ST-70 XLR Balanced Driver Boad

cfelliot · 17th June 2011, 01:22 PM

I've looked around and I can't seem to find anything. Does anyone make or have a schematic for a fully balanced driver board for a ST-70 amp?

HollowState · 17th June 2011, 03:23 PM

The Audio Research circuit is fully balanced. All you need do is not use the inverter stage. Connect the lower 12AX7 grid to the other balanced input. The circuit is in this thread.
Grounding the 4ohm tap

zigzagflux · 17th June 2011, 07:35 PM

Could check out K&K Audio. With the input transformer, you can run balanced or unbalanced inputs.

K & K Audio - Lundahl Transformers, audio DIY kits and more

cfelliot · 17th June 2011, 07:40 PM

There are many options to convert to unbalanced, but why convert just to go through a phase-splitter and be back to balanced?

I'm also curious about differential feedback.

17th June 2011, 01:22 PM	#1
cfelliot diyAudio Member Join Date: Jul 2010	ST-70 XLR Balanced Driver Boad I've looked around and I can't seem to find anything. Does anyone make or have a schematic for a fully balanced driver board for a ST-70 amp?

17th June 2011, 03:23 PM	#2
HollowState diyAudio Member Join Date: Aug 2006 Location: Taxland, New Jersey	The Audio Research circuit is fully balanced. All you need do is not use the inverter stage. Connect the lower 12AX7 grid to the other balanced input. The circuit is in this thread. Grounding the 4ohm tap __________________ "The supercomputer is technologically impossible. It would take all of the water that flows over Niagara Falls to cool the heat generated by the number of vacuum tubes required." ~ Professor of Electrical Engineering, New York University

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17th June 2011, 07:35 PM	#3
zigzagflux diyAudio Member Join Date: Oct 2006	Could check out K&K Audio. With the input transformer, you can run balanced or unbalanced inputs. K & K Audio - Lundahl Transformers, audio DIY kits and more

17th June 2011, 07:40 PM	#4
cfelliot diyAudio Member Join Date: Jul 2010	There are many options to convert to unbalanced, but why convert just to go through a phase-splitter and be back to balanced? I'm also curious about differential feedback.

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