Yeah, I know I will be forgetting to turn the amp to standby after waiting for 30min to roll by. So I will go watch TV in the bedroom and forget. Wake up in the middle of the night and turn the amp to standby. I thought I was so slick, like I invented penicillin… too funny… 
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So, I just turned off the Roon and read an audiophile magazine for 30min and boom, the REL subs go into standby. About 30s apart. I then went over and placed the BHK250 and BHK Preamp in standby. Zero hum at any level. Looks like I found a solution that works. Now I have to train the monkey (me) to make sure I rinse and repeat every evening. I just have to turn the amp & preamp on in the morning and I do that before my coffee. I could have shut off the pre 30min ago; however, using the pre tube hrs for the amp tube hrs to so I turn them on/off at the same time, every time. I replaced the tubes for both and added dampeners at the same time over the holidays. I like to know the tube life in hrs…
Yeah, if I had tubes I would be the same way. I am really glad that is going to work out, one less thing to worry about.
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Is there a way to use the 12v triggers from any of the other components to turn the subs off?
I don’t believe so for my subs, don’t know about Veneet’s subs. My REL S3/SHO subs have a standby auto that senses the signal level and automatically turns on when it is above a certain level or below a certain level. One way to control them is as Veneet does, using the P20 in a zone approach…
You can also eliminate hum by using the REL HT-Air kit to remote the sub to any location without cabling restrictions.
It takes RCA Input from your pre-amp or DSD, RF to the receiver, and RCA Out to the sub.
I wasn’t sure. Just trying to eliminate having to remember anything. I have to automate as much in my life as possible due to encroaching memory issues.
Yeah, as Cadri said, I have the T9i (2 of them), so I have to use the zone feature, which with so many outlets on the P20 its not big deal, even on the P10 it wasn’t so bad either, I put the subs in the HC outlets (zone 5) and don’t worry, the only other big HC thing is my amp which is in a zone on its own.
The remote automates it, but, like I said I need to make an activity for 2channel only as I don’t need the TV and OPPO and stuff
Right you are - the approach I used just connected the amp GND (RCA connector) to the unused RCA on the REL S3/SHO. This got rid of the hum during full BHK250 operation. However, the BHK amp disconnects during standby and you would get the humming if you kept the REL sub on as the BHK250 goes to standby. My approach for BHK standby is to use the auto standby feature of the REL sub. Turn off the Roon; wait 30min for REL sub amp standby to kick in and then turn off the BHK250. It seems to work like a champ. In the morning, I just turn on the BHK250 along w/ BHK Preamp and start using Roon, when the signal reaches the specified REL standby to on level, the sub amplifier turns on. The only downside is turning Roon off for more than 30min during the day. However, if it does, not big deal, turn Roon back on and subs come to life…
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Sorry if this is just regurgitating the solution described above. You run an RCA from the PSA 250/300 RCA input (you’re using XLR) to the unused RCA input on the REL (interconnects signal ground to each device). You also run the REL in auto-standby. You hear hum after the 250/300 goes into standby until the REL shuts down in auto-standby.
Thanks for the deep dive as always!
Edit: the REL site says to use the .1/LEF jack on the sub.
@amsco15 - I use RCA cable to connect GND of the BHK250/300 to REL GND on the .1/LEF input (not used) on my setup. I use the XLR input for signal. Make sure REL .1/LEF potentiometer is CCW. I use REL speaker cable Baseline Blue (red & yel) from BHK250/300 (+) to REL input. I float the REL blk line. I never turn the BHK250/300 to standby without the REL S3 SHO going into standby (auto sense) first. REL amp goes into standby after 30 min not sensing signal. At the end of evening I turn off Roon and wait 30min so REL sub goes into standby. You have to have auto sense sub for this approach. If you place the BHK250/300 into standby before the REL is in standby, REL sub will hum. I never turn the REL sub amps off unless I am reconfiguring my rack or going on VAC. I like all my electronics in standby at end of evening and on before my first cup of coffee in the morning. The tubes warm up quick enough on the pre and amps.
Some just turn the subs off using P20 or just flip the switch. I like everything automatic so I take advantage of the REL auto sense. I place the REL in auto-sense. The down side is the training to make sure I turn off the BHK250/300 amps after 30 min when I see the REL LED go from bright white to low level amber. Easy to see from entrance of music room.
Also, when I went to BHK300s I tested the hum and it was still there if I turn off the BHK300 before the REL is in standby or OFF.
Hope this helps.
Specifically, from the RCA input jack on the BHK to the RCA .1/LEF on the REL?
Since there’s no way I’m waiting for the REL to auto shut off before turning the amps off (and going to bed at the end of an evening listening session), how bad is the hum till the RELs auto shut off? I’m assuming not that bad.
Thanks!
@amsco15 - yes, you are just picking up the GND. Bad in my mind, I can hear it from entrance of my music room. In addition, if I went to sleep with that hum no matter how tiny, I would start contemplating damage to the RELs over a period of time even if they were not getting damaged… just me.
[Note 1] Some REL subs do not have auto sense.
[Note 2] That hum is irritating for sure; however, if I’m not in the room it only bothers me in my head…
To specifically answer your question, I never attempted to see if the REL auto-sense worked while they hummed… good point…
I will try it now and let you know.
08:05AM - stop Roon, turn BHK300s to standby, hum present, irritating; however, not that bad. Will monitor REL white LED and indicate auto-sense time frame (if turned to standby (white to amber) & when) and if hum went away if auto sense worked.
08:34:00AM - left REL sub went to standby and hum stopped
08:34:30AM - right REL sub went to standby and hum stopped.
So, the answer is you can turn the BHK250/300 amps to standby and the hum will stop after 30 minutes.
The question for me is thinking about the times I forgot to turn off the BHK250/300s and pulled life from the tubes, plus an additional 182.5 hrs a year on the BHK250/300s tubes, or dealing with the hum impact for 30 min every evening. Thanks for getting me to go through that exercise, I think I can deal with the hum for 30min knowing the auto-sense works will hum is happening and it is only for 30 min.
I use a Blue Jeans one meter RCA cable from BHK300s input to REL .1/LEF input. Also, using Iconoclast one meter UPOCC XLR from BHKPRE output to each BHK300 input.
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I appreciate the experiment. I figured the RELs would shut off but in this crazy hobby…nice to know there’s a solution ahead of time.
Thanks again!
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@amsco15 - yeah, this helped me too because there is ~250hrs a year gone to not listening, plus all the times I forgot to shut down the amps… ~10%. So, another 365 * 10% * 8hrs = ~ 500hrs. So, ~750hrs out of 7500 hr (change every 1.5years @ 5000hrs per year = 7500hrs. Yeah, 10% of tube life and having to go back to music room every evening… I’m just turning “crotchety old person” in a few months so it gives me one less thing to complain to everyone about…
What RELs did you go with?
Likely stereo pair of T/7i. Really based upon geometry. Size matters and I don’t have space for subs much bigger. I have time to decide. I’ll re-evaluate when I get everything set up again after my remodel.
OK, I checked really quick to make sure you have auto-sense and it looks like you do… w/ standby and on always switch. I have the S3/SHO and was not sure. I love REL subs. They complete the low end and you do not notice they are there until you turn them off and go… holy crap, what happened to the low end.
I wish I would have went the Carbon Fiber special S5; however, that is long down the road cause I love these S3/SHO…
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@amsco15 - read the last sentence of the snapshot, I just caught it… looks like 110V models does not come w/ standby switch and then look at S3/SHO rear panel. There is no standby switch on S3/SHO cause it is automatic.
Ahhh…sharp eye. Crap! Weird since that’s a 120V NEMA plug…and the 120V box is checked.
@amsco15 - same w/ T9. Sorry, another way is to turn it off…