New Build: Mojo British 100

[LedZepp007]

Thanks for the help everybody!

[LedZepp007]

And... The hum is now back. Perfect.

Odd question: if the input jacks weren't properly grounded would it cause my guitar to also not be grounded?

I'm still getting noise from the guitar that would suggest that the bridge/strings aren't grounded (I checked continuity and they should be grounded to earth through the amp). So either there's a small grounding issue in the amp or there's an earth ground issue that could cause a big problem if something goes wrong inside the amp (I.e., electrocution).

[neikeel]

You must ground the input jacks by a dedicated screw near the jacks.

Ideally you ground the heater centre tap here too (see Larry grounding schem)

- other guitars do it?

[LedZepp007]

You must ground the input jacks by a dedicated screw near the jacks.

Ideally you ground the heater centre tap here too (see Larry grounding schem)

- other guitars do it?

I grounded the jacks to a screw securing the filter cap can Under the board. I'm wondering if the jacks aren't fully grounded, though. I grounded the heater center tap to a filter cap screw closer to the power transformer.

Hmmm. I can check if the guitar does the same thing elsewhere, but I think it's likely to be an issue with the amp and not the guitar.

[neikeel]

I grounded the jacks to a screw securing the filter cap can Under the board.

That is not the same as a dedicated ground.

I'm wondering if the jacks aren't fully grounded, though. I grounded the heater center tap to a filter cap screw closer to the power transformer.

That is how I would have done it in the past but on a new build the Larry grounding scheme is better.

Hmmm. I can check if the guitar does the same thing elsewhere, but I think it's likely to be an issue with the amp and not the guitar.

always worth checking that and if you have close by fluorescent tube or another device plugged into same wall socket etc.

[LedZepp007]

Turns out the outlet I was using wasn't grounded properly. Another outlet improved things.

Still the slight 60 cycle hum when the MV is up. Additionally, I got the dreaded "helicopter" noise the other day at high volumes. Filter cap? Bad solder joints?