Pauper mods

Mike McLane

Active member
I had the opportunity to A/B my Pauper with a real P-O-T. Very satisfied with overall outcome EXCEPT it had noticeably less distortion when the Gain was max'd out. Yes, the Boost/OD/Dist switch as well as internal DIPs were matched on both. Any suggestions as to a component "swap" that would boost the Gain in this baby slightly? BTW, slight variations given identical "knob settings" are not the concern. It just doesn't have as much "grit" on the top end when dimed.
 
You could try increasing R3, which would be like having a larger drive pot.

One possible theory: schematics of the PoT/KoT I’ve seen have 2 diodes (one each direction) in the hard clip mode. The pauper has 4 diodes (2 each direction) in hard clip mode. This means a higher clipping threshold, so less distortion. This theory would be proven if the pedals sound the same with the gain pot maxed in soft clip mode, (original and pauper have same diode configuration in soft mode).
 
Thx for the quick reply. I went back and did a second A/B with a fresh set of ears. The delta was more slight than originally thought. I found that some of the perception of more dirt seemed partly attributable to the Tone setting. The POT seemed more "solid" (i.e. mid rangey), the Pauper a bit more "spikey". When I dialed back some of the highs in the Pauper and got a better tone match I could kick up the Volume slightly and that seemed to match up much better. And both similarly distinct from my Tommy, Mach I or Kliche.
 
Got a friend who really likes the Pauper and wants me to build one up for him. I was able to source real MA856's on my build (well, the guy on Ebay said they were real?!?!), but I'd rather find diodes in current production for moving forward. Any recommendations. . . . what is Analog Mike doing?
 
Pedalhacker has ma856s, legit. 2.25 a piece though. They also sell 10 packs of BA100 diodes for 4$ Or 10 IS1588s for 7$. I’d give those a shot but I bet if you found a current production diode with a .75v-ish forward voltage it would work fine. Or just do what everyone does and use 4148s haha.
 
Yeah, I looked back and Pedalhacker is where I got my MA856's. I had some sort of "standard issue" diode in there before. . . I think 4148's. When it's all said and done, if you learn your craft and play with commitment the difference btw the two diodes is way down on the list of importance. That said, if you want to get picky, paying an extra $10 is peanuts everything considered. . . $35 instead of $25 to build a $150 boutique pedal? Still a deal at twice the price! :cool:
 
Oh heck yeah. I’ve just never found there to be any real magic sauce beyond the forward voltage and reverse leakage.
 
Not being an experienced electronics guy I'd appreciate some sort of bare bones tutorial that explains the key specs at play in the selection of op amps, diodes, caps, etc. and how substitutions and experimentation is not to be feared. I've always heard about forward voltage being a key in diodes . . . tried to read a spec sheet once, but to no avail. If somebody put it as simply as you just did that would be great. I heard something on a DIY site the other day about polarized vs non-polarized electrolytic caps. The guy was saying something like 'use non-polarized in the signal chain, but polarized in the power supply circuit' . . . don't really remember. BUT, my understanding is that polarization is immaterial (other than installing it properly). In order build a larger value cap, but keep it physically smaller in size the design required a specific direction of electron flow. Otherwise it's just another cap. Did I get that right? Some real basic 'how to's" like this could really broaden PPCB's market. I started out as a guy who could replace pickups, modify/rewire his guitars and build his own chords, etc. Now I'm saving hundreds of dollars on pedals (at least that's what I tell my wife).
 
Most of the stuff about semiconductors that matters in pedals is not specified in the datasheets. Pedal designers rely on experimentation, happy accident and building on the work of others. The same parts will behave differently in different circuits. Anyone who has built a Thermionic has noticed that of the four LEDs on the board, only two of them light up. They're all performing a clipping function, but they're doing it differently and creating different sounds in the process. This is all to say there are no simple answers for diodes, transistors or opamps. Use sockets and experiment.
 
There is a lot of, shall I say...alchemy to it. Experimentation is a terrific asset. I know absolutely nothing about electronic engineering theory but my knowledge base has come from years of trying!
 
I agree that experimenting has been the key to some cool effects, with some lucky accidents and "betther-than-the-original-part" substitutions thrown in for good measure. but there are also some good sites you can go to for articles about the theory behind some of the tone shaping that goes on inside these musical circuits. take some time to explore the different things at Jack Orman's site: http://www.muzique.com/
 
I agree that experimenting has been the key to some cool effects, with some lucky accidents and "betther-than-the-original-part" substitutions thrown in for good measure. but there are also some good sites you can go to for articles about the theory behind some of the tone shaping that goes on inside these musical circuits. take some time to explore the different things at Jack Orman's site: http://www.muzique.com/
Brian Wampler also has or had a book on designing effects, not sure if it's still in print, I got it years ago before he started selling his own pedals along with one on modifying effects
 
I’m considering building a couple of these. I’ve built 2 KOT’s and noticed there are no 1s1588 diodes in this one, just the 4-ma856’s. Does anyone know if that’s per the original POT? Thanks in advance.
 
On another thread pedalpcb said that the Pauper is set up like the original PoT (which is different from the KoT hard clipping like you noticed).

The PoT description on the analogman site says “The DISTORTION mode is improved though, for a louder, stronger distortion sound.”(He means compared to the KoT). This Stronger, louder distortion sound is because there are 2 diodes each direction to VR on the PoT, instead of 1each direction on the KoT.

not sure if he did it becausehe actually preferred the sound, or to save $ onthe rare diodes...
 
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