PedalPCB Crystal Drive/EarthQuaker Devices Chrysalis Overdrive 1590b

OD is Glorious

Well-known member
Build Rating
5.00 star(s)
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Decent circuit that sounds like many other overdrive pedals. Similar in timbre to the Greer Amps Black Mountain Crunch and perhaps the SheepyLove Bee Sting. Unity is with all knobs around 12 o'clock, and from there you can roll off the drive for a fairly transparent boost. When you start turning that drive potentiometer you are headed from low gain/clean to mid gain/smooth turning all the way get you to slightly unharmonic, rolling, sustaining full saturation. Fuzz like. The tone knob adds some shimmer. So it is cool and it sounds terrific - I first hooked it up to my PPCB Auditorium Platform and it worked straight away. I guess it is a tube screamer with more aggressive sustain and some fuzz-like saturation .

I used a blue Tayda powder coated 1590b and I applied a waterslide decal. I did my own design for the decal rather than copy the original. I then clear coated with Spraymax 2k satin clear. I used WIMA film capacitors and short Electrolytic capacitors. I used low profile enclosed side jacks and a Lumberg D.C. top jack. The knobs are Davies 1510 and the LED is a yellow 3mm in a clear Freznel. This circuit clips with two BAT48 and I used two MPSA18 NPN low noise transistors from Stompbox Parts. I put a dab of epoxy to hold the D.C. jack in place for good.

This is a low parts build and it produces a circuit with useful tones. Without the enclosure finishing you can complete this circuit in a few hours.

Notes
  1. No op amps buy you need two MPSA18 transistors
  2. You need three BAT48 diodes but you can socket as I did here and try other diodes.
  3. 1590b build requires the low profile electrolytic capacitors or you need to be creative with tall ones
 

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