Valve/Mosfet Hybrid Op Amp Module - PCBs

[Ray P]

Just wondering if anyone would be interested in some bare pcbs for a versatile valve/mosfet hybrid op-amp module that I've been working, here's the background....

After being disappointed by Welborne Labs rip-off non-delivery of some Cato modules a few months back I set about plugging the gap. I found that the circuit used by Welborne in their Cato module, designed by the late Erno Borboly, is actually in the public domain, here are some links to sites featuring it;

http://www.enjoythemusic.com/diy/1108/borbely.htm

http://headwize.com/?page_id=147 (about a quarter of the way down)

http://www.vestnikara.spb.ru/vestn/n5/ga.htm

And here's a link to the Welborne Cato kit

http://welbornelabs.com/cat/catomodule.htm

Anyway, I've worked up a small (about 75mm * 85mm) mono pcb and will be ordering some shortly, (professional high-quality manufacture similar to Andrew's power supply boards). If there is any interest I can get some extras made, which I'll sell for £5 each (plus postage, two required for stereo) to help offset the setup costs for the board manufacturing. I can supply a schematic and generic parts list.

The modules can be used as a headphone amp, a line stage (with gain from unity up to 40dB easily configured) and I've previously used some cato modules very successfully as a dac I/V output module - which is why I want some more.

The PCB is for the audio section only so some suitable power supplies will be needed (+/- 24VDC).

As the circuit is publically available and the pcb layout is entirely my own work I don't believe I am impinging on Welborne's claimed copyright, which can only be for their actual pcb.

So, any interest?

Ray

[Paul Barker]

It's an interesting concept.

But you don't know if the deceased willed the rights to a benefiticary and you have assumed Welbourne Labs hadn't paid for the rights.

Anyway, I won't need one.

[Ray P]

It's an interesting concept.

But you don't know if the deceased willed the rights to a benefiticary and you have assumed Welbourne Labs hadn't paid for the rights.

Anyway, I won't need one.

Thanks Paul, I have given serious consideration to the points you make but the first of the links I included above wasauthored by the deceased and openly encourages people to use the circuit so I see no issues on that score. As for Welborne Labs.....

If Nick feels that there is any possibility of vicarious liability I'll happily remove the post?

I suspect there will not be any takers anyway.

Ray

[ed]

just had a look at the old circuits I saved when I was interested in the moskido.......there was a thing called the buzkido, but I can't find it at the moment.....

anyway, point was, if you're not sure about copyright issues it shouldn't be too hard to get a good result with srpp(ecc8x) into buz900 or buz600...my memory is a bit vague but I remember sketching something out...I'm pretty sure it was one of those mosfets...

might be worth testing.....IIRC there was a lot of interest on diyaudio around 2009/2010.