Can one of the pedalbuilders look over this layout?

TheBassBoss · #1 12-24-2012, 12:32 PM

I've designing a Big Muff to fit my needs, and today I made a veroboard layout for it using DIY Layout Creator. However, I have never designed a veroboard layout before, so can one of the pedalbuilders on here look over this to make sure there aren't any errors before I start building? For reference, I used this schematic.
http://www.pisotones.com/BigMuffPi/psst/schm-third.jpeg

The modifications I made to this circuit are removing the emitter resistors and increasing the collector resistors to maximize gain. I also added in a tone switch to change between the stock tone stack and a flat mids tone stack. Thanks!

TheBassBoss · #2 12-25-2012, 08:19 AM

Bump for the holidays!

Skrogh · #3 12-25-2012, 08:44 AM

Is it layout or design, you want looked at?

~~Also, what are SW 1-9 connected to? And how.~~
Never mind.

TheBassBoss · #4 12-25-2012, 09:59 AM

The layout, I would just like to have another set of eyes look over it before I start building, because I've never created a veroboard layout before and I have a feeling there is an error I'm overlooking.
The design should be fine as far as I can tell, because it is a combination of several mods I read about online.

TheBassBoss · #5 12-25-2012, 10:05 AM

After looking over it again, I just realized that the 1u cap before the Sustain pot should be electolytic.

Here is the layout with that correction.

moose23 · #6 12-25-2012, 01:09 PM

Your tone switch looks really complicated, what are you achieving with it that you wouldn't get from switching between the 3.9n cap and a 10n cap?

TheBassBoss · #7 12-25-2012, 01:54 PM

The tone switch is to switch between a late (V3) and a flat mids tone stack. I got the values from this site: http://rkerkhof.ruhosting.nl/Taas/Mods/Big%20Muff.htm
This isn't entirely necessary, I just wanted to give myself more options. I could just have a tone bypass switch, which would be simpler to wire. I guess I will have to decide on whether or not that much wiring is worth it.

johnk_10 · #8 12-25-2012, 02:22 PM

all of the 1U caps could also be non polarized film caps instead of electrolytics.
if you want it even more versatile for different types of grit/distortion, you could add diode options (led's, germanium, silicon etc) in the first and /or second clipping sections.

johnk_10 · #9 12-25-2012, 02:28 PM

and here's some verified muff versions that already have some tone stack options:

http://tagboardeffects.blogspot.com/...l#comment-form

the supercollider is also a good one:

http://tagboardeffects.blogspot.com/...l#comment-form

and the blackout effectors Musket is also worth a look:

http://tagboardeffects.blogspot.com/...l#comment-form

TheBassBoss · #10 12-25-2012, 07:41 PM

Thanks for the layouts John! I've seen your pedal building threads, and they are really awesome! I really like the layout of the Green Russian version, so I am creating a layout based off of that using the values from the first layout I posted. One thing that confuses me on the Green Russian layout though, is the diode in between the power and the rest of the circuit. Wouldn't the diode lower the voltage for the whole circuit? Is this diode necessary?

johnk_10 · #11 12-25-2012, 08:08 PM

Quote:

Originally Posted by TheBassBoss

Thanks for the layouts John! I've seen your pedal building threads, and they are really awesome! I really like the layout of the Green Russian version, so I am creating a layout based off of that using the values from the first layout I posted. One thing that confuses me on the Green Russian layout though, is the diode in between the power and the rest of the circuit. Wouldn't the diode lower the voltage for the whole circuit? Is this diode necessary?

it's not necessary to the circuit . it's just a protection diode for using the wrong polarity to power it.

TheBassBoss · #12 12-25-2012, 08:14 PM

So as long as I use a center negative power supply, I don't need the diode?

TheBassBoss · #13 12-25-2012, 08:29 PM

Also, shouldn't there be a wire or a third capacitor connecting points 2 and 5 on the switch? Otherwise half of the tone stack wouldn't be connected.

TheBassBoss · #14 12-25-2012, 08:59 PM

Well, here is the layout I've been working on that is based off of the Green Russian layout. As John suggested, I added a switch between silicon and germanium diodes in the second gain stage. The tone switch is the same as in the Green Russian, but I still think there should be something connecting points 2 and 5.

Bakkster_Man · #15 12-26-2012, 06:44 PM

I printed a Big Muff board as part of a university project, but had a lot of noise and bad feedback. Like 2kHz oscillations whenever I wasn't playing. I'm pretty sure it's due to the impedance and capacitance from the long lines, especially heading to the pots. This is a super high gain pedal, and thus incredibly succeptible to bad effects from substandard layout. Your high gain segments need as short wires as possible.

Put simply, learn from my failure. I'm unfortunately betting you won't be able to make it work well. There's just going to be too many long wires, especially to the gain pot. I'm pretty sure the BMP needs board mounted pots to be practical.

TheBassBoss · #16 12-26-2012, 07:05 PM

I'm not entirely sure how I would use board mounted pots on veroboard. Do you have any tips on how I would get this to work? Or would a small built-in noise gate help? I haven't started building this yet, so any suggestions are helpful.

Bakkster_Man · #17 12-26-2012, 07:35 PM

I have no idea, I never solved the problem. You could try board mounted pots on three adjacent lines, with the high gain node components as close to them as possible. Then cut the strips just after the components to minimize the trace length. The sustain stage seemed the one feeding back, but any of them might given long leads.

Another thing to try is I think I could reduce the oscillations by adding a 1pF or so capacitor to ground on the oscillating node (or at least change the pitch and isolate the offending node). It may be handleable, but you may be better off finding a prebuilt boar which could be modified to your needs. Are you just switching in and out capacitance and resistance? That might be possible with a General Guitar Gadgets board, with flying leads going to the components being changed.

johnk_10 · #18 12-26-2012, 08:09 PM

I've recently built four big muff variants using veroboard and not a single one of them has noise or oscillation issues.

the ones that I built are:
Green Russian
Supercollider
Musket
Pharaoh (which is a super high gain BM)

moose23 · #19 12-28-2012, 03:49 PM

Only problems I've ever had with excessive noise is dodgy power supplies. I'd say I've built around forty big muff variants mostly tweaked from the Tall Font with a good few Ram's Head and Triangles in there.

I'd suggest a diode lift on the first diode stage over the germ diode switch on the second, this gives you a nice bit of (almost) clean low end through the pedal ala the Jumbo Tonebender.