Back plane

Helvellyn

KiCAD schematic and pcb files for the Helvellyn console project.

Helvellyn is a modular, DIY console design by Ramshackle Recording. PCB's for various modules will be available from www.ramshacklerecording.com

The backplane PCB for the console is released as an open source project for self-etching/manufacture and improvements, updates etc.

PCB's for the four-module backplane will also be available from Ramshackle Recording.

The Concept

The Helvellyn console system is based on the Eurocard and eurorack format and aims to be:

• Modular
• Expandable
• Analogue signal path
• Customisable

Each backplane PCB has space for four 7HP wide eurocard modules, or two 14HP modules. Modules mate to the backplane via a 32-way DIN connector, which provides the following functionality:

• Two balanced inputs per module (I.e there are allowances for +, - and 0v on each input)
• A direct output (or 2 unbalanced outputs)
• 12 audio buses ('Normal' configuration will be 4 mono auxilliary buses, 3 stereo mix buses and 1 stereo master bus)
• +Ve, -Ve power buses (normally +/-16V)
• Four ground/0V buses (normally used as reference voltage for power, audio, relay/logic power and fader)
• A single, unbalanced output. Normally used to send audio to an external fader.

The backplane can be fixed to a standard 3U Eurorack such as: http://uk.farnell.com/schroff/24563-131/subrack-3u-175mm-84hp/dp/1370391

With the Helvellyn system, it will be possible to build anything from a single 'lunchbox' rack of individual modules, to a large console with all the usual facilities.

Modules

Ramshackle Recording is actively developing a set of modules which can be used to produce a small-format, high quality mixing desk. The first modules to be released will be:

• EasyPSU: an 'onboard' PSU for powering a single rack
• Easy69: an easy-to-build high quality EQ, based on the famous Helios type 69.
• ISA-ish: A preamp. Something like the Focusrite ISA, but with modern components.