Messages

I'm using a 3 pos. rotary switch for LP/BP/HP. Can I use a 4 pos. rotary to add a N (notch filter) position to simulate the Mutron III+? I think I read somewhere you can add a resistor and combine the LP and HP wires to the 4th position that will give the notch effect. Can this be done?

Hi All,

Just finished my first Madbean build, the Egghead.  I love this darn thing, it's got everything I'm looking for in an overdrive; slight compression, no mid-hump, dynamic response to pick attack, and the most useful tone knob I've ever used.  A full build report with photos will come shortly.

Anyway, I notice that Brian takes a no mojo bs approach to his builds and I really appreciate that.  What I can't understand is why a silver mica is required in the Egghead in the feedback loop along with other designs where it's clearly stated that "a silver mica is recommended for Cx".  Can someone explain why this is and how it could affect the tone to use a cheapie or better quality dipped ceramic in its place?  Just curious!

-Pete

any cap at or below 1000pf in the signal path I always use a silver mica. to me they sound clearer and have a unique "shine" to them. they are fairly cheap on ebay. I would avoid the china sellers because of counterfeiting

I've been using it for awhile and it sounds great. I was thinking about expanding it. Is it possible to add a rotary switch with different caps in place of the 82pf so I can get a variety of tones? would there be any adverse effects?

just put together a bloviator pedal, sounding really sweet, its interesting to hear how the sound is enhanced so much by this circuit, when you turn it off the guitar sounds so weak and 2 dimensional. I cannot figure out with my ears exactly whats happening to the sound - its just warmer and fuller but no real db boost going on. Nice. Subtle but sems to enhance chorus and phase effects as well.
How about a bass version - is it possible to swap out an input cap or filter to get a bass-friendly version of this?

I made a bass version of this pedal and it sounds incredible. These are the changes I made.

C2 4.7uF poly film
C3 rotary switch 1n/3n3/6n8/13n6
C4 rotary switch 22n/47n/68n/100n
I put rotary switches there so it can boost different frequencies. You can turn R15 into a mid boost/cut by substituting the 39K for 10k res + 50K linear pot in series. and you can turn R17 into a gain boost by adding a 50K linear pot in series with the 56K resistor.

I was wondering what is the purpose of the charge pump in the BaconBits pedal. I own a BBE Boosta Grande opamp booster and it doesn't have a charge pump. Can the BaconBits be built wihout one?

what works for me is I spread the soldering over a period of days instead doing it all at once. then I ALWAYS check each part for continuity to the next part in the path

when I turn the pots I hear that DC scratchy sound. I tested with MM and it reads 4 volts going through both pots, which is around half the supply voltage. Is this normal? I'm trying to figure out where I soldered something incorrectly. The voltage readings at the tips of the input and output jacks seem to be normal, very low millivolts.

I used a 32K resistor in series with a B50K pot for R17. I also lowered R1 & R19 to 100 ohms. more than enough gain for me

on IC3 pins 1, 5, & 8 are floating and not connected to anything? not to ground? I'm at this stage in the build and still learning 

thanks for the info. I was comparing this circuit to a state variable filter I built that uses the same quad chip. the designer put a volume pot right after the output cap instead of a resistor and I was going to emulate that. but then again, it is a different design and i don't know how the caps and resistors interact with each other. I guess the R19
1K resistor on the Bloviator has to be considered also

finally got all the parts. time to build. I was wondering if there was a way to add a volume or gain control. is there any way to tap in a gain or volume pot? could R18 be substituted with a pot?

having a drill press is going to help you a LOT. when I have to drill a PCB I have to wing it with a Black & Decker, vice grips, and a 2 by 4. I've got the best results when I notched each pad dead center with a small nail before drilling. the notching is tedious but it will make drilling a snap. when drilling keep the bit going at top speed and drill SLOWLY.

1N4001 vs 1N4004 in that position shouldn't have made any difference at all, but obviously it did for you, so who am I to disagree? Whatever works, right?

I was thinking the same thing. maybe the 1N4001 was bad or the solder joint was cold

This is my next project and I'm building it for bass. Would the R2 10M resistor make the sound way too bright for bass? Could I use a lower value like maybe 1M?

count me in!