Attempting to solve hum on p80/s300

[George Hincapie]

Take it all apart, rebuild it on a clear bit of floor and see if issue persists.

[Geoff_Burns]

A long shot, but -

When I installed my phono stage (the NVA one), I had an annoying hum appear - I moved the phono stage 2m from the Preamp and the problem vanished.

[DaveyTed]

I had a similar fault after changing to a new phono stage which actually had an inbuilt linear power supply.
The new phono stage was picking up a hum from the SMPS of my CD player. Grounding the case of the CD player solved the problem.
Good Luck - hums can prove very frustrating and to me sometimes illogical.

[Ageagainstthemachine]

Thanks again for all the replies. I had another play earlier and found that it is a mixture of environment and noise on the mains.

I took the earth cable connected to the phono earth on the back of the pre and touched the rca cables that came from my cassette player (which was unplugged from the mains and pre) and the hum got quieter. I then touched the earth to a nut on my DIY hifi rack and it went even quieter. The nut is on a length of threaded bar but is otherwise isolated.

Then the fridge came on and a new fizzy sort of hum was introduced....

So I have some answers and some idea of what to try. I will report back in case anyone finds it useful in the future.

[Ageagainstthemachine]

To save starting another post can anyone advise on rca interconnect length? I'm thinking about separating most if my sources and my DAC has a high output so I'm thinking about a 5m cable... Would this be OK? I would also run longer lengths from the cassette player but I use a buffer with it so that should be OK. TT phono leads will stay the same but I will try and maximise separation between the amp, pre and TT

[Ageagainstthemachine]

I also have a Topping D30 in use and it is a very basic (but surprisingly good) little DAC that can generate unwanted 'noise' when idle. My recommendation would be to get a newer-generation Topping or similar (SMSL, Sabaj, Loxjie etc.) unit that will improve your SQ and have a better build with regard to EMF / noise.

Also, a new Chi-fi DAC is probably cheaper than a 5m length of decent interconnect cable.

Check Hifi-express or Amazon for offers.

https://hifi-express.com/

[r3xj0hn570n]

Ah the fun of EM field pickup. One of the useful things i've discovered over the years is the usefulness of an input shorting RCA plug. Make em up, fill up all your unused inputs with these things. Oh and solder a wire to one of them and use it as an earth wire to experiment with.

[TheMarlin]

I also have a Topping D30 in use and it is a very basic (but surprisingly good) little DAC that can generate unwanted 'noise' when idle. My recommendation would be to get a newer-generation Topping or similar (SMSL, Sabaj, Loxjie etc.) unit that will improve your SQ and have a better build with regard to EMF / noise.

Also, a new Chi-fi DAC is probably cheaper than a 5m length of decent interconnect cable.

Check Hifi-express or Amazon for offers.

https://hifi-express.com/

I have a Topping P50 spare. It’s a linear power supply upgrade for the D30/D50.

It works, but has an intermittent fault, where it powers off and on. Probably just a loose wire inside.

If you’re skilled with a soldering iron, happy to send on. Could be an easy repair, and an nice upgrade for your DAC

I’ve got a few topping DACS, from the humble but brilliant little D30, to a D70 velvet (office system with powered Adam monitors, and two D90’s (different specs). Topping make great DACS

[Ageagainstthemachine]

I also have a Topping D30 in use and it is a very basic (but surprisingly good) little DAC that can generate unwanted 'noise' when idle. My recommendation would be to get a newer-generation Topping or similar (SMSL, Sabaj, Loxjie etc.) unit that will improve your SQ and have a better build with regard to EMF / noise.

Also, a new Chi-fi DAC is probably cheaper than a 5m length of decent interconnect cable.

Check Hifi-express or Amazon for offers.

https://hifi-express.com/

I have a Topping P50 spare. It’s a linear power supply upgrade for the D30/D50.

It works, but has an intermittent fault, where it powers off and on. Probably just a loose wire inside.

If you’re skilled with a soldering iron, happy to send on. Could be an easy repair, and an nice upgrade for your DAC

I’ve got a few topping DACS, from the humble but brilliant little D30, to a D70 velvet (office system with powered Adam monitors, and two D90’s (different specs). Topping make great DACS

I'd be interested if no one else is

[TheMarlin]

I also have a Topping D30 in use and it is a very basic (but surprisingly good) little DAC that can generate unwanted 'noise' when idle. My recommendation would be to get a newer-generation Topping or similar (SMSL, Sabaj, Loxjie etc.) unit that will improve your SQ and have a better build with regard to EMF / noise.

Also, a new Chi-fi DAC is probably cheaper than a 5m length of decent interconnect cable.

Check Hifi-express or Amazon for offers.

https://hifi-express.com/

I have a Topping P50 spare. It’s a linear power supply upgrade for the D30/D50.

It works, but has an intermittent fault, where it powers off and on. Probably just a loose wire inside.

If you’re skilled with a soldering iron, happy to send on. Could be an easy repair, and an nice upgrade for your DAC

I’ve got a few topping DACS, from the humble but brilliant little D30, to a D70 velvet (office system with powered Adam monitors, and two D90’s (different specs). Topping make great DACS

I'd be interested if no one else is

If @Ageagainstthemachine doesn’t want it, you’re next in line.