Can you share your simulation? Its not quite correct. The amp was designed before the simulation tools were available. In any case its performance is a little better than you show.
Thanks for the info.,wondering what 1audio thinks of your work up…..are the voltage numbers accurate??
You are showing 62 VDC on output,45 VDC on input driver….
Thanks,Dave
You are showing 62 VDC on output,45 VDC on input driver….
Thanks,Dave
Are the voltage numbers accurate?? I only reference above information, so I am not sure anything.
ltspice file as attachment, please enhance it and share. Thanks!
ltspice file as attachment, please enhance it and share. Thanks!
Suggestion above schematic: M7 M8 shold change to middle-power MOSFET like IRF610 IRF9610 , VN1306 VP1306 are unsuitable .
Thanks for the input,I’ve already found out the originals Vn/vp1306 are hard to find…
My question on voltage is regarding the schematic,is this Spectral OEM…
Thanks,Dave
My question on voltage is regarding the schematic,is this Spectral OEM…
Thanks,Dave
the same mosfets were used in the Hafler DH500 amplifiers with +/-85v power supplies if memory serves me. the smaller 2SK135/J50 devices typically used +/-70V so +/-62V seems low to me. maybe just for the drive stage with a higher voltage on the output devices.
This VERY old post (originated in 2003!) was touched earlier this year - the OP claims he STILL has some of the Supertex MOSFETs that may be needed. BTW, this is information; NOT a recommendation!
Sorry for the slow response on details. I have another instrument on the bench I need to finish before I can Open and check out my CAW- DMA 50.
Damien,
thanks for offering to help,it means a lot.
No,there’s no hurry,other than my own expectation to get the project going!
Thanks Again
Dave
thanks for offering to help,it means a lot.
No,there’s no hurry,other than my own expectation to get the project going!
Thanks Again
Dave
The covers for amp and power supply….
This Spectral amp is already a winner..dead quiet,dynamic,musical to a fault…been listening from a distance,has qualities that astound me…😳
Has to still prove to me reliability before I install in main system,driven presently direct by a Roon Transporter endpoint through cheap *** Pioneer bookshelf speakers…all I can say is I’m shaking my head at the musicality of this amp…..
This Spectral amp is already a winner..dead quiet,dynamic,musical to a fault…been listening from a distance,has qualities that astound me…😳
Has to still prove to me reliability before I install in main system,driven presently direct by a Roon Transporter endpoint through cheap *** Pioneer bookshelf speakers…all I can say is I’m shaking my head at the musicality of this amp…..
Attachments
Looks good - glad you're happy with the results!
Did Demian ever come back to confirm the front-end schematic that was posted earlier?
Did Demian ever come back to confirm the front-end schematic that was posted earlier?
I finally got a chance to review the schematics posted above. They are close but not quite there. The corrected file shows how the output circuits are connected. Zener diodes are used as current limiters on the outputs. We tested them in production by shorting the output at full level. The circuit was set up to use Jfets as cascodes but the mosfets work better and don't need biasing, shown in DMA 50 driver revised. The 3V threshold works well with the low noise Jfet front end which should run at 10 mA (2X J511). Current diodes were once $.50. No more. The diodes on Q4 and Q10 are Baker clamps that prevent the transistors from hard saturation so it recovers from clipping instantly.