G
Guest
Guest
i got this transformer for the reamp box, but which leads are which. my dvm measurements arent making too much sense. the spec sheet from edcor is only viewable with a pc application. hows that for not useful?
Help Support GroupDIY Audio Forum:
Kev
Well-known member
[quote author="chikkenguy"]the spec sheet from edcor is only viewable with a pc application. hows that for not useful?[/quote]
which file ? where ?
perhaps one of us can repost it so you can see it
which file ? where ?
perhaps one of us can repost it so you can see it
G
Guest
Guest
the model number was under the subject heading, the edcor 150:10k. i found the file at www.edcorusa.com. i went on to my friend's computer and viewed the document that edcor had for it. it was still no help. it just had physical dimensions.
i was thinking a bunch last night and realized what the issue was with what i was doing.
i was trying to find the primary and the secondary with my dvm and my ohm readings were coming out different than what the xformer is specd as. i realized though that that was because i was taking a dc resistance measurement. if i measured the ac impedance i would come up with something closer to 150:10k im sure.
there are 6 leads, 3 on one side of the bobbin and 3 on the other. the center tap is the center lead on both sides. comparing the dc measurement of one side to the other, there is ~1:8 ratio. which is what the transformer is wound as.
hopefully that wasnt confusing, and what it all means is that i figured it out.
i was thinking a bunch last night and realized what the issue was with what i was doing.
i was trying to find the primary and the secondary with my dvm and my ohm readings were coming out different than what the xformer is specd as. i realized though that that was because i was taking a dc resistance measurement. if i measured the ac impedance i would come up with something closer to 150:10k im sure.
there are 6 leads, 3 on one side of the bobbin and 3 on the other. the center tap is the center lead on both sides. comparing the dc measurement of one side to the other, there is ~1:8 ratio. which is what the transformer is wound as.
hopefully that wasnt confusing, and what it all means is that i figured it out.
NewYorkDave
Well-known member
Edcor makes at least two different 10K:150 transformers, the WSM series and the PC series. Tell us which one you have and we can tell you the pinout. I'm pretty sure the WSM has the pinout printed right on a label stuck to the case.
As for the PC-series, I just grabbed the following pinout from the PDF file on the product page:
As for the PC-series, I just grabbed the following pinout from the PDF file on the product page:
G
Guest
Guest
its the wsm. sometimes i miss some really obvious things, but im pretty sure that it doesnt have the pinout printed on it. thanks for the help.
> my dvm measurements arent making too much sense.
Don't use a DVM to read the ohms of a coil. Use a simple analog meter. If you can still find a $10 multi-meter, that's ample.
> the spec sheet from edcor is only viewable with a pc application.
What "PC-only application"? Mac versus PC is tons of fun; I wrassled a Mac-CD on my PC today. But most companies use PDF and there are PDF readers for most platforms. You may have run into a DXF or other mechanical-drawing file; these may be no use at all without a $4,000 program.
> the model number was under the subject heading, the edcor 150:10k
Most tranny winders make the same impedance part under several models.
> my ohm readings were coming out different than what the xformer is specd as. i realized though that that was because i was taking a dc resistance measurement.
Yes. If the DCR were equal to the audio impedance, performance would be really bad.
> if i measured the ac impedance i would come up with something closer to 150:10k im sure.
Sort of. The "150" side will be 10 or 20 ohms DC, 150 at "the bottom of the audio band" (whatever the maker defined that to be), and much higher than 150 over the rest of the audio band, if the secondary is not loaded. With rated load, the primary would read 150 over most of the audio band, falling in the sub-audio range and going a bit wild at and above the top of the audio band.
For a first-guess approximation, if the DC ohms is 10Ω the intended AC impedance is probably 100Ω-200Ω. Or nominal AC impedance is 10 to 20 times higher than DC resistance.
And this is why Digital meter readings on iron-core coils are sometimes bogus. To save power, DVMs shoot short pulses of test current into the item being measured. Because the AC impedance of a coil is much-much higher than its DC resistance, the meter can't get a fix on a reading. I nearly threw out a perfectly good transformer, because my DVM said the primary was open-circuit. The tranny was 60+ hard years old, so this was plausable. Yet my plain old analog meter said 800Ω, about right for a 5K SE output transformer, and indeed the thing worked fine.
Don't use a DVM to read the ohms of a coil. Use a simple analog meter. If you can still find a $10 multi-meter, that's ample.
> the spec sheet from edcor is only viewable with a pc application.
What "PC-only application"? Mac versus PC is tons of fun; I wrassled a Mac-CD on my PC today. But most companies use PDF and there are PDF readers for most platforms. You may have run into a DXF or other mechanical-drawing file; these may be no use at all without a $4,000 program.
> the model number was under the subject heading, the edcor 150:10k
Most tranny winders make the same impedance part under several models.
> my ohm readings were coming out different than what the xformer is specd as. i realized though that that was because i was taking a dc resistance measurement.
Yes. If the DCR were equal to the audio impedance, performance would be really bad.
> if i measured the ac impedance i would come up with something closer to 150:10k im sure.
Sort of. The "150" side will be 10 or 20 ohms DC, 150 at "the bottom of the audio band" (whatever the maker defined that to be), and much higher than 150 over the rest of the audio band, if the secondary is not loaded. With rated load, the primary would read 150 over most of the audio band, falling in the sub-audio range and going a bit wild at and above the top of the audio band.
For a first-guess approximation, if the DC ohms is 10Ω the intended AC impedance is probably 100Ω-200Ω. Or nominal AC impedance is 10 to 20 times higher than DC resistance.
And this is why Digital meter readings on iron-core coils are sometimes bogus. To save power, DVMs shoot short pulses of test current into the item being measured. Because the AC impedance of a coil is much-much higher than its DC resistance, the meter can't get a fix on a reading. I nearly threw out a perfectly good transformer, because my DVM said the primary was open-circuit. The tranny was 60+ hard years old, so this was plausable. Yet my plain old analog meter said 800Ω, about right for a 5K SE output transformer, and indeed the thing worked fine.
NewYorkDave
Well-known member
WSM pinout is:
Primary: 1 and 4 (centertap: 2)
Secondary: 5 and 8 (centertap: 6)
The pin numbers are molded right into the bobbin.
Primary: 1 and 4 (centertap: 2)
Secondary: 5 and 8 (centertap: 6)
The pin numbers are molded right into the bobbin.
G
Guest
Guest
which pins on the secondary are out of phase with the primary? the pins on the same side of the assembly(ie. 1 and 5)? or the ones diagonal from each other(ie. 1 and 8)?
clintrubber
Well-known member
Isn't that all indicated on the TX itself ? I have my Edcors here now (thanks Tony !) and all is marked clearly on the thing itself.
Regards,
Peter
Regards,
Peter
G
Guest
Guest
i figured it all out, but there is no indication of which pin is which on the unit i have.
clintrubber
Well-known member
OK, I see. The units I saw have three labels and the pin-numbers 'in 3D' on the plastic of the bobbin. Good they seem to have changed this now.
Bye,
Peter
Bye,
Peter
