Page 3 of 3

Re: Attempting to solve hum on p80/s300

Posted: Wed Sep 06, 2023 11:21 am
by Ageagainstthemachine
20230906_110826.jpg
20230906_110826.jpg (107.8 KiB) Viewed 6764 times
I spent the day moving things around.
This is about the best I can do for component separation, any cables that have to cross have been crossed at 90 degrees.. my digital gear is to the right of the pic but the hum is still there. When I next get chance I will play around with a ground wire again and see if I can reduce the hum as before.
I know its only a small issue but it would be nice if I could improve it.

Re: Attempting to solve hum on p80/s300

Posted: Wed Sep 06, 2023 11:44 am
by Fretless
What about noisy mains ? Is the humming more or less at certain times of the day or on certain days ?

Fridges, freezers, washing machines ?

Industrial usage in your neighbourhood ? Solar panels ?

All things that RD used to moan about as NVA amps are sensitive to that.

Re: Attempting to solve hum on p80/s300

Posted: Sat Sep 09, 2023 5:04 pm
by Ageagainstthemachine
Fretless wrote: Wed Sep 06, 2023 11:44 am What about noisy mains ? Is the humming more or less at certain times of the day or on certain days ?

Fridges, freezers, washing machines ?

Industrial usage in your neighbourhood ? Solar panels ?

All things that RD used to moan about as NVA amps are sensitive to that.
I have an open living room/kitchen in a new build apartment with two mains circuits on the switch box for all sockets. As far as I can tell one circuit is for the living room/kitchen and the other for the hall, bedroom and bathroom. I had an electrical inspection and they're coming back to uprate the rcd's(?) as power dips and the speakers cut off for a fraction of a second.. Happens even if I switch the kettle on. I will ask him to clarify the circuits for me when he comes.... And possibly ask him about DC offset 😅

But I did make some progress and found that the cassette player and phono power supply are the two main culprits for hum. Not really an issue when I can just switch them off at the plug if I'm using the digital side.

I played around with earthing leads and it didn't have the same effect as it did before I moved everything around. I thought I'd whip the cover off the cassette player so I could be sure of a proper earth connection but found heat damage on the pcb. I know this damage is recent as I'd carried out a visual inspection a couple of months ago and now I'm curious if this damage could contribute to the hum... Or possibly the old electrolytics that are due replacement.

Re: Attempting to solve hum on p80/s300

Posted: Sat Sep 09, 2023 7:13 pm
by DaveyTed
Henley Audio can supply a power supply fitted with a three pin connection to minimise any hum problems. If you buy a new Project turntable I understand the dealer will change the power supply free if required.