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Question BK XLS Question - Humming?

TheRoverdog

Active Member
Hi Members - Question - I have just received a lovely BK XLS400 purchased on these very forums and I have carefully set it up in position and cabled up with my Marantz NR1606 7.2 set up.. The Question... The Gain from the previous owner was set to 0 on the dial.. Once turned on I could hear a very slight hum/buzz - really low volume but you could JUST hear it if you had your head at the back of the unit.. Turn the Gain Dial one quarter and it gets louder, Turn Gain dial to half way it gets louder still and turn gain to max it's a very obvious louder Hum.

Is this normal for a BK XLS400? Do Other BK XLS400 users just get used to it?

Thanks Guys - I hope someone can help as it's a lovely looking Sub -
 

shotokan101

Distinguished Member
Is it there with nothing connected and how are you connecting it?

Basically shouldn't have a hum if it's ok and all your mains and earthing connections are ok
 

TheRoverdog

Active Member
Thanks for reply buddy - So...

1. When plugged into mains ONLY (No other cables connected) - Gain on 0 - No hum - Turn slowly to Max Gain - No Hum..

2. I have tried TWO different low level connections to Receiver Sub output (1 x Male to 1 x Male connection and also purchased a 1 x Male to 2 x Sub Male cable) - Gain on 0 - Slight Hum - Turn slowly to Max Gain - Hum gets louder..

So I am going to return the second cable (unless there is any benefit for having a double connection at the sub end? Who knows? Someone on here maybe..

But any thoughts from the members here (including Shotokan101) would be appreciated. I was really looking forward to using it after buying it from a lovely bloke on the forums last week - But I just don't want the hum when using it - I was using a T2 (KEF) before which was perfectly silent... :(
 

shotokan101

Distinguished Member
Sounds as if the hum is coming from other equipment - pun intended :)

How are you connecting the sunpb and your amp to the mains - powerstrip or individual mains sockets?
 

TheRoverdog

Active Member
Yeah I thought about the mains maybe being an issue - I just tried it plugged into the same extension strip as the receiver.. still a hum when RCA connected, tried it in it's own mains plug on other side of room... still a hum (but I think less - or that's in my head) - Tried turning off (one at a time - Freezer, Fridge, Microwave... Couldn't think what else to turn off?!)
 

shotokan101

Distinguished Member
With sub cable (not just a spare phono/RCA?) Connected Oly to the sub and not amp is there a hum and how long is the sub cable?
 

TheRoverdog

Active Member
OK ta... With Just Sub Cable plugged into Sub (Not connected to Receiver, just sat on floor) Hum gone.. With Gain at MAX you can hear a tiny teeny hum but pretty sure that's just the power of the amp on the sub (you can't hear it more than ear 10cm away :) IF I go to unplug the cable whilst powered on my hand touching the RCA socket on the sub causes hum but that's probably my fingers causing that...
 

shotokan101

Distinguished Member
So maybe something plugged into the receiver? :(


Possibly - can you just confirm that the connecting cable is a proper shielded sub coax and not a spare RCA phono cable?

Is the hum present with the amp connected but in standby and what about if powered off but plugged into mains?

Obviously worth disconnecting all devices from amp and rechecking and if no hum then connect one at a time to narrow it down

Jim
 

MI55ION

Distinguished Member
Hi Members - Question - I have just received a lovely BK XLS400 purchased on these very forums and I have carefully set it up in position and cabled up with my Marantz NR1606 7.2 set up.. The Question... The Gain from the previous owner was set to 0 on the dial.. Once turned on I could hear a very slight hum/buzz - really low volume but you could JUST hear it if you had your head at the back of the unit.. Turn the Gain Dial one quarter and it gets louder, Turn Gain dial to half way it gets louder still and turn gain to max it's a very obvious louder Hum.

Is this normal for a BK XLS400? Do Other BK XLS400 users just get used to it?

Thanks Guys - I hope someone can help as it's a lovely looking Sub -

This little device can work wonders to remove hum from a system.

Amazon product
You'll also need a pair of rca to 1/4" TRS cables.

Amazon product
 

TheRoverdog

Active Member
Morning peeps.. ok.. did a process of illumination test this morning.. sub in gain max so easy to hear hum..

1. Sub on.. no rca connected.. no hum
2. Sub on.. rca connected without any remote connection.. no hum
3. Sub on.. rca connected to receiver but receiver off at mains.. no hum
4. Sub on.. rca connected to receiver, mains on but in standby.. HUM
5. Sub on.. rca connected to receiver, receiver plugged directly into mains (not extension).. HUM
6. Sub on.. rca connected to receiver, all other devices disconnected.. HUM

So.. I guess.. the Sub is getting hum from receiver solo when it has any power to it, even in standby..
 

TheRoverdog

Active Member
Oh well that didn't work lol.. having spent out on cables, loop isolaters etc. I've now paid more than I could have got a refurb direct from BK for ha ha! :^(

Maybe these BK XXLS400-DF subs just hum.. who knows.. I've dropped the Gain back to halfway so the hum is way quieter. Maybe back to the KEF T2.. I read about BK Hum or REL Hum and I guess people just accept it as part of having one but having come from a silent T2 it's just annoying :^(
 

EdwardScissors

Active Member
hey guys im the seller. I had it plugged straight into a wall. Im not an expert but it sounds like something else is causing it. Im not trying to shift the blame im trying to help. I just dont know why your other sub was fine but this one isnt.
 

password1

Well-known Member
Maybe it's the receiver. do you have a different reciever or amp you can try? Does it hum from a maibs in a different room?
 

TheRoverdog

Active Member
I've found a workaround! :^) I've increased the sub level on the Marantz NR1606 and turned the Gain down on the BK so all good. Too be fair I shouldn't have the gain past half way anyway.. All good chaps.. this gives me the bass without Gain being high so all good..
 

TheRoverdog

Active Member
I'm getting a new receiver in two weeks anyways. Looking for an Earc one... it could well be the NR1606.. To be fair if I have the Sub ON with no RCA connected with max gain.. no hum.. RCA connected to marantz (powered off) no hum.. it's as soon as power goes on on receiver.. hum from gain halfway to gain max (never going to have it passed halfway anyway) .. the sub is mint, I'm happy with it, I just wanted to know if the Hum was normal thats all really.. buying new cables and bits etc made me realise gain max would have a hum anyway on any receiver....

Maybe it's the receiver. do you have a different reciever or amp you can try? Does it hum from a maibs in a different room?
 

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