SOLVED Marigold fuzz weirdness

[JHKcustoms]

just completed my Marigold Fuzz build and I’ve got some weirdness,

First of all my tone knob seems to work backwards, ie it’s more trebly to the left and more bassy to the right, I’m not sure if this is a thing or not but it’s odd.

The other thing is that it seems to be “ducking” kinda like a limiter when playing it,
So if I strike the strings it kinda ducks and comes back to volume wise when I let the note sustain.

I’ve got plenty of volume out of it, the fuzz pot also works normally, like I say the tone seems to operate backwards.

Been testing this on the “auditorium” test platform which by the way is so so useful!

Here’s a few gut shots

 

[PedalBuilder]

First of all my tone knob seems to work backwards, ie it’s more trebly to the left and more bassy to the right, I’m not sure if this is a thing or not but it’s odd.

This is indeed a thing. The Tone Bender Mk. III/IV family tone control is backwards compared to a Big Muff and most other drive pedals. If you want, you can swap lug 1 and lug 3 on the tone control and it will work in the opposite direction.

The other thing is that it seems to be “ducking” kinda like a limiter when playing it,
So if I strike the strings it kinda ducks and comes back to volume wise when I let the note sustain.

It’s possible that your germanium transistor might not be leaky enough. Did you measure the gain and leakage? Or the collector voltage in circuit? (It also looks like it might be counterfeit; all the OC140s that I’ve seen were glass SO-2 package devices.)

Edit: If that is a Soviet D2 or D9-type germanium diode, then you installed it backwards. On many Soviet germanium diodes the stripe marks the anode, while most other diodes use the stripe to mark the cathode.

 

[JHKcustoms]

Right on thanks,
Good to know on the tone, I thought I had really messed something up!

As for the OC140 I’m honestly not sure it was from smallbear as was the Diode.

It is indeed a Soviet D9 I was wondering if that could be flipped but I wasn’t sure and wanted to make sure before digging in and flipping it.
Here’s a better picture for confirmation of orientation.

 

[JHKcustoms]

Yep it was the diode! Instant awesome!
I’m kinda head over heels with this fuzz !
I had issues with a recent sunflower that never really got resolved so when I had issues here I was like “no more germanium transitor based fuzzes!” lol but my faith has been restored! This thing is insanely great and I would 10/10 recommend anyone build it!
Thanks for the help!!

 

[mybud]

This thing is insanely great and I would 10/10 recommend anyone build it!

Thanks for this and I hope I'm not hijacking your thread hereby but, inspired by your recommendation, I breadboarded this just now.

I couldn't agree more with your recommendation. It's certainly 'insanely great' as you say

I had to make do with substituting what's available in my parts stash, so I used (as per closeup shot below) 2N3904 for Q1, polypropylene caps (not for their inherent 'massive mojo factor' but because they fit across adjacent spaces on the breadboard unlike film caps), my last available 1N34 as the Ge diode, a 5V1 Zener (because I don't have any 4V7s), and finally a 2N1304 NPN Ge for Q3.

After sorting out a number of 'off-by-one' errors and some similar cloth-brained mistakes, it burst into life and sounds fantastic.

I'm not strictly a fuzz kind of chap, but breadboarding this took me back to my earliest forays into fuzz when I rediscovered this hobby some seven years ago now.

Big fun. Thanks again.

 

[JHKcustoms]

That’s awesome to hear!
I’m glad you had fun with it!
I’ve been wanting to bread board more and just haven’t gotten bits for it yet. I’ve been looking into the coppersound pedal bread board platforms.
I’d love to see the images from your build but for sadly they go to dead links.
Either way really fun build and I’m glad my diode misplacement lead to more good than just realizing my own mistake! lol
Cheers
-JHK

 

[mybud]

That’s awesome to hear!
I’m glad you had fun with it!
I’ve been wanting to bread board more and just haven’t gotten bits for it yet. I’ve been looking into the coppersound pedal bread board platforms.
I’d love to see the images from your build but for sadly they go to dead links.
Either way really fun build and I’m glad my diode misplacement lead to more good than just realizing my own mistake! lol
Cheers
-JHK

Thanks, JHK. I’ll see if I can edit this to fix the missing links.

Done. Please see next post.

 

[mybud]

Something went funny with the attachments in my recent post, so here’s one with the relevant pics.



Overview of Marigold breadboard.



Close up of mojo components (nudge nudge, wink wink).

 

[mybud]

Yep it was the diode! Instant awesome!
I’m kinda head over heels with this fuzz !
I had issues with a recent sunflower that never really got resolved so when I had issues here I was like “no more germanium transitor based fuzzes!” lol but my faith has been restored! This thing is insanely great and I would 10/10 recommend anyone build it!
Thanks for the help!!

If you like, you can mark the thread as solved. I believe there's a dropdown available to do this within the original post.

 

[JHKcustoms]

Oh yeah please do, I assumed it did it when I marked it on the poster that sorted it!
Thanks man

 

[mybud]

Would with pleasure but I don’t think I can because it has to be the OP. There’s a dropdown left of the heading (post title) AFAIK, where you can do this.

From @MichaelW:

The Troubleshooting forum is such an incredible resource for beginners and seasoned builders alike.
I've learned so much about pedal building and electronics in general (as a person with no electrical background except how to turn an amp on..... )

There are a number of true guru's on this forum that really put in a lot of time and effort scanning this forum to help folks out that are stuck with a problem build.

When the traffic picks up with lots of threads asking for help, it's easy for your post or question to get lost in the mix.

Please help with the "hygiene" of this forum by marking your thread as "Solved" after you're received the help you needed from these fine and super smart folks.

You can do this by going to your first original post, click on the "Edit" button. Then in the "TITLE" of the post on the left hand side there is a "Prefix" drop down menu. Select "Solved" then "Save". (see pic). This really helps with folks that still need help to get the help they need.

 

[JHKcustoms]

Got it thanks man!
Here’s the final product of my marigold build

 

[comradehoser]

Right on thanks,
Good to know on the tone, I thought I had really messed something up!

As for the OC140 I’m honestly not sure it was from smallbear as was the Diode.

It is indeed a Soviet D9 I was wondering if that could be flipped but I wasn’t sure and wanted to make sure before digging in and flipping it.
Here’s a better picture for confirmation of orientation.

Somebody once pointed out that if you have a glass diode, look at the end where the germanium pellet is--it's what the bar in the schematic symbol for diode is representing (cathode/k).

 

[Erik S]

Somebody once pointed out that if you have a glass diode, look at the end where the germanium pellet is--it's what the bar in the schematic symbol for diode is representing (cathode/k).

That is a very useful piece of information! I just wrote that on a post it note and put it in the drawer with my diodes in case I forget. Thanks!

 

[mybud]

I've been having lots of fun with this here Marigold circuit on breadboard. Have implemented all of our ever-esteemed @Chuck D. Bones' mods, checked transistor betas (settled on BC108 for Q1 @ 311, stock BC109C @ 570, and finally an AC176 @ 80). Q3 collector measures 3.19V with a 3.3V Zener, as close as I could get to Chuck's measurements below.

The mods are fun and clean the murky signal up quite a bit but there seems to be an issue with using the bass pot mod. This only kicks in about one third of the way through the pot's rotation. Would love to remedy this and will appreciate any advice on how to do so and will provide any voltage measurements necessary. TIA, folks.

Chuck's mods summarised for convenience. I bolded all my changes:

"I breadboarded mine stock to begin with. It's definitely got the characteristic raspy Tone Bender buzzsaw sound. I'm not liking the TONE control. Bass end (CW) is quite dark and the mid scoop make a dead spot with TONE at noon. I used an MP38A and a 4.7V zener, got 2.66V on Q3's collector. A 5.6V zener yields 3.08V on Q3. Also tried a 2N1308; the higher hFE required a larger base-collector resistor (330K vs 220K). I agree with your assessment of the FUZZ knob. I ended up changing mine to B100K and increased the 100Ω resistor at the bottom of the FUZZ control to 10K. Even with that change, the useful settings are above 10:00.

If you're not using the FUZZ control to vary the gain, it's easily repurposed as a variable bass cut. Remove the resistor at the bottom. Jumper the 10nF cap and install a 4.7nF cap from pin 2 to pin 3 of what used to be the FUZZ control. B100K or C100K will have a better feel than A100K. You could also try other cap values.

Next, I'll try retuning the TONE network. Dropping the 100nF to 33nF gives a flat response in the middle. 47nF gives a very slight dip at 1KHz. I don't believe that the TONE pot needs to be W20K. B20K or B25K should work well.

[FWIW I made a switchable cap change from 33n to 33n + 47n for more bass at the extreme low end].

I changed the FUZZ control as described above, ended up with C250K as the BASS pot. 4.7nF in parallel seems to be a good value. I upped the 100nF cap between Q1-C and the pot to 220nF for more bottom when BASS is dimed. As Laky says, the guitar's volume control does the same thing the old FUZZ control did, but now we have a TIGHT/SLUDGE knob to go with the FUZZ knob on the guitar. I changed the 100nF tone cap to 47nF and that made the top half of the TONE controls range less dark."