Marantz 1060 Ground Loop Noise

[user0]

In the U.S., all of the stereo equipment of that era (1970's) only used a 2-prong AC plug... no ground pin. In fact, the plug was not keyed so you could even reverse the hot and neutral wire connection into the AC socket. That changed in the U.S., some time ago where now a 2-pin plug is polarized with one plug spade wider than the other. Having said this, I would think that it would be OK to run it that way. But then again, I am not familiar with your local electrical codes. In the hardware stores here, you can buy a "cheater" AC plug adapter that effectively adapt a 3-prong plug to a 2-prong plug socket. So, it sounds like the issue is the grounding of the PC and the 1060.

Thanks! I've been reading some passionate views from each side of the arguement, (it's all quite entertaining) and I needed someone to say it's probably going to be okay

 

[user0]

Sparse information on the PT8888 EMI specs online but from what I can gather it will reduce EMI from entering/leaving the power strip, but NOT between sockets on the strip. This won't protect you from EMI if you have both the PC and 1060 on the same strip. Try this test: 1) take the PC off of the Jackson PT8888 and plug into the wall and see if it improves, 2) plug the Marantz 1060 into the power strip so it will be EMI protected. If it helps good, otherwise reverse it, 1060 into the wall... PC into the power strip. Any different? Packaging and datasheet doesn't say much.
View attachment 3309974

Thanks! I'll try this - sounds promising!

 

[user0]

Some HQ more elaborate and pricier power strips or power conditioner distribution blocks (Tripp-Lite/Monster Power for example) claim to have some kind of individual filtering at each of their sockets that reduces noise creating equipment from the adjacent power socket`s to thwart back feeding equipment`s noise interfering with each other.

I also wonder if a HQ L/R audio signal ground loop breaking isolation transformer RCA to RCA type inserted between the computer`s sound card`s analog audio line might help, like Jensen transformer Co. and other manufacturers offer ?
Again just a suggestive thought.

Thanks again. This was going to be the last thing that I try. Hopefully it doesn't come to this. And the end of the day, I think I'm more happy with circumventing the ground pin on the 1060 plug than buying one of these.

 

[user0]

You are a brilliant man Bill! This will most likely be the problem. I'll look at it, thanks.

For reals... I didn't want to admit it earlier, but I did not screw the psu into the case at all. The price of ignorance I suppose. I'll have to test the 'standard black' screws I have to see if that coating is conductive, but this sounds very logically to be the problem to me.

 

[Bill Ferris]

You are a brilliant man Bill! This will most likely be the problem. I'll look at it, thanks.

Well Sir. I don`t know about the brilliant compliment, but I have had over the yrs. to occasionally need a audio isolation transformer with success breaking annoying ground loops between various pieces of audio equipment.
If transparent HiFi quality is important the Jensen transformer specifications indicate ruler flat frequency response from 5hz. to 20khz., though that stereo RCA jack L/R model isn`t cheap, but performance never is .