[andyr]

Well, as I started this thread, I thought it was time I got back in and wound it up a bit!

To all you naysayers out there ... "go ye forth and multiply"!     Whoops, what I really meant was "go ye forth and read the following AA post" ... someone actually tried it out!
http://www.audioasylum.com/audio/tweaks/messages/106569.html

However, Pete makes the point that not all the improvement he heard is due to replacing the steel toroid bolt - putting it on the foam isolation material (and decoupling the vibrating toroid from the amp chassis) undoubtedly helped.  I myself use a 6mm Sorbothane pad for this purpose.

Hence, Malcolm, hot melt gloo just won't doo!  

And note the substitution of an aluminium top "washer" instead of the stock steel one.  Good thinking, 99!!

As far as bolts are concerned, though, I've just bought some 6mm x 75mm nylon bolts from Keables (that wonderful relic from the 1950s!).

Regards,

Andy

[Lost81]

Lost 81:, I also replaced ALL semiconductor-to-heat-sink mounting hardware with brass

Brass, did you say BRASS Benny! Putting aside other debate about the properties of this substance,  there can be an unfortunate electrochemical reaction between brass and aluminium that leads to poor electrical connection over time. A white oxide deposit forms ...  not sure if it's Zinc oxide from the brass or Aluminium oxide.  There are some auto fuses available in aluminium that gradually become non-conductors when used between brass connectors.

Jules

Oh. Thanks for the tip again.

What if the brass mounting hardware is not serving as an electrical connection, but merely as a mechanical fastening device?

Copper sounds safe though.

Copper fastening hardware seem rare though.
Any ideas where I may be able to locate them?

Thanks!


-Lost81

[Jens]

For strong fastening I use stainless steel bolts and screws. The ones I use are completely unmagnetic, and corrosion will never happen.

Stainless steel is extremely tough and you'll never have to think about it again.  

Cheers,

Jens

[jules]

Benny,

I'm inclined to agree that the screw material might not be all that important considering that the surface area of the semi-conductors is probably significantly larger than the contact area of the screw head and threads. Maybe anything with a strong broad head that can be done up fairly tight without causing distortion [or damage of course] in combination with careful surface preparation. Copper fasteners ... dunno, but I'm sort of interested for some apps. I'll tell you if I find some. Earth links do seem to get forgotten where other connections get endless attention.

Jules

[kyrill]

hi Jens

steel or metal doesn't need to be magnetic to resonate and thèn they will play their song in the EMI dimensions. When they are magnetic too, their influences will be just more intensive.

[Jens]

hi Jens

steel or metal doesn't need to be magnetic to resonate and thèn they will play their song in the EMI dimensions. When they are magnetic too, their influences will be just more intensive.

Absolutely, but such resonances can be cured with a good lump of Sticky Tack/Blue Tack stuck to the middle of the bolt (inside the toroid), and obviously you should try to put the trannies on absorbent materials, such as sorbothane or bituminous felt, as has already been suggested.

Another solution could be to tie down the trannies with wire strips. These are made of very strong plastic - no EMI there  

Cheers,

Jens

[Gordy]

Great suggestion on the bundling straps Jens, thanks.  I've been using velcro straps as well, for temporarily fixing some trannies.  Self adhesive 'Industrial strength' velcro seems to work well as a vibration damper too, if used underneath as a bed.  Maybe the hot glue or an 'ever soft' silicone based RTV would make it suitably permanent?  I don't trust the self adhesive on the transformer itself.

Lost81, Gotcha  It's just that in my world, the moment I would most need it, the nylon would have long crumbled or split

All the best...

[jules]

A solution sometimes used for turntables:- Have the torroid floating on three light springs. Something like 30mm diam(attached at both ends to give some location), quite thin radius wire. Keep the, modified, centre bolt only as a tie down for transport [or to prevent extreme movement].  

Another possibility would be to put legs on the lower torroid washer and extend them through the floor of the amp to support the tranny independently but thats getting a bit extreme isn't it   ?

Jules

[AKSA]

I have been pondering this conundrum.  Nothing like a conundrum to loosen the mental sluices.......

I feel the only viable solution here, and one with extraordinary Faraday cage advantages, would be to float each toroid in a small but contoured bath of mercury.     This notion is based on Lighthouse Technology of 70 years ago, which used the same liquid element to suspend the lighting platform (but which enjoyed somewhat better ventilation!).  Hydrargyum has density 13.6, and should float even a 2.1 Kg toroid down to about half depth.  Of course, ca va sans dire, the toroids may need special sealing to prevent Hg ingress, but this is mere detail......

The toroids should be secured with stronger than steel, fine guy ropes from the sides, at intervals of 45 degrees.  These guys should be comprised of spider web, for which purpose the Huntsman should be pressed into service, their webs having the highest Youngs Modulus.  Together with the very high density of mercury, such an approach would kill all oscillation in its tracks (and unless the progenitors are removed after the construction phase, quite possibly the listeners as well........ ).

A small container should be contructed of mu-metal to suitably enclose the assembly, which ideally should take on the shape of a tiny nuclear reactor (...and doubtless be just as dangerous! Ed.).  It should be round of course, which may require some recuring of the mu-metal to preserve its magnetic integrity.  The chamber should be sealed hermetically to prevent the low vapour pressure of Hg from affecting the health of any audiophiles in attendance;  this stuff does cross the blood brain barrier after all.  

Speaker cables comprising mercury in special plastic tubes have been made here in Melbourne.  My understanding is that the creator died young of a particularly rare cancer, however.  Various sonic reports of 'gravitas', and 'body', and 'shimmering highs' have done the rounds.  An article on this very issue was published with some fanfare by Electronics Australia about 15 years ago, proposing ground ceramic fittings to contain the mercury.  Sadly, no kitset was ever released.  There were some rumours that the mercury needed constant replacement to deliver its best;  I have no way of checking on this.

Certainly there are always options, in no way limited by the bounds of human imagination or rationality.......

Let the games begin!!!    

Cheers,

Hugh

[Seano]

Take a trip in the other direction.

What's wrong with two great lumps of polished Australian hardwood and some bloody big nails?

Sandwich the toroids between the hardwood and hammer the nails home. Those toroids will be too damn scared to wiggle after that sort of treatment.  

If you want to get technical, you can use copper nails but you'll need to pre-drill (incidentally if you want copper fasteners, ask a boatbuilder who makes timber boats where he/she/it gets theirs).

If you want to get really technical then you can use bolts.  To my mind the bigger the better.  Three big high tensile bolts.   YEAH!!! Wind 'em up and squeeze those toroids tight.

Bugger the delicate esoterica.  Let's go for a new class of audiophilic equipment.

Ladies and Gentleman, here's to Built Like A Brick Dunny Hi-Fi  

[EchiDna]

this thread is getting better and better each time I read it

Hugh, you might have stumbled onto the ultimate isolation rack with the mercury floatation idea... have you seen the price of some of them??

[jules]

stumbling into a mercury isolation rack sounds extremely dangerous echidna!

I'm quite sure that this site is mined for ideas by such creative genii as Marantz, the makers of the .5" copper based $x0,000 CD player

Jules

[kyrill]

I have seen that player, felt it with my hands, and my technical man opened it for me to see its innards. Yes solid thick very red copper all the way. Neat and build like a tank.  No mercury in sight though, not one drop..

no kidding.Drop the idea of securing the toroids in any special way. Just remove the toroids form the case at all. Bann them from the EMI fields of the pcb's and grant them their own house. Let them vibrate and resonate their own way. They will play their song in empty space at least from a practical perspective, as one yard or more awayform the amps  is half a universe too far to intervene in AKSA's way.