grounding a vox vt40x

[elvisd]

This one originally had a korg adaptor that knocks the voltage to 19v/3.2A before entering the amp. It was a very fragile cable with a grounded plug on one end, but no grounding went past the adaptor itself- just a very thin wire (like 20 ga it seemed) with a laptop plug on the end. It got stepped on, and korg no longer makes that model. The closest thing I can find is ungrounded, probably used for computers. Needless to say, it's even noisier, now.

Would it be possible if I popped open the adaptor to enclose it in a new box with a fresh grounded line running to it, and the ground line running to the chassis in the amp to improve the noise? If so, would it be best to have the metal chassis part of the adaptor part of the grounding, or just bypassed?

I like the amp ok, but it was a bit noisy even before the original adaptor broke- probably due to no grounding going to the amp itself- and it's a lot noisier now. Or would it be better to keep searching for an adaptor that matches the original?

I know the vox 20's didn't have a ground at all- sounds awful.

[Jazz P Bass]

I don't know what the grounding scheme on the power supply itself is.

The mains input side has a three prong 'grounded' cord.
The output is a dc jack, 19Vdc pin positive.
Whether or not the negative out is connected to the mains earth pin, you will have to figure out.

Or, simply buy a new one: https://www.ebay.com/itm/AC-Power-Su...-/162777953614

[elvisd]

I don't know what the grounding scheme on the power supply itself is.

The mains input side has a three prong 'grounded' cord.
The output is a dc jack, 19Vdc pin positive.
Whether or not the negative out is connected to the mains earth pin, you will have to figure out.

Or, simply buy a new one: https://www.ebay.com/itm/AC-Power-Su...-/162777953614

That's the replacement one I"ve already bought. It has no ground.

[elvisd]

That's the exact replacement one that I bought. It has no ground.

[Jazz P Bass]

It has "no Ground" where?

The supply itself has a three prong grounded plug.

The amp does not require a "safety ground".

[The Dude]

It's unlikely a grounding issue. I'm more apt to believe it is just gain noise. Is the noise hum, hiss, etc. It's a modeling amp and has built in noise gates (global and per patch). Have you tried adjusting the gates?

[elvisd]

It has "no Ground" where?

The supply itself has a three prong grounded plug.

The amp does not require a "safety ground".

No, the replacement supply you linked to does not. The original one did. That's the point. I can keep searching for one with a ground, but was asking if a hack into the replacement one would work. That is the question I'm asking.

[elvisd]

I'll try to look up patches for noise gates. Haven't used any patches yet.

This wasn't an issue when I had my original power supply that DID have a ground plug. It began when that one got broken and I had to find a replacement fast, so it probably does have something to do with it, though I'll certainly try your suggestion for finding noise gate stuff to add to the settings.

[J M Fahey]

J.R.T.F.M

As in: "just READ the F*****g Manual"

[nickb]

It's unlikely a grounding issue. I'm more apt to believe it is just gain noise. Is the noise hum, hiss, etc. It's a modeling amp and has built in noise gates (global and per patch). Have you tried adjusting the gates?

This is my first reaction too. The big question is what does the noise sound like? Is it white noise a bit like rushing water or a sort of whine? If the former then it's probably what the Dude suggests. If a whine then I'd suspect poor filtering in the power supply, a bit of a common problem with cheap imports with no noise specs.

[Jazz P Bass]

My bad on not seeing that the supply that I linked to only has a two conductor mains plug.
(the photo is poor the way they have the wires bundled)

In any case, The two conductor cable simply means that the power supply is "double insulated".
Appliances that are double insulated do not need an earth wire. They only require a two-core cable.

The 'missing' earth wire that got broken off of your original supply has nothing to do with "noise" in the amp.
It was stated that the amp always was a tad noisy and that you feel that it got worse since the earth connection was lost on the plug.

Coincidental events.

Look at the cable that actually goes to the amp.
It's a two conductor cable.
So the amp itself never has/ had a connection to 'Earth Ground" no matter if the supply is safety grounded or not.