Occasional hum

[mikeyb]

Have you tried a different phono stage?

I'm assuming you have and if it removed the noise and it was me I'd be putting a different one into play especially if it was bugging me.

[CageyH]

Yes. No problems with the other phono stages. The Reflex M and Accession M both work fine, but I have to keep shipping them out when people want to borrow them.
The AG1500 removes the problem on the BB3, so I have noisy mains that the BB3 is susceptible to.
Ideally I want a simple solution to get rid of that noise, that I can fit inside the case.
If I can't do that, I will keep the AG1500 in place.

[Macca]

I'm not convinced about the noisy mains thing, everyone's mains is noisy. If it was a real problem hi-fi wouldn't exist.

Is it not more likely it's some sort of ground loop? Using the AG1500 might be fixing that?

[CageyH]

Now I know it is most likely to be a 100Hz interference signal, I am also thinking it is a ground loop issue.
But why is it just the analogue part of the system affected?

[Macca]

ground loops can be buggers especially if the set-up is complex i.e lots of boxes.

The BB3 will probably be fine in a different system.

[CageyH]

I am going to swap my pre out, and see if it is a mixture of SE and Balanced connections.

[CageyH]

But thinking about the last statement, the noise was present when the BB3 was the only thing connected to the mains, and the audio clip was done. It fed the PC sound card directly, so a change of Pre is not going to help.

[Macca]

The PC was connected to the mains though? And the phono stage was connected to the PC?

Load of ground loop threads here https://www.audiosciencereview.com/f...=ground+loop&c[title_only]=1&o=relevance

You might find a solution there - or at least more things you can try.

[CageyH]

I have just altered the grounding “scheme” of my BB3, and the hum has reduced significantly.
It is not 100% gone, but I am almost there.

I do have to point out that it is with the volume cranked right up at levels I do not normally use, with no music playing.
I am almost at a point now where the hum is acceptable.

[Lawrence001]

I do have to point out that it is with the volume cranked right up at levels I do not normally use, with no music playing.
I am almost at a point now where the hum is acceptable.

Is this more to do with the fact you know it's there rather than the impact on the music then? I'd try and live with it for now and you might forget about it.