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Re: Strange Hum

9/4/2005 12:31 AM
Greg	Re: Strange Hum Fred, Yes, that's exactly right. 1. If I turned it up, with nothing connected, I got the usual extra gain noise you'd expect from turning up the pre-amp (sounds just like the '54 Deluxe I used to own), but no ground hum. Strangely, with the non-shorting jack, it didn't give that open circuit hum, you'd expect, as I turned up the volume either. 2. If the socket wasn't connected to the chassis, but had a guitar pluged in, there was no hum either, which is why the plastic Marshall style jacks would work, as there was no connection to the chassis. No, the Ceriatone chassis didn't come with a brass plate. Does the brass plate do more than just allow easier connection? So, at the moment, I basicly have a 'star' ground setup, with the only connection to the chassis being the jacks and the ground wire coming from the mains. Previously, it was connected at the same lug as the ground wire from the mains power. Wild Bill, I only had one jack on each input and didn't have the 1 meg resistor in the circuit and still don't. I thought the one meg resistor was just to pad down the second jack. Does it do something else? Thanks Greg

9/4/2005 12:31 AM

Greg

Re: Strange Hum

Fred,

Yes, that's exactly right.
1. If I turned it up, with nothing connected, I got the usual extra gain noise you'd expect from turning up the pre-amp (sounds just like the '54 Deluxe I used to own), but no ground hum. Strangely, with the non-shorting jack, it didn't give that open circuit hum, you'd expect, as I turned up the volume either.

2. If the socket wasn't connected to the chassis, but had a guitar pluged in, there was no hum either, which is why the plastic Marshall style jacks would work, as there was no connection to the chassis.

No, the Ceriatone chassis didn't come with a brass plate. Does the brass plate do more than just allow easier connection?

So, at the moment, I basicly have a 'star' ground setup, with the only connection to the chassis being the jacks and the ground wire coming from the mains. Previously, it was connected at the same lug as the ground wire from the mains power.

Wild Bill,

I only had one jack on each input and didn't have the 1 meg resistor in the circuit and still don't. I thought the one meg resistor was just to pad down the second jack. Does it do something else?

Thanks
Greg