I want to stack 2 22V 400 VA transformers to save on internal component space. Building up in some areas instead of out!!
Will this cause a magnetic or other problem between the two transformers????
Is there ANY reason not to do it???
Thanks,
Dominick
Will this cause a magnetic or other problem between the two transformers????
Is there ANY reason not to do it???
Thanks,
Dominick
as long as there is no circuit around either of them it will be fine.
by circuit i mean a conductive path that gos through the middle of the transformer(s) and back on itself.
this would count as a "winding" and bad things could happen.
by circuit i mean a conductive path that gos through the middle of the transformer(s) and back on itself.
this would count as a "winding" and bad things could happen.
if i remember right, boulder amplifiers stacks their transformers for their big amps. they have a pair of 2kva's in there.
I've stacked toroids before without any problems. As far as heat goes, a transformer in an audio application never gets close to it's maximum heat dissipation. For example; A transformer rated at 500va probably only delivers around 150va average power even in the most demanding music application. This is because of the dynamic rather than average nature of music. The reason large transformers are used is to maintain a better voltage regulation.
If the amplifier is class A then the average heat will be higher, but in class A you would want to use a larger transformer anyway.
So stack away, just be mindful that the top of the central bolt must not touch the case.
Cheers
If the amplifier is class A then the average heat will be higher, but in class A you would want to use a larger transformer anyway.
So stack away, just be mindful that the top of the central bolt must not touch the case.
Cheers
Here you go:
An externally hosted image should be here but it was not working when we last tested it.
Is this considered a significant advantage for a "dual mono" design over a single toroid of twice the power rating with two sets of secondary windings?
Thinking in the other direction, the ultimate in dual mono would include a double-pole power switch switching two power cords, one for each toroid.
Now that I've said it, I have no doubt someone will build it,
Thinking in the other direction, the ultimate in dual mono would include a double-pole power switch switching two power cords, one for each toroid.
Now that I've said it, I have no doubt someone will build it,
just to put in some numbers so that we know we are talking about the same thing.
Take a 100W+100W pair of amplifiers.
Take two 160VA transformers 35+35Vac @ 2.3Aac per winding and power up the dual mono amplifier.
Now take a 320VA transformer with four 35Vac @ 2.3Aac windings and power up a stereo amplifier.
I think the 4windings will allow the two amplifiers to perform better.
The common chassis for the two amplifiers makes that part the same.
The separated secondaries makes isolation the same.
The higher VA primary and the higher VA core should make for slightly improved load driving ability when one channel is delivering more power than the other.
One time I gutted a BGW 7000B and put a stack of 6 200VA tranformers horizontally where the original transformer was. There is no thermal problem doing it if the tranformers are sufficiently oversized for the load and there is no magnetic issue per se.
However. If you were to strip the same six cores and re-wind them together you'd wind up with a much more efficient, lower impedance, and lower weight transformer because you get rid of almost half the wire. As usual, just don't stick anything metallic through the middle and expect to be able to close the circuit around the outside and not make a shorted turn.
However. If you were to strip the same six cores and re-wind them together you'd wind up with a much more efficient, lower impedance, and lower weight transformer because you get rid of almost half the wire. As usual, just don't stick anything metallic through the middle and expect to be able to close the circuit around the outside and not make a shorted turn.
Last edited:
I found this thread while Googling 'stacked toroid transformers' while researching replacement transformer possibilities for my Bryston 4B - circa 1988.
I am replacing the old EI cores with 2 toroids.
I was hoping to find 2 500VA toroids that could be stacked within the confines of the 5" height of this enclosure. One of the few that fit the bill were the Avel Lindbergs, but I wasn't sure about their quality, so I ended up ordering two Plitron's at twice the price.
As they are too tall to stack within the case, they will end up sitting side by side like this.
I am replacing the old EI cores with 2 toroids.
I was hoping to find 2 500VA toroids that could be stacked within the confines of the 5" height of this enclosure. One of the few that fit the bill were the Avel Lindbergs, but I wasn't sure about their quality, so I ended up ordering two Plitron's at twice the price.
As they are too tall to stack within the case, they will end up sitting side by side like this.
Two circuits...
That's great, but leaves something to be desired, since large amps
could influence the AC power voltage at the outlet. I'm thinking
that a duplex outlet with the links removed, a separate non-metallic
cable, each fed from it's own circuit-breaker panel with each panel
being fed from it's own service-entrance cable and pole transformer
would be the ultimate "Dual Mono" Power Amp System, just saying.😀
Woo-hoo!, I wanna' know if someone ever does it that way!😱
That's great, but leaves something to be desired, since large amps
could influence the AC power voltage at the outlet. I'm thinking
that a duplex outlet with the links removed, a separate non-metallic
cable, each fed from it's own circuit-breaker panel with each panel
being fed from it's own service-entrance cable and pole transformer
would be the ultimate "Dual Mono" Power Amp System, just saying.😀
Woo-hoo!, I wanna' know if someone ever does it that way!😱
if stacked, place a "spacer" between them
it has also been suggested that by turning one trafo you may achieve some cancelling effect giving less strayfield
it has also been suggested that by turning one trafo you may achieve some cancelling effect giving less strayfield
Look at Bryston's large amps. They stack 1kVA toroids just fine. That should be convincing enough, I hope.
Why stop there? You clearly need two separate feeds from two completely independent power plants. Naturally, these feeds need to be strung from cryogenically treated oxygen free 99.99999999999 % pure gold wire supported only by myrtlewood power poles.
On a serious note, I don't see any issues with stacking toroids. Just be careful you don't crush the windings where they exit the transformer and put a rubber spacer between the transformers. As others have said, you could even attempt to cancel the leakage field by ensuring that the magnetic field flows in opposite directions in the two cores. I.e. stack the transformers "back-to-back" not "front-to-back".
~Tom
Seriously....
Seriously, there should be no perceptible interaction between
two stacked toroidal transformers because magnetic flux in
the cores flows through the core, perpendicular to the wire
and very little flux even escapes the cores to cause any
interaction.
The temptation to embellish the Dual-Mono, extremely
isolated power feeds idea was too much and I just had
to be silly. Separate cords would be reasonable
somewhere between 1KW and 2KW per channel, for
real, though.
Seriously, there should be no perceptible interaction between
two stacked toroidal transformers because magnetic flux in
the cores flows through the core, perpendicular to the wire
and very little flux even escapes the cores to cause any
interaction.
The temptation to embellish the Dual-Mono, extremely
isolated power feeds idea was too much and I just had
to be silly. Separate cords would be reasonable
somewhere between 1KW and 2KW per channel, for
real, though.
toroid hijacker
While the toroid experts are convened in commitee, I need 100 VDC very low milliamps roughly to run the transistor preamps of my H182 organ when I replace the tube amps with chip amps. I found this 240 VAC to 120 VAC toroid on a little board inside a 400 VA computer switching power supply (dead) that converts 240 to 120 in based on the switch on the back. If I use this to convert 120 VAC to 60 VAC for this purpose, (with standard bridge rectifier and filter caps) will it cause a lot of noise or something? Most of my most hum free equipment is Dynaco with shielded (enclosed) EI transformers, so I am nervous about using something that naked looking. ???
While the toroid experts are convened in commitee, I need 100 VDC very low milliamps roughly to run the transistor preamps of my H182 organ when I replace the tube amps with chip amps. I found this 240 VAC to 120 VAC toroid on a little board inside a 400 VA computer switching power supply (dead) that converts 240 to 120 in based on the switch on the back. If I use this to convert 120 VAC to 60 VAC for this purpose, (with standard bridge rectifier and filter caps) will it cause a lot of noise or something? Most of my most hum free equipment is Dynaco with shielded (enclosed) EI transformers, so I am nervous about using something that naked looking. ???
Last edited:
Lowest Flux Leakage
I've actually used a 240v primary transformer, that had twice the needed
secondary voltage, on 120v, to minimize hum-flux interference with low
level preamp stages nearby. It's a great technique to reduce magnetically
coupled hum in circuits that don't consume a lot power.
I've actually used a 240v primary transformer, that had twice the needed
secondary voltage, on 120v, to minimize hum-flux interference with low
level preamp stages nearby. It's a great technique to reduce magnetically
coupled hum in circuits that don't consume a lot power.
- Status
- Not open for further replies.