2N7000: good for fuzzes?

Started by Mugshot, July 13, 2009, 02:30:40 AM

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Mugshot

i was shopping the other day for components (caps, resistors, diodes etc.) and included was 6 pieces of 2N3904 for my new project (a transistor muff fuzz). having built one using 2N5088 sometimes i swapped 2N3904 for this circuit, i already have an idea that these NPN trannies work for this particular circuit. however, i found out later that 4 of the supposed 2N3904 i got from the store were actually 2N7000, and searching the net i found out that these were mosfets, but can be used as npn(?) (http://wa5znu.org/2007/07/2n7000/n6kr-2n7000.txt, click the link). to quote,

QuoteThe 2N7000 is a DMOS MOSFET transistor that is great for switching uses: it
can be used just like an NPN transistor, but requires no current-limit or
bias resistor at the base lead (its gate lead draws no current).  In fact,
in the TO-92 package, its leads are in the same order as a bipolar
transistor:  S-G-D correspond to E-B-C.

since my muff was built with sockets, i pulled Q1 out and installed the 2N7000 out of interest. what i got though was a poorly biased tone, like what you'd get in a typical fuzz face circuit and raising the resistance to the collector of its transistors. i pulled it out, installed 2N5088 back in Q1 and then installed the 2N7000 in Q2. why, it works! but im not sure what i am actually getting.

out of ignorance, i tested the gain of both 2N5088 and 2N7000 using an analog meter. now im a noob when it comes to this, and i dont exactly know if im doing it right  :icon_biggrin:. it goes like this: tester set to X10, positive probe to emitter, negative probe touching both Collector and base. for the 2N5088, i got 500+, while for the 2N7000 i got roughly 120+ something. pardon my laziness guys, but i have a VERY limited internet accessibility at present, and im just using someone else's PC just to log in  ;D

if my method for testing the hFE is right (which im sure is not), im inclined to believe that 2N7000 may be good for FFs. but then again..

back to the muff. if i were to use 2N7000, i understand i should use lower resistance for the base(gate?) right?

i am what i am, so are you.

Hanglow

#1
have a look at this
http://www.runoffgroove.com/multiface.html


didn't see that yours was a muff  :-[  Still, they sound good in FF circuits, although you don't get FF sounds out of them, don't see why they couldn't work in a Big muff

km-r

or build a SHO [serious hard-on]

is the runoffgroove.com omega a mosfet based rangemaster workalike?
Look at it this way- everyone rags on air guitar here because everyone can play guitar.  If we were on a lawn mower forum, air guitar would be okay and they would ridicule air mowing.

Ripthorn

My favorite project with 2N7000's to date has been soulsonic's freya distortion.  It is a Soldano SLO100 emulator that is awesome.  The SHO is another decent project.  As far as I know, the Omega uses a mosfet and a jfet (or maybe it's an npn) and I plan to build one at some point.
Exact science is not an exact science - Nikola Tesla in The Prestige
https://scientificguitarist.wixsite.com/home

WGTP

#4
The 2N7000 and the BS170 (pin out reversed) are the 2 primary N channel Mosfets used around here.  Definitely check out the Multiface article.

Also this at AMZ  http://www.muzique.com/schem/fuzzface4.gif

Isn't the non-opamp Muff Fuzz a Fuzz Face with diodes at the output?  (that could easily be switchable to LED's or nothing)   :icon_cool:
Stomping Out Sparks & Flames

Mugshot

yeah, ive read the MultiFace article yesterday. if memory serves me right, the collector of Q1 for the muff fuzz is biased by a 100K resistor and its base too with a 100K. i dont know if that is relevant to why the muff crackled with the 2N7000 at Q1, because in Q2 (2N5088 on Q1), it was fuzzing alright.

tonally i think the opamp muff fuzz sounds better than the transistorized version, but the clean up is better with the transistoried one though.

so a question:

1) what gain(?) does 2N7000 usually have? would it be alright for muff fuzz project? if so, what modifications do i need? im guessing lowering the resistance to the supply tied to the collector of both Qs, no?

thanks for the replies guys  :icon_biggrin:
i am what i am, so are you.