When firing up the RP10 recently I’m hearing a constant low rumbling sound coming through the speakers before the needle is on the record. It gets louder with increased volume. In quiet passages during replay I can also hear the rumbling sound. I’m wondering if it’s some sort of earthing issue but I’ve not had it before so it’s strange.
Any ideas what it is and how to fix it?
Cheers
Dave
Hi Dave,
A low rumbling is normally associated with bearings or motor, but as you said this is an RP10 it would seem very unlikely?
Have you moved any equipment, or changed anything recently however minor?
“Did the earth move for you, dear?”
“Only when I’m in anticipation of a record starting to play!”
No not changed anything
An earthing issue is usually evidenced as a 50Hz hum. Your rumble sounds deeper than that. Is the Rega power supply on a different circuit to the Naim?
Yes it is on the other mains circuit to the dedicated hifi circuit and always has been.
I just put the 552 input to Aux1 which is what I use for vinyl. The rumbling sound is there through the speakers even when the RP10 is not powered up, the TTPS is switched off.
No similar sound when any of the other connected 552 inputs are selected (CD for my NDS and Tuner for the NAT01).
Moving the 4pin to 5pin interconnect that runs from the SCDR to the 552 from AUX1 to AV creates the same sound through the speakers with volume up and AV is selected.
Have you tried another source through AUX1? does it hum?
Have you tried the TT via another input?
I just powered everything down and checked the connection for the 4pin to 5pin at the 4pin end going into the SCDR. That interconnect was touching the 17pin burndy from SC to Superline so I reconnected it and redressed the cable. Powered back up and it’s better (hardly audible). I wonder whether it might have been that?
Possibly Dave - the Superline can be quite fussy. Do you use any capacitive loading ?
Hi James - I use a Z-airplug which I think is the 110 version.
Hi Dave - That sounds like the Resistive plug, any loading on the Capacitance socket ?
No nothing in that socket James.
Try adding one of the capacitive loading plugs - try the 1nF first and see if that gets rid of the noise. How old is the SL and the Supercap powering it ?
Ok. Many thanks James. I’ll try the 1nf.
The SCDR is a 2014 model and the SL is a 2018 staff build (Mark Raggett’s son was selling it) but was unused when I acquired it in 2019.
Ah ok - shouldn’t be an issue with the age then. Just curious as to why it’s started happening but it’ll be interesting to see if adding some additional capacitive loading stops the noise.
James - thank you very much. Inserting the 1nf plug seems to have fixed it. There is now no rumbling noise through the speakers when the RP10 is powered up. It’s a strange one though as it only started happening in the last few days. Anyway you have taught me about the value of capacitance loading on the Superline or at least the option to use it to see if it fixes the problem. Thanks again!
That’s good - hopefully minimal effect on SQ (might roll off treble - see what you think). Possibly some mild RF pickup affecting the SL. As it’s only started happening it might be worth a question to Naim for some more specific advice just to ensure it’s not a sign of a possible future issue.
I suspect the phono preamp… there might be a capacitor that has gone out of tolerance…
Can you try a temporary phono preamp to see if it goes away?
If you mean do I have a spare phono stage to replace the Superline then no I don’t.