AW: Most instantly looping hardware looper sought for

["Rainer Thelonius Balthasar Straschill" <rs@moinlabs.de>]

> - pressing a start pedal starts recording instantly, pressing 
> same button again starts the first loop.
> - pressing start again would get back to recording (not 
> overdubbing but
> replacing) and another hit on start would start the new loop 
> again at its new loop length.
> - a second pedal could be used to overdub on a loop playing already.

You need:
        * a DL4
        * some 74xx series ICs
        * a soldering iron

In looper mode, the logic of the DL4 is like this (footswitches and LEDs
numbered from left to right):

* In the beginning, all LEDs are off ("standby mode").
* Start recording with FS1. LED1 and LED2 light up. ("recording mode")
* You close the loop with FS2 (LED1 goes out, LED2 stays on) ("playing
mode")
* To start a new loop, you have to press FS2, (LEDs go out, "standby 
mode"),
then start from the beginning.

So the logic you need for your one-pedal looper to react to a press of that
switch is:

if NOT LED2 then                        -- standby mode
        FS1
elseif LED1 then                        -- recording mode
        FS2
else                                    -- playing mode
        FS2, FS1 after delay    -- wait an unnoticeable delay, e.g. 1ms,
then start recording
end if

Or for your two-pedal looper (sw1 - start pedal, sw2 - overdub pedal)

if sw1'event then
        if NOT LED2 then                -- see above
                FS1
        elseif LED1 then                
                FS2
        else                            
                FS2, FS1 after delay
        end if
elseif sw2'event then
        if LED2 then            -- only does something when a loop is
playing
                FS1
        end if
end if

Use 74xx logic gates and a 1ms delay and wired OR to wire those two pedals
to control FS1 and FS2, also taking in LED1 and LED2.

If you're crafty, you can fit it in the original box and spend considerably
less than $10.

        Rainer