UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

Diabolical Artificer · 15th Feb 2016, 4:04 pm

Thanks for the heads up Joe, will look them up and thanks for the analysis David, havnt had time to read it properly yet, but will do later when it calms down here- school hols.

With the latest drivers etc I got 91w with 1v P-P 1khz input, HT at 380v ish, using 3 6SN7's. I upped the current to 20mA on the followers and configured the LTP for more voltage swing.

I tried an 8 ohm pot in parallel with the 8 ohm dummy, at four ohms load OP power was cut by roughly a third, adjusting the pot made little difference. I also took out a pair of valves and tried various settings, no improvement. I've also experimented with the bias. I I'm sure I can squeeze a bit more out; I'll look at David's figures. A bit more power would be nice, for NFB.

Andy.

15th Feb 2016, 4:04 pm	#114
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,676	Re: 807 (maybe) amplifier build. Thanks for the heads up Joe, will look them up and thanks for the analysis David, havnt had time to read it properly yet, but will do later when it calms down here- school hols. With the latest drivers etc I got 91w with 1v P-P 1khz input, HT at 380v ish, using 3 6SN7's. I upped the current to 20mA on the followers and configured the LTP for more voltage swing. I tried an 8 ohm pot in parallel with the 8 ohm dummy, at four ohms load OP power was cut by roughly a third, adjusting the pot made little difference. I also took out a pair of valves and tried various settings, no improvement. I've also experimented with the bias. I I'm sure I can squeeze a bit more out; I'll look at David's figures. A bit more power would be nice, for NFB. Andy. __________________ Curiosity hasn't killed this cat...so far.