The ST-70-C3 was a modification by Audio Research Corp. Not a Dynaco at all actually, but an ARC design scaled into the Dyna chassis and using only the iron. Some details and pics can be found here:
http://www.arcdb.ws/ST70C3/ST70C3.html
I built a few of these way back... added DC balance to the output stage and a few other bits. Overall a very nice amplifier.
Regards, KM
http://www.arcdb.ws/ST70C3/ST70C3.html
I built a few of these way back... added DC balance to the output stage and a few other bits. Overall a very nice amplifier.
Regards, KM
Actually, it was based on the ARC D-76 power amplifier but scaled back due to both physical space limitations and available power for filaments, etc. from the original components. Here's info for the D-76:
http://www.arcdb.ws/D76/D76.html
Regards, KM
http://www.arcdb.ws/D76/D76.html
Regards, KM
ARC ST-70C3 kit
Hello
I built the amplifier on this page, or at least the amp showing in the botton view.
If you look closely, you will notice a regulator chip there for the first tube fillaments and a small bias trandformer next to the power transformer.
The original Dyna transformer ran the tubes at 450v B+
I changed the transformer for a lower voltage tranny, but 400ma versus 300ma for the original.
I had to add the bias transformer because the new transformer did not have a bias tap.
bob
http://www.arcdb.ws/ST70C3/ST70C3.html
Hello
I built the amplifier on this page, or at least the amp showing in the botton view.
If you look closely, you will notice a regulator chip there for the first tube fillaments and a small bias trandformer next to the power transformer.
The original Dyna transformer ran the tubes at 450v B+
I changed the transformer for a lower voltage tranny, but 400ma versus 300ma for the original.
I had to add the bias transformer because the new transformer did not have a bias tap.
bob
http://www.arcdb.ws/ST70C3/ST70C3.html
ARC ST-70-C3 PCB layout
The diagram you seek is on page 14 of the St-70-C3 Modification Manual, a PDF copy is in the link toward the bottom of my webpage dedicated to this amp:
http://mpbarneyamps.googlepages.com/audioresearchst-70-c3amplifier
Best regards,
Mike
The diagram you seek is on page 14 of the St-70-C3 Modification Manual, a PDF copy is in the link toward the bottom of my webpage dedicated to this amp:
http://mpbarneyamps.googlepages.com/audioresearchst-70-c3amplifier
Best regards,
Mike
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