Isolating power transformer from chassis

[mtl777]

Alright guys, newbie time...

My DAC has an R-Core transformer which has a metal frame that is screwed to the chassis. I want to remove the screws and mount the transformer on rubber to reduce or dampen its vibration (the rubber will be glued to the chassis and the transformer will be glued on top of the rubber). If I do this, do I need to connect the transformer's metal frame to chassis ground, e.g., by soldering a piece of wire that goes from the transformer's metal frame to the chassis ground?

My gut feel says yes but I just want to be sure. I would really appreciate any help. Thanks a lot!

[richie00boy]

Only if the transformer has an electrostatic screen.

Why are you doing this? Have you got a bad buzz?

[mtl777]

Originally Posted by richie00boy

Only if the transformer has an electrostatic screen.

Why are you doing this? Have you got a bad buzz?

Not really, at least not something that I could hear. But it's one of the mods that I've read about, and I thought it might be worth doing. Even if there's no buzz, I think it wouldn't hurt to do it, and if there's even a tiny bit of buzz that is subsonic that I just don't hear then it might help.

What's an electrostatic screen? Do R-core transformers have an electrostatic screen?

Anyway, testing with my DMM, I was able to get continuity between the screws (that bolt the transformer's metal frame to the chassis) and the chassis ground. However, I was unable to test for continuity between the transformer's metal frame and the chassis ground because the metal frame has a clear gloss (laquer?) coating that prevents my probe from conducting to the metal. Regardless, does the mere fact that there is continuity between the screws and the chassis ground indicate that the transformer's metal frame should be connected to chassis ground if I get rid of the screws and do this mod?

[DigitalJunkie]

Yes,the transformers frame should be grounded. The major reason is safety,in case the transformer were to develop a fault.

[sumaudioguy]

McMaster-Carr Look at style 3 or style 4. These things work very well. Pick the one based on the weight of the transformer. You may need to drill the transformer feet. New hardware probably will be needed. Only tighten until the grommet is compressed about 20%. Not to tight!

=SUM

[mtl777]

Originally Posted by DigitalJunkie

Yes,the transformers frame should be grounded. The major reason is safety,in case the transformer were to develop a fault.

Thanks, I'll ground it then!

Originally Posted by sumaudioguy

McMaster-Carr Look at style 3 or style 4. These things work very well. Pick the one based on the weight of the transformer. You may need to drill the transformer feet. New hardware probably will be needed. Only tighten until the grommet is compressed about 20%. Not to tight!

=SUM

Thanks, that's a great alternative to what I had in mind!

[Bonsai]

This is a safety issue. Don't dick around with the grounding of the transformer. I doubt that mounting it on rubber will give you any sonic benifits anyway.
An electrostatic shield is a good thing where you have the secondary
windings wound over the primary - EI and torroids benefit especially.