Mach 1/Mahayana Dual Pedal Switch Pop

[The Grand Wazoo]

Greetings,

Well there is no shortage of switch pop posts. I'm at my wits end here. I've read more than I care to about switch pop. Unfortunately, none have solved my issue. If anyone has ideas of what the issue can be, I would welcome your input.

• On the Mach 1 side, I get a pop when engaging and disengaging.
• On the Mahayana side, I get a pop when engaging but not disengaging.
• On the 4PDT order switch I get a pop both ways.
• Changing the order switch does not change the behavior of the Mach 1 or Mahayana popping.

Here's what I've tried.

• Went through the @comradehoser troubleshooting order of operation
  • Verified component values
  • Voltage reading for ICs and transistors (below)
  • Continuity checks between components and off-board items
  • DIdn't use the audio probe because I'm getting the effect - they sound great! - they just pop
• Tried putting a 1M pull down resistor on the output jack - no help
• 1M resistors from the 3PDT switch ground to output - no help
• Disconnected all LEDs - no help
• Put a 100nF cap across the input terminals on the 3PDT switch
• 
  • This actually helped a great deal but rolled off ALL of the high end.

Probing and measurements:
Mahayana Side
NE5532 Op Amp

• Pin 1: 4.7V
• Pin 2: 4.46V
• Pin 3: 4.17V
• Pin 4: 0V
• Pin 5: 4.43V
• Pin 6: 4.46V
• Pin 7: 4.46V
• Pin 8: 9.14V

Q1

• Drain: 4.47V
• Gate: 4.47V
• Source: 4.34V

Q2

• Drain: 4.46V
• Gate: 4.46V
• Source: 4.38V

DC on I/O

• Output Jack: 0.5mV
• 3PDT Out: 0.7mV
• Input Jack: 1.3mV
• 3PDT In 0.5mV

Cap and diode polarity:

• All correct

Wiring

• Solid

Grounds

• All connected including enclosure
• Used the DC Jack Breakout

Mach 1 Side
OPA2134 Op Amp

• Pin 1: 4.96V
• Pin 2: 4.97V
• Pin 3: 4.48V
• Pin 4: 0V
• Pin 5: 4.95V
• Pin 6: 4.96V
• Pin 7: 4.96V
• Pin 8: 9.13V

DC on I/O

• Output Jack 0.5mV
• 3PDT Out 0.3mV
• Input Jack 1.3mV
• 3PDT In 0.5mV

Cap and diode polarity:

• All correct

Wiring

• Solid

Grounds

• All connected including enclosure
• Used the DC Jack Breakout