Noise on effects loop

Hasie

Hey folks,

I have recently started using the effects loop on my amp - a Blackstar HT-5R.
There is a lot of hum when using it.

When touching the metal sleeve on any of the TS connectors in the effects loop, there is less hum.
I've tested every cable in the setup directly into the front of the amp and there is no noise on any of the cables; and also checked for "bleeding" on the cables using a multi-meter.
There is only a looper in the effects loop on a power supply - when connecting this to the front of the amp and not in the effects loop, there is no noise.

The speaker magnet in the combo is very close to the effects loop connectors, if that information is relevant to you.
The effects loop level is set to -10dBV

Is this normal or should I have an amp tech check it out?

peterleroux

Can you run the looper on a battery instead of mains? If you do, does the noise go away?

Hasie

peterleroux wrote: Can you run the looper on a battery instead of mains? If you do, does the noise go away?

It can't take a battery. It does have true bypass, so when unplugging its power, there is still a hum, but very shrill sounding.

Hasie

I ran a cable directly between the send and return and it is quiet.
So it is either the pedal or the power supply.
The power supply's 12V adapter is only two point.