Zonk machine mk1

[pauldumbell]

Hey all,
I posted a few days ago about a tonebender pcb, and decided to build the zonk machine instead...this is a super finicky circuit. I am getting fuzz, but my god the sputtery decay starts almost immediately. I used this schematic

http://fuzzcentral.ssguitar.com/schematics/zonkIschem.gif

with this pcb
http://fuzzcentral.ssguitar.com/pcbs/zonkpcb.gif

and this layout
http://fuzzcentral.ssguitar.com/pcbs/zonklayout.gif

some things i changed.

i used .047uf instead of .47uf and a 33k instead of a 3.3k the 33 k really helped a lot, but its still very spitty, and ive rotated about a dozen various germaniuum transistors around which has varying degrees of improvement on the level of fuzz, but then of course, more noise, which is fine. My question is this. Is this simply the nature of this pedal? I watched some youtube demos of it, and Im pretty sure it is not.  Are there some resistors I should pull up or down to get the sputter outta the house? Or is this an exercise in futility?
Thanks all
PAul

[Arcane Analog]

Have you read the recent MKI threads? That would be a good start.

[pauldumbell]

Yes sir I have, and I have been applying many of the suggested tips on my build, But no adjustment of voltages on q2 or q3 has relieved the spittyness problem. Maybe my problem has its root elsewhere in the build.
cheers
paul

[Arcane Analog]

As I mentioned abundantly in the other threads, adjusting voltages will not always guarantee you a good sounding pedal. You can adjust the voltages until you drive yourself crazy and it still might not help any. 'Experts' might suggest trimmers but in my experience nothing short of swapping transistor combinations until you are satisfied will guarantee you a good sounding build without the crappy noise and artifacting on the decay. The MKI/Zonk is a picky beast and it will only accept the certain germanium devices. Even devices of the same type and brand with the same HFE and leakage will sound and behave differently. Keep swapping and try different brands/types. You need a solid amount of germanium to build these circuits.

For noise issues, using sheilded cable will help out as well.

[pinkjimiphoton]

+1

voltages, resistances, all that is hooey. you can have everything right, and it may sound like poo.

swap the transistors around seems to me to be the best way to get the tone. yes, some things you can just plug anything in, but all too often with fuzz, you'll only be happy if ya use your ears.

[Arcane Analog]

This circuit is one that I do not find a massive difference in tone with different transistors. However, I do prefer AC125s and OC75s as they seem to handle the MKI and give you the best chance of a successful build.

[pauldumbell]

I  tried 2n1307 the nte102a. no dice on either. I might abandon this one. I only wanted to use up some of the germanium transistors that I had laying around. Apparently none of the dozen or so that I have laying about are suitable for this application. pretty annoying really.

[pauldumbell]

can anyone suggest a decent 3 ge transistor fuzz that is less picky?

[Arcane Analog]

What are the HFE and leakage for each device?

[pauldumbell]

Ok, here is what i opted to do. i swapped all the zonk schematic values for the tonebender values and VOILA, it works. the input cap is a bit weird though. The zonk called for a .001uf and the tonebender for a .01uf. the .001 sounds fizzy, and the .01 is so bassy making my low notes pop and even cut out, put a .0068 sprague in there and it sounds pretty damn good now. Didnt measure voltages. Just going by what my ringing ears say. glad i didnt give up!

[Arcane Analog]

Nice. The boomy input cap is pretty typical for the MKI.

[pauldumbell]

A little update. I scored a ton of old stock transistors and I put in general electric 2n1305's in. with these hfes
q1 53
q2 126
q3 98

everything else to stock original values.
it kills now. sounds EXACTLY as it should.
Cheers

[Arcane Analog]

All without trimmers everywhere!

Enjoy!

[fuzzymuff]

A little update. I scored a ton of old stock transistors and I put in general electric 2n1305's in. with these hfes
q1 53
q2 126
q3 98

everything else to stock original values.
it kills now. sounds EXACTLY as it should.
Cheers

That's GREAT.  You would post a demo/sample?

[pauldumbell]

Ok, yet another update. I jumped the gun on saying I had this circuit working. I apparently had a mini bridge which in essence made one hell of a fuzz box, but NOT a tonebender. when said bridge was removed, plunky farty sounds galore. after much thought and experimenting I tried a wide variety of pnp germaniums, so many different ones that I cant even say WHAT I used. This circuit loves leaky transistors, but the more leakage you have the more noise you have. Im using a peak transistor tester to measure hfe and leakage( it giives the leakage in mA, and with 1.13mA of leakage the fuzz is great but the noise is outta control), and the 2n1305 is a rather stable transistor for a germanium. not much leakage at all...so not really a good candidate for the mk1 in any case. Im sticking by the hfe posted earlier in this thread, but looking for more leakage. Still experimenting on it to get the ultimate punch in the gut. Shame about the 1305s not being the hit , but Im sure I can make something with them.
more later!
Paul

[pauldumbell]

yet another update. I breadboarded this, which I should have done from the get go, and Im getting a pretty good sound out of the 2n1305 ransistors. apparently my transitor sockets that I made out of ic sockets sucked. pretty embarrassing really. when I get the ultimate tone from this, Ill post measurements.

[newperson]

Hi,
Why not travel down the different road with the bridge?  Map out the schematic and see where that takes you instead of making the MK1?  Seemed like you was really happy there for a min.

I jumped the gun on saying I had this circuit working. I apparently had a mini bridge which in essence made one hell of a fuzz box, but NOT a tonebender. when said bridge was removed