WOW Signal Fuzz. Ideas anyone?

Started by digi2t, November 04, 2012, 07:31:37 PM

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LucifersTrip

Shootout build finally done, so I can screw around with the fuzz section of this more...

As I noted above, if you want Q1/2 collectors to sit at ~ .5V you need higher gain transistors. You were totally correct about needing 2 that were very close in hfe's or you'll get some gating.  An MPSA18 (hfe ~800) was perfect for the NPN, but I could not quickly find a PNP close enough to that hfe. What modern PNP will hit the 800 hfe mark?

Ironically, I had to settle and wound up using what you initially tried, a 2N5087(392)/2N5088(401) combo. This put Q1/Q2 collector at .67V with a 9.6V supply.

Unbelievably, I tuned Q3 by ear with a P416 in there and hit 24.9K exactly. I did a double take on DMM.  Btw, you wrote "Not too far from the 29.4K that's in the original", but the schematic shows 24.9K

As always, I wanted to see if I could get a better fuzz and it was really easy. I figured the guys at Spaceman used the P416 because it was cheaper and more predictable than older US, UK or Japanese germaniums.  It may not sound identical to the original that you're shooting for, but IMO, the fuzz was smoother, fuzzier and all around better with most vintage transistors I tried with gains of 70-150 with reasonably low leakage. It is the exact same phenomena when I use these "almost no leakage" (shows zero on the peak Atlas) Russians as Q2 in a Fuzz Face. They are harder, tighter with less smoothness, softness and saturation....actually, they sound somewhere between a silicon and a vintage germanium.

I'm going with a 2N428M with hfe 134 and leak .20mA

Thanx very much for posting this. It is always cool to see another fuzz with a different topology.

always think outside the box

digi2t

Thank you Luce for looking at it. Your insights and info on fuzz circuits is always appreciated.

You caught me in a typo  :icon_redface:. It is indeed 24.9K, and not 29.4K. My apologies, although 27K isn`t too far, one way or the other  :icon_lol:
But I must say, using a trimmer here does allow you to fine tune things if your gains aren`t exactly to spec.

Hmmm... PNP tranny with a gain in the 800`s? Got to look into that one. I still have the whole thing on the breadboard right now, so I can still tinker with it. I thought I was going to start putting it together, but I got side tracked by the Space Station / 27C1001 conversion project. Just as well I guess, gave you time to stir the sauce a bit.

So many pedals... soooo little time. :icon_rolleyes:
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LucifersTrip

#22
Quote from: digi2t on November 20, 2012, 10:58:53 PM
Thank you Luce for looking at it. Your insights and info on fuzz circuits is always appreciated.

You caught me in a typo  :icon_redface:. It is indeed 24.9K, and not 29.4K. My apologies, although 27K isn`t too far, one way or the other  :icon_lol:

you're actually closer now!

Quote
But I must say, using a trimmer here does allow you to fine tune things if your gains aren`t exactly to spec.

It actually alters the tone more than anything. The fuzz actually sounded decent all the way from around 10K-15K to 50K (50K trimmer...I didn't try higher). The big difference is that at 10K, there's more treble (play single notes on the high E) and the treble disappears slowly as you increase the K. I think they went for 25K because it's smoother as the highs go away....

Quote
Hmmm... PNP tranny with a gain in the 800`s? Got to look into that one.

No idea...I don't have nearly as much silicon variety as I do germanium. Though, I do wonder how they matched 2 to get ~ .5V and have a smooth non-gated fuzz. You need at least a 600-700 hfe pair to pull that off !

edit: I actually considered making a Darlington pair out of 2 really low gain (~25-30 hfe) PNP's

Quote
I still have the whole thing on the breadboard right now, so I can still tinker with it. I thought I was going to start putting it together, but I got side tracked by the Space Station / 27C1001 conversion project. Just as well I guess, gave you time to stir the sauce a bit.

sounds cool...good luck on that one...

I was also considering building the fuzz section from the Honey, but on a quick glance, it's probably too similar to the Superfuzz.


always think outside the box