Monthly Archives: June 2013

Wiring – Stage 2


Pots, from L-R are: Control pots P2, P1 and P0 then the Output and Input Level controls for the valve preamp, the input jack socket and the ‘peak’ LED..

I’ve finished wiring the pots and the ‘peak’ LED on the front panel. That should be the front panel now completed and ready for the application of the self-adhesive film with the control labels and graphics.

Wiring – Stage 1

Connecting the EchoTapper Universal Interface shield (designed by Piet Verbruggen) to the Eccamatic Valve eTap2hw pcb (designed by Eric Thacker aka ‘ecca’).

The blue (Pot0), violet (Pot1) and grey (Pot 2) wires send the control voltages from the Arduino to the SKRM module (not yet mounted) on ecca’s board. The brown (+3.3V), red (SW0) , orange (SW1) and yellow (SW2) wires send the echo model select signals to the SKRM, replicating the action of the original BCD switch in the manual eTap2hw.

The rotary encoder, the push switches and the input jack socket are also wired on the front panel. The next stage is to wire up the front panel pots and the ‘peak’ LED.ImageImage

3D Model in SketchUp

I used Google Sketchup (a free 3D modelling package) to design the layout of the Valve Preamp EchoTapper. Here are a couple of views


An isometric view of the complete 3D model


Top half of the case ‘removed’ – you can put components of your model in different Layers in SketchUp and hide or show layers as you wish – a neat feature 🙂

Back panel removed

Back panel removed

Mounting the PCBs

I’ve now mounted the pcb’s for the valve pre-amp and the Eccamatic motherboard. I made a last-minute decision to mount the Eccamatic pcb in a vertical orientation after I suddenly realized it would fit that way. This frees up a bit of space for the connections between the boards and leaves a bit of room for future expansion – if I think of anything to do with it 😉