SPFFy Lace Bypass Loop Selector

Here’s the latest creation from the Mr. Furious Audio lab, which has haunted me for several months.

It’s a mash-up of my previous SPFFy Bypass Loop Selector (can’t find a link, I guess I haven’t written about that), and a Mammoth Lace Looper kit. In non-tech terms it doesn’t make any sound on its own; it’s for turning multiple other pedals on or off with one stomp and no clicks or pops.

I had to hack and kludge a bit, but it finally does everything it’s supposed to do. It’s mostly for recording, but might possibly see live use for future h&s stuff (beyond V for Voice, depending which direction we go after) or for Sneaky Sneaky Snakes.

The various modes described below all have their uses in creating different effects textures and timbres for various sections of songs, plus the silent relay switching ensures no thumps or pops from standard 3PDT footswitches are recorded.

< TECH TALK WARNING >

SPFFy Lace has four modes:

  1. Lace mode – A single relay-switched true bypass loop, controlled by the master bypass footswitch (farthest to the right). No other controls are active in Lace mode.
  2. Series mode – Two relay-switched buffered bypass loops in series. The second loop has a volume cut/boost and polarity inverter available when active and reverb/echo trails when deactivated.
  3. Parallel mode – Two relay-switched buffered bypass loops in parallel. Both loops have a volume cut/boost available when active and reverb/echo trails when deactivated, and the second loop has a polarity inverter.
  4. Flip-Flop mode – Two relay-switched buffered bypass loops in series; turning one on automatically turns the other off (!) *unless* the “FFX” (flip-flop kill) momentary switch is *also* engaged. The second loop has a volume cut/boost and polarity inverter available when active and reverb/echo trails when deactivated.

Improvements over the first version of the SPFFy include:

  • Lower noise
  • Master bypass switch
  • A true bypass loop
  • Silent switching (via the Lace)

Most of my time spent on this project was figuring out how to combine the Series/Parallel/Flip-Flop routing of the SPFFy with the Lace Looper relay bypass PCBs. I went into the project assuming, incorrectly, that the Lace PCBs used a three-pole design analogous to how I’d wire a standard 3PDT switch.

Instead (and this makes sense in retrospect) they use a variation of the two-pole “Millenium bypass” (Google it if you’re interested) design. Once I realized this, I had to tear up my original plan for splicing the SPFFy and Lace sections of the circuit together and re-design it.

Then, when I built that version, I realized that I hadn’t quite reverse-engineered the Lace relay and PCB correctly. I attempted to desolder one of the relays, destroyed it in the process, and had to order a replacement. After a final re-design, the whole thing worked as originally intended.

Unfortunately, the Lace relays have some latency; when you turn one on or off there’s a split-second of silence. This will be acceptable in some situations (live, recording with plenty of reverb/delay, recording anything in Parallel mode) and not in others. There may be a third SPFFy in my future some day, perhaps using optical bypass for the loops.

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