@amonmasters The reason for multiple possible solutions is because there are multiple ways to get the signal ground. RCA plug, ground lug in the back, chassis screw. As for why none of these have worked for you is rather confusing. One did eventually work for DustyYevski and shows that it can be resolved. Have you tried reaching out to REL to see if they have any comments?
@Veneet Very little. Without anything playing, they pull about 35-37W each if my memory serves correctly.
@jamesh Thanks! I thought it wasn’t too bad
@jamesh This was @DustyYevski last post, where he indicates that when the sub is on and the S300 is in stand by, that the Rel hums. That means he hasn’t managed to fix the issue and his workaround is to turn the sub off - which is what I am trying to avoid. The issue he was trying to fix, was the hum when both the S300 and Rel were both on, a seperate issue that shouldn’t be confused as there are a number of posible solutions to that problem as you have rightly pointed out. I don’t have that issue as grounding the Rel to the S300 chassis removes that hum for me - which @DustyYevski tried and discovered also worked for him. What I am trying to eliminate is having to turn off my sub when I put the S300 into standby. Currently none of the solutions to the other hum issue (Rel hum when both S300 and Rel are on) work to eliminate the hum when the S300 is in standby (or fully switched off).
Sounds like TJ Tomasetti believes he has the solution with the resistor kit he is proposing. Hope that ends up working for everyone. Turning the sub off when not in use wouldn’t be a big issue for me, but apparently it is a problem for others.
In your setup, the REL did not go stand by when idle?
I don’t think so – blue light stayed on constant.
You’re right. Sorry for my confusion. I’m troubled because I’ve worked with countless customers where at least one of the solutions works when putting the amp in standby. As TJ mentioned above, you may need the resistor kit that REL offers. If you haven’t already, shoot TJ an email and he’ll be able to get you this info. tjt@psaudio.com
I’ve spoken to TJ and going to test out the resistor kit he suggested. Fingers crossed. If it works then it would be great to post the solution. Might even be a good contender for a manual update.
My Rel (T9/i) goes in to standby after 5 minutes or so (don’t know exactly how long though) when the S300 is powered on and there is nothing playing; when the red and yellow go to the left and right posts and the black to the grounding lug on the back of the S300. It wont however go into standby if the amp is off as that produces a hum from the Rel - which I am hoping to solve with the resistor kit suggested by TJ.
So the S300 did not go standby when idle ? i just wonder if the Rel goes into standby when fed nothing from S300 and the S300 went standby,
About the hum, you have to leave S300 ON for not getting hum, even play nothing?
how about hum when S300 goes standby and wakeup by the trigger port on the back, or the S300 just ON/OFF remotely without standby mode ?
Sorry i’m not getting my M700 yet
The S300 doesn’t go into standby when nothing is playing. Can’t think of an amp that is designed like that. Perhaps someone has an example. At present, I have to leave the S300 on to not get hum from my Rel, which is what I am hoping the resistor kit will fix.
In PS Audio’s defence, the Rel is very sensitive in picking up noise. With the speakon connector/cable plugged into the Rel and the wires not connected to anything, the Rel produces hum on its own. Because the S300 is balanced, there is no reference to ground and putting the unit in standby switches a relay that isolates the speaker connectors from the amp circuit. In essence, it is like unplugging the wires at the end of the speakon cable, which as I mentioned above, produces the same hum. The resistor kit should theoretically terminate the connection when the relay in the S300 is switched to “standby” and the speaker connectors become isolated. That’s the theory from what I understand. Will see if it works in practice though.
BTW @Elk, I think the conversation around the hum issue should be split out from this thread or the title renamed as there is some very useful information in here for people experiencing hum issues with the S300
It is great information, but is not the entire thread after the first couple of posts about addressing hum with the S300 and REL subs? I changed the title of the thread to reflect this.
Does this make sense?
@amonmasters
It sounds strange to me, my Rel T7i does not hum at all when connect to nowhere, i just do a quick test to disconnect it from my current Cambridge Audio CXA81 integrated amplifier, REL sub is ON and not in standby mode
I don’t get this issue,
if your Rel still hum even connect to nowhere then you need to check from REL sub first, then trace step by step to amplifier up stream
Do you mean you disconnect the wires or you unplugged the speakon connector?
@amonmasters
I disconnected the sub wires from the amplifier side only, the high level speakon connector still plugged on to test IF the hum is there by noise on the cable or not. It is quite, I then slightly touched the red/yellow wire checking for hum, i do see the hum when contacts to human body resistor, but not loud much. So my REL T7i is quite when connect to nowhere with cable plugged on sub.
I think i will not encounter the hum when connect to my coming M700 power amplifier with grounding
to chassis ( not sure if sub goes standby if idle )
UPDATE: i disconnected the sub wires when ON ( i know what i’m doing) with volume down (20%) to make sure the sub not in standby, if you power down the sub, then disconnect the amplifier speaker binding post then turn ON, the REL will not be active , it is in standby mode and only activate when feeding by the amplifier with sound signals, (The red led on the back ON) so you will not be able observing the hum in REL standby state.
Update again:
Connect the speakon cable ground wire to chassis/disconnect chassis while yellow/red wire taped did not get any HUM, the SUB is really quite
I am having the problem with my Rel hum with the S300 off. If I leave it on all the time there is no hum. I have tried all the above and nothing works. Can anybody confirm if the resistor kit works?
I can’t as of yet. I was told I would be receiving a kit that was being made up as a trial/experimental thing to see if it would eliminate the hum, but I have not received it yet. But your problem is the same as what everyone was experiencing: if the sub is on and the amp is off, there will be hum. Somewhere earlier in this thread, or in the one I started with a title something like “Is the Stellar S300 considered two monoblocks for the purpose of REL sub pairing”, there is an explanation from one of the PSA engineers about why the hum occurs when the amp is off.
Thus far I have just been making a point of powering up the amp before turning on the sub, and turning off the sub first at shut down. (Sub as last thing on, first thing off).
Best of luck.
Here is that explanation –
Here’s the answer from the Head Engineer:
“Our amplifiers have a relay on the output that disconnects the speakers from the amplifier when the amp is placed in standby.
The REL subs have a fairly high input impedance and can pick up noise easily.
When the relay disconnects, not only is the REL not terminated to the amplifier anymore, but it is also connected to the long unshielded speaker cables, the speaker internal wiring, and the drivers themselves. This is a nice big antenna for picking up noise.
The resistor kit just adds some terminating resistors on the output side of the relay to shunt the noise. Note that the newer production of BHK amps (the ones that have the ground post on them) have that resistor built in.”
i just wonder why don’t you move the sub to another place and leave it there in standby mode ( red led ob the back) with the high input level cable connect to nowhere to see if the hum still there ?
we need to track down the line from top to botton to eliminate where the hum coming from first
Make sure you can check:
1/ Sub is not humming with connecting to nowhere with cable disconnected from S300 but plugged to sub port
2/ sub is not humming when connect to other system having sub port, even you have to bring it to friend’s house to check if hum is not there and your sub is safe.
3/ sub is not humming with at other place in the room , can be different room if need to make sure you are not closed to strong EMI, RFI area.
4/ grounding all your audio component present in the system serially , one to another and make sure the ground pin on power strap where devices connected to is ground correctly, ( i personally suspected your grounding having some issue, that cause of some ground loop)
5/ if need , try to borrow the power strap having filtering function , check if the ground led is bright green of it is dimmed green, or even not green. you will know how your grounding is.
if passed #1-2-3-4 , then your can move up to the upper stream , the S300 → DAC/phono stage /CD… if had, one by one connect to system, have them play something, continue untill you find the step that hum is found.
I think you should resolve the issue yourself , people over here just read your post and have comments , but your issue still there , that means you need to resolve on your own and should not expect too much.
the S300 and the M700s are the same class D so i believe the ground on both are the same . I just got the M700s and wiring the sub. mine is REL T7i , i just connect the yellow, red core to the + binding post of two M700s, the black core is just connect to one of the two M700s, can be any of them.
I DON;T HAVE THE HUM AT ALL, AND THE SUB GOES STANDBY MODE in 30 minutes inactive. worked as designed.
I don’t need this KIT, if i have HUM, i would rather find another way to resolve the problem by it root cause, or even buy another sub , return the amp … I would not take this KIT as life saver.
Just my thought, Hope you don’t mind it