EB-0F fuzz; passive fuzz possible?

[Bernardduur]

Hey all!

I just read upon some info on my bass (EB-0) and there was this note that Gibson once produced the EB-0F in which a passive fuzz was present. Somewhere else I read that it should be some fuzztone..... are those also in passive?

I am just quite fond of fuzz and would love to implement this fuzz into my bass

[black mariah]

Simplest passive fuzz is the "Black Ice" style that StewMac sells.

It's just a diode clipping pair. Replace the cap on your tone control with two diodes pointing different directions. Done.

[choklitlove]

i did that in a guitar of mine.  two schottky diodes.  worked pretty well.  little volume drop, but that's to be expected.

that reminds me: passive ring modulator.  seems pretty cool.
http://www.thesquarewaveparade.com/images/mingrod-perfboard.gif

[ambulancevoice]

so just put some clipping diodes after an output and done?

[choklitlove]

check this:
http://projectguitar.com/tut/madsci/blackicetweedoverdrive.JPG

[darron]

i've been playing with this. put an 1n5819 from your signal to ground. it will give a farty sort of distortion. this will only clip one side of the wave of course. you can then try adding another one going the other way. it will sound a lot better but you'll notice the volume drop a lot more. you'll get a different effect with single coils vs humbuckers.

[Bernardduur]

Thanks!

I guess it won't be a passive fuzz but will do!

[darron]

Thanks!

I guess it won't be a passive fuzz but will do!

well, a fuzz is sort of an overdrive/distortion without the bass limited before drive. there will be no filters so it does sound a bit fuzzy.

[Bernardduur]

Thanks!

I think the "old" EB-0F would have an active fuzz, not a passive version (as Gibson / Maestro shared)

Just noone opened it up

[g3rmanium]

I just read upon some info on my bass (EB-0) and there was this note that Gibson once produced the EB-0F in which a passive fuzz was present.

You also might be interested in The greatest circuit of all times 

[Bernardduur]

WTF?

Awesome; must try THAT!

[Sir H C]

Realize too that those Gibson bass pickups put out an insane amount of signal.  Easily over a volt (Ampeg worked hard to make their preamps not clip with these basses according to the Ampeg book).  So diodes work pretty well with a passive clipping here.  Germanium could work well too.

[Mark Hammer]

Diodes will lace a fixed limit on the voltage that passes.  If the diode goes to ground then anything OVER that critical amplitude value will be shunted to ground.  So, if the diodes set a voltage drop of .500v (500millivolts) then any signal OVER that amount doesn't show up in the output.  If a pair of germanium diodes set that drop at 240millivolts, then the output signal will not be any hotter than +/-240mv peak-to-peak.

As it happens, it is rarefor instruments to have an output that hot except for the initial peakiest peaks, after which the signal level declines down to something much more modest.  Sooooooo, any distortion that uses diodes MUST raise the signal level (through gain stages) up to the point where the clipping action the diodes provide will apply to almost all the notes most of the time.  That's why distortions are rarely passive.

The "Black Ice" product, which has been around for several decades now, uses a pair of Schottky diodes that have a clipping threshold below 200mv.  This is low enough that an unamplified signal of the right type is capable of being clipped by them.  However, people who have used it will tell you that a) you need to have fairly hot humbuckers, b) you need to dig into the strings not just brush against them, and c) you can't turn your volume down.  In other words, in the absence of any gain applied to the signal, you need to do what you can to keep the signal level up there so that the diodes can do what they do.  Even under optimal conditions, though, this is NOT a Fuzz Face.

Now, consider that the signal amplitude will always be greater (all other things being equal) for a wound string than for an unwound one, and that the thicker the wound string, the heftier the output.  That means that basses tend to put out pretty robust signals.  Though not always true, many bass pickups, especially those of an EBO, will capture a pretty doggone fat and hot signal.  The kind that would likely meet the level requirements for being clippable by a pair of Schottky OR Germanium diodes.  Since the goal of distortion on a bass is also one of really adding more grunt rather than serious sizzle, the rather limited manner in which such diodes clip is actually an advantage rather than a shortcoming.

In sum, I see no reason why a pair of selected diodes would NOT function decently, in a passive circuit, in an EBO.  You should probably do the following, though:

1) Place them ahead of your volume pot (in parallel with the tone pot is probably best) so that your volume pot does ot affect their performance.

2) Measure them with a meter and hand select for optimal voltage drop.  Most clipping will occur with lowest voltage drop (e.g., 120mv), and subtler clipping will occur with higher voltage drop (e.g., 250mv)

[Bernardduur]

Thanks all!

I tried

The sound sucks

[Mark Hammer]

That is one of the unfortunate aspects of passive; you can't tailor the tone nearly as much as when active electronics are involved  On the good side, it'll NEVER need batteries.

[Bernardduur]

True

Still, it is so unusuable........ I really need to DIG into my strings to make any faint sound........

So........ not for me

[analogmike]

I had an EB0F and it needs a battery to work. Same as the maestro fuzz tone I think.

[Bernardduur]

Thanks man!

Any chance you know which version of the fuzztone it was?? Or the value of the battery??

[Pedal love]

Not sure of the battery. The fuzz was an early version fz-1, I think.pl

[Isaiah]

Thanks all!

I tried

The sound sucks

Which circuit? The Ge transistor fuzz?
I know it defeats the point of it being a passive circuit, but how does it sound with a boost in front of it?

Thanks,
Alex