Hi Zenmod
If we look back at an early posting:
http://www.diyaudio.com/forums/pass-labs/235847-aleph-5-clone-shorting-ouput.html
I wonder if the ribbon transformer I'm directly driving with the Aleph is effectively acting as a short... and as such abusing the Output mosfets and thus leading me to these failures....?
Hmm. I think I'll measure the impedance of the Transformer....probably very low I suspect..
Cheers -
If we look back at an early posting:
http://www.diyaudio.com/forums/pass-labs/235847-aleph-5-clone-shorting-ouput.html
I wonder if the ribbon transformer I'm directly driving with the Aleph is effectively acting as a short... and as such abusing the Output mosfets and thus leading me to these failures....?
Hmm. I think I'll measure the impedance of the Transformer....probably very low I suspect..
Cheers -
Impedance measured.
Including speaker leads the Aleph output sees a load of abt 0.4 ohms....
Hmmm
sounds great though....
Including speaker leads the Aleph output sees a load of abt 0.4 ohms....
Hmmm
sounds great though....
how you measured that ?
what's ribbon Rdc and what's voltage (winding ) ratio of xformer ?
hoping that here is enough inductance ......
what's ribbon Rdc and what's voltage (winding ) ratio of xformer ?
hoping that here is enough inductance ......
Hi Zenmod
Very good questions
Resistance measured with digital multimeter.
AS for transformer spec's -no idea... bought off ebay and was designed and sold as an impedance matching transformer for a Decca Ribbon.
vendor was in the UK
I used the original windings and added 3 turns of heavy gauge copper wire on the ribbon side.
Impedence of ribbon itself---er ....not much at all.
The transformer may not be designed to go as low as it is used (650hz)
but as per previous comments - sounds good..
Very good questions
Resistance measured with digital multimeter.
AS for transformer spec's -no idea... bought off ebay and was designed and sold as an impedance matching transformer for a Decca Ribbon.
vendor was in the UK
I used the original windings and added 3 turns of heavy gauge copper wire on the ribbon side.
Impedence of ribbon itself---er ....not much at all.
The transformer may not be designed to go as low as it is used (650hz)
but as per previous comments - sounds good..
disconnect xformer from ribbon
measure Rdc of primary
measure Rdc of secondary ( if possible , it's certainly ookin low)
write here also what's reading of your ohmmeter with probes shorted
now - feed primary of xformer with 400Hz (max 1KHz) from music card of your PC , using SigJenny program ........ (or from your signal generator , if you have it )
let signal be whatever you can squeeze in - from 1 to 5Vac (measured across primary) and write it down
without any load across secondary , measure Vac and write it down
if you have L meter , measure inductance of both windings
however ......... something's fishy with these xformers .......
measure Rdc of primary
measure Rdc of secondary ( if possible , it's certainly ookin low)
write here also what's reading of your ohmmeter with probes shorted
now - feed primary of xformer with 400Hz (max 1KHz) from music card of your PC , using SigJenny program ........ (or from your signal generator , if you have it )
let signal be whatever you can squeeze in - from 1 to 5Vac (measured across primary) and write it down
without any load across secondary , measure Vac and write it down
if you have L meter , measure inductance of both windings
however ......... something's fishy with these xformers .......
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