Proper way to hook up a REL Sub

[j3brow]

Originally Posted by Rick U

Chuck did not discuss using a grounding screw. I believe that was in the REL manual. I might be wrong.

Jason do you still have the 452 w/ REL?

I had a 402 paired with REL
I have not heard the 452

Both Jim (MC1.2) and Josh (MC601) paired REL G1 subwoofers with their balanced McIntosh amplifiers. I don't see why your 452 cannot be properly connected. I believe Josh's G1 was connected and dialed in by a Sumiko rep/speaker guru and if there was a problem pairing Mc and REL this guy would of recognized it.

Go forward with confidence.

[Rick U]

Here is one of Chucks replies:
You Can NOT use the speaker level connection on the MC452, it is not a common ground amp and using the REL speaker level connection will cause the amp to go into power guard at %10 power.
I want to be positive the spkr level connection works with the 452.

[j3brow]

Hmmmm interesting. I wonder if he realizes how a REL sub works. The Mc amp is not 'driving' the Rel. The resistive load is quite high on the REL sub. I am certainly no electrical engineer and I can't dispute his concern for power guard. Maybe the REL load can be a problem for the amp. Dunno. But I have never shut down my amps in 5 years BUT I am not a 500w bury the needle type of listener either. Sounds like a call to Sumiko would clear things up

[Rick U]

He understands. Speaker level connections are a very high impedance so they do not change the load when connected in parallel with other speakers, you can use any of the taps, it will not make a difference.
The above was in reference to the 302.

Maybe he doesn't recommend taking a screwdriver to a screw that might be holding something in pace inside the amp.

[tdelahanty]

Originally Posted by j3brow

Hmmmm interesting. I wonder if he realizes how a REL sub works. The Mc amp is not 'driving' the Rel. The resistive load is quite high on the REL sub. I am certainly no electrical engineer and I can't dispute his concern for power guard. Maybe the REL load can be a problem for the amp. Dunno. But I have never shut down my amps in 5 years BUT I am not a 500w bury the needle type of listener either. Sounds like a call to Sumiko would clear things up

Your Mac amp (the 501 is a fully balanced design) is indeed driving the REL sub. The REL speaker level connection is a high impedance load (basically voltage driven), therefore requiring very little current and no load to the amp.

[tdelahanty]

Rick U: I looked at the block diagram for your new 452 amp, it is a true fully balanced design and has no ground connection at the speaker binding posts.

Connect the REL's speaker (hot) leads to the right & left red (hot) speaker binding posts on your amp, then connect the REL black (gnd) wire to the chassis or one of the RCA input's gnd, either place should work fine, if one hums try the other. Be sure to keep the volume control set very low.

If you are not comfortable with my suggestion, talk it over with Chuck at Mac.

[miner]

I have a REL B1 hooked to my MC452 via the speaker binding posts (hot and ground). No hum with mine. My dealer did the actual install. And I have gone way past 10% power with no power guard problems.

[j3brow]

Originally Posted by tdelahanty

Your Mac amp (the 501 is not a fully balanced design) is indeed driving the REL sub. The REL speaker level connection is a high impedance load (basically voltage driven), therefore requiring very little current and no load to the amp.

Thanks tdelahanty!! I'm still trying to figure out how I need to hook my rel up properly. According to Mc website, the 501 circuit configuration is "quad balanced". Stereophile review of 501 says that it is a "double balanced push-pull" circuit. "each half of the amp is fully balanced from input to output". "Each phase rendered in balanced configuration". The only time I get hum with either my old 402 (quad balanced) or 501 amp is when I forget to turn off sub before I unplug the banana plug at the amp. Maybe I should just stick my head in sand and ignore but I don't want to damage the amp over time. It doesn't run hot per say but my amps are loafing at .5 to 5 watts about 98% of the time. To confuse matter further I have aftermarket cable which combines the 3-lead wire (red,black,yellow) into a standard two lead system ((I forget if its two hot and one ground or 1 hot and 2 ground ---- I presume it's 2 hots combined yellow and red??))

[j3brow]

Originally Posted by miner

I have a REL B1 hooked to my MC452 via the speaker binding posts (hot and ground). No hum with mine. My dealer did the actual install. And I have gone way past 10% power with no power guard problems.

Glad to see its not just me!!! No hum here either. I'm puzzled.

[tdelahanty]

I stand corrected, the 501 is quad balanced, I looked at it's block diagram. If your cable is two wire instead of 3 wire, it has one hot and one ground. I don't quite understand why you're unplugging the REL from the amp !!! I always left my REL connected to the amp (fully balanced Levinson 335).

CONNECT THE GROUND WIRE TO THE GROUND SIDE OF ONE RCA INPUT. You should be able to leave the sub connected all the time with no hum.