DIY guitar effects/stomps - Any enthusiasts?

Knifey Spoony

kneeelix wrote: »

Haha cheers knifey. The power ratings I saw on farnell and radionics are just there for completeness i think alot of the smaller pots are rated in the mW region so I was unsure and i didnt want to spend a fortune as some of the pots listed are like 22euro a pop.

What do you use reverse log pots for? I know the reason for log pots is to try and match the way the ear percieves an increase in sound. we think its linear but its not. I can see the difference clearly from the graph but is there a physical or noticeable difference between them or when to use them or does it really matter?

I think that graph is wrong, it may have mixed up the antilog and log graphs or could just be the varibles that it's plotted with that I can't get my head around. Anyway, this is what I know as a log graph and this is an antilog or reverse log or exponential graph.

No idea what you would use a reverse log pot for. Just looking at the graphs, one would give you more sensitivity to small changes for a certain range of the pot. Like, the log graph would have a relatively large change in its resistance for small changes of rotation of the pot near the start of its range (low resistance region) and a relatively small change for changes in rotation near the end of it's range (high resistance region).

But, at the end of the day it won't really matter which you would use, I would imagine, as they both you do the same thing, just a different way of doing it and I would say that you might not notice the difference in them if you are just using them as standard volume controls and not constantly varying the volume for some effect, like a volume pedal.

***EDIT: forget the above about the graph being wrong and use the graphs that I provided as a guide to the differences between what log and exponential pots can give for resistance.

shizz

Knifey Spoony wrote: »

I think that graph is wrong, it may have mixed up the antilog and log graphs or could just be the varibles that it's plotted with that I can't get my head around. Anyway, this is what I know as a log graph and this is an antilog or reverse log or exponential graph.

No idea what you would use a reverse log pot for. Just looking at the graphs, one would give you more sensitivity to small changes for a certain range of the pot. Like, the log graph would have a relatively large change in its resistance for small changes of rotation of the pot near the start of its range (low resistance region) and a relatively small change for changes in rotation near the end of it's range (high resistance region).

But, at the end of the day it won't really matter which you would use, I would imagine, as they both you do the same thing, just a different way of doing it and I would say that you might not notice the difference in them if you are just using them as standard volume controls and not constantly varying the volume for some effect, like a volume pedal.

Both graphs can't be compared as they are of different logarithmic functions.

The graph you show is the simple log(x) function, where as the human hearing ties in with decibels which can be shown by a different function.

I'd imagine this is why but I don't know enough to clear it up any more but it can just be said that you cannot treat both graphs as equal.

This might help, http://www.kemt.fei.tuke.sk/Predmety/KEMT320_EA/_web/Online_Course_on_Acoustics/hearing.html

Knifey Spoony

shizz wrote: »

Both graphs can't be compared as they are of different logarithmic functions.

The graph you show is the simple log(x) function, where as the human hearing ties in with decibels which can be shown by a different function.

I'd imagine this is why but I don't know enough to clear it up any more but it can just be said that you cannot treat both graphs as equal.

This might help, http://www.kemt.fei.tuke.sk/Predmety/KEMT320_EA/_web/Online_Course_on_Acoustics/hearing.html

Actually yeah, I should have made it clear that both graphs shouldn't be directly compared. What I should have said is that those graphs are used to just highlight the difference between a logarithmic increase and exponential increase in resistance for the pots.

Anyway, this is getting away from DIY pedals and into audio engineering. But, I still think that the different type of pots shouldn't matter and might even be worth trying them out and see if there is a noticable difference.

shizz

Knifey Spoony wrote: »

Actually yeah, I should have made it clear that both graphs shouldn't be directly compared. What I should have said is that those graphs are used to just highlight the difference between a logarithmic increase and exponential increase in resistance for the pots.

Anyway, this is getting away from DIY pedals and into audio engineering. But, I still think that the different type of pots shouldn't matter and might even be worth trying them out and see if there is a noticable difference.

The only place i can see where they would matter is if your circuit is frequency sensitive eg. a wah pedal. In a wah pedal the linear pot wouldn't produce the same sound.

I wouldn't worry about it too much. Linear would be better suited for say changing distortion and log for volume to replicate the human hearing response. But at the end of the day all you are achieving with log over linear is a slower to larger increase of resistance values, or vice versa, depending on which type of log. So if you are designing I would imagine a lot of it may depend on your frequency response or preference.

JonathanAnon

Hi lads, does anybody know any DIY pedal for wave synth sounds?

oh and how do you make the PCBs I remember in college they had a special machine for doing this.. But could I do the same by just drilling the holes and joining with wires?

shizz

JonathanAnon wrote: »

Hi lads, does anybody know any DIY pedal for wave synth sounds?

oh and how do you make the PCBs I remember in college they had a special machine for doing this.. But could I do the same by just drilling the holes and joining with wires?

Like a phaser pedal?http://www.youtube.com/watch?v=r3Svjr0tfxA&feature=relmfu

Ive made my own pcb's, but the crudest ones you can. By etching the design into a copper board using Ferric Chloride. I depends on how well you transfer the design onto the board before etching but it turned out good.

In my college they made the boards by like milling out the design in a copper board. They had a machine to do it but I never seen it being done, but that's what it looked like happened.

Maybe_Memories

Hey Shizz, if you don't mind me asking how much did it cost you to build the BSIAB2? Including the casing, electrical components, etc.

shizz

Maybe_Memories wrote: »

Hey Shizz, if you don't mind me asking how much did it cost you to build the BSIAB2? Including the casing, electrical components, etc.

Oh mmm I dunno? I had a few parts here and there but I'd say about 20 euro I guess? It's not that expensive as long as you don't count all the things you have to buy like a soldering Iron and such. The dearest parts were the case and stomp switch. Just get the bill of materials and source them from here http://www.banzaimusic.com/

I'll try do it for you if your not sure but I'm busy at the moment.

Maybe_Memories

Okay cool. Is the sound quality good from home made pedals? Like say if I got the schematic for a Russian Big Muff would it sound the same as an original if I made it myself?

shizz

Maybe_Memories wrote: »

Okay cool. Is the sound quality good from home made pedals? Like say if I got the schematic for a Russian Big Muff would it sound the same as an original if I made it myself?

If you use everything they say to use and you do it correctly. Theres no reason why it shouldnt