Uses for Mooses, er, 2n7000

Started by Somicide, June 15, 2004, 05:18:43 PM

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Somicide

Any ideas on what i could use these for?  All I've done with em is put them backwards with a trannie (made a very interesting BMP, tell you what...) and I have a good 6 left.
Peace 'n Love

petemoore

Convention creates following, following creates convention.

Transmogrifox

I have been working on a MOSFET distortion using 2N7000's that sounds pretty darn sweet.  It's based on a differential pair, similar effect of the "differential fuzz" except using mosfets and frequency set-up to have a better crunchy-blues pedal flavor.  The distortion tends to fall into a similar vein as Blackstone Appliances MOSFET overdrive sound.  Much more responsive to pick-attack than the standard TS-9 clone/diode clipping OD, very sensitive to volume and tone controls on the guitar, and has a generally nice "sizzle" and "grind" balance.  The harmonics produced are very musical.  Turning up the distortion and doing a 2-string chord riff, I can hear the cross-modulation terms playing a low harmony with me, like you hear with a tube amp.  It also works VERY well as a "real" overdrive pedal as it works on a 15V supply and has lots of clean headroom to drive the hell out of the input stage on a tube preamp.  I think this thing nearly castrated my amp.  It allowed me to get that nice "grunt" out of my amp like BB King gets when he digs in (I saw him live once--there's a good case for the "It's all in the hands" camp).  Though I would say it's in the heart, and he has done a good job over the years of making his hands the faithful slave....the pedal and amp are just slaves under slaves.  If you have the right slaves, you can dictate the tone that's in you.  If you don't have tone, you better hope your slaves mis-behave in a favorable way.

RANT:  This is NOT a tube-sim pedal, but it has some interesting qualities that make it unique like tubes have interesting qualities that make them unique in their own way.  The reason I rant about using MOSFETs to simulate tubes is that I am generally disappointed with the sound with various circuits I have attempted, or pedals I have played (Peavey Transtube a good example of poor tube modelling) when I'm thinking "tube".  If I'm thinking MOSFET distortion, then I can tailor it to its own unique sound, and be satisfied with it sounding good.  A MOSFET fuzz-face clone is a good sounding device, but it's not a tube preamp...just a good sounding distortion.

~END RANT


I am very happy with the distortion part, but have been utterly frustrated in trying to design a good post-EQ stage.  I was trying to pull it off with a single tone-control with various approaches, from a low-resonant feedback eq to a simple BMP pi style and the low eq adds distortion, but makes it a better metal pedal sound while the BMP control makes it more of a mushy fuzz distortion, yet some BMP type tone control makes it more of a squishy Peavey transtube sound (not good in any way).

My amp's eq makes it sound nice, so I'm thinking of simply doing a cut/paste job and see if that sounds good.

The moral of the story is, if you're interested--I intend to post schems and audio samples soon...whenever I can get to it.

Also, check out some of Joe Davisson's projects, I'm sure that many of his devices could be easily modified to use mosfets, and sound good.
trans·mog·ri·fy
tr.v. trans·mog·ri·fied, trans·mog·ri·fy·ing, trans·mog·ri·fies To change into a different shape or form, especially one that is fantastic or bizarre.

Somicide

That sounds pretty cool;  when you get your design all worked out, lemme know, it sounds like it could be just what I'm looking for.  As far as what i did with my BMP, I swapped the E & C of the Transistors, then put a 2n7000 in the original orientation.  Damn thing nearly blew my practice amp.  Got REALLY loud.
Peace 'n Love

zener

There are knowm circuits here where you can use the 2N7000.  I know three of them: AMZ Mosfet Boost, Multiface at ROG and older versions of Obsidian. The latter doesn't exist anymore at Joe Davisson's site. Tell me if you want it and I'll send it to you.

Zener
Oh yeah!

SlyN

I'd second the vote for the multi-face with the 2N7000, sounds cool, not too subtle though. On a different tack what about building a couple of Millenium 2 bypass boards. I just added one to my 'Eighteen" and it works like a charm.

Seeya
Sly

Transmogrifox

Quote from: somicideThat sounds pretty cool; when you get your design all worked out, lemme know, it sounds like it could be just what I'm looking for.

Here's the schematic:

http://www.geocities.com/transmogrifox/SchorchedEarth

Make sure you copy and paste this link to another browser as geocities generally doesn't let it fly the first time

I ended up getting the BMP tone topography to work well after all.  I just had to design it with a cross-over frequency that was not immediately intuitive.

Audio samples will probably be another week or so because I just started transferring the rest of the circuit to perf board, however, let me know if you breadboard it or anything.  I thought it was a similar concept to Blackstone Appliance's OD after listening to his audio samples.  This Scorched Earth distortion is voiced slightly differently and has a bit more grit to it.  The "Fizzle" switch and LED clipping is purely optional.  This just makes it sound a bit more like a "Distortion" pedal instead of an "overdrive".

One of the greatest assets to this circuit is that it's guitar volume knob sensitive.  I can max the distortion control on the pedal and roll my guitar back to about 2 or 3 and get almost completely clean output, then roll the knob up to max and have a raging crunch.  YOu can get fuzz out of this if you roll your tone all the way back and crank the pedal's distortion.
trans·mog·ri·fy
tr.v. trans·mog·ri·fied, trans·mog·ri·fy·ing, trans·mog·ri·fies To change into a different shape or form, especially one that is fantastic or bizarre.

supertulli

Hi Transmogrifox and everyone else,

I've recently picked up this wonderful hobby of pedal making, and am looking for a nice 2n7000 fet circuit, stumbled upon this thread, but the geocities link is dead. Would there be any chance to post it again?

Thank you! and cheers to everyone!

Pedro

Axldeziak


marcelomd

Zvex has a couple MOSFET pedals. Super hard on, Box of Rock and Box of Metal come to mind.
They use BS170, but the 2N7000 sounds more or less the same. Pay attention to the pinouts.

GibsonGM

I use 'em anywhere a BS170 would work (like the BOR etc. that Marcelo posted).  Again, watching that pinout!   They are good in gain stages...for preamps, distortions and what have you.
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