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i've got a toroid in a power conditioner that occasionally vibrates, and suspect that some mods i can do to in include:
1) change mounting bolt to brass
2) remove steel top plate & replace w/ wood (or other non-magnetic material)
3) damp vibrations by isolating toroid from mounting base
here's my dilemma: i'm not fond of trying over & over to find the right answer, so would appreciate feedback on what would be the ideal material to isolate the toroid from the base.
blue tack?
chunks of MDF?
norsonex (dead / sad) balls? (i've a lot of them)?
brass nuts?
rubber grommets?
any other suggestions or feedback welcome.
tia
rhyno
Follow Ups:
To stop toroid vibrations getting tranmitted to the chassis, use a 1/4" Sorbothane square pad which extends to the diameter of the toroid.
I also change the steel bolt to a 1/4" nylon bolt/nuts.
If you want to go "all the way" then, yes, change the steel top-plate to a copper one. All you're doing with this is reducing eddy curfrents (I think!).
Regards,
Andy
I've tried using acoustic foam with some success. Cut a piece as large as your toroid and use it on the bottom.
I've read that just getting rid of the bolt helps. Then just put the transformer on some type of isolation materials and put a bag of sand on top.
The toroidal transformer is the heaviest object inside the amp. Shipping stresses have been known to break conventional steel fixing bolts.
nt
Bryston uses the capacitors/diodes for dc blocking in their power amps which use toroid transformer, you can down load the sch from here:
http://www.bryston.ca/BrystonSite05/BrystonDocs.html
I've had the same problem with an outboard DIY PSU. Was not using the clamps and bolts at all (see Al's other posts as to magnetic interactions), just a sandbag under it and neoprene on top of it and the pressure on top and bottom of the PVC housing. That still had some vibrations that were mildly audible.
Last weekend I treated the torroid's external circumference to a Ti-Shield grounded ring, but that was cushioned by microcorb. I got the lightbulb idea to use the microsorb top and bottom as well and that setup really does help markedly. Not necessarily completely, but enough to be worth the expense. I haven't used Blue Tac, but it's the same idea, so it's worth the try and readily available everywhere.
FWIW, I love using Norsorex for vertical isolation in my system (if you've got some extra dead balls you'd like to send along, I'd be quite pleased!) where it works very very well. If you do the above, I'd suggest using them below your unit as footers, where I suspect they'll give you that added isolation you'll like.
Might as well damp your box/housing; rope caulk, dynamat - pick your poison...
Is there any change in the performance of your system after putting a Ti-Shield grounded ring to the torroid's external circumference ?
Thanks.
Yes, I now do get a clear impression of improvement from the Ti shielded toroid arrrangement. Took a few days of burn in and some critical listening with nobody around today. It became quite apparent. Cymbals, bassline, depth are the areas where it was most apparent.
Again, each of these RFI/EMI changes seems to be cumulative and each iteration brings similar effects, just moreso. It's as though you cleaned the grease off your stovetop, then cleaned it again and saw more shine, then cleaned it yet again with another product and it got shinier still. Or think of the eyeglasses analogy; take your pick.
:-)
:-)
This one's still mystifying me. All other Ti applications gave immediate results, but this one's less apparent. I'm still burning in and haven't had time to evaluate. I can tell you that there's no downside to my ears, so it didn't hurt anything.
It's entirely possible that I have a loose connection or that I did something differently or wrong here. Either would invalidate the answer. So I"m going to check it out this weekend.
The other thing with a lot of these RFI tweaks is that they're cumulative. At some junctures the differences become less apparent, but if you remove them you realize how much impact they actually had.
I'm not going to remove it for testing and this particular tweak does not lend itself to A/Bing. So it's going to be a check through and retesting by ear and I'll let you know.
If there are intervals when the transformer hums, that start and stop suddenly, then suspect a device in your or your neighbors' house that causes "DC" on the AC. Changing the transformer mounting won't cure the problem.
The power transformers in my monoblocks hum for a minute or two on school day mornings, a few minutes before my school teacher neighbor leaves for work. It is likely to be her hair dryer.
All that said, you may obtain a profound improvement in the deep bass fidelity of your system if your toroid is mounted on a flexible chassis plate and you provide damped support for it. I've done this with two amplifiers. I take off the amplifier feet and rest the chassis upon a sheet of Deflex rubber on a rigid base. End-grain butcher-block cutting boards work well. In one case I had to drill a shallow hole in the board to accommodate the head of the transfomer fixing bolt.
Not sure how safe it would be on the line side of the xfmr. If there was room inside the equipment the components could be wired in down stream of the equipment fusing. If built as an outboard device I would recommend the circuit/components be installed a a metal enclosure. If the components were mounted well insulated from the enclosure, (double insulated) I don't think there would be any need for fusing ahead of the components. After all the circuit/components are in series with the load. No chance of a hot to neutral short circuit. Worse that could happen is an open circuit.
One other thing that has to be considered is heat generated from the diodes.
Whats your thoughts?
The capacitors are there to provide the low impedance path for the AC current, and the diodes are there to protect the capacitors from reverse-bias in case of an overload. One could specify larger current capacity diodes. Rectifiers are cheap.
> >
I don't think changing the bolt or nut to brass will help much if any as brass resonates pretty well. Perhaps sandwich it between two thick sheets of sorbothane so the vibes get soaked up in the lossy material.
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