Nuts! So this REL interconnect scheme is not compliant with the universally understood XLR balanced analog interconnect system (as in AES48 & AES54 standards). The posts about REL problems really don't belong in this thread!
The issue with the REL is due to the connection scheme that it uses. Th REL does not ( although it can) connect to the RCA output, instead it connects to the speaker output of the amp. I actually believe this to be a superior connection scheme. Problem is that if one is using a 'balanced' amp, then there is apparently no grounding at the speaker outputs on the amp. ( This is something that needs to be made VERY clear in the instructions of both the amp and the sub...and unfortunately it is not)
Ralph, my amp would not have developed this problem if it was a single ended amplifying device. The fact that is is 'balanced'...and because I was unaware of that ( as was the rep for the subwoofer) has lead to this unfortunate circumstance. Therefore, the benefit in my mind of the 'balanced' configuration has been overshadowed by the potential and actual damage to the amp by this incorrect hook-up. Yes, one can argue that this is not something that can be laid at the 'balanced' configuration...
I have owned a model 8 long ago. Is part of the model 8 instructions, available on-line from Jeff Rowland:
WARNING: Both positive and negative PARALLEL OUTPUTS
are electrically active with respect to chassis and/or system ground potential.
It is important that both of these outputs are electrically isolated from system
ground potential. This precludes the use of this Amplifier in certain loudspeaker
switching configurations (sometimes used in retail demonstrations)
and testing or servicing situations where either positive or negative outputs
can be connected to ground potentials. Failure to observe these precautions
may result in damage to the Amplifier and may void your warranty. Consult
the factory first if the Amplifier is to be used under these conditions.
Nuts! So this REL interconnect scheme is not compliant with the universally understood XLR balanced analog interconnect system (as in AES48 & AES54 standards). The posts about REL problems really don't belong in this thread!
Yes, it is not a balanced system. It is a custom, non standard use of the Neutrik Speakon plug to connect left , right and ground in the same plug. As you say the safe way of doing it is using a higher impedance differential input.