Noob question - Bass, mid, treble control for overdrive/distortion

[jfrabat]

Yup.  I did use 3.3nF on the breadboard.  I used the Eagle file as my build reference, so I defenetly used 3.3nF instead of 33nF.  Will replace it today.  Will check back with the update once it is done.

[jfrabat]

Yup, that cap was certainly the issue.  I replaced it with 2 15nF ones (I was out of 33nF, so I measured my stock of 15nF, and used 2 that measured at 16nF), and VOILA!  Mid control works just fine.  Also the pedal is quieter; with single coils, if I use 2, there is little noise.

This is the schematic now:



Again, I am adding the 2 parallel caps so that if I print it, I will just use what I already have.

[Elijah-Baley]

Great!
If it work for you I can't see why I will can't make work mine!

[jfrabat]

Hi, Guys.

I got a couple more questions regarding the pedal (everything is working, but I am trying to personalize the sound to the taste of the user). 

On the breadboard you can see I got all kinds of diodes for clipping options:

• Blue LED
• Red LED
• BAT41
• 914
• 1N270
• 1N4004
• 1N4148
• 1N34A - I think they are, anyway; there is no lettering in them!

I simply need to change one connection to switch it around.  I know a couple of those should not even be in the list, but my intention is to show him the effect of the clipping diode can have on sound.

As far as transistor goes, I am not sure how much the change the sound (have not tried it yet), but I am taking:

• 2N5088 - what you hear in the test
• 2N5089
• 2N2222 - what I have in my own version of the Electra
• 2N3904 - I think this is the original Electra transistor, right?

Do these really change the sound much?  Is it worth taking them?

I am also taking different caps for IN/OUT.  I have:

• 68nF - Currently being used
• 47nF
• 22nF
• 10nF

My understanding is that the lower the cap, the more treble will go through (or the least bass anyway), right?

[Elijah-Baley]

I forgot to suggest you how try to fix that little issue that makes clip the signal with the Treble at max. How I told early, probably boosting the treble make to clip the signal, maybe even if you can't hear distortion in the signal there's a bit of gain. Did you use single coil guitar pickup? Anyway, you should try to raise up the 1.8k next the Treble pot. Some other configurations have 3.6k or 3.9k. Probably you will have a smaller range, but it could enough.

Diodes.
If you want just to show the difference sound of the diodes just change them on the breadboard. Else, you need a rotary switch to select every pair of diodes.

Transistors.
Some transistors have higher hfe and some have lower hfe. This can determinate the gain level. But there's just a way to to know how a transistor sounds: try it! Those four transistors are rather common, if you are going to build something else I'm pretty sure you could use the three you don't use for this circuit in other project.

Input cap.
Changing the value of the input cap C4 (but also C5, C6, C7 and C12) change the cut of the low frequencies. Bigger cap cut less bass. A 1uF cap cut little bass, and maybe this circuit could work with a bass guitar. With a 1nF cap you can hear just the highest frequencies.

[jfrabat]

Hey, guys.  Got together with the friend who asked me to make this pedal, and he is really digging how it is sounding.  This is the last schematic with the changes he liked:



He was asking me if it is possible to make it have more gain.  I assumed I could just add another gain stage, so I tried that on the breadboard, but there is actually LESS gain when I add it AFTER the current gain stage, and it sounded like CRAP if I added it before (FYI, I used a 5.2K resistor to ground to kind of make that stage mid gain), so I took it out. 

So, a couple of educational questions:

• What is the best way to add more gain to this pedal?
• If C4 and C12 are 10nF, I would be perfectly fine using 10nF for C5, C6 and C7, right?  Or would that change the tone in any way?

[jfrabat]

Since I am no longer talking about the tone control, I am starting a new post for this part here.

[Elijah-Baley]

It's not necessary have the same value for those caps. The 10nF cap will cut bass.

[ElectricDruid]

What is the best way to add more gain to this pedal?

You could make it more crunchy by using less diodes in series, or by using diodes with a smaller forward volt drop. If you just want it louder, you could increase R6.

If C4 and C12 are 10nF, I would be perfectly fine using 10nF for C5, C6 and C7, right?

No, that doesn't logically follow at all. C4 and C12 might be fine as 10nF, but that's because of the situation they're in. C5, C6 and C7 are in different situations and therefore probably require different values. Each and every cap needs working out for its particular situation.

Or would that change the tone in any way?

Yes, probably radically!