SOLVED Death Cap Fuzz

[punchy712]

I'm not sure how to describe this issue, but the pedal just doesn't sound right. It maybe sounds like it's gated somehow, the best way I can describe the sound is that it's "broken". I recorded a quick clip here (all knobs at noon): https://on.soundcloud.com/Xs2vb

It's a pretty small build, so I rechecked all the component values and all knobs do work in that they change the sound, but I can't get a good sound out of it. If someone with a working build would be able to share the voltage values at some key spots in the circuit that would be appreciated (I'm thinking the two transistors).

EDIT: marking solved and nothing was actually wrong with the pedal, instead I didn't think of turning off the buffer at the beginning of the chain.

 

[BuddytheReow]

What kind of pickups are you using. SOmetimes if the input signal is too hot then your "gating" will occur. Try turning down your guitar's volume knob and see if that helps.

 

[punchy712]

What kind of pickups are you using. SOmetimes if the input signal is too hot then your "gating" will occur. Try turning down your guitar's volume knob and see if that helps.

I have pretty much all hum buckers. The clip was recorded with a Les Paul using the stock Gibson pickups (bridge, honestly not sure which one). I have the same issue with all guitars, though granted most of my pickups are pretty hot. Turning down the volume reduces the gain, but the same sound remains.

I built a bunch of other fuzz pedals and this is the first one that just sounds wildly off and not what I expected.

 

[BuddytheReow]

Hmm. Try dialing back the BIAS control and see if that helps. This circuit is nothing more than a booster into a bazz fuss with a few added bells and whistles. Where did you get your BJTs?

 

[punchy712]

Hmm. Try dialing back the BIAS control and see if that helps. This circuit is nothing more than a booster into a bazz fuss with a few added bells and whistles. Where did you get your BJTs?

Thank you for the help, really do appreciate it. I agree with you that it's pretty basic which is why I'm not even sure how to debug. I did try lowering the bias all the way done, and it's still very similar.

I got the 2N5089s from Mouser, where I usually source all my parts. Those are the ones I was thinking could be the issue, I was hoping to get some ideas for what voltage values to expect from others with this pedal.

 

[BuddytheReow]

FWIW, this is a circuit on my "to breadboard" list. The messiest part will be wiring all the knobs.

A long time ago I breadboarded the Heavy Spider which does have some "gating" like you mention here. I had to add some emitter resistors to tame it and was happy with the result.

Perhaps you can measure the voltages for us and see what others have to say here.

 

[punchy712]

Good point, I don't know why I didn't just do that from the beginning. Below are the voltages with guitar and everything connected, but not actually playing anything.

VCC: 9.24V

Q1
pin 1: 0.067V
pin 2: 0.647V
pin 3: 1.439V

Q2
pin 1: 0V
pin 2: 0.564V
pin 3: 0.768V

edit: changing the BIAS takes Q1 pin 1 from about 1.6V to close to 0V

 

[BuddytheReow]

There's your problem. Your collector (pin 3) voltages are too small. Double check your component values and solder joints again.

 

[punchy712]

There's your problem. Your collector (pin 3) voltages are too small. Double check your component values and solder joints again.

Awesome, thank you so much I'll be taking a look at that.

 

[Erik S]

Are you sure your cap values are correct?

The red box-film cap in the middle should be 4.7nf - Looks like the one you have there is 5mm wide like your 1U caps. That seems large for 4.7n. Took a quick look in Tayda and didn't see any in that size format.

 

[punchy712]

Are you sure your cap values are correct?

The red box-film cap in the middle should be 4.7nf - Looks like the one you have there is 5mm wide like your 1U caps. That seems large for 4.7n. Took a quick look in Tayda and didn't see any in that size format.

It does seem quite large for what it is, but I'm pretty sure it's a 4700p cap. Also, I don't think it would explain why the collector values mentioned above would be so low, which seems like would be the major problem to fix currently.

Here's a better shot of the side of the cap

 

[KR Sound]

47(3)= 47,000

That last number tells you how many zeros follow.

 

[Erik S]

It does seem quite large for what it is, but I'm pretty sure it's a 4700p cap. Also, I don't think it would explain why the collector values mentioned above would be so low, which seems like would be the major problem to fix currently.

Here's a better shot of the side of the cap

Yup. Looks good to me. Just a chunky boi I guess.

 

[Coda]

Yup. Looks good to me. Just a chunky boi I guess.

= more/better tone…

 

[punchy712]

47(3)= 47,000

That last number tells you how many zeros follow.

Thank you for the explanation, I honestly didn't know how to read it (always just used an online calculator).

I assume you're referring to the Panasonic cap, which is indeed 47n. I was referring to the WIMA behind it, labelled 4700/63 and I thought this meant 4700p (4.7n) and 63V. I'll gladly be wrong though as that would be an easy fix.

 

[KR Sound]

Thank you for the explanation, I honestly didn't know how to read it (always just used an online calculator).

I assume you're referring to the Panasonic cap, which is indeed 47n. I was referring to the WIMA behind it, labelled 4700/63 and I thought this meant 4700p (4.7n) and 63V. I'll gladly be wrong though as that would be an easy fix.

Gotcha. You are correct on the Wima.

 

[punchy712]

I couldn't find anything wrong with my circuit yet, but of course that doesn't mean there isn't so I'll keep looking.

Out of curiosity I wanted to simulate the circuit and see what voltage values to expect so I drew it in LTSpice and the collector values for the transistors are low as well (around 0.8V) so I'm not really sure what is going wrong.

 

[VanWhy]

My build is doing pretty much the same thing. I also thought it didn't sound right since I did own a death bloom and it didn't sound like that. I just kind of put it on the shelf to be re-evaluated at some point. I'll dig it up this weekend and dig into it.

 

[punchy712]

My build is doing pretty much the same thing. I also thought it didn't sound right since I did own a death bloom and it didn't sound like that. I just kind of put it on the shelf to be re-evaluated at some point. I'll dig it up this weekend and dig into it.

If you could, that would be very much appreciated.

 

[comradehoser]

Seconded.

Did enjoy the Algal Bloom/Pleco, but found the Death Cap/Doom Bloom pretty uninteresting.