#1
I know about germanium and how it is inferior stuff for makin p/n junctions because of the leakage, but for our purposes is it just better?

I had an old script logo MXR distortion + which got stolen at one of my last gigs ever back in the mid 1990s. I went out and bought a new Dunlop one thinking that it couldn't have changed that much, but it did. It didn't sound smooth at all. It sounded "brittle". I'm sorry, but that's the best word I can think of to describe it.

Now I find out that the originals had germanium diodes in them, which allegedley gave them the smoother sound. The non-leaking, superior (from an engineering stand-point) silicon diodes they use in the Dunlops provide for a harsh tone?

And we all know about the germanium transistors used in the Dallas Arbiter Fuzz Faces.

The reason why I am asking this question is this: I have a DOD FX69 Grunge that I want to screw with, to see if I can improve the tone, and I am thinking about replacing the silicon diodes with germanium diodes. Will this have an effect, or will it be a waste of time?
Lois: How am I supposed to live in this town if I'm a social pariah?

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#2
Personally I wouldn't use germanium diodes for anything clipping related. I find them REALLY fuzzy on their own. If you use them in combination they're OK but I prefer silicon.




Oh and FWIW your source of knowledge is pretty crap: the phase 90 only uses diodes to stabilize the voltage source and is not in the signal path so wouldn't affect the tone one iota.
For sale: Early 1985 Ibanez AH10 (Allan Holdsworth signature model) PM for details
#3
Quote by power freak
Oh and FWIW your source of knowledge is pretty crap: the phase 90 only uses diodes to stabilize the voltage source and is not in the signal path so wouldn't affect the tone one iota.


I was talking about the Distortion+ and here is the drawing. I don't know where it came from, but it's the only drawing of an MXR Distortion+ I have ever seen.



You can see the verbiage in the top right. I can't vouch for the accuracy of what it says, but I can vouch for the fact that I went from owning an original scrpit logo Distortion + one week to owning the Dunlop version the next and I noticed the difference. After seeing this drawing, I presumed that it was due to the germanium diodes, but I am more than willing to admit I that I don't know what I am talking about. That's why I am asking.
Lois: How am I supposed to live in this town if I'm a social pariah?

Peter: What's that? That them little fish that eat cows?
#4
Quote by McDuffie
I was talking about the Distortion+ and here is the drawing. I don't know where it came from, but it's the only drawing of an MXR Distortion+ I have ever seen.

[snip]

You can see the verbiage in the top right. I can't vouch for the accuracy of what it says, but I can vouch for the fact that I went from owning an original scrpit logo Distortion + one week to owning the Dunlop version the next and I noticed the difference. After seeing this drawing, I presumed that it was due to the germanium diodes, but I am more than willing to admit I that I don't know what I am talking about. That's why I am asking.

Ah sorry... I don't have a clue where phase 90 came from. I guess after reading script logo it's like a reflex.

Anyways, yes they did use germaniums originally and that's what gives them that undefined fuzzy sound. Swapping the diodes will certainly change the character significantly, as they're cheap I'd reccoment buying a bag of random diodes from radioshack or something and soldering in a couple of crocodile clips to switch between them quickly. Just swap them until you find something that sounds good (none of them will damage the circuit.)

It must be said it's not necessarily the diodes changing the tone though. Sometimes they use different parts with different qualities. Also in the newer version they may have changed the type of 741 chip, this would change the tone significantly too. The older ones probably have a worse slew rate which causes the tone to be even fuzzier. Again this part is interchangable (but you can't use any old opamp.) Just go into an electronics catologue and look at the 741 replacements, the TL071 generally has a more hifi repsonse and a clearer top end but you'll lose the fuzziness and grit of the 741.

That being said on a high gain design like a grunge pedal you may not notice the changes as much as with a lower gain TS style pedal but it's still worth a go because it doesn't cost much.

For sale: Early 1985 Ibanez AH10 (Allan Holdsworth signature model) PM for details