TT grounding problems - please help

[Mike g]

I swapped out amps last night and have some grounding issues. Kit is: gyrodec with Hera psu, origin live arm with audio origami arm cable, trichord dino with standard psu, nait xs with a teddycap. When I connect the arm grounding cable to the dino there is a high pitched sound like morse code which I think may be a ground loop. When I connect it to the xs grounding nut the high pitch noise goes but is replaced with interference noise which gets louder as the volume goes up. I know there can be some background noise with a TT but this is more than I've ever had before. I tried a wire between the dino and xs ground nuts but this didn't help. I had a similar problem when the arm cable was connected to the dino when I had my 42.5/hicap/160 but it went away when the arm grounding cable was attached to the 42.5.

I've tried a couple of the din inputs on the xs and same with each so don't think that's the issue.
Any ideas?

[YNWaN]

Earth loop is usually a hum not a high pitched noise and not like Morse code - very odd.

[Mike g]

Could it be some sort of interference or rf? I think the Hera may be the culprit as turning it off and on changes it. May try moving it away from everything else though would mean finding somewhere other than my rack for it.

[YNWaN]

Could your phonostage be picking up noise radiated from a power supply or phone base station?

[Mike g]

It might be that. I wasn't a problem before I got the gyrodec (had a gl75 using same arm and phononstage) so might be something to do with the Hera or the gyrodec motor possibly.

[struth]

I had something similar witha phono stage and a pre amp and turntable. I found by moving the mains cables and any psu's away from the TT and phono stage did the trick. eliminated it

[Ammonite Audio]

The Dino is very susceptible to RF interference from cordless phones, wireless networks etc, so as Marks says, I'd check these things first.

[Mike g]

So after playing about...I've swapped the grounding strap that comes with the gyrodec onto a different screw beneath the armboard that doesn't have the plasticine stuff around it (assume previous owner did this on purpose - a fact I hadn't picked up (idiot!)) and when arm cable ground attached to the xs most of the noise has gone away (there is a tiny amount of noise that I've had with most tts).

Might try and reorganise the power supplies and plugs but in the meantime many thanks for the help etc.

[YNWaN]

Well that cool, so it sounds like it was just a grounding issue. However, that in itself raises some concern with me because the phonostage (which is likely to be the component being effected by the grounding problems) shouldn't really have been behaving in the manner you described.

[Mike g]

I think the problem with the phonostage is rf and picking up noise from other components. I've done a bit of reading and there seems to be an issue with the dino due to its acrylic case. Some posts on forums have said it needs to be away from all other components. Why it is only like this when the TT grounds through the dino and not the xs (I'd have thought it would be the same as in each case the dino is part of the signal path) I have no idea.

[YNWaN]

Ground loops are very odd as is the manner in which they interact with components. My phonostage is also in an acrylic case (the sides and top are acrylic) and yet it doesn't seem to be sensitive to RF so there are no set rules. However, as you say, I have also read that the Dino (and all the Tom Evans designs) are sensitive in this respect.

[struth]

I had a dino that did not give me any problems but in the same situ, a whest one did. once I moved it a little and adjusted the routing of mains cables in relation to it and its cables it was fine.