52 Pre Amp Balance Knob crackling

Posted by: Steve2 on 25 August 2018

I am the proud owner of a 52 pre amp which I had serviced about five years ago.  If I turn the Balance knob when music is playing from my CDS3 it gives a loudish crackling sound.  Yesterday I switched on my system and the right hand speaker was making a crackling sound before I had even started playing any music.  I turned the Balance knob and it made the noise louder and the rubber membrane on the bass driver moved quite substantially.  It then stopped crackling abruptly.  The driver is a Scanspeak 18WU 4741T00.  If anyone has any idea what might be causing the problem I would be grateful for your advice or do I just need to bite the bullet and send it back to Salisbury where it was last serviced.

Thanks in anticipation for your time on this.

Steve

Posted on: 25 August 2018 by Sounsfaber

Hi Steve, firstly place the 52 in mono. Blance left to right if it’s in both channels then it’s the balance pot, if it’s the only in one speaker then that speakers an issue. Also be sure that your speaker terminals  are tight at both ends as well. No big deal don’t worry, my 52 had a blance pots go rogue on me, not expensive. A very easy fix via Naim agent or the mothership.

Always remember if it’s broken it can be fixed????

Posted on: 25 August 2018 by Richard Dane

Steve, sounds like the balance pot has gone noisy. Did you have a POTS board upgrade when you had the NAC52 serviced?  

Posted on: 25 August 2018 by Steve2

Thanks sounsfaber and Richard for your advice with this.  I shall check the terminals and cables thoroughly.  I cannot find the receipt from when it was serviced so I am not sure about whether or not it had a Pots board upgrade so I will give Naim a call on Tuesday with my serial number and find out.

Once again, thanks for your time and effort on this, it is much appreciated.

Steve

Posted on: 26 August 2018 by Innocent Bystander

See this thread - exactly the same cause and solution(s), just different potetiometer.

https://forums.naimaudio.com/t...le-adjusting-volume?

Posted on: 27 August 2018 by Steve2

Thanks Innocent Bystander for your sage advice!  I did what you said and powered up to hear absolutely nothing!  A good result that has saved me a load of money and stress.

Enjoy the rest of the Bank Holiday.

Steve

Posted on: 27 August 2018 by Richard Dane

Switch cleaner works well, but it's usually only a very temporary fix, and performance-wise, never as good as changing the pot for new.  Unfortunately the crackle will return at some point sooner rather than later and then you may find that more switch cleaner no longer works so well. But as a short term fix, it can certainly appear to do the job.

Posted on: 27 August 2018 by Innocent Bystander

Depending on whether the issue is dust or wear (although seemingly the latter may be unlikely on a balance pot, it is possible that the constant contact in the same spot, as often will be the case, could be the cause) the rapid rotation method can be a permanent solution (or as permanent as anything). I did once on a 20 year old preamp, and in the 10 years that followed no repeat of problem. The effect of switch cleaner may likewise depend on the root cause, and also the type of pot.