Ge/Si hybrid Orpheum Fuzz success

[superferrite]

I've had this idea for a long time, after making various FuzzRITE variants.
The FuzzRite is a one trick pony with a great trick, and although I have a Shin-ei Companion on my board right now, it is more of a WASH-OF-FUZZ effect rather than a playable one like a Fuzz-Face.  An all-Ge fuzz is not fun for many reasons here in Arizona due to 40 degree temp fluctuations every day!

I replaced Q1 with a salvaged Matsush*ta Ge transistor with an hFe of 150 or so and I have a 2N2222A (hFe 153) as Q2.  The only other mod is a reduction in the biasing resistor to Q1 from 100K to 47K.  I used the Orpheum because that huge 1Meg tone pot offers a ton of sweep.

The result:
A very user-friendly "player's fuzz" with a range from mild overdrive to almost gatey Fuzzrite tone and attendant high-end buzziness.
The volume knob does have to be tweaked when the tone is used because output varies a bit, and I found that a pre-gain pot helps tame the rougher settings without monkeying with your guitar volume knob a lot (and attenuates that high end a bit).

Incidentally, it does clean up nicely without much splatter using the guitar volume, unlike most 100%  silicon fuzzes I've made.

Build one for a winter project and tell me what you think.

[Mark Hammer]

Consider experimenting with the amount of resistance on either side of the cap to ground for Q2.  Various schematics will show a 100k and 47k resistor in series, between V+ and the collector of Q2, with a .1uf cap between their junction and ground.  If you keep the overall series resistance the same, but move the partitioning of it around, you get varying amounts of bass, or what one might call "body".

One arrangement is to use a 33k resistor, 100k linear pot, and 15k resistor, or a 27k, 100k and 20k, etc.  The larger of the fixed resistors goes to V+, then the pot, then the smaller resistor.  The two outside lugs of the pot go to the fixed resistors, and the cap goes between the wiper and ground.  The arrangement lets you keep the overall collector resistance constant, but move around  how much resistance occurs between V+ and the cap.

A very useful addition.  Worth trying.

[LucifersTrip]

I used the Orpheum because that huge 1Meg tone pot offers a ton of sweep.

Do you have the full schematic for that one?  A commonly circulated schematic has a 200K tone and 250K volume, both in silicon & germanium versions:
http://tonebender.webs.com/orpheum-SILICON.GIF
http://www.luciferstrip.com/fuzz/orpheum.jpg
http://analogguru.an.ohost.de/193/schematics/Orpheum_Fuzz-Ge.gif

I'd like to see if there are any other differences other than the control pots. I did actually try the 1M and 100K (w/ the GE version) and I got a more trebly sound with less fuzz.

On another note, a very simple and excellent mod (as I mentioned in previous posts) is a 50K pot instead of the 47K off Q2's collector. I also use that as a test to see if I have a good transistor combo. If I can turn that down to 0K and still get a killer fuzz (it'll be buzzier) that doesn't sound flat or gated, I know I picked the right pair.

Also, both Mark & I noted that the Orpheum sounds excellent with a low Q2. I usually use something in the 40-80 range.

[superferrite]

http://www.aronnelson.com/gallery/main.php/v/DRAGONFLY-LAYOUTS_0/album18/FUZZ+PCB/ORPHEUM+OLD+SCHOOL+LAYOUT.GIF.html
http://www.aronnelson.com/gallery/main.php/v/DRAGONFLY-LAYOUTS_0/album18/album144/album109/ORPHEUM_FUZZ_VERO.gif.html
Although I am aware of the other schematics, I had built it years ago with one of these layouts and it worked.  So that was fine for me!

I'll try and reduce the 1M pot and swap some transistors so I can explore it some more.
Thanks!

[LucifersTrip]

http://www.aronnelson.com/gallery/main.php/v/DRAGONFLY-LAYOUTS_0/album18/FUZZ+PCB/ORPHEUM+OLD+SCHOOL+LAYOUT.GIF.html
http://www.aronnelson.com/gallery/main.php/v/DRAGONFLY-LAYOUTS_0/album18/album144/album109/ORPHEUM_FUZZ_VERO.gif.html
Although I am aware of the other schematics, I had built it years ago with one of these layouts and it worked.  So that was fine for me!

I'll try and reduce the 1M pot and swap some transistors so I can explore it some more.
Thanks!

thanx...those are the layouts I found...was hoping for a schematic for easy comparison.

It looks like the the 2nd one is the only one of the 5 (incl my 3 links) with a 10-fold smaller input cap (.01 instead of .1). if you used that with the 100K vol, it has to have a thinner sound...which, of course could also be cool

[superferrite]

WOW--I missed that, and I indeed have a .0iuf input cap on there.
I'll have to experiment further now, although it sounds pretty sweet as-is!

[superferrite]

You guys were right.  That .01uf input cap was choking the fuzz potential out of this beast.

I fixed it with a nice fat ceramic .1uf cap from some Japanese sixties trash and it is a fire-breathing lunatic now!