[Bob in St. Louis]

Seems recently I've been collecting dead amps (but that's another story). 
In my workshop are the carcasses of several units taken apart and spread across the workbench. Most can not be fixed. Seems a shame to toss them in the trash. A more "ecologically friendly" person would do something more responsible than toss them of course.

However, as I stare at all of this iron and copper, I was wondering if there was a market for transformers. Now mind you, none of these are high grade tube amps, they're plate amp type quality transformers, so don't get too excited. 
But what's wrong with the amps don't seem to be the iron, it's the boards that failed.

So, what do you think?

Thanks fellas,
Bob

[mgalusha]

IMO one cannot have too much spare iron, unless of course one has to move it...

I'm sure there is a market, I have bought a fair number of used transformers. The tricky bit is getting a good idea on the VA rating.

[*Scotty*]

Bob you might remove them from the plate amp assembly and try an experiment. Pick the largest transformer by weight out of the lot of them,then isolate and insulate from one another the secondary leads. After doing this attach a 2 or 3 foot twisted pair of 14ga or 12ga stranded THHN cable with an AC plug to the primary leads,there should only be two wires.
 What you are doing is using the transformer as a slave inductor to store energy in the magnetic field in the transformer core. When you plug the transformer into the same outlet as your power amp or preamp/front end you have some extra energy on hand to keep the voltage from sagging under instantaneous demands of current made by your system. The improvement in sound quality is similar that which occurs when the power supply transformer's VA rating is substantially increased over the stock rating.
 I use two Hafler DH 500 transformers in parallel on the AC receptacle that my power amp is plugged into. This about 50lbs of iron on the power amp, I also have a 15lb transformer from a Quatre Gain/Grain Cell in parallel with my front end.
There isn't an enormous gain to be had from doing this but if you already have the iron laying around it is a cheap thing to do.
Scotty
 

[Æ]

You could always recycle the copper. . . .

[Bob in St. Louis]

The recycling is my last resort. I wouldn't throw them in the trash, that's too much of a waste of material.

Scotty, interesting project. I've got a Leibert UPS, so I'm in good shape for "sags", but I'm a sucker for "yet another" project. haha
But I should skip that one.

Mike, I don't know how to measure one. 

Bob

[*Scotty*]

These slave inductors provide a near instantaneous squirt of current into the AC line as the system demands it. When a transient occurs there is a demand for current from the power supply which has to come from the wall and this generates a very short period voltage drop. As the voltage drops on the AC line that the slave inductor is in parallel with the collapsing magnetic field in the core of the transformer generates a flow of current into the AC line which keeps the AC line voltage propped up from moment to moment.
 A long term demand of current will not be supported by the slave inductor as the voltage will sag long term as well and the total magnetic field strength in the core will be proportionally lower.
Ideally a slave inductor should be connected in parallel with the load after any power conditioners or power filters.
Scotty

[Steve]

An interesting idea. The only precaution I see is that of switching off the "slave" transformer. Without any sort of load on a primary or secondary winding(s), an inductive "kick" will result. I would place some sort of load (resistor) on the high voltage winding to limit the voltage spike.

Cheers.

[*Scotty*]

Actually the ability to deliver that instantaneous voltage spike from the collapsing mag field is the property we are looking for.
 As there is just a short power cord and no on/off switch we won't be listening to a noise spike at turnoff. These things are intended to be plugged in and forgotten about.
Scotty
 

[Steve]

Actually the ability to deliver that instantaneous voltage spike from the collapsing mag field is the property we are looking for.
 
 As there is just a short power cord and no on/off switch we won't be listening to a noise spike at turnoff. These things are intended to be plugged in and forgotten about.
Scotty

I mention the caution because as sure as the sun goes down, some will want to turn it off overnight in order to save a little electricity.
Just covering you in case one has a failure. 

As such the right value resistor will limit the spike to safe values while offering "instantaneous" energy (scope needed). Might be a good idea to fuse the transformer as well.

Cheers.