Maestro Fuzz Face

[Evil Hoodoo]

Recently acquired a vintage DA Germanium Fuzz Face from ebay. I realized upon opening it that the polarities of the caps were reversed and noticed that the AC128s inside were installed later versions, which sounded under par. After addressing the electrolytic polarities and replacing one of them, I sought to replace the AC128s with the NKT275s I had on hand. I tested the trannies for gain, and although I found ones with high gain / moderate leakage for Q2, I couldn't find a suitable NKT for Q1. Going into the tranny bin, I tested a handful of alternatives. I threw in 2n408s, 2n2613s, 2n270s and even a Toshiba transistor in the Q1 position to see if they sounded good compared to the nkt275. Using two NKT275s from the stock that I had (higher gain for Q2, lower for Q1) produced a unsatisfactory sputtery and nasaly tone. However, out of the other alternatives, the 2n270 and the 2n2613s actually were quite nice sounding to my ears.

I decided to go with the 2n2613 in the Q1 position, as it sounded surprisingly good. Lot's of sustain and a rich foamy 60's fuzz which was pleasing to my ears. Also, it cleaned up nicely as well with a roll-off on the guitar's volume.

Based on the data sheet for 2n2613 http://www.pemberton1.btinternet.co.uk/transistors/2n/2N2613.html I assume it should be safe in the circuit http://www.geofex.com/article_folders/fuzzface/fftech1.gif as it's rated at 30v. From an expert standpoint will the circuit be stable with the addition of this transistor? Who knows, only time will tell, but it sure sounds good.

[Evil Hoodoo]

Board shot.

http://jongreen.com/images/FF_mod_guts.jpg

Face Shot 

http://jongreen.com/images/Fuzz_Face.jpg

[Electric Warrior]

Interesting one. Silicon era board, but the enclosure is earlier (same type as used for the last NKT units and the earliest BC183L ones).
You might want to consider restoring this one back to Telefunken BC108Cs, if you can find any.


Here's what these are supposed to look like:



If you want to use it with PNP germaniums, you need to turn the electrolytics around again.

[Evil Hoodoo]

Ha! That's why the caps were reversed. Interesting. I like the sound of Germaniums for now so I'll reverse the caps again.
Mine had the same gold Sprague as shown in the above pic, but I removed it. It didn't look stock to me, so I figured I'd put in a nice freshie Sprague.
I will start the process of looking for the specific bc108s you mentioned? How do they stack up to the Dunlop JH bc108s I wonder? Thanks.

[Electric Warrior]

Don't know if they would sound any different compared to modern stuff. probably not. I hear the Dunlop JH BC108 Fuzz Face is very good.

For a proper restoration Telefunkens (TFK) are the right stuff, though. Maybe a forum member can hook you up with some?

[Evil Hoodoo]

Are there any other mods needed to accommodate the GE trannies or is it just the caps orientation? I don't need to reverse the power leads or anything?

[Electric Warrior]

since the pedal was modded when you got it, power leads might already be reversed.  

[Evil Hoodoo]

Well, in the gut shot picture above, that's the way the lead orientation is. It seems like they match other Ge boards lead orientations. The + on mine goes to the (now) + lead of the 2.2uF electrolytic.

[Electric Warrior]

That's not the +. It's the signal input.
The battery should connect with the black lead (3rd from bottom) and the input jack. Color codes (black/white) of the power supply were the same in germanium and silicon versions, so check how the battery connects.
If the pedal was working when you got it, chances are that it's correct already.

This should give you an idea what's going on inside of these (jacks are wired up a bit different on vintage units; the old input jacks have two switches. one opens, one closes on plug insertion):

[Evil Hoodoo]

That's a big help. Thank so much for the infos and the diagrams.
I may post a clip a little later. Maybe you can give me your opinion on the sound.

[Evil Hoodoo]

Clip of the "Maestro Fuzz" (2N2613 in Q1)
Apologies for my crappy playing.

http://www.jongreen.com/mp3s/FuzzFace.MP3

[Electric Warrior]

Very bright amp, but sounds good. Seems to clean up well.

[Evil Hoodoo]

Thanks. Yeah you're exactly right. It's a little Vox practice amp 
I'm happy with the sound for sure...