Interesting ways to mount toroidal transformers.

[2wo]

If you don't like how it sounds, you can always take it to BattelBots...John

 

[MagicBus]

Oh my... I wasn't thinking that when building my little speedy and punchy amp!


Blacksmith vs. Minotaur - BattleBots - YouTube

 

[djn]

Here is my GM70 amp with the filiment power supply and driver tube B+ in the green chassis. I mounted the toroidal in back under a custom chopper air cleaner.

 

[OldHector]

Love both of those!

 

[lavane]

He does build interesting equipment. I loved the steam punk look of one of his other creations.

 

[HeyBill]

Wheel done!

 

[danny_66]

When using a bolt through the middle of a toroid you have to watch out that it doesn't make an additional single turn with the chassis and bracket.
The bolt, bracket and chassis becomes a shorted winding over the secondaries and will overload/overheat the primary,
until something melts or burns, hopefully the fuse.

 

[Gusser]

Don't forget, no shorted turns allowed from the mounting hardware.

Hah! In the 80s I did some consulting for a company making a piece of broadcast TV gear. It was a one RU chassis and they made a C shaped bracket with the toroidal transformer inside and a bolt through the center clamping it all together.

The young engineer on staff was baffled why the line fuse kept blowing and was blaming the transformers.

Hey, nothing beats practical experience. College doesn't teach you everything you need to know.

They solved it with a nylon washer under the screw head. I didn't like that for long term reliability but that was not my area of work.

 

[Demonkleaner]

My go to toroid mounting bolts. I prefer new over used

https://www.amazon.com/Toilet-Plast...1625246535&sprefix=toilet+bolt,aps,271&sr=8-9

 

[rayma]

They solved it with a nylon washer under the screw head. I didn't like that for
long term reliability but that was not my area of work.

Hope that was a shoulder washer.

 

[Gusser]

It was a countersunk screw no less, 6-32 IIRC. I suggested an L bracket made form heavier gauge metal and simply do not encircle the transformer. NIH prevailed!

 

[rayma]

Shipping damage probably also prevailed.

 

[lavane]

My go to toroid mounting bolts. I prefer new over used

https://www.amazon.com/Toilet-Plast...1625246535&sprefix=toilet+bolt,aps,271&sr=8-9

Bookmarked, thanks. The transformer should be here soon.

 

[lavane]

This is what I'm using to mount the transformer vertically.
https://www.amazon.com/Morton-Stainless-Machined-Thread-Diameter/dp/B00GKZF798

 

[egellings]

Are there similar tires on the other side?

 

[TMM]

It claims to drive 60W into 8 ohms, yet the output tubes are 125mA maximum rated, 8 of them can manage 1A at best. Some strange new meaning of 60W I wasn't previously aware of I guess.

125mA is average, not peak rating.

A 6AS7G operating in Class B can peak at about 350mA with reasonable reliability in a HiFi application.

350mA peak -> (0.35*0.707*8tubes)^2 * 8ohm = 31Watts at clipping

Where they get 60Watts is probably assuming it's driving a square wave with 350mA peaks -> (0.35*8)^2 * 8 = 63Watts into 8ohm, or they have a looser idea of what 'reasonable reliability' is and allow the current to peak much higher.

 

[wg_ski]

While this particular build isn’t a *tube* amplifier, it does show an interesting way to mount toroids. I will likely mount the power and output trafos this way when I get around to that kilowatt tube amp using a bunch of LW6’s driving an Antek 15T950. There is a 6U box waiting for that build.

 

[lavane]

This is kind of what I'm going for. I stole the picture from a other thread. I noticed the rod end bolts are isolated from the chassis with rubber washers or grommets. I'll probably use a section of an inner tube to cover the windings so it looks better than the mylar wrap.
I may also cut out the chassis to recess the transformer just enough to hide the wiring.
I have one more small parts order and I can start building the 6L6 PP amplifier.