PNP vs NPN fuzz

[petejt]

I know the basic electronic differences between NPN & PNP transistors.

 

But how do they differ sonically? Handle gain? Tone, texture, all that stuff?

[petejt]

Surely someone here knows? I saw a photo of a fuzz pedal that both an NPN-based fuzz and a PNP-based fuzz.

[petejt]

Could someone please help me with my query?

[melx]

I don't know mate, I think most of the old germanium fuzz pedals were originally PNP though.. fuzz faces etc.

 

so maybe PNP has a more vintage vibe.... or maybe I don't know what I'm talking about.

[melx]

ok found this...

 

The only major difference between the two types is that the NPN transistor has a higher frequency response than does the PNP (because electron flow is faster than hole flow). Therefore high frequency applications will utilize NPN transistors.

[(⌐■_■)]

no real audible difference well at least in comparison to the differences in circuit design and components used

[Byronamatron]

ok found this... The only major difference between the two types is that the NPN transistor has a higher frequency response than does the PNP (because electron flow is faster than hole flow). Therefore high frequency applications will utilize NPN transistors.

 

I have read this as well. However, I think the difference may be negligible in gainy guitar effects, which mostly use grounded-emitter configuration for maximum gain, as opposed to high frequency accuracy. I think guitar speakers tend to top out at 10 Khz.

 

Also, effects using PNP's often do so because they are the more common germanium type. Many ge boosts and fuzzes have a low enough input impedance to probably negate any remaining difference.

[freeRadical]

Generally the Germanium Fuzz faces are discernibly warmer and more sensitive to input volume adjustments in that they can clean up better as the volume pot on the guitar is turned down. They are more temperature sensitive. They often mess with un-isolated DC power supplies with other negative center pedals connected.

 

The Silicon NPN Fuzz faces are generally more temperature stable. They can often get higher gain, and have a harder or harsher edge or 'bite' to their tone because of the higher frequency response.

[OXFUZZ]

I make both and i find the usual things apply.

 

Ge is fatter, warmer, and smoother. Bottom seems less defined.

 

Si is usually brighter, higher gain, and has a tighter bottom.

 

There`s something about a solid germanium fuzz that can`t be beat.

[soulsonic]

NPN germaniums tend to be more difficult to use than PNP germanium. The specs on some of them vary wildly, and some have ridiculous leakage current and temperature instability (not a good thing most of the time). It's like it seems to be just plain easier to make a quality germanium transistor as a PNP device. But NPN silicon are awesome perfect modern transistors. Silicon of all types are generally great most of the time.

 

Here's the thing about the Silicon vs. Germanium sound... nearly any Silicon circuit can be tuned to sound as good as its Germanium equivalent, it's just a matter of designing the circuit to be optimized to the silicon's spec. You can't just swap silicon into a germanium circuit and have it automatically sound good. I think it's possible that much of the hate towards silicon fuzzes has come from too many silicon fuzzes that weren't properly tuned.

 

That being said, I love the sound of a good germanium fuzz! It's this love for a good germanium sound that's been pushing me to work hard on equivalent-sounding silicon circuits.

[Ronsonic B]

I have matching germanium Fuzz Faces I built, one PNP, one NPN. They sound identical. I sorted through piles to get matching zisters and well, it all matches.

 

Usually when someone makes that distinction what they're really talking about is the difference between the early PNP germanium Fuzz Face and the later one that used silicon transistors. Those are generally a bit brassier and aggressive sounding. That's the material, not the junction type. Like Soulsonic says (and I'd never argue with a brother Sonic) you can get the goodness out of silicon. It just takes more work than the guys who built the things by just substituting transistors did.

[monto]

i miss my burns buzzaround clone

 

[petejt]

Thanks folks, I really appreciate it.

 

 

 

I tried out some silicon fuzz pedals on Wednesday. I noticed that the way I had them set, was that there was less 'headroom'- when I played notes on the lower strings they muddied out, but playing single notes on the higher strings sounded great. It was like the fuzz couldn't handle the extra bass frequencies coming from the lower strings, especially when chugging on them.

 

So in a way I guess I made the silicon transistors sound like germaniums?