I like symmetrical topology, and today, i try to build this front-end, for my next project.
I's based symmetry topo, like Symasym, Mongrel CX, Gold Mouth
...
LTP used BC550C matched pairs. It's very good small signal transistor. Of course, you can use JFET (as 2SK170, 2SK30 or dual matched in one package like LSK389B/C, 2N3958, 2N5564 to better). I suggested 2mA - 3mA for BJT and >4mA LTP Iq for JFET ver.
Vas is simply. First, the Vas's current mirror used 2-Q mirror, but i have some problems with unbalance Ic of Vas. I read Rod Elliott page Current Sources, Sinks and Mirrors in Audio and I try with the Wilson improved current mirror 4-Q. He wrote it's extremely balance currents, improve dynamics, banwidth, distortions...
Wow, two Ic of Vas very balance. I set 12mA for Vas (6mA each). If you want, you can change R17 (10K/3W) by one PNP Medium power trans (2SA1381E is a good choise) - Active load of Vas differential.
In prototype circuit, i used EF2 like PB120/PB250N of Mongel II with 2 pairs Sanken power trans 2SC2922/2SA1216, drivers are 2SC2344/2SA1011 (Toshiba 2SC5171/2SA1930 are better, but i can't buy).
For last, i'll build EF3 output stage, to improve dynamic. And use ON-Semi audio power trans, like MJL4281AG/MJL4302AG...
For power supply, this project named by ''X250'' - it's means 250W per 8 ohms, 500W per 4 ohms and maybe 1KW @ 2R if i become rich man, keke (OMG, i don't want my money go away by this project , in my country, ON-semi power trans arevery expensive, about 10$/each.) The rails about 75 - 80VDC to make it. In this prototype, i used +/-55DC.
Anyone can comments about this? Thanks!!!
I's based symmetry topo, like Symasym, Mongrel CX, Gold Mouth
... LTP used BC550C matched pairs. It's very good small signal transistor. Of course, you can use JFET (as 2SK170, 2SK30 or dual matched in one package like LSK389B/C, 2N3958, 2N5564 to better). I suggested 2mA - 3mA for BJT and >4mA LTP Iq for JFET ver.
Vas is simply. First, the Vas's current mirror used 2-Q mirror, but i have some problems with unbalance Ic of Vas. I read Rod Elliott page Current Sources, Sinks and Mirrors in Audio and I try with the Wilson improved current mirror 4-Q. He wrote it's extremely balance currents, improve dynamics, banwidth, distortions...
Wow, two Ic of Vas very balance. I set 12mA for Vas (6mA each). If you want, you can change R17 (10K/3W) by one PNP Medium power trans (2SA1381E is a good choise) - Active load of Vas differential.
In prototype circuit, i used EF2 like PB120/PB250N of Mongel II with 2 pairs Sanken power trans 2SC2922/2SA1216, drivers are 2SC2344/2SA1011 (Toshiba 2SC5171/2SA1930 are better, but i can't buy).
For last, i'll build EF3 output stage, to improve dynamic. And use ON-Semi audio power trans, like MJL4281AG/MJL4302AG...
For power supply, this project named by ''X250'' - it's means 250W per 8 ohms, 500W per 4 ohms and maybe 1KW @ 2R if i become rich man, keke
(OMG, i don't want my money go away by this project , in my country, ON-semi power trans arevery expensive, about 10$/each.) The rails about 75 - 80VDC to make it. In this prototype, i used +/-55DC.Anyone can comments about this? Thanks!!!
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