I just got two REL S/510. When I connect them the correct way, I hear a VERY loud huuumee.
This is a known issue and can be fixed with connecting the black wire from the REL sub to ground on the amp,
As I understand it, newer models of the BHK 250 has a grounding post.
How can I add a grounding post to my BHK? Can you answer that @Paul ?
I really need to fix itbefore I can use the subs.
The subs are also connected to my AV receiver using LFE.1 RCA.
Found this picture of a chassis ground terminal. I want one
I’ve since sold my BHK250 but as I recall it was just a matter of screwing them into previously threaded/tapped screw holes. It came with directions, a super easy install.
Slick, I’m jazzed we got it to you so quickly. Any chance you could post a picture with the instructions? I got a request from someone up here to post but I don’t have an easy way to post them.
Waiting for my ground post from PS Audio.
The ground post will only help with hum when the amp is on.
To remove the hum when the amp is in standby mode, you need two special Y-cables from REL.
I am going to make them myself.
You need 4 1K ohm resistors and some connectors for the ground post and speaker terminals.
It’s going to be very crowded on the back of the amp.
From the REL sub, yellow+red twisted goes to the plus terminal. black goes to the ground post.
The REL Y-cable. Attached to the ground. Then the two ends with the 1 Kohm goes to the plus and minus speaker terminals. Se attached picture
does anyone else have a new bhk 250 with what looks like a grounding lug/post installed? I am not even sure that’s what it is. nothing in any of the manuals about it…
It’s to help with connecting REL subwoofers. Because the BHK has a balanced output and because REL (and us) recommend using the high level input on the REL, which comes from the speaker outputs of the BHK, this is how you ground the REL.
The ground plug for the bhk 250 only helps the hum when the amp is on, if you put the amp in standby, and the rel is on, you get a hum.
I did read on another forum that your employee James stated that you can use the rca input on the amp to plug into the rel to get rid of the hum when the amp is in standby mode. Is this true? If so, which input on the rel do you plug it in? I’m using the hi level input from the 250 to the rel instead of getting the rel “y” cable with 1k resistors.
I have the psa airlens going to the DS sr dac, then using balanced xlr cables from the dac to the bhk 250
Thanks
If you haven’t already, you can try grounding the RELs with an RCA cable and open jack in the system. If this doesn’t work, you will need the resistor kit from REL.
You can easily eliminate the hum by connecting the ground wire of the REL to an alternative grounding point in your system with either Class D amps or differential balanced amps like the BHK’s and others. Easiest solution is the ground lug on another piece of gear or the line conditioner. If one is not available loosen a chassis screw on the rear of one of the pieces. This may require extending the length of the REL ground wire but easy to do. The reverse applies if the amps in the subs are Class D.
