July 8th, 2020, 11:37 am
July 8th, 2020, 11:40 am
July 8th, 2020, 11:44 am
July 8th, 2020, 11:47 am
July 8th, 2020, 11:53 am
July 8th, 2020, 1:16 pm
Roscoe Primrose wrote:I've never been a big fan of fixed bias, but for 300Bs in that circuit you don't have enough PS voltage to use cathode bias. Of course, for 2A3s you've got too much B+ to not use cathode bias
Roscoe
July 8th, 2020, 1:27 pm
July 8th, 2020, 1:35 pm
Grover Gardner wrote:Old Al used a common DC supply for the 300Bs, but I don't like the idea of balancing the tubes off the plates--any opinions on that?
I can't get 32wpc as he claims, but that may be 1) power supply limitation, or 2) modern 300Bs don't quite have the power of the originals, or 3) I need to tweak it a little more and do some more tests. I'm also thinking of replacing the Sofia outputs with a pair of Dynaco A470's I have on hand. The Sofias are 5.5K p-p and rated for 25 watts output. Al used what Ithink is a Triad 4.5K p-p, 50W OPT, so that might help, and they'll drop right in. But even as is this is a nice amp. Compared to my Williamsons it has that nice direct-heated honesty and lack of distancing from the music.
July 8th, 2020, 1:38 pm
July 8th, 2020, 1:47 pm
FerdinandII wrote:Walt just used the words 'efficient' and 'Magneplanars' in the same breath.......
Whaaaaaatt...????
Just kidding.
I agree with you, lots of speakers that you think need lots of current don't necessarily sound better on the 4 ohm tap.....