Just wondering how much something like this is worth? It's about 18cm across and 7cm tall and nice and heavy!
Here's some pics:
(matchbox for scale)
Here's some pics:
(matchbox for scale)
It's a big lump, probably cost more to ship than it's worth. Not much of a market for big 220v Chinese toroids of unknown quality.
aahhhh shame. maybe I should just build something with it then, but rails are a bit high voltage unless I want like 6 transistors on each output.
https://www.diyaudio.com/community/threads/ab100-class-ab-power-amplifier.227503/
Too much voltage and not enough current for Class A.
Patrick
Too much voltage and not enough current for Class A.
Patrick
Spot price for copper is currently around $10 per kg... Price for new electrical copper wire is somewhat higher of course. If its not UL rated I'd never plug it in, who knows what the insulation quality is? Or what the laminations are made of?
It’s probably not constructed any differently than any other toroid, say Antek. Fuse the primary and use the thermal cutout (Yellow wires).
+/-67V with class AB is still enough to heat your house in winter. Just play the music loud. Or if you are feeling really adventurous, +/-134V in H-class. Then you’ll have more heat coming off the speakers.
I can’t use it unfortunately because I need a 120v primary available. I’d get +/-73 or 146 with 240v in. +/-73 is for home use, where 240 is not typically available. +/-146 is too high for 2-step class H (it would need to go to 3). Even then it needs to be strappable for 120 or it can’t be used at a venue without a 240V source. With 60 Hz it would be fine at 240 primary, should someone decide to go that route. I’ve used surplus 100V/50 Hz primary toroids at 120/60 before and they work beautifully - at 20% more VA capacity. Still quiet, too.
+/-67V with class AB is still enough to heat your house in winter. Just play the music loud. Or if you are feeling really adventurous, +/-134V in H-class. Then you’ll have more heat coming off the speakers.
I can’t use it unfortunately because I need a 120v primary available. I’d get +/-73 or 146 with 240v in. +/-73 is for home use, where 240 is not typically available. +/-146 is too high for 2-step class H (it would need to go to 3). Even then it needs to be strappable for 120 or it can’t be used at a venue without a 240V source. With 60 Hz it would be fine at 240 primary, should someone decide to go that route. I’ve used surplus 100V/50 Hz primary toroids at 120/60 before and they work beautifully - at 20% more VA capacity. Still quiet, too.
My experience with cheap chinese mains transformers is not good - primary ECW touching secondary ECW, leading to bursts of noise (insulation on point of failure). Your mileage may vary, I will avoid.
If the input voltage is halved, the output voltage halves too. 48:2*1,41=33,84, so 36V is accurate.
It is 220V rated, today mains are 230V, in my house closer to 240V.
These big ones suffer heavily from over voltage on primary, IMO it will buzz a lot unless another step down transformer is before it.
Best to plug it and hear if it behaves.
These big ones suffer heavily from over voltage on primary, IMO it will buzz a lot unless another step down transformer is before it.
Best to plug it and hear if it behaves.
The primary voltage increase by 9% at 240V, which is well within the normal tolerances. To my experience that's not causing any issues unless that increases the secondary current significantly or the transformer is designed very poorly.
You are right, it might actually be a bad transformer build and it will show, one or the other way. Unfortunately, you, or a buyer for that matter, can't know in advance unless it comes to a test. I've salvaged two toroid transformers from an old PA amp rated at 2x400W but they were able to easily deliver double that power with practically no voltage sag or temperature increase. On the other hand, another amp rated at 2x400W waved the white flag when delivering just over 350W (voltage dropped over 1/3, heated up very quickly).
By “hear” he just means mechanical noise. Running the voltage high will increase the flux density and make mechanical noise worse. May be conservatively designed, may not. But a trafo designed for 50 Hz can run 20% high in voltage at 60 Hz, and still run at the same flux density. Idling, it won’t be any louder. At war volume it could be louder, but the music should be loud enough to drown it out.
Mechanical noise, voltage sag, and temperature rise aren’t necessarily all perfectly correlated. Anteks tend to sag more than the premium ones that cost 3X as much, but are very quiet at 125v/60 Hz and run COLD compared to a lot of things I pull out of amplifiers that are similar sized. Turns per volt on them is conservatively high for as inexpensive as they are, and that’s responsible for the other characteristics. I pulled some big Ulveco’s out of telecom power supplies that ran stone cold at high load, didn’t sag a bit, but you can hear them running in the next state. The one in the Behringer EP2500 will boil spit after a gig.
Mechanical noise, voltage sag, and temperature rise aren’t necessarily all perfectly correlated. Anteks tend to sag more than the premium ones that cost 3X as much, but are very quiet at 125v/60 Hz and run COLD compared to a lot of things I pull out of amplifiers that are similar sized. Turns per volt on them is conservatively high for as inexpensive as they are, and that’s responsible for the other characteristics. I pulled some big Ulveco’s out of telecom power supplies that ran stone cold at high load, didn’t sag a bit, but you can hear them running in the next state. The one in the Behringer EP2500 will boil spit after a gig.
The Behringer EP2500 isn't a bad amp but Behringer isn't known to oversize any parts either. And yes, there are much more relevant parameters which sets cheap and expensive transformers apart than the hobby electronics enthusiast or even more experienced ppl give credit to it. I just wanted to say that a 9% increase of primary voltage does not neccessarily cause noise or heat issues - but that does not apply to every transformer. EI-core transformers are often more forgiving but at the end it depends on every transformer, there's no rule you can perfectly rely on.
That said, I'd guess you could probably get 40-50 bucks for it on eBay. But you never know, I've scored a 2x24V 400VA transformator for just 12€+postage - which was the minimum bid.
That said, I'd guess you could probably get 40-50 bucks for it on eBay. But you never know, I've scored a 2x24V 400VA transformator for just 12€+postage - which was the minimum bid.
Monster would be a distribution transformer at the electric sub-station.
This is big compared to those in some home use amps.
Toy in comparison to even a welding transformer used in fabrication shops.
See if you find a use for it, or sell it off.
Price will depend from 50% below scrap copper to what a desperate buyer is wiling to pay, if he wants it pronto.
As for quality, the Chinese do make very good stuff, and lots of barely adequate stuff.
Not worth the effort for me to find out who made it, and their quality standard, I get them locally, two factories in my city, fast delivery if standard windings.
A week at most for a custom unit, much cheaper landed than shipped from China, shipment is expensive.
Some of my plastic articles sell for 220 Rupees a kilo, shipping to Dubai is 350 per kilo if it is less than 100 kilos.
So, see how much a new one costs landed at your location, and offer a discount, how much is your choice.
This is big compared to those in some home use amps.
Toy in comparison to even a welding transformer used in fabrication shops.
See if you find a use for it, or sell it off.
Price will depend from 50% below scrap copper to what a desperate buyer is wiling to pay, if he wants it pronto.
As for quality, the Chinese do make very good stuff, and lots of barely adequate stuff.
Not worth the effort for me to find out who made it, and their quality standard, I get them locally, two factories in my city, fast delivery if standard windings.
A week at most for a custom unit, much cheaper landed than shipped from China, shipment is expensive.
Some of my plastic articles sell for 220 Rupees a kilo, shipping to Dubai is 350 per kilo if it is less than 100 kilos.
So, see how much a new one costs landed at your location, and offer a discount, how much is your choice.