Greer Green Giant

[Beaker]

Paul, Zach is correct - the layout with the tone control needs further work.

If I were you I would build the Mark1 version, and socket the 680r resistor, diodes and caps, or the Mark2 version with the trimmer, and socket the same. (Obviously you will be using a MP38 transistor and Ge diodes, rather than the specified silicons shown on the layouts.)

That way you can have a good play around with different diodes, and cap values - bear in mind we upped the caps to 470nF to prevent bass loss. You might prefer different values with your guitar/amp setup.

[rocket88]

Oop. Stupid me. Yea I ment to say series, but typed parallel. I have no idea why I typed that. Too much studying for me. Been spending all my time studying the skull, and I think I've finally lost it.

This is what happened at 1am last night while studying.

I call him agent Johnson. At this point in the night he was angry that I wasn't letting him listen to my music, so I let him use my headphones for a bit. Turns out he's a big Motörhead and Sword fan.

It got worse as the night went on.

[Beaker]

He looks familiar!



One of my favourite albums.

[Chris60601]

No no no Rockett, that's what happens when you listen to Leif Garret at 1:00 am

[knight_yyz]

I, same as Paul would like to attempt this pedal.  It was suggested to try the Mark 1 or Mark2,  but none of the schematics are marked as such.  I'd like to attempt one of the germanium schematics, but which one?  

[Travis]

Do you have NPN or PNP Ge?

[Luke51411]

I built up a green giant with trimmer and germ tranny and diodes and it sounds great! I thought this would  be a fun MOJO build and I have some eyelet board and eyelets I'm wanting to experiment with so I made a layout for that. This is my first layout and I've just drawn it by hand (Hopefully I didn't miss anything this should be a simple enough version) I made two versions, one is 5 across and one is more compact at 4 across. Let me know what you think and point out any errors I've made. Thanks. Also, there is no trimmer on this but I plan on omitting the 680 ohm resistor for testing and alligator clipping in a pot to dial in desirable biasing and then installing the nearest value resistor.

I'm thinking I'll build the first version but add series polarity protection with a 1n5817 between the top left corner and bottom left corner. If anyone wants to make a diylc version of this layout, go for it.

[knight_yyz]

I have no germaniums yet.  That's why I am asking which is mark 1 and which is mark 2.  The schematics are not named that way

[motterpaul]

I have to agree that it would be nice if someone just pointed out which build is the official Germanium Giant. I am pretty sure it is the second one named "Germanium Giant" with the trimpot, but I am not entirely sure.

I think this build needs its own thread - and also a demo. Rocket, - I would put up a demo for you (I have built this three or four times now in different versions) but I did not want to presume to "represent" your build. You are the "Master of the Ge Giant" so you should be the one making the demo.

By the way - Knight - I could be wrong but I am going to take a stab and just say that if you want to hear this build made with silicon trannys, then just built the Greer Green Giant. That's all the Germanium Giant appears to be (as far as I can tell) is the Greer with NPN Germanium transistors  substituted for the original silicon trannies (plus a trimpot to help to bias the Ges, though the trim didn't do much for me, as I recall I had it on full). The one with the tone pot is still a work in progress AFAIK.

Some of us tried building power inverters to hear the circuit with PNP Ge trannys, but it isn't quite the same. I now have 50 NPN Ge trannies with nothing else to use them for  just because I wanted to hear this thing. Suggestions happily accepted.

If I am wrong about any details - I apologize, but this is what I have perceived based on the information here, and if I am wrong, then putting up just the correct information in a new thread would be a service to the entire community here, including me.

[Silver Blues]

There was never an "official" germanium giant build but the below layout with germanium transistors and diodes is accepted as the working version.


Paul - go ahead and do the demo if you want. Literally no one will be offended if you do so and it would be much appreciated if you did.

If you want to hear it done with silicon transistors, either the very first layout of this thread or the layout I've copied above will work for you. Just substitute the appropriate components. The "germanium giant" is the original Green Giant with all semiconductors, that is transistor and diodes, swapped for germanium. Yes, anything here with a tone pot is a work in progress.

The circuit sounds fine with PNP transistors, you just need to find the right ones. I've tried a number of PNP germaniums and found at least two that sounded really good. The consensus is that the MP38 (an NPN device) is the "default" device for the 'Germanium Giant'. Personally I found the best sounding device I tried was a PNP, and my layout should work fine as one with an inverter as well. I will also reiterate that you should avoid the AC125 in this circuit. This is not to say avoid all PNP transistors, but avoid this one in particular.

EDIT cleaned.

[rocket88]

there is no official version of the germanium giant, so both the NPN and PNP versions are fine as long as you use the RIGHT transistors for the circuit and it's biased correctly. the circuit is a simply electra distortion, but instead of having the diodes always in the circuit 100% they are placed inline with a pot so you can control how much signal passes through the diodes. this gives you control of how much distortion you get, because as you play with the pot you'll get some level of clean tone and some distorted.

this and the nick greer pedal are topographically the same, but sound completely different. the effect with Si transistors and Si diodes, will NOT sound like the effect with Ge transistors and Ge diodes. so making one with Si will not give you and indication of how the effect should sound.

there really can't be a good demo for this as what transistor and diodes you use will complete change the effect. this is why if you read earlier in the thread someone asked what is everyone using, and there weren't any two that were the same.

if you're looking at building this what i suggest is following the notes on the NPN layout. relabeled and reposted below



you're going to want MP38's with hfe 50 and up, i suggest MP38a's as for me they're been more consistent with gains but they are fundamentally the same transistor, and some selection of Ge diodes. put sockets in for the diodes and swap until you get something you like. the diodes listed in the notes are based on the first build of this and beakers first experiment with diodes. the trimmer will allow you to dial in the bias for the exact transistor you're using.

again, whatever transistor and diode you use will have a massive effect on this. MP38's are known to be on the darker side, if you use a tesla 104NU71 it will sound much brighter.

[Silver Blues]

I don't know, I think some sort of demo might be good. Even though you are correct in that everyone will use a different combination of semiconductors, it would be beneficial for some people to have a  general idea of the tone. I've seen the MP38/38A plus D9D combo mentioned a few times, maybe do a demo with that?

[rocket88]

I'm not saying it would be useless, just saying that's why there isn't any. I think beakers has d311's or d310's now. Mine has also changed diodes like 8 times. Lol

I'll gladly do one, I have to anyways. It's just going to take a bit of time, cause I have no time now to build or anything really.

[clockman]

@ silver blues- I will second that. there are currently 111 posts and 3600+ views on this particular post. there is indeed interest.  Just sayin'.
Demo anyone? shootout with different combinations of parts?

[Silver Blues]

Lol yeah fair enough. We should just have a bunch of people contribute clips of their builds and edit them into one video or sound clip!  Get like a guitar battle thing going on

[Beaker]

Well I have just got back from my holiday to Iceland. I made the very long trip up to Flateyri in the Westfjords to pay Geiri a visit, and take him my first Germanium Giant build for his fathers museum.

He is a really nice guy, and his workshop is impressive to say the least. Lots of new designs in pre-production, and he told me he has a stand at Winter NAMM, so if anyone is going to that, call in and see him.

He also has a box of ten thousand (!) D9E diodes, so Zach we can't blame you for hording all the best components now!

[rocket88]

see!!!! i told you it wasn't all me!!! lol

[Travis]

Cool. I live close to where they hold winter NAMM, so I'll have to hit Geiri up

[traktop]

I'm building this circuit for a friend's son as a birthday "first pedal" gift:

It's a so simple circuit to build, but there is one thing. The cut under the 2m2 resistor makes me wonder if I'm missing something here...
Cheers, Gilberto

[rocket88]

You're not missing anything. It's probably left over from when I was moving everything around and didn't realize it was still there. Lol