Occasional hum

[CageyH]

I think it could be an earth loop problem.
Probably related to the SL1200 power supply, linking in to the arm, feeding the phono stage, and in turn linking to the preamp.

I returned the iPurifier, and have a Gnd Defender instead. So the power amp, pre amp, phono stage, DDC and TT PSU are plugged in to my mains block (Furutech TP60e). The Gnd Defender is plugged in to my phono stage. The hum has decreased dramatically.
I have the volume turned up way beyond my normal levels, and I can hear it now and again, so is it a ground loop?

Really not sure. My next step may be a different (filtered) mains block, like the Puritan Audio jobbies, as this is driving me mad.
I may swap out my cables from the phono stage to pre for some coax based cables, in case it is the shield (connected at one end) acting as an antenna.

[Macca]

I'd bet money it's a ground loop. Might be wrong but I'd try the various solutions to that first.

Power conditioner or filter might remove some very high frequency noise but since you can hear the noise it's not very high frequency.

[CageyH]

I have tried earth straps from the different equipment, and nothing seems to change it.
I have done some extreme cable dressing, which I never bothered with before, and no real change.
I still get the occasional burst of hum.

What does EMI sound like?

[CageyH]

There is a podcast on noise and hub in this attached link, might be worth a listen?

https://parttimeaudiophile.com/2023/...n-your-system/

Thanks Jim. I had a listen to a lot of it. Most things I have already tried, but thanks for thinking of me.

[Jimbo]

Thanks Jim. I had a listen to a lot of it. Most things I have already tried, but thanks for thinking of me.

No problem just thought there maybe something in there that might be worth considering?

[AJSki2fly]

I recently had a similar issue that I thought was an Earth-Ground loop issue, and spent several months trying to track it down. Like you I tried various leads, earth straps, mains cables etc. It turned out to not be an earth loop, and I found it by accident when I got a new Hifi stand, initially it disappeared when setting the system back up and then it came back, and I did not know, or could not think what had caused it.

Then one day I had to move the Hitachi Tuner to get to the pre-amp to change some settings. I powered the system up and you've guessed it no annoying hum in the background. The difference was the tuner was not in place or plugged in. So I put it back and plugged it in, not powered up, and immediately the hum returned. I then simply unplugged the Tuner and hum went. The Tuner is not directly earthed it has an old 8 socket, live and neutral only, the issue was if plugged in the unit was on standby with the transformer powered up, so it was radiating a nice 50Hz RF that the system was picking up somewhere, so now unless I am listening to the Tuner it remains switched off at the socket.

Your occasional burst of hum is odd, but if you have not already done this it might be worth unplugging everything apart from pre-amp and amp in the system,powered up, and then plugging one in at a time to the mains to see if the hum returns. I would even try removing the Furutech TP60e and replacing with basic simple extension blocks, you never know.

I hope it helps, I know how frustrating this sort of thing can be.

[struth]

Could be the 5g tower

[CageyH]

Thanks Adrian. I shall investigate further.
I have already replaced the TP60e with a big standard unit. No difference.

This morning, I have unplugged the power line network adapters, and fitted a cheap filter. The hum is still there, ever so slightly, but less pronounced at the moment. So it is not them. It does not sound like the typical noise on these devices.

Earth leads have been fitted to pre, phono and amp, so I don’t think it is an earth loop. I guess I could detach the internal earth lead in my SL1200 and see if it is that.

All 2 pin plug devices are unplugged, electrical and signal cables. I need to wait to see if the hum/buzz comes back.
Yep, it is still there….

[CageyH]

I have now swapped out my Phono stage, only thing left to do really.

[CageyH]

Silence…..

I have found the source.