Particle Accelerator - Alembic F-2B clone

[Mike McLane]

I'm implementing a foot switchable RAW feature into my second build. To clarify, I assume the pins on the PCB Mid socket correspond to the pins on the schematic to the right of the attachment. In both cases we're looking at the "underside" of the pot. Pls verify.

 

[vigilante398]

I'm implementing a foot switchable RAW feature into my second build. To clarify, I assume the pins on the PCB Mid socket correspond to the pins on the schematic to the right of the attachment. In both cases we're looking at the "underside" of the pot. Pls verify.

View attachment 47493

You're on the right track, but minor corrections. Pin 1 of the Mids pot goes to ground in the stock configuration, the idea of the Raw control is that it interrupts that ground connection, so the Raw pot needs to go between Mids pin 1 and ground. Also pins 2 and 3 of the Mids pot are jumpered, so you'll need to make sure if you're running the pot offboard that you jumper those pins.

 

[Mike McLane]

A bit confused. Under standard wiring doesn't the signal comes in on P2 and out P3 to GRD, a 10K variable resistor??? My Deluxe clone is wired that way, but then P3 goes in series to a second 250K variable resistor (RAW pot) which is ADDITIVE to the Mid. The foot switch just takes the signal from P3 straight to GRD so that RAW pot is bypassed.

 

[vigilante398]

A bit confused. Under standard wiring doesn't the signal comes in on P2 and out P3 to GRD, a 10K variable resistor??? My Deluxe clone is wired that way, but then P3 goes in series to a second 250K variable resistor (RAW pot) which is ADDITIVE to the Mid. The foot switch just takes the signal from P3 straight to GRD so that RAW pot is bypassed.

When wiring a potentiometer to act as a variable resistor there are two methods, leave one lug unused or jump two lugs together. There is no functional difference between the two, but as a design preference I always do the latter. This is reflected on the schematic shown in the build doc.

 

[Mike McLane]

Well. . . good news and bad news. Bad news is my foot switchable RAW has been voted down . The pro player I have testing the PA is also testing the preamp I made which has the foot switched RAW. He thinks it doesn't function well as a "dual channel thing". RAW's great for making the preamp more aggressive, but its still a "single sound" box. You just need to find out where you want the settings and go with it. Good news is I (we) don't have to putz around with the foot switch wiring, etc. I'm going to sub an 50K or 100K for the Mid pot. At the upper reaches it gets a great growl, but the Fender mid range (6.8K) still lies around 11:00 so its easy to dial in.

 

[MichaelW]

Well. . . good news and bad news. Bad news is my foot switchable RAW has been voted down . The pro player I have testing the PA is also testing the preamp I made which has the foot switched RAW. He thinks it doesn't function well as a "dual channel thing". RAW's great for making the preamp more aggressive, but its still a "single sound" box. You just need to find out where you want the settings and go with it. Good news is I (we) don't have to putz around with the foot switch wiring, etc. I'm going to sub an 50K or 100K for the Mid pot. At the upper reaches it gets a great growl, but the Fender mid range (6.8K) still lies around 11:00 so its easy to dial in.

I think the EQ voicing is the best part of the PA to be honest. @vigilante398 did such an awesome job with the tone stack. Clean tones just sound YUUUUUGE in front of an amp.

 

[Mike McLane]

@MichaelW - You're right. Fender blackface preamps are classics. The big MID cap doesn't change that. Just gives you more MID range, but the standard Fender value is still in there. The PA isn't as aggressive as the blackface Reverb models because it lacks the extra umph the add'l preamp tubes provide. I believe?? that's why @vigilante398 put the tone stack AFTER the two gain stages in the Underground Accelerator.

 

[Betty Wont]

Do you guys get oscillation with both the gain and treble dimed? I was really surprised with how much gain and distortion I got out of it.

 

[Mike McLane]

I'm running strictly as a preamp into a Class D power amp so no "over the top" behavior.

 

[MichaelW]

Do you guys get oscillation with both the gain and treble dimed? I was really surprised with how much gain and distortion I got out of it.

Nope, no oscillation but I don't tend to run it flat out.

 

[tremelo68]

Also just finished my Particle Accelerator and it too sounds fantastic. Changed the LED after taking this picture. This 5mm orange didn't light it up well, but a 3mm yellow is showing in the second picture. Thanks again for making some DIY options available.

 

[Silver Blues]

Same colour scheme I'm going with, knobs notwithstanding Looking good!

 

[tremelo68]

Thanks!

Admittedly, I got lazy on the aesthetics and just did a quick letter punch for each knob and some blue candy paint over the bare enclosure, but I do like the look of candy over bare. It just chips super easy if you aren't careful. Even with clear coat. And the knobs were what I had on hand that fit this very tight arrangement of pots. I have a really great selection of knobs, but they are all too big for this. Same for the Diplomat.

 

[Mike McLane]

In the 5F6A thread you recommended a B500K potentiometer as a variable "output pad" just ahead of the Master Volume. The Particle Accelerator just has a straight 220K resistor to pad the output. Not the voltage divider. Is there an electrical difference btw the two approaches, could either work? I'd like to build some variability into the PA by replacing the 220K and the simplest way I can think of is to shoehorn one of PPCB's Trimmit's in there and stick a 250K trimmer in it as a variable resistor. That work?

 

[Mike McLane]

Just completed this build for a good friend who's a pro player. Has an extend gig playing bass in a "big band". Loves the Part Accelertaor cause it sounds great and takes up so little room on the bandstand. Asked me to build one for him. I call it "Deluxe" because the schematic is vintage blackface (AB763) Fender. . .



Yeah, I know I got the wiring icon wrong (center positive!?!?). I corrected it before I shipped it.

 

[jimilee]

Just completed this build for a good friend who's a pro player. Has an extend gig playing bass in a "big band". Loves the Part Accelertaor cause it sounds great and takes up so little room on the bandstand. Asked me to build one for him. I call it "Deluxe" because the schematic is vintage blackface (AB763) Fender. . .

View attachment 49375

Yeah, I know I got the wiring icon wrong (center positive!?!?). I corrected it before I shipped it.

What style does he play? When I think big band and bandstand, I think jazz.

 

[drgonzo1969]

Thanks!

Admittedly, I got lazy on the aesthetics and just did a quick letter punch for each knob and some blue candy paint over the bare enclosure, but I do like the look of candy over bare. It just chips super easy if you aren't careful. Even with clear coat. And the knobs were what I had on hand that fit this very tight arrangement of pots. I have a really great selection of knobs, but they are all too big for this. Same for the Diplomat.

Looks great! what letter punch's do you use?

 

[Mike McLane]

Stripped the logo from a photo and cleaned it up and then the pedal was UV printed.

 

[Mike McLane]

jimilee - From what I understand its a "show band". . . a lot of pop stuff, horns, backup singers, etc. Primarily a guitar player, but plays a lot of bass, too.

 

[MichaelW]

This pedal sounds awesome in the return of an effects loop on a tube amp.
Kinda like having a completely different amp. For me this is @vigilante398's best DIY pedal.
Absolutely love it for both guitar and bass.