Stickman393
Well-known member
Alright. This one...woof. This took a while.
I'm still planning on changing out the knobs. Kinda wanted to do bare aluminum on em to really bring out the contrast.
So, the DEFX Larry, a clone of the Mu-Tron Flanger. Mu is the 12th letter of the greek alphabet, and the suffix -tron tends to denote either a machine or a subatomic particle. So...Engine XII.
This pedal started its life as a Steve Vai Little Alligator. Gutted it, sanded down the bottom.
The switch and LED holes did not line up with the new board, so I had to fill those and re-drill. Little bit of Steel Stick epoxy putty worked great, with a silver sharpie to hide it. The fact that I had to change around some of the stock holes led me to cut out the front plate on my CNC from 0.5mm carbon fiber. Makes drilling *much* easier.
But, going all the way through poses some challenges. I had to use a "Stencil" font, otherwise I'd end up losing interior parts of letters. Plus, even with my 0.25mm tip ball end mill, some of those details are just too fine. I had to adapt my labeling to account for that. Play for start, Hexagon for Stop, A lil circle ouroboros for feedback, and the letter "V" for speed.
This pedal offered some challenges. How do I do the shutter? Well, because I have a CNC machine, I chose to make one out of 0.5mm carbon fiber. Cool.
Then, there are some components that are either difficult to find or are just, simply, not available. The 2SC828s I subbed with 2SC1815s. The LED I chose was a diffused yellow Chanzon from amazon. The Waitrony KE-10720 LDRs? I used a pair of GL5528's.
Of particular note: I had to add a 10pf cap in C18 during calibration, and I had to drop R31 from 220K to 100K in order to achieve 11.60V in toe down. Also: I wrapped the bottom of all indicator LEDs with heat shrink tubing to prevent their bleed from impacting the LDR.
Calibration was a bear. The clock was simple enough, but I found that Trim 2 had a greater impact on the high frequency range and that Trim 4 had a greater impact on the low frequency range. Reversed from the way the build doc recommends adjustment.
The BBD Bias? Damn near impossible at TP2. There's simply too much noise at this point in the circuit. Do yourself a favor: verify that you *have* signal at TP2, but then go and adjust bias at IC10 pin1. That's after all the filtering and makes dialing in a nice sine wave *much* easier.
BBD balance: no idea what this thing is doing. Mixing the signals from pins 7 and 8 from the BBD? No clue. It didn't seem to do much to either waveform when I adjusted it, plus it had the unfortunate distinction of being in the same, extremely noisy point of the circuit as TP2. My scopes a cheapie, though, so I have no idea if I was doing that right or not.
BBD output level? Do it by ear, or do it by scope and match the voltage of the signal to the output at the output pin to bypassed. Easy as pie.
Pedal sweep range? Oh fuck my eyes. I was originally using GL5516's, as those seemed to match the spec sheet of the Waitrony LDRs...but no dice. They were SLOWWW to respond to darkness, and I couldn't get anywhere near 11.6V at toe down. I swapped with the GL5516's, messed with R31 a couple of times, and bingo. Got it. But its important to note that the trimpots here don't actually impact the top end all that much: those are for setting your 2.29V toe up voltage.
Thoughts:
I've fucked around with it clean a bit, and it's pretty cool. I'm thinking I'll probably end up replacing the "rate" pot with a log taper 50K pot. The speed ramps up too quickly with the linear taper. Its got a hell of a range on it. Got me itching to build more flangers.
Anywho, the photos are garbage. My phone camera lens is scratched to hell. This is about as good as I can do:
I'm still planning on changing out the knobs. Kinda wanted to do bare aluminum on em to really bring out the contrast.
So, the DEFX Larry, a clone of the Mu-Tron Flanger. Mu is the 12th letter of the greek alphabet, and the suffix -tron tends to denote either a machine or a subatomic particle. So...Engine XII.
This pedal started its life as a Steve Vai Little Alligator. Gutted it, sanded down the bottom.
The switch and LED holes did not line up with the new board, so I had to fill those and re-drill. Little bit of Steel Stick epoxy putty worked great, with a silver sharpie to hide it. The fact that I had to change around some of the stock holes led me to cut out the front plate on my CNC from 0.5mm carbon fiber. Makes drilling *much* easier.
But, going all the way through poses some challenges. I had to use a "Stencil" font, otherwise I'd end up losing interior parts of letters. Plus, even with my 0.25mm tip ball end mill, some of those details are just too fine. I had to adapt my labeling to account for that. Play for start, Hexagon for Stop, A lil circle ouroboros for feedback, and the letter "V" for speed.
This pedal offered some challenges. How do I do the shutter? Well, because I have a CNC machine, I chose to make one out of 0.5mm carbon fiber. Cool.
Then, there are some components that are either difficult to find or are just, simply, not available. The 2SC828s I subbed with 2SC1815s. The LED I chose was a diffused yellow Chanzon from amazon. The Waitrony KE-10720 LDRs? I used a pair of GL5528's.
Of particular note: I had to add a 10pf cap in C18 during calibration, and I had to drop R31 from 220K to 100K in order to achieve 11.60V in toe down. Also: I wrapped the bottom of all indicator LEDs with heat shrink tubing to prevent their bleed from impacting the LDR.
Calibration was a bear. The clock was simple enough, but I found that Trim 2 had a greater impact on the high frequency range and that Trim 4 had a greater impact on the low frequency range. Reversed from the way the build doc recommends adjustment.
The BBD Bias? Damn near impossible at TP2. There's simply too much noise at this point in the circuit. Do yourself a favor: verify that you *have* signal at TP2, but then go and adjust bias at IC10 pin1. That's after all the filtering and makes dialing in a nice sine wave *much* easier.
BBD balance: no idea what this thing is doing. Mixing the signals from pins 7 and 8 from the BBD? No clue. It didn't seem to do much to either waveform when I adjusted it, plus it had the unfortunate distinction of being in the same, extremely noisy point of the circuit as TP2. My scopes a cheapie, though, so I have no idea if I was doing that right or not.
BBD output level? Do it by ear, or do it by scope and match the voltage of the signal to the output at the output pin to bypassed. Easy as pie.
Pedal sweep range? Oh fuck my eyes. I was originally using GL5516's, as those seemed to match the spec sheet of the Waitrony LDRs...but no dice. They were SLOWWW to respond to darkness, and I couldn't get anywhere near 11.6V at toe down. I swapped with the GL5516's, messed with R31 a couple of times, and bingo. Got it. But its important to note that the trimpots here don't actually impact the top end all that much: those are for setting your 2.29V toe up voltage.
Thoughts:
I've fucked around with it clean a bit, and it's pretty cool. I'm thinking I'll probably end up replacing the "rate" pot with a log taper 50K pot. The speed ramps up too quickly with the linear taper. Its got a hell of a range on it. Got me itching to build more flangers.
Anywho, the photos are garbage. My phone camera lens is scratched to hell. This is about as good as I can do:
