Diodes for metal ?

[Krinor]

Which diodes will produce the best clipping for a metal type distortion ?
How about zener diodes... Or am I better off using the ordinary silicone ones ? Any thoughts ?

[GibsonGM]

My thoughts are Germanium.  I've seen them used in the DOD Super Metal Pedal.  They'll clip earlier than others, giving maximum distortion.  I think the rest is up to how much you boost pre and post clippers, and what's up with the tone stack.  Obviously mid scoop is desired, so maybe try something that distorts using Ge diodes and play with an EQ pedal after it to see what areas sound best to you....

[Krinor]

Thanks for sharing your thoughts on this.
I've been playing around with a Dist+ circuit for a while. So far the best result I've come to was using three germs in an asymetrical setup. I just wonder how zeners will sound since I don't have any at hand right now...

[raulgrell]

I'm more curious about schottky's (or something like that) than Zeners.
Maybe an older member can she some light on this...

[bumblebee]

i use 6 silicon diodes  in my dist+ (3 in series each) and its pretty good, also lower the 4k7 resistor to 2k2 or just mess with various values. it helps a fair bit.

i imagine germanium may be a little better and plan on trying it myself.

[GibsonGM]

The only issue I'd have with other diodes is the Vf, where they start to clip.  You'd have to really crank it up (to the zener voltage, actually), if you used those.    You want low Vf for more fuzz, early clipping, so Ge's only make sense.  Are some Schottky's lower turn-on than Ge's, tho?  They might serve better. 

[Krinor]

i use 6 silicon diodes  in my dist+ (3 in series each) and its pretty good, also lower the 4k7 resistor to 2k2 or just mess with various values. it helps a fair bit.

i imagine germanium may be a little better and plan on trying it myself.

I changed the 4k7 resistor to 3k9. Sounds good. And I also changed the 0.047uF capacitor to 0.068uF. This was said to give better low end.

The only issue I'd have with other diodes is the Vf, where they start to clip.  You'd have to really crank it up (to the zener voltage, actually), if you used those.    You want low Vf for more fuzz, early clipping, so Ge's only make sense.  Are some Schottky's lower turn-on than Ge's, tho?  They might serve better. 

Well... The Ge's have a somewhat higer Vf than the silicone ones, isn't that so ? They just sund so much better (IMO)... Maybe it's because of the subtle addition of hiss that is actually somewhat pleasing ?

[GibsonGM]

Yeah, the Ge's are fuzzier, they're pretty cool )  Vf is just the forward voltage of the diode....how much voltage it takes to turn it on.    A typical Ge might have a Vf of .25 v, and a typical Si is about .7.    So, you start 'fuzzing' faster with a Ge; but get a lower output from the clipping section - you can always add a boost section after that, tho.   I was wondering if you could find a schottky that would turn on even sooner!   

[bumblebee]

I changed the 4k7 resistor to 3k9. Sounds good. And I also changed the 0.047uF capacitor to 0.068uF. This was said to give better low end.

maybe try 2k2 and .1uF, its nice and thick...
also, i have a LPB with a MPSA13 wired before the dist+ which helps a huge amount with sustain.
i gotta get back into this project myself and etch a PCB for the LBP/dist+ combo circuit.

[Krinor]

Cool idea.

I've got an unused LPB pcb lying around somewhere myself. Guess I'll try that too. Would be nice to put a switch between them also.

Concernng the .1uF ; Won't that make it more grumpy ? I find my Dist+ nice and dark as is. Actually it would be nice to put some caps on a switch for that one too... Sort of "Lo - Hi" kind of thing.

[bumblebee]

well my fav fuzz is a woolly mammoth so all my other fuzzez need to be similar to satisfy me.
i dont own a fuzz thats not modified for more bass, i just prefer it, but i hate mud so i always get as close to it as i can without actually being muddy. the .1uF is very very close to mud.
but if your happy, leave it, its your opinion that counts man!

[Krinor]

Ha ha I see. 
Well, I always thought of the Dist+ as a more 80's sounding razorsharp kind of thing. But I never seem to get close to that with this replica of mine. Actually what I (have just come up with that I) want to do is to have as much nice and fat distortion as possible with as little mid frequuncies as possible. Is there anything I can tweak to get there with this circuit ?

[petemoore]

Well, I always thought of the Dist+ as a more 80's sounding razorsharp kind of thing.
  Used for 80's type stuff for sure, 'razorsharp' would be depending on whats going into it what it's going in to.
But I never seem to get close to that with this replica of mine.
For the specified field, dist+'s are often thought of as a central part of a distortion 'picture', with other elements contributing to the overall 'distorted guitar' sound.
Actually what I (have just come up with that I) want to do is to have as much nice and fat distortion as possible with as little mid frequuncies as possible. Is there anything I can tweak to get there with this circuit ?
  Yupp...put a MiniBooster or boost of choice on the output, with selected tone control [see AmZ]. A Dist+ driven Mu Amp produces a more complex tone [2x distortion generation circuits], and the additional output may also be useful for driving subsequent stages.

[Krinor]

Thanks.

I've tried putting a TS and various boosters in front of it. Never thought of putting anything behind. Will try that. 

[AL]

Here's what I did with the MXR+

1) Put a 250K pot on the input
2) Hard wired the Distortion (no pot) so it's maxed - don't really need the distortion pot with the pot on the input.
3) Used 4 LED's for clipping
4) Added an AMZ presence control - thanks Jack !!   

http://www.muzique.com/lab/tone3.htm

The tone control really helped fatten things up. The MXR was too thin without it.

AL

[col]

For a more 'metally' sound I prefer LEDs or power diodes such as 1N400x. If you have a broken low power light bulb you'll find about a dozen in the base along with lots of other good stuff for free including two power transistors, just don't break the glass bit!
I have always found Ge diodes to have a more 70s sound and built a distortion circuit that changed between 6 different types of clipping diodes. All sounded different but IMO only the LEDs sounded good will all guitar and amp combinations. I also liked one I experimnted with which had one power diode and one LED. A lot of people have had good results with mixed diodes. There are no rules, experiment.
A while ago someone put a link to their dissertation on here which looked at the results of trying different diodes. Do a search, the link might still be active.

[Krinor]

 Very interesting Colin. I agree with the 70's sound of Ge's. However personally I'm not a fan of leds for clipping. At least not on my rig. Actually not on any of my amps. I can hear that there is an enormous potential in leds, but I feel that they need a bigger amp and loads of power and a large cabinet to sound really good. For practice amp situations and 5W class A tube amps I prefer diodes.
Actually I just threw out the leds from a Marshall Jackhammer today and replaced them with a couple of Ge's (AA119). Sounds VERY good. Heavy LA saturation with a british lilt. I noticed however that I lost a lot of volume when I replaced the leds. I have noticed before that leds tend to be pretty loud compared to diodes, so I'm guessing the manufacturer has put in some sort of levelling feature to make the transition from leds to diodes (the overdrive/distortion switch) less earcrushing?

[bumblebee]

Here's what I did with the MXR+

1) Put a 250K pot on the input
2) Hard wired the Distortion (no pot) so it's maxed - don't really need the distortion pot with the pot on the input.
3) Used 4 LED's for clipping
4) Added an AMZ presence control - thanks Jack !!   

http://www.muzique.com/lab/tone3.htm

The tone control really helped fatten things up. The MXR was too thin without it.

AL

similar to mine:
no distortion pot, hard wired
6 diodes for clipping
LPB with MPAS13 before it, hard wired on full
BMP tone stack
4k7 changed to 2k2
.1uF output cap
500k vol pot

mines not really a distortion, its a fuzz...kinda rat like but definitely a fuzz.
its a really cool pedal.