I've a pair of unknown transformers (may be 250/350W) in very good shape, I think they were recovered from a pair of inverter power supply (so unknown and probably unusable voltage ratings)
I've also some old PT that are in bad shape (and must bee rewound as to be usable)
I'm wondering if the laminations of this transformers are usable to build bass and/or guitar OT (I need a big OT as to use some GU50 tubes I've for a very big amp)
Thanks
K
I've also some old PT that are in bad shape (and must bee rewound as to be usable)
I'm wondering if the laminations of this transformers are usable to build bass and/or guitar OT (I need a big OT as to use some GU50 tubes I've for a very big amp)
Thanks
K
In addition to usually being welded, MW transformers are designed for mainly harmonic current, accounting for their unusually high power rating for such core volume. The coils are usually saturated in very strong varnish and would have to be cut off. The core material is usually not very high quality even though they may be slightly thinner lams than everyday 60Hz transformers, and would have a lot of loss in the high kHz.. To reconfigure with full interleaving would take a ton of work to remove all the burrs after separating the welded I's from the E's. End result: probably not worth it for audio output.
The frequency range of a guitar is about 80Hz up to about 8KHz. The bass goes down to 40Hz and also up about as high. But in HiFi terms there are no "highs" so don't worry that the PT laminations will be rather thick compared to what a HiFi OT might have
As a rule of thumb just figure if you have a 100W PT that it will be good for only a 50W bass amp or a 100W guitar amp
One question is the size of the window. A OPT will have many more turns of wire and it will have a few taps for 4, 8 and 16 ohm speaker loads
True, if you need the gap things are tilted much more in favor. I think you'd probably still want to cut the weld though, and discard the shunts.
Question: What is the turns ratio of a typical microwave transformer? I'm just wondering if there might be use some audio use for them as is.
For example if the answer "about 150:1" then it could be used directly for a very small single ended amp using a 12AU7 as a power tube. Might work for headphones or a guitarist's practice amp. Using a 1,000 watt transformer in a 1W amp seems a waste but, it would otherwise go into a landfill.
are you saying that MWT's can be used as single ended output transformers?
and if, at what wattage?
yes, once you have separated the E's and I's.....it becomes simple to remove the old coils and put in the new coils, gapping material in between the E's and I's and there you have it.......
as to power handling, you can de-rate by a factor of about 5(my engineering guess) so that a MW traffo good for 100 watts at 60hz may do no more than 20watts in SE...
Typically they have about 1:20 to 1:25 ratio.
The ones I have, have 2690Vrms output voltage.
jer
P.S. I didn't include the 2 to 5 volt filament winding though.
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If you had two identical ones you might be able to get away with using them as they are, once you remove the shunts, using the filament winding as your output.
Also one side of the HV winding is connected to the core and this would also have to be changed some how.
Do protect yourself and insulate them should you try it.
I had hooked one to an amp once to check it for frequency response for use on a ESL and it was not bad at all.
But I was mainly looking to use them for lower frequency's.
But since the transformation ratio was to low for my use I got side tracked playing with the most powerful HV it produced off of my Crown DC300a amplifier.
I believe I used the filament winding as the input or maybe I added a separate winding I don't remember.
jer
Also one side of the HV winding is connected to the core and this would also have to be changed some how.
Do protect yourself and insulate them should you try it.
I had hooked one to an amp once to check it for frequency response for use on a ESL and it was not bad at all.
But I was mainly looking to use them for lower frequency's.
But since the transformation ratio was to low for my use I got side tracked playing with the most powerful HV it produced off of my Crown DC300a amplifier.
I believe I used the filament winding as the input or maybe I added a separate winding I don't remember.
jer
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yes, get two identical MW traffos is the first requirement.....the next is to remove all the coils and just use the iron cores.......
put in the new coils and you are done.....this is a 1, 2, 3 thing....
having said that, i have 2 japanese luxman lv103's that i harvested the power traffo, it is also welded, the core quality seems good since it has also 0.35mm thick lams...
put in the new coils and you are done.....this is a 1, 2, 3 thing....
having said that, i have 2 japanese luxman lv103's that i harvested the power traffo, it is also welded, the core quality seems good since it has also 0.35mm thick lams...
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