Is this a Nelson Pass Amp?

[Drummy66]

Hi all hope you can help. I've had these two cirquit boards lying around since the early nineties. They're supposedly for a 40W Class A Threshold Amp by Mr. Pass. Can anyone confirm this? if so, is there some building instructions and component list to get hold off? If so I would love to get started on this killer project. Any help much appreciated.

 

[aspringv]

It may be this...
http://www.firstwatt.com/pdf/art_a40.pdf

 

[analog_sa]

You're going to build an amp just because you have those nasty looking boards? Seriously?

 

[Drummy66]

You're going to build an amp just because you have those nasty looking boards? Seriously?

Care to elaborate Analog_sa.
Have heard an Amp made by exact same boards sounded awsome.....

 

[jam]

Amazingly great sounding amp which can drive low impedance loads.
Output devices are no longer available so you will have to find subs or build a discreet Darlington output stage.

Jam

 

[Dennis Hui]

On parts substitution:

PassDiy

 

[osscar]

mj11016/15 will fit. Nice PCB - i like DIY pcbs.

 

[analog_sa]

Care to elaborate Analog_sa.

These days a professionally produced pcb of this size costs just a couple of dollars. With perfectly drilled holes, solder masks, silk screens. Plus an hour or so to create the gerbers.

What is the total cost of an amp? A few hundred?

 

[gary s]

The Pass A40 was way ahead of its time back in the days when Nelson presented it to the DIY community and is still worth building today with newer substituted parts.

 

[MEGA_amp]

Looks like an A40, those boards look a bit dodgy though. I just finished the A40, its superb! Its the first amp I've built, after being here for so long, that received an actual built case, no top though. These boards work great: OSH Park ~. Also, everything you've ever wanted to know and then some: FIRST WATT

 

[gary s]

Good to see MEGA-amp, can we buy actual new boards from the supplier OSH Park you have linked, or do they only do new boards from people who send Gerbers.? I assume they are in China - any further details, and I assume you have used 2 of these actual pcb's in your build.

Regards,

Gary..

 

[MEGA_amp]

alexcp provides the gerbers in the thread link below, he also provided those same gerbers to OSH Park, the same gerbers are also avail for download on the oshpark project page. There's a min order of three boards (45USD) from them, their US based/manufactured. Its kinda like a group buy, you have to wait for other people to purchase other types of boards, once they hit some number, they send it to fab. Took an additional week before my boards were sent out. The boards are pretty thin, but once populated and bolted down, they're fairly rigid, but most importantly they're functional.

FS: one pair of Nelson Pass A40 PCBs

 

[hirscwi]

I've bought several boards from OSH Park and been very pleased with the quality.

 

[DaveG]

the DIY boards look great. And no silkscreening to mess up the top side-

 

[bobgroger]

These days a professionally produced pcb of this size costs just a couple of dollars. With perfectly drilled holes, solder masks, silk screens. Plus an hour or so to create the gerbers.

What is the total cost of an amp? A few hundred?

Those boards are period correct. That is the way it was done. You must be a younger lad....

 

[mpmarino]

It's great that the A40 keeps resurfacing - never dies

I'll have to make one someday, using DIY boards of course

 

[vdi_nenna]

I've bought several boards from OSH Park and been very pleased with the quality.

Are you forced to share your board design with OSH Park? What I took from it was that I had to make my board design public. I hope I got that wrong. That would suck.

 

[PRR]

> Are you forced to share your board design with OSH Park?

AFAIK: no. You "can" share, and their original vision was shared projects, but they do not share without permission.

If you truly have a Secret Project, obviously you don't let others do your work. However the likelihood of any audio project being "stolen" is nearly zero. Nobody has time to comb through the vast assorted krap which gets sent in, much less discern the purpose without a Parts List, or to understand why vdi's board is superior to all others.

 

[vdi_nenna]

Ok, good to know. My concern is uploading an amp board like the AB100 and making it openly available. (If anything the board should be available the diyaudio store.) I wouldn't want to break some sharing etiquette when someone is being generous and making their IP available.