Hi friends
I have some goodlooking toroid transformers, with unknown brands.
Is there a method to evaluate their quality?
Thank you and all the best
David
I have some goodlooking toroid transformers, with unknown brands.
Is there a method to evaluate their quality?
Thank you and all the best
David
Cheaply made toroids might draw excessive magnetization current or make mechanical noise, but that’s really about all you can do wrong when making them. Other than a sloppy tape job or random scramble winding, which is easy enough to see and avoid. If you put the trafo on a dim bulb with no load and it stays dark, and doesn’t make mechanical hum idling or under a load it’s “good” for most purposes.
Load regulation can vary, tends to be better the bigger it is. If the wire is undersized it can run hot. If you don’t know the VA rating compare by weight to a known unit or use 3.2 amps per square mm (wire size) as a guide. That is roughly half of the wire’s rating for typical building wire application (ie, #12 good for 20 amps at your breaker panel, and 10 amps in a trafo - and that AWG’s work like reverse dB’s, +/-3AWG is a -/+ factor of two).
Load regulation can vary, tends to be better the bigger it is. If the wire is undersized it can run hot. If you don’t know the VA rating compare by weight to a known unit or use 3.2 amps per square mm (wire size) as a guide. That is roughly half of the wire’s rating for typical building wire application (ie, #12 good for 20 amps at your breaker panel, and 10 amps in a trafo - and that AWG’s work like reverse dB’s, +/-3AWG is a -/+ factor of two).
Attachments
Transduktor is Swedish I think, and those other two are Finnish, so really top shelf stuff!
Hope you can build some nice headphone amps!
Hope you can build some nice headphone amps!
Fair enough, although they‘re looking good, not „so“ good good, IMHO
🙂View attachment 1007933View attachment 1007934View attachment 1007935
🙂View attachment 1007933View attachment 1007934View attachment 1007935
They do look nice I admit. And the name, „muuntosähko oy“, sounds magic (to me at least, probably isn‘t anything fancy)…
i shall see what noble cause they will serve.
It's both fancy AND magic! Sähkö is Electric, and Muunto is Conversion (or transformation). The "OY" is like German "AG."
Connect them to a suitable power resistor or lamp to draw about half power ~20-25W to see if they hum or have a hot spot. What is their history?
Connect them to a suitable power resistor or lamp to draw about half power ~20-25W to see if they hum or have a hot spot. What is their history?
I think all toroids where windings are not twisted sound the same, too clinical and too much bandwith.
But if u twist wires 2 times per winding, i think this toroid will sound instantly "warmer" without any output inductor on an amplifier output.
Did some experimental... "twisted wirings" sound warmer in overall.... in some frequency range... depends on where you twist your wires - amplfier powersupply lines ? Signal inputwires or amplifier output wires ?
Too much twisting everywhere will eventually un-compensate the effect and the result will be awful. So, balance is needed.
I am not sure...... but i guess that with good "warm" sounding toroid we can use "simpler" and more effective schematics as an amplifier - leaving more room for fun and efficiency.
But if u twist wires 2 times per winding, i think this toroid will sound instantly "warmer" without any output inductor on an amplifier output.
Did some experimental... "twisted wirings" sound warmer in overall.... in some frequency range... depends on where you twist your wires - amplfier powersupply lines ? Signal inputwires or amplifier output wires ?
Too much twisting everywhere will eventually un-compensate the effect and the result will be awful. So, balance is needed.
I am not sure...... but i guess that with good "warm" sounding toroid we can use "simpler" and more effective schematics as an amplifier - leaving more room for fun and efficiency.
220V primaries on (likely) 230V mains voltage... very old types... I guess they will hum....
BTW if you will use them you will still need the rubber rings and mounting stuff.
BTW if you will use them you will still need the rubber rings and mounting stuff.
Ah, nice. It seems I snatched some gems? I don’t know about their history, purchased them very cheap from a very friendly guy on our swiss „ebay“…
But looking at them indicates they have been treated well.
hummmm… 🙂
Like physically?
Like so that you can hear them singing 50 Hz. Still... always try them out. They can be real good.
Yes, will do! I got them for either my salas pre and salas ufsp project… (both projects quite „demanding“ a good tranny I guess.
Thanks for joining in!
And merry xmas to all!