UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Eagle SA-80 do they come any simpler than this ?

Paul Stenning · 25th Nov 2007, 6:35 pm

Are the smoothing caps really 150V as on your circuit? That's quite low HT for 8W output from class A. Unless of course it's 8W total, 4W per channel. Or not RMS.

If there's enough gain you could probably improve it a bit (if you wanted to) with some negative feedback. A resistor and capacitor in series between the two anodes (look at some radio circuits for typical values) would be a good start. Also try replacing the common output valve cathode resistor with separate resistors for each channel (double the present value) and not fitting caps across them. It depends if you are planning to use it regularly though, and if the sound quality as it is bothers you.

25th Nov 2007, 6:35 pm	#6
Paul Stenning Administrator Join Date: Dec 2002 Location: Cardiff Posts: 9,073	Re: Eagle SA-80 do they come any simpler than this ? Are the smoothing caps really 150V as on your circuit? That's quite low HT for 8W output from class A. Unless of course it's 8W total, 4W per channel. Or not RMS. If there's enough gain you could probably improve it a bit (if you wanted to) with some negative feedback. A resistor and capacitor in series between the two anodes (look at some radio circuits for typical values) would be a good start. Also try replacing the common output valve cathode resistor with separate resistors for each channel (double the present value) and not fitting caps across them. It depends if you are planning to use it regularly though, and if the sound quality as it is bothers you. __________________ Paul Stenning Forum Admin/Owner and BVWS Webmaster