Jafreeman, I couldn’t find a schematic for your Ref 210 monoblocks, but given that it is a fully balanced ARC design that does not provide an RCA input, I suspect that in respects that are relevant to connection of a REL sub it is similar to the Ref 250 monoblocks that are used by the OP in the thread I linked to in my previous post.
If so, whether or not a ground-related noise issue would arise connecting in the manner you described (which would be an appropriate way to connect the speaker-level input of a sub to most other amps), may depend on the happenstance of how circuit ground and AC safety ground are handled in the particular sub, and possibly also on how AC power is distributed to the subs and to the amps (e.g., via conditioners of various types, via separate dedicated lines, etc.). In the case of the OP in the thread I linked to, obvious symptoms did arise. But I suppose that even in the absence of obvious symptoms it is conceivable that sonics could be at least slightly compromised in situations such as yours.
My suggestion is that you ask ARC which of the amp’s output terminals is connected to the amp’s circuit ground. If (as I suspect) the answer is the 4 ohm terminal, rather than the 0 ohm/common terminal, it may be worth your while to try connecting the black wire to the 4 ohm terminal, and the red and yellow wires to either the 8 or 16 ohm terminal. Using the 16 ohm terminal for the red and yellow wires, with the black wire connected to the 4 ohm terminal, should result in the optimal setting of the sub's level control being about the same as the setting you are presently using. Connecting the red and yellow wires to the 8 ohm terminal, with the black wire connected to the 4 ohm terminal, would necessitate a somewhat higher setting of the sub’s level control.
Of course, continue to connect the Maggies in the same manner as you have been doing.
Regards,
-- Al
If so, whether or not a ground-related noise issue would arise connecting in the manner you described (which would be an appropriate way to connect the speaker-level input of a sub to most other amps), may depend on the happenstance of how circuit ground and AC safety ground are handled in the particular sub, and possibly also on how AC power is distributed to the subs and to the amps (e.g., via conditioners of various types, via separate dedicated lines, etc.). In the case of the OP in the thread I linked to, obvious symptoms did arise. But I suppose that even in the absence of obvious symptoms it is conceivable that sonics could be at least slightly compromised in situations such as yours.
My suggestion is that you ask ARC which of the amp’s output terminals is connected to the amp’s circuit ground. If (as I suspect) the answer is the 4 ohm terminal, rather than the 0 ohm/common terminal, it may be worth your while to try connecting the black wire to the 4 ohm terminal, and the red and yellow wires to either the 8 or 16 ohm terminal. Using the 16 ohm terminal for the red and yellow wires, with the black wire connected to the 4 ohm terminal, should result in the optimal setting of the sub's level control being about the same as the setting you are presently using. Connecting the red and yellow wires to the 8 ohm terminal, with the black wire connected to the 4 ohm terminal, would necessitate a somewhat higher setting of the sub’s level control.
Of course, continue to connect the Maggies in the same manner as you have been doing.
Regards,
-- Al