[GST]

I am currently working on the parts list and layout to build the Clarion 2A3 single ended amplifier. My understanding of circuits in this area is limited, and I am uncertain about the connections for the V2 2A3 heater supply as indicated in the schematic. The full schematic is in this PDF file:

http://www.hagtech.com/pdf/clarionarticle.pdf

On page 2, in the bottom right corner, there are two coil symbols with dots which are connected to V2 output tube, with a +40V connected between them. The heater supply is a Hammond 166L2 - a 2.5V center tapped filament transformer. I presume the dots above the end of the coil symbols that are attached to V2 at points 4 and 1 are ‘phase dots’. If so, this suggests to me that these two coil symbols are the windings from a single transformer, with +40V attached to the center tap of the transformer.

This would bias the AC 2.5V sine wave to ride on +40V DC. Is this correct?

[hagtech]

Yes, you have it correct.  The 40V is generated by the self bias of the tube.  The 55mA or so through that resistor creates the 40V drop.

jh

[GST]

Jim,

Thank you for the confirmation and the explanation. I look forward to building your design, and really appreciate you making it available on the web with such excellent documentation.