SSBS Mini

marksescon

Active member
ssbsm1.jpg ssbsm3.jpg
I used this schematic that I redid from FSB. Gray Bench Electronics also did a teardown of the pedal that showed a few variances like the Bass potentiometer (C500K -> C1M) and the Gain potentiometer (B100K dual gang -> A100K dual gang) and JFET selection.

PCB was designed in Eagle. I did do a version to allow for SMT JFETs; however, the SMT versions of the JFETs are not available at this time. I opted for a J201 for the first JFET sourced from PedalPCB and 2N5457 for the other JFETs sourced from StompBoxParts. I also changed all the trimmers to 50K because the 10K on the Bias control didn't allow me to adjust the voltage appropriately. I put some "empty pads" on the PCB so I could easily adjust the voltages with my multimeter probe. Chuck's insight about biasing JFETs and this runoffgrove article helped with the biasing of the JFETs.

I built this in a 125B Pro from StompBoxParts. I highly recommend it; it's legitimately one of the best looking plain aluminum enclosures I have ever seen. My drilling was a bit off and I had to drill bigger potentiometer holes to allow for more "play" to allow better positioning, but I think it turned out fine. Graphic art is from Daiso, a Japanese dollar store in my area.

If you are interested in building your own, here are the free Gerber files with build instructions: https://github.com/marksescon/themini. I removed moniker from the PCBs as well.
 
Cool. I also noticed effects layouts now has a mini PCB as well for sale, in case anyone wanted to go that route as well
Yup - it's known as the Liliput on their website. Their PCB can be purchased here.

The only difference between Effects Layout's schematic and mine are components selection. I was more loyal to Gray Bench's teardown:
  • Bass pot. Effects Layout opted for the C500k, which appears to be on some models. The Mini that Gray Bench popped up had a C1M. Another person who build a clone based on the Effects Layout PCB noted that swapping out the C500K pot for a C1M pot made a huge difference (better/more Bass response).
  • Gain pot on the Effects Layout version is B100K dual-gang. Gray Bench noted at A100K dual-gang. "Gain" in this pedal controls the volume of two of the JFET stages and the audio-taper makes more sense in this case. However, I tried both and, anecdotally, noticed no difference.
  • Different power filtering. Effects Layout uses a 100uF electrolytic capacitor on their PCB. The original schematic sports a 220uF electrolytic capacitor. (Oddly enough, Effects Layout's perf/etched-board denotes a 220uF capacitor.)
  • JFET selections: Effects Layouts opted for 2x J201s and 1x 2N5457 - endorsed by Brain/SSBS on Tagboard's site, but from what I've read there some models with 1x J201 and 2x 2n5457, 3x 2n5457, etc.
The only recommendation I will vehemently advocate for is to change the Bass pot! C1M for Bass makes a massive difference!!!
 
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