CONTEST What? Another Contest?

CONTEST
I had come up with a cool idea a week or two ago and I was really hyped to try it out, but I can’t for the life of me read the schematic I drew out— awful penmanship. I miss DipTrace 😅

Hopefully I can breadboard something eventually, or at least get access to the workbench again lol. Even though I haven’t come up with anything, this has been a very fun challenge to ponder.
 
Dan M's Wah-Boost on my breadboard. I may have tweaked it a little. 😉 Works pretty well as a fixed wah-type filter.

L-R: VOLUME - BLEND - FREQ

Dan M Wah-Boost on Chuck's breadboard.JPG

If I can find my friggin' 2N6027's, I'll breadboard the Fuzz-olo.
 
Chuck D. Bones said:
I may have tweaked it a little.
Click to expand...

Your layout is easier to follow. My breadboard looks like a lawn mowed by a 10 year old, but I'm getting better.

Did you try bumping the frequency sweep greater than 10k? I struggled picking that pot value because I wanted fine control in the ~0-7k range, but it could be useful to go above 10k. Ultimately, I didn't like the sounds above ~15k with my setup and my ears. So I stopped messing with it.
 
I had a lotta room, so I spread it out. Most of my breadboards are not so neat.

I have the sweep going from 360Hz to 3.2KHz. Most of the good tones happen in the middle of the range. I am using a larger FREQ pot. I can make more comments after the contest ends. To preserve fairness, I don't want to help the contestants too much. ;)
 
I need more breadboards. I know you're not actually supposed to cook them, but it doesn't take a lot of heat to make 'em a bit gooey.
 
BuddytheReow said:
Here's another one I cooked up between last night and this morning. The main sound I got last night and finished the TONE control this morning. This one is a heavy overdrive/fuzz circuit I'd like to call AIR NUTZ. To build this one the board you will need to bypass the third transistor stage. To make the TONE control (it's really a BRIGHT control, but I'll stick with Muffin terms, LOL) better I added a 820ohm resistor to ground after the TONE knob. I've designated this one R200.
View attachment 21564
View attachment 21565
Click to expand...
I wanted to name a a pedal called
“Hair-on Deez Nutz “ in a 5 person vote I lost.
 
fig said:
That's niiiiice! I like the tone cap values and the dual-clip action. What's that wire coming from the sustain pot?
Click to expand...
Oh, that's a 100k resistor on a 100k pot. I forgot to clip it off. I'm really digging the sounds I'm getting. I just got some PCBs for this in today, right after I made the final changes to this. Seems about right. :ROFLMAO:
 
That won't sound quite the same as a 50K pot. I will sound the same at 0 and 10, but the volume will drop more around noon with a 100K pot than with a 50K pot. The tone sweep will be slightly different too.

When you get a chance, can you measure and report the collector voltages?
 
Chuck D. Bones said:
That won't sound quite the same as a 50K pot. I will sound the same at 0 and 10, but the volume will drop more around noon with a 100K pot than with a 50K pot. The tone sweep will be slightly different too.

When you get a chance, can you measure and report the collector voltages?
Click to expand...
Right, but the 100k resistor on a 100k pot will more or less reduce the part of the rotation that doesn’t do much. It would hurt the sustain pot to keep it at 100k.
Q1 3.84
Q2 4.86
Q3 3.68
Q4 7.34
 
Thanks for the reply!
Which part of the rotation is that? Are you comparing your setup with a 100K or a 50K pot? The 47K load (R3 on your sch) has a huge effect on the tone network.

There are as many opinions on how a BMP tone stack should be constructed as there are BMP builders. I'm no exception. I use that style tone stack on many of my designs, and each time it's a little different.

Same goes for the SUSTAIN pot. Some folks like A-taper, some like B-taper. C4, C5, R13 and R19 (on your sch) interact strongly with the SUSTAIN pot near the max end of rotation.

For a simple circuit, there is a lot going on in the BMP.

Those collector voltages are as I expected.
 
Got the Fuzzduster built on a muffin PCB and in a box. Build report is here.

Used BF862 JFETs this time and it's working great. My caveman bias method is to find the minimum IDSS on the JFET's data sheet and calculate a resistance that will give 70% of that at 18V and use a value close to that for the drain resistors. I then use a pot with some leads attached to dial in a resistance on the source to give about 5.5V at the drain and pop in a fixed resistor of the value I get on the pot.

So, for the BF862, the min IDSS is 10mA. That means I need to calculate a resistance to give 7mA at 18V, since I might plug in to 18V at some point. This comes out to about 2.57K, so I used 2.7K for the drain resistors. Then I grabbed a 5K pot with a couple wires and calculated the source resistors, which all came out between 330R and 470R.
 
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