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REL Subwoofers, Class D Amps and Neutrik Cables.

I have a Rel 505 and just purchased a a Peachtree grand integrated amplifier which is a class d amp. Unfortunately the Negative speaker terminals on D amps in which the neutrik cable connects to are not a ground which could cause damage to the amplifier. I contacted Sumiko (Rel) and they confirmed this. It sound the like best solution would be to use a neutrik cable that has "Caps" on the black wire or something. I've seen them selling on Audiogon A few years ago but not lately as Rel's new subs do not have the issue. Does anyone have any knowledge of this or has anyone seen seen this type of cable anywhere lately?
puffbojie
puffbojie OP
115 posts
 
Thanks Al.
dynguy's avatar
dynguy
66 posts
 
Thanks for the thread and I will read along and try some of the suggestions here. I moved from a multi-channel amp to mono amps recently.

I am now having the same issues as my negative posts are live on my Simaudio mono amps. I have tried the connection to chassis to no avail.

When my amps go into standby I get a pretty loud hum from my REL B1. When moved from standby to on humm stops. Ugh.

Got frustrated and disconnected the Neutrik cable but really want this to work of course.

Will follow the thread if okay and watch for additional suggestions.

REL B1 and Simaudio 400M mono amps.

Thanks Rick
dynguy's avatar
dynguy
66 posts
 
Actually the stupid light bulb just went off. I'm using the new monos for front three and am having the issue with humm at idle. Ground to chassis did not resolve as I stated BUT I just ordered a stereo amp yesterday to drive my rears. It didn't even cross my mind that I should now be able to ground on the new stereo amp as negative terminal is not live. I hope this works. It didn't even cross my mind that ordering a stereo amp for rears yesterday may also solve my REL issue. Will know later in week when it arrives.

If I still have an issue will be at a loss but this should work.

Thanks again for letting me tag along with your suggestions above.

Rick
kijanki's avatar
kijanki
4,433 posts
 
Al, Icepower uses only positive supply voltage and "H" Mosfet bridge for the output. That way at zero output (50% duty cycle) both speaker terminals have half of supply voltage vs. GND.

Hypex usue positive and negative voltage plus only two output Mosfets.
almarg's avatar
Ag insider logo xs@2x
almarg
9,670 posts
 
Kijanki, thanks. Your expertise on Class D is always valuable.

Rick, as a point of information REL usually recommends that if a single sub is being connected to monoblock amps it is usually best to connect the black wire to a ground point on the preamp. Ideally, IMO, to a circuit ground point such as an RCA shell, but preamp chassis might work just as well, depending on the specific design.

Also, since your Simaudio's are Class AB, the DC offset issue that has been discussed isn't a concern in your case.

Regards,
-- Al
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