Greer Green Giant

[rocket88]

man you guys are killing me with this johns thing, you guys are just busting my balls. i think mark did something . but in case no one knows, i'm zach, the one that mark mentioned on the main site about beating me to making this layout. lol

but seriously, if you want frank i'm sure i can send you one or two NPN Ge's to try out. i should have enough to spare that many.

[Frank_NH]

Sorry about the name thing...Zach it is.

And thanks for the transistor offer, but I really need to finish some other projects before proceeding with more builds.  I have purchased a number of PCBs that I want to start building (including one for a Klon clone.  I can't call myself a true DIY pedal builder until I've built my first Klone!).  Those PCBs will be a piece of cake after building with vero.  They even have the components nicely marked and oriented on the board - hey!

[rocket88]

nice. it's all good frank. i'm just messing, i'm not upset at all. it's just funny that as soon as i mention that my name is showing up wrong, i just knew i wouldn't hear the end of it. and of course mark had to start it off.

the klon is on my list, but i have so many others on the list that i want/need to build before it. btw, if you do want a couple of transistors just let me know. i got you buddy.  just don't wait too long i may use them all, i mean i think i have like 300-500 MP38a's, and have been blamed for the reason no one can find them anymore.

[Frank_NH]

Hello all,

Some interesting information about the Electra Distortion that I didn't know and pertains to this circuit:

http://www.harpamps.com/schematics/electra.pdf

"This distortion was posted to the net by Bruce E. (?), [e-mail] on 5/14/94.  It is supposed to sound amazingly like a Tube Screamer. With the exception of the diodes, the circuit is the same as the circuit for the Electra Power Overdrive module, which was fitted inside some Electra guitars in the 70’s. It’s important to use germanium diodes to get the right sound.  Silicon is supposed to produce more power and less distortion. Ge gives 0.4 volts of signal out, Si gives 1.4 volts. The values of the collector and emitter resistors can be changed to give more or less gain and distortion. The unit is not just a hard diode clipper, as the diodes load the output of the transistor and modify its gain as they turn on, giving softer clipping than you would expect."

So...using germanium transistors and diodes appears to be the way to go here.  Let me know if someone completes this build - love to know how it sounds.  My current 2n3904 unmodded version is OK but nothing remarkable.

[Beaker]

Frank_NH wrote

So...using germanium transistors and diodes appears to be the way to go here.  Let me know if someone completes this build - love to know how it sounds.  My current 2n3904 unmodded version is OK but nothing remarkable.

I've built it already:

 first "stock" with 2N3904 silicon transistor and 1N4148silicon diodes. Sounded good - 6/10.

Swapped the transistor for a MP38 Germanium. Sounded better - 7/10.

Swapped the diodes for D9k Germanium. Sounded fantastic - 10/10.

Swapped the transistor back to 3904, but kept the germ diodes. Not quite so good - 9/10.

In my opinion, don't worry too much about the transistor, (I tried loads of other silicon alternatives before swapping it to a Germanium - they all sounded good), it's the Germanium diodes that hit the jackpot with this one. Which ties in with what that article says.

Soundwise it nails that "just starting to break up" stinging tone tone that I love, but find hard to get at sensible volume, as my amp is master volume only. It colours the tone slightly, but in a good way, and I find I don't need the tone control - I tried it, then took it back off. KISS is my motto at the best of times, but this circuit is so simple and elegant, it seems a shame to me to add any complexity at all to it.

[Frank_NH]

Thanks for the report Beaker!  Great info.

Just to clarify - did you build a PNP version (hence the use of a 2n3906)?  I may just rebuild this with sockets just to check out some Russian Ge diodes I have (D9Es).

[Beaker]

No Frank, my bad,  double typo.

It was not PNP , I used 2n3904, so used what was suggested on the layout. (I'll edit my post to avoid confusing anyone else too).

If you have D9E's then stick a couple of those in. I guarantee you a big improvement. I only have a couple of D9E's left as I only bought 20, so used the first of a new batch of D9K's in this. I socketed them to do a sound comparison between the D9E, D9K, and a bunch of silicon ones.

The D9's won hands down - the difference between the two (E and K) was miniscule to my ears.

[Beaker]

Ok guys, not sure the best place to put this, so put it here anyway.

I realise that this is something of a collaborative effort, with valuable input from several contributors, and so with many thanks to all of you involved, I give you;


THE GERMANIUM GIANT.

First, the outside.





Then, the insides.




Close up of the board. Erm, upside down to layout, sorry.


I worked from Mark's layout, as I had the board finished before Zach (Rocket88) put up his own version.

Changes to original spec. listing are as follows:

#1. 25k Mix pot changed to a 20k - simply because my pot dealer only has 20k's. I don't think it makes any major difference.

#2. 2N3904 transistor changed to a MP38 germanium.

#3. 1N4148 diodes changed to D9K germanium.

#4. 680R resistor changed to 1k. This removed any hint of distortion when turned to minimum mix.

#5. The 100nF cap between input and base changed to 470nF. This prevented any loss of bottom end from my signal. With 100nF, a bass cut was very noticeable. Doing this negates the need for a tone control, as the effect tone compared to the bypass tone is to my ears a least, now identical.


I honestly can't believe that such a simple circuit can possibly sound so good, so thanks again to everybody - you ROCK!

Mark.

[Frank_NH]

I love it Beaker - great job.  Those graphics are awesome.

This project is a good example of what I like about DIY pedal building - take a good circuit and make it great (and unique) though experimentation, collaboration, and knowledge sharing.  Thanks all.

[Beaker]

Thanks Frank. It's just sprayed military green with a red star sprayed on top (it's actually red undercoat), using a cardboard stencil that I cut to size.

The lettering is with a Brother P-Touch using a free "wonky typewriter" font called Special Elite.

[Silver Blues]

Beaker wrote

simply because my pot dealer only has 20k's.

Seriously though it looks really good.

[rocket88]

agreed. looks awesome

[Mike B.]

Hey, Beaker. Your pedal looks great! With the germanium transistors and diodes, how loud does it get? Can you get much of a boost or is it pretty close to unity with the volume maxed?

[Beaker]

Thanks for the compliment. I have absolutely no artistic ability whatsoever, so I just stick to dead simple.
The label printer is a godsend to me, as my lettering is just plain embarrasing without it.

Volume boost? Depends on how it is set. The mix control adds clean signal to the overdiven tone (effectively diverts increasing amounts of signal away from the diodes), so the volume increases the cleaner it gets.

Full CCW on the "Mix" knob (max overdrive / min clean signal), there is a slight volume boost. You will need to turn up the volume knob to around 3 o'clock for unity.

Full Cw on the "Mix" knob (min overdrive / max clean signal), there is a huge volume boost. you will need to turn the volume knob down to around 9 o'clock for unity.

This pedal really reacts well to your guitar's volume knob, and is very sensitive to the power of your pickups.
With low power lipstick tube pickups, I can get a lovely subtle just breaking up sting out of it. With P90's, it roars at the same pedal settings.

[rocket88]

i've been looking at the layouts with the switchable diodes, and think i did something stupid, so someone please correct me if i'm wrong. the way the diodes are placed on the switch will NOT cause the same kind of clipping in the original circuit, because the diodes don't go to ground, which causes hard clipping. the way they're wired would cause soft clipping because the audio signal has to pass through them on the way to the clean pot.

now if i'm correct in my thoughts, how should i have wired the switch to allow the choice of diodes going to ground, creating 2 different versions of the original? i think i see how, but i don't want wires in the middle of the board....

the reason i thought about this is because i'm putting together a layout for a peppermill with switchable diodes on the output, and this is a daughterboard, and i have the same issue. how to make it hard clipping and have everything connected correctly.

[Heath]

Z-Dude, I had no intention of building a Green Giant (already built the Sucker Punch and Ghetto Stomp and am just swimming in ODs and Distortion pedals) but now... yeah, I gots'ta build me a Germanium Giant.

[Surgeon]

rocket88 wrote

i've been looking at the layouts with the switchable diodes, and think i did something stupid, so someone please correct me if i'm wrong. the way the diodes are placed on the switch will NOT cause the same kind of clipping in the original circuit, because the diodes don't go to ground, which causes hard clipping. the way they're wired would cause soft clipping because the audio signal has to pass through them on the way to the clean pot.

now if i'm correct in my thoughts, how should i have wired the switch to allow the choice of diodes going to ground, creating 2 different versions of the original? i think i see how, but i don't want wires in the middle of the board....

the reason i thought about this is because i'm putting together a layout for a peppermill with switchable diodes on the output, and this is a daughterboard, and i have the same issue. how to make it hard clipping and have everything connected correctly.

If it were me, I'd simply take your Ge Giant layout (w/o the diode switching), remove the two diodes and send a wire from the top hole of one of the diodes to the center pole of a DPDT, have both antiparallell pairs on each sides, then take the opposite center-pole back to the lower-hole of one of the diodes. It won't be elegant (such as having the wires on the sides of the board) but it will work nicely still.

[rocket88]

yea, that's what i figured when i was looking at it the other day, but i was trying to keep it so that there's not any wires in the middle of the board, it doesn't seem that neat. i think i've been trying to model my layouts from what i've seen mark and miro do. lol. so i keep trying to get them as small as possible and neat as possible.

but you're right, that would keep the diodes in the original orientation as they are in the circuit, plus the layout gets 1 column smaller.

side note, i just built mine, but currently testing different diodes. i tried the D9K like beaker, but i don't know if those are what i'm going to go with yet, still need more testing. i used my layout with the 5k trimmer. the changes i made were
1 - both caps, input and output, to 470nF
2 - MP38A 66hfe, trimmer adjusted by ear to where i thought it sounded best and had the most volume.
3 - used 20k instead of 25k, because i didn't have knurled 25k pots.

couple comments though:
1 - for mine when the clean knob is at full CCW, so all the signal going through the diodes, there is a lot of volume loss with Ge diodes. still has more output then bypassed signal, but noticeable difference.
2 - sounds freaking awesome on bass when its mostly clean, with a hint of grit. beaker is right it gives it some growl with Ge's.
3 - tiny circuit, HUGE sound and personality. definitely a must build for someone looking to add a little something to their signal, and if you go full CCW you still get a little clean signal so it retains some clarity.
4 - experiment with diodes to get the sound you want. if you're using D9 diodes you can here differences in each type, at least i could. i could hear how some have more treble, or break up later, or breakup more when you dig in and be cleaner if you play lightly. the diodes can change the personality of this effect.

side note: if you build this and have some 1D507A diodes, i got some from our favorite bulgarian seller, they were part of my gift, they sound monstrous. thick and creamy distortion. they are moving up my list of my favorite diodes. plus i checked to see how much they normally go for on ebay, and they're cheap. you might want to check them out.....

[Beaker]

(Strokes chin)- verrry interesting. I am going to have to build another with the trimmer.

Try the D310 or D311 diodes in it - I had to add a couple of columns as they are so huge. They sound lush too.

Totally agree with your point 3. in term of character to size, it's off the chart.

BTW, just got a load of Motorola 2n2222 from Great Uncle Bulgaria, I just love these in Superfuzzes.

[Surgeon]

One moretiny point. Your pnp layouts say 21x6 and 20x6...however, it's 7 rows, not 6. I must be the only dumbass who cut his vero without counting but I thought I'd point it out nonetheless..