Quad Green Pre build

[lorcan]

Hi all,

I just completed my quad green build, which has a few tweaks/customizations:

• preamp pcb modified to use small relays instead of switches and shorten signal
• new pcb psu with thicker traces, room for heatskinks, etc.
• switch control board using Atmel ATTiny 2313 controller
• 4x control panel pcb's to hold the leds and the illuminated switches

I think the relay/microcontroller combination + pushbuttons turns out about the same as good quality switches in terms of price.
You get visual feedback 'for free' from the leds, which can be seen from a distance, which is nice.
Given the panel was done by hand, I opted for a minimalist design, no lettering, just color codes for the switches. Forces you to use ears only 
I was a bit worried the avr might induce some noise, but in fact it's just as quiet with the logic control part on.

Sound is great, much better than the RME Fireface preamps I was using before, so I'm very happy especially since this is my first preamp build.
If anyone's interested, I might take the time to clean up my layouts and other files and send them to you.
Beware there's quite a lot of mechanical work and adjustment to do though , especially for the front panel.
If I had proper CAD skills and access to a proper pcb machine, I would have made bigger boards.

The front panel, with illuminated MEC tactile switches. Drilled this by hand to save costs .. might have saved the time instead

The inside

Cheers,

Lorcan

 

[sam system-d]

beautiful one! Great work.
I'm fixing mine actually

 

[dissonantstring]

great work locran!  i know how chaotic things can become when doing a quad channel of anything.
maybe you could post a small thread about controller pcb and make it a separate utility project.
very nice preamp build (especially for your first of many preamps i'm sure  ).

 

[peterc]

Very nice work

Peter

 

[lorcan]

Thanks for the kind words 
And special thanks to Peter of course for making all this possible, in true diy spirit  8)

I think I'll leave the iron to cool off for a bit now and heat up the guitars and vocal rather, after all that's what these gizmos are for, aren't they ?
Though I might try a Neve channel some time in the future when I get a mic to do it justice, and more importantly, work on my vocal & recording skills.

I'll work on documenting the stuff that's currently in my brain only and put this in a .zip.
One potential difficulty for builders I foresee is that the atmel chips needs a programmer, and although you can those quite cheap on ebay, that might be a deterrent.

See you soon

 

[PeteC]

quite inspirational lorcan  !

.. I'm just building my own green pre - simple 2 channel V1 green pres with peterc's lates PSU V6 
- no bells and whistles - just want the high quality pres instead of my edirol and Maudio interfaces.

build quality and complexity like yours is really stunning.  well done.

cheers
PeteC

 

[lorcan]

@PeteC: actually it's probably the cabling that makes it look a bit complex. If we could put all of it, or maybe 2 channels on a single pcb it would be much simpler.
That kind of stuff would require very careful planning though, doing the pcb and front panel at the same time, using precision 'industrial' tools.
I guess that's the way a 'proper' manufacturer would do it, or someone who offered this in kit form (not my intention).
Good luck with the build.

 

[lorcan]

Update: added the PSU project files here: http://www.lorcan.me/wordpress/wp-content/uploads/2011/09/Green-Preamp-PSU.zip

 

[rob_gould]

I'd also be interested in learning more about how you used logic for the switches.

This is something I've been tempted to investigate before, but never really got round to.

Great build by the way 

 

[toneboner]

amazing stuff Lorcan. wow. i'd be totally interested in seeing whatever other files you have for your mods. really cool work, dude.