Spectral DMA 100 Help needed

[1audio]

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.

 

[tannoy133]

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

 

[tannoy133]

Sorry backwards voltages quoted…watching hurricane Milton coverage at the same time…pray for all in Florida….

 

[stoneku]

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!

 

[stoneku]

Suggestion above schematic: M7 M8 shold change to middle-power MOSFET like IRF610 IRF9610 , VN1306 VP1306 are unsuitable .

 

[tannoy133]

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

 

[Zero Cool]

Oh man, would love to own that amp/project should you decide to sell it!!

 

[Zero Cool]

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.

 

[1audio]

Thanks for sharing the simulation. I have a board here (attached) and I'll check what I did 40 years ago. I'll revise the simulation to better match the board. This is the CAW revised version. I may be able to share my later versions if I can find them.

 

[mlloyd1]

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!

M

Thread 'Transistors for Krell, Spectral,....(VP0120N5 or VN0116N5)'

2003-12-18 4:21 pm

After having udge problems to find the transistors VP0120N5,
I finally bought the last stock of parts VP0120N5 manufactured by Supertex (same as VP0116N5,VP0216N5, VP0220N5) available on the whole WEB....
I you have an old hifi amplifier such as Krell KSA100, or Spectral DMA200 (as I have), I can bring you a few pieces as a life insurance...
If you are interested just mp me....

CHarles

• moirasc

 

[1audio]

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.

 

[tannoy133]

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

 

[tannoy133]

Hi,just finished my latest project,any help on the waiting Spectral project would be great…
I have ordered stick on graphics,the preamp is a resurrected Curcio Daniel 6dj8 preamp,sounds great……

 

[tannoy133]

Hi,have started layout,here’s a prelim layout with a 5u case…..how hot can I run these boards?

 

[tannoy133]

Finished Spectral DMA 100 yesterday,burnin on bench for a few hours…..

 

[tannoy133]

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…..

 

[mlloyd1]

Looks good - glad you're happy with the results!
Did Demian ever come back to confirm the front-end schematic that was posted earlier?