Greer Green Giant

[Beaker]

MP38 and D9K in mine, MP38 and D311 in my sons.

[kirshman]

I was just going to ask people favorite combos today.  I've got some mp38's coming.  Super excited for this one!

[rocket88]

I've been thinking about the low output issue with the diodes fully engaged, and may have a way to solve it. I was thinking about this as my kids were taking a standardized test a little bit ago and drew this up.



The idea is simple. If we want to keep the vibe of the original, why not just have the germanium giant infront of a second that is missing the clipping diodes. If we loose the original volume and just make it a fix 100k resistor, we'll be at full output going into what is essentially a gain recovery that has the volume control at the end. With the fixed resistor there shouldn't be enough output to cause the second stage to distort, and without the diodes the elektra has massive boost.

My other idea is what about raising the value of the volume pot. If the level is raise less signal should be allowed to go to ground, thereby providing more output. I could be wrong though.

[Neil mcNasty]

Congratulations with such a sweet tweak. It sounds really nice.
I tried it today with a lot of other germs, but the MP38 sounds best, no doubt. The other ones becomes quite thin and can not retain the bottom end as good as the MP38.
I just made a 2 stage version of this on my breadboard, almost as you suggested, but I have not fired it up yet...
What I've done is to use a 1K from Emitter to ground of Q1 and removed the diode clipping, then the rest is almost as usual, except for the Bias (offboard) that I changed to a 1K with a 220R resistor to ground.
I also added a "Range" pot at the input ala the Red Rooster. That should give it quite a nice specter of tones I hope...

Honestly I would say that this circuit sounds way much better without the diode clipping (or with a 1-10K to ground, preventing full clipping), and rather push it into saturation/distortion trough the Transistor. Much more dynamic and open sounding.
But then I have to mention that I have developed a hate relationship to hard diode clipping...
I simply just hate a compressed signals and that harsh edgy sound you sometimes get out of it, unless you add a 1-10nf cap in parallel in order to remove clipping from the top end of the signal. For me dynamics are essential to a good pedal, and hard diode clipping destroys that...
You can probably tell from that comment that I am not a metal-head, or have a lot of distortion pedals on my board (boosters & fuzz does the job for me...) but that's a matter of taste and setup...

Anyway: Thanks for your wonderful contribution! It's been a long time since something like this has generated such a great enthusiasm amongst this crowd... Great Job! This circuit should absolutely be experimented on further (centered around thew MP38 of course)
 I know I certainly will...

[rocket88]

nice, can't wait to hear how the 2 stage one works out. it was just something that came into my mind, and i quickly drew something out. hence the lack of values. can't wait to hear the values and such for it man.

[Neil mcNasty]

After experimenting with a 2-stage version as suggested, I noticed that 2 MP38's did not yield much of a difference. So I ended up putting a 104NU71 in Q2 position in order to get some crunch out of it (love those Tesla Germs)

[rocket88]

first off this sound fucking awesome and i'm going to have to give it a shot, and am going to have to grab some of those Tesla's. second, i'm touched at the idea of having this named after me, it's just one of my ridiculous ideas that somehow works out. just glad that it's something good and others can make use of it.

[Neil mcNasty]

A slight note on the Tesla's:
They do not retain the bottom end the same way that the MP38's do, which are very heavy in the bottom and not very bright. The Tesla's might be slightly bright for some, but since I use the Humbucker at Neck position of my Tele Custom a lot, it help clear out some mud.
I guess many different transistors will work magic as Q2, so stick whatever NPN Germanium you got in there and check out how it sounds.
One thing I have learned, is not to pay too much attention to part numbers when it comes to transistors. Most stuff works as long as you get the pins correct, and you also might discover some new favorite transistors...

After I boxed the Germanium Giant and played around with it today, I've actually dialed the diodes back in a bit (assuming about 7-10K resistance on the pot) as it gives it slightly more grit before compressing too much (for my taste)
I now use your Germanium Giant with single coil in Bridge position to fatten it up a bit with some crunch, and my version for the Neck Humbucker to clear out some excessive bottom end.

Seems like both of them will stay on my board, so re-boxing them in one enclosure seems like a good idea. I'm gonna call your version "Germanium Rocket". No Doubt!
I also have to mention that I am very glad someone brought back some attention to the Electra in a different way than we have seen before, instead of Lovepedal's constant recycling of the circuit.
Therefore I think it deserves a name with a reference to you and your contribution to this lovely community!

My version is more like a Preamp/Booster than a overdrive, specially with low gain pickups. But with a high output humbucker it starts to growl more like an overdrive. I'll call that one the "Nasty 88 Preamp".
But I'm not finished with it yet... This invites further experimentation. I have a feeling that there is a lot more variations to get out of what you have started here...

Your experiment is a very good example of how it pays off to play around with circuits, no matter how inexperienced we feel, or how simple our ideas are.
This is the way I have ended up with many of my favorite pedals, and sometimes even the fact that I made a mistake has given me some of my most pleasant surprises.
One instance specially comes to my attention: I was building a Rangemaster (PNP version) on my breadboard and by accident put the electrolytic coming from the Emitter to +9v instead of Ground. WOW!!! This resulted in 18v range and a lot more output and clarity. A highly recommended experiment and something I often try out when working with Positive Ground circuits. So far the Rangemaster has been the most successful in this matter.

Cheers to everyone that has been contributing to this forum. I am proud to be a part of such a friendly and playful community. Most of the stuff I have learned has come from this site. THANKS!

[iggy]

Wow, it's been a while since I've been on here. and look at what you guys are up to. This looks killer. I'll have this on my build board as soon as I get a chance. Germanium Giant. Love it. And Sorry John. I think I've been calling you Zack all this time. My apologies. :giggle

Great work guys.

[alex.s]

I was doodling as well today and thought about trying the circuit with PNP Ge's for NPN daisy chaining...

Any idea if this would work?

[kirshman]

Hey guys, just finished this thing.  What a great pedal.  i tried, d18,d9e, d9k, sfd106, and 1n270, before i picked the d9k so far.  I am still waiting for my d311s to get here before soldering though.  I was wondering if any of you who were involved in making this thing ever posted a demo?  It would be awesome to hear the tone that first sold you on it!

[iggy]

Hey Rockett,

 I've been playing with your layout. and i have a couple questions for you. What did you end up biasing the tranny at in your build? I've been playing with that setting, but the bias adjust with that 5 k seems very limited on my build.

and do you get a even change from clean to dirt with yours. I seem to be getting mostly clean then a massive change at the end of the pot. and also a huge drop in volume. Have I messed up something? it's got some nice sounds but mainly as a clean boost or full on drive.

cool project. thanks for working on this.

[rocket88]

i'll have to check to see how mine is biased, but the transistor did bias with a 5k trimmer no issue. the pot is kinda like that, but it's not like completely clean for the majority of the way then suddenly massive clipping, it'd definitely a slow incorportation of the diodes but it does get dirtier quicker at the upper end of the pot.

you will have a huge volume drop with the diodes fully engaged. it should be like a hair over unity when you have the diodes fully engaged. remember the diodes send signal to ground at the output of the circuit, without a gain recovery stage at the end. think of it like changing clipping diodes from Si to Ge, you'll loose output. it's just the nature of the beast.

[iggy]

Thanks for the quick reply. It does sound good as a boost and loud. and as at the full dirt end. But i think i've messed something else up in the middle. I'll give it another another build.

[rocket88]

anytime buddy. it's also, not like you don't have my email . what transistor are you using?

[eldredracing]

I have the exact same problem using multiple MP38As (hfe ~60).  The trimmer needs to be maxed out to get near unity volume when diodes are fully engaged.  Once the clean knob is barely rotated from fully CCW, the volume jumps up.  

I'll change out the trimmer and / or rebuild soon to test.

[rocket88]

that's not an issue with the trimmer, it's due to the clipping diodes on the output. what you can do is double up on them, you'll get the same tone and distortion, but more output since you'll have a higher Vf. this is one of the reasons that you'll get more output from using Si diodes or LEDs for clippers.

[Silver Blues]

That pot response seems like something that could be remedied with an antilog taper pot.

[iggy]

i thought to try a 25kC pot. But didn't have one in stock. I think there's a different issue thats more of a problem with my build. It goes from clean boost to a cleanish boost with an annoying buzzy type of distortion in the background. then full on overdrive. Both ends sound good, it's just all the mess in between that I'm not happy with. Think I'll build a new board. I probably messed something up. Way to many parts to keep it all straight. LOL.

Anyone record any samples from this circuit? I have high hopes for this one. It's all about the GE for me.

 I built the Green Giant with the bias trimmer version. Is that what everyone else is using?

[Neil mcNasty]

Iggy: if you do not have any C-tapered pots, I would just use a standard A-tapered (Log) and flip/reverse the wiring (move Clean 1 to lug 3)
That way you'll get the same response as a C-tapered pot, but what is now happening when dialing clockwise will now be anti-clockwise.
Since it's not a volume pot that logicly should go clockwise for louder volume, it's should not matter much which way you dial the pot to get the desired effect. The taper response becomes the main issue/desire... (at least in my world)

From your description of buzzy distortion, it sounds like you might have a bad connection somewhere, or it could be a bad/faulty pot.
I would try re-flowing the solder and replace the pot.
If you are using stranded wire without pre-tinning them, you could also look for tiny strands of wire that touches components on the top side of your board...