 posts
 
Would anyone know if there’s a hum using a single Pass Labs monoblock
with a single Rel Subwoofer via speakon connection? Rel Acoustics claims you need to connect 2 subs when using monoblocks.
golfnutz
231 posts
 
Yep, they have the "Subwoofer Finder" tool, and suggest what sub(s) to use, but don't mention anything in that tool about using monoblocks, they only ask what type of speakers. Lots of helpful information on that site, and it would be worthwhile reading some of it prior to making a purchase.
I was hoping someone like @karmapolice would be willing to disconnect one of his Rel subs from one of the monoblocks and report back if there is any hum (assuming he still has rel sub and pass labs monos), or anyone else for that matter. 
golfnutz
231 posts
 
@wolf_garcia - yes, I got that from their website:

Here they’re talking about "Balanced/Differential/Class D" connection.
When doing so, please combine red and yellow leads together to form a single composite “+” or “hot” conductor as shown in the diagram below. Do not connect the black wire to the output terminals. Instead connect it to a chassis bolt as shown below.

However, they go on to say:
We do not recommend use of a single REL with ANY brand of monoblock amplifier as it is possible to observe slight channel-to-channel dc offset that can result in mild oscillation. For any monoblock, we recommend use of stereo pairs of the appropriate model of REL sub.
I’ve read issues with some Macintosh monoblocks, and I’m asking specifically about Pass Labs monoblocks with regards to connecting a single Rel sub to one of the monoblocks (using high level connection into sub).



golfnutz
231 posts
 
And that's why I only want to run a single sub, it should be plenty. I really don't even need a sub for 2 channel, but I know it will enhance the experience somewhat. I do however require a sub for home theatre. I just wish someone with Pass Labs monoblocks would disconnect one sub from their system to see if there's any low level hum. Is Rel Acoustics saying you need 2 subs as a CYA, or is it 100% guaranteed the hum will exist when running monoblocks with a single sub?
golfnutz
231 posts
 
@jacobatrel 'Jacob at Rel', thanks for joining the discussion.

Is it 100% certain, regardless of what monoblocks are being used that the low level hum will exist, or is this a strong recommendation just in case.

I'm really not concerned about having mono vs stereo imagining. I've had mono and dual subs in my system in the past. I agree two is better than one. I don't use a preamp, so the low level input isn't possible.
golfnutz
231 posts
 
Thank you Jacob.
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