L-MOSFET G.Randy Slone

[macgman2000]

Hello,

I am relatively new to the DIY high power audio scene. I specialize in a different branch of electronics and thought I would work on an audio DIY amp for experimentation. I picked up G. Randy Slone's High-Power Audio amplifier contruction manual.

Art work 11.8 with the L-MOSFET configuration is what I am interested in. To photo etch the board is going to be a problem since he over layed the parts outline and numbers on the top view of the PCB artwork. The photo etch is going to reproduce the component outline and short out traces.Does anyone have a clean version without all the overlay clutter?

Thanks,
Nick

 

[richie00boy]

One of the amps in his book will never work and I think it may have been that one. It's been covered on here in depth. Have a search before you potentially burn all your parts.

 

[mlloyd1]

the one to avoid was the one with the complementary symmetry (npn and pnp diff amp) input stage with current mirror loads.

the other projects were "safe"



mlloyd1

 

[macgman2000]

which schematic?

Does anyone have the High-power audio amplifier construction manual by Randy? Is the amplifier featured in figure 11.8 the infamous problem amp? Or is the 11.8 amp a good design?

There are a couple of L-mosfet amps in the book, not sure which one it is.

Thanks,
Nick

 

[mlloyd1]

ok, i'll try again.
take a peek in this thread:
http://www.diyaudio.com/forums/solid-state/165530-heeeelllppp-m-randy-slone-mirror-image-topology-construction-troubles.html

mlloyd1

 

[alex mm]

PCB ....LMOSFET amplifier

Hi, PCB layout in 2009 may help you someway ......
Alex.

 

[macgman2000]

Thanks for the info !!! I am sure I will have even more questions trying to make sense of it all.

Nick

 

[wojo411]

Dude, art work shouldn't be a problem. Appendix Figure C.11 is the artwork for the amp in Figure 11.8. Figure C.9 & C.10 include the components on the artwork for reference when you're filling the board.

Now, the current mirror on the differential input stage, I understand, might be a problem. Never tried it. Good Luck.

 

[dino zoff]

Hi, Alex mm. Could you, please, post here your PCB from 2009. I want Very much to build this amp. A PDF ready for ironning technique would be Nice. Thanks a lot in advance. SEE you.

 

[Bonsai]

You can solve the problem by slightly imbalancing the current sources. If you don’t want to do this, you need ‘common mode current control loop’.

See here for some discussion on this

PGP Amplifier

If you are after an easier build that performs well and has been built dozens of times here on the forum see here

diyAB Amp The "Honey Badger" build thread

Lots of folks here can lend you a hand with this amp.

Good luck with your amplifier journey!