Getting More Output: I Thought Diodes Would Do It...

[railhead]

I'm working on an overdrive based off of the Electra circuit, and I'm wanting to get a little more output volume (I'm using a 100k pot, FYI). I haven't drawn up the schematic yet, but I'm running a 2N2222A into a clipping pair of 1N5817/1N4004 going to ground. I thought that by adding a second clipping pair, I could get more output -- but I'm not hearing it. I'm chalking it up to my misunderstanding of course, but what I did was just tap an additional diode to each existing diode, making things 1N5817-1N5817/1N4004-1N4004.

Should I have things setup as signal -> diode pair 1 -> diode pair 2 -> out? That seems like I'd just be clipping the signal a second time, which would change the tone.

Where am I confused?

THANKS!

[mountainking]

Not sure I understand what your saying you did. Did you add a second diode in series with each of the two diodes or did you add the extra diodes in parallel with each of the two diodes?

[suprleed]

Theoretically you're on the right track.  Putting diodes in series will increase the proximity to clip thus producing a less clipped signal and higher output.  I think the 1n5817's are schottky's.  I've never used them myself, but I think they clip very early.  You may try adding a third 1n5817 to that series to see if that helps.

Are the cathode ends (the end with the stripe or band) of each diode pair facing opposite directions?  You normally want them facing opposite directions as one pair will clip the positive wave of the signal and the other pair with clip the negative wave of the signal.  If both pairs are facing the same direction, then they are both clipping the same side of the signal and this may be why you're not hearing any major volume increase (the 4004's are trying to clip a signal that's already been lopped off by the 5817's).

I swapped out a 1n4001 with a LED on one of my single tranny distortions (tweak-o) and it created a noticable volume increase.  This follows the same concept as above.  LED's clip later and thus result in higher output just like multiple si or ge diodes in series.

[railhead]

I put the leads of each diode together, like you can do with multiple resistors. So, I literally had the cathodes and anodes of both 5817s together, and the cathodes/anodes of the 4004s together, then dropped them into their sockets -- so in series (?). And yes, I have them opposite.

[Zben3129]

This is the setup you should have:



The 2 left diodes could be your 58's and the right pair could be the 40's. Also, if you wanted to raise the clipping ceiling even more and gain more output, you could have 3 58's and 3 40's, and so on.


Hope this helps!

[soulsonic]

Instead of having to string a zillion diodes together, you could use a zener diode. It would clip at whatever voltage it's rated for, ie; if you used a 5 volt zener it would clip at 5 volts and therefore, 5 volts would be the maximum output you could get. A standard silicon signal diode clips at 1-something volts - that's why your output so low, because everything gets chopped off at that voltage - putting more in series raises the voltage cutoff "threshold", but I think using a zener is alot easier.

[Zben3129]

Very true,

I still stick to the diode strings, as I like the sound of the diodes i use better than the zeners

Just a thought

[railhead]

Putting the 4004s in series made a good difference. I didn't like the sound of both pairs in series, though I suppose I could add a third 4004. Man, this has been a GREAT learning experience, and it's been a BLAST totally customizing a sound that fits my needs (which is why we all love the hobby so much, of course). I've got this wicked AC/DC crunch going on, and it's wicked responsive to my pick attack.

I'm wanting to try a couple of different input cap values before I'm totally pleased, so sound clips soon!

Thanks for all the help.

[Zben3129]

No problem!

Glad it worked out for you, have some fun with it!


Zach

[Electric_Death]

More diodes means smoother clipping from what I've experienced. You could use a couple with a high voltage rating or, string together a half dozen in series/series parallel. You'll still get great harmonics and the sound of your distortion will be smoother even if it's deep into hard clipping. I did this on an overdrive with a ridiculous amount of gain, there's no comparing the fatso high voltage diodes to the low voltage I put on in series.
The high voltage pair in parallel are harsh, the 5 in series/parallel are nice and smooth and set to clip at the same voltage.