ORPHEUM FUZZ !

[Dragonfly]

i just drew up the layout and built it.

the 2n3904's i used were hfe 116 and 120.

AC

[Sir H C]

The circuit is very beta/hfe dependent.  Though not the worst biasing method, the base/collector resistor with no degen often has to be tweeked for the specific transistors to get the voltages right.

[nightingale]

I used 2N12219A for the transistors (hFE150) and I'm having nasty squealings when the volume is up.
Though my voltages are close to the targets:

FWIW,
I also have an original until that squeals from time to time. It seems to get worse when the battery is low.

hope this helps,
ry

[petemoore]

  Warioblast...
  Q1:
C: 6.5
B: 0.5
E: 0

Q2
C: 0.9  Collector
B: 0.9  Is the same as base on Q2...
E: 0
  Not sure how this one is supposed to bias [see Dragonfly's posted voltages on page 1], but look for a short between Q2, B/C

[warioblast]

  Warioblast...
  Q1:
C: 6.5
B: 0.5
E: 0

Q2
C: 0.9  Collector
B: 0.9  Is the same as base on Q2...
E: 0
  Not sure how this one is supposed to bias [see Dragonfly's posted voltages on page 1], but look for a short between Q2, B/C

I gave up. 
My last measurements weren't that bad though
Q1:
C: 6.89
B: 0.53
E: 0

Q2
C: 0.89
B: 0.54
E: 0

[Sir H C]

The base-collector resistor on Q2 should be made larger.  You can see that you are getting a .35 volt drop across it.  If you found a transistor with a much lower Hfe/beta you would get a bigger drop, or just make that resistor bigger to give a bigger drop thereby raising the collector voltage.  4.7 meg would be a good starting point.

[electrobuster]

Just wanted to say thanks for the layout Dragonfly.
I bullt this a couple of nights ago and its wicked.
This is a fuzzfiend delight. It has some similarity to a Controfuzz at low to medium "tone" settings with a fundamental boost and top end fizz . The boost gets that misbiased gatey squash that a Greenringer has. This thing has many classic tones. Try rolling back the volume at mid to high "tone"  for absolute balls.
I used 3904, 120 hfe.  High "tone" setting gets very shrill.
Maybe a ge trans substitute would be good to mellow some of the top end?

Just thought I'd give my two cents, been hanging around reading and learning for a while. this place is a fuzz junkies dream. thanks guys 

[bluesdevil]

I just whipped this up on the breadboard and I'm getting the same ControFuzz results  as Electrobuster, but I don't really like it... sounds very mediocre to my ears.  Dragonfly's sound clips sound a lot wilder....  a lot more over the top and Scrambler like.
      I tried various trannies with lowish hfe..... the best was a 3904 with 116 hfe in Q1 and another 3904 with a hfe of 195 in Q2 spot.
         I didn't like the Mosrite Fuzzrite either, so maybe this type of circuit just dosen't work well with my rig. On to the Superfuzz!!!!!!!!!

[bluesdevil]

Just a quick update: I started noodling around with it some more and found a very low hfe  NPN germanium in the Q1 spot really takes out the fizz and actually gives a smoother fuzzy sustain that I like. Not the greatest fuzz pedal in my arsenal, but different and more to my liking than before.
   Glad I finally found a use for the ultra low gain Russian NPN germs I bought off eBay last year!!

[electrobuster]

The Orpheum has that not quite right factor. Thats what I like about it. I think it would have a great ability to punch out single note melody lines.
If I reversed the battery polarity could I try some of my salvaged PNP ge trans? Yes, I build by numbers

[bluesdevil]

Yes, since there are no electro caps in this circuit, you should be fine with just  reversing the battery polarity.
   I think using germs smooth is an improvement ...... please post back with your results and let us what you think.
     

[bluesdevil]

Electrobuster - I went ahead and tried out some PNP germs in the hfe  range that Dragonfly used for his 3904's and that definitely did the trick for me.... smooth but fuzzier than the those low hfe  Russian NPN germs I tried earlier and not as harsh  as the silicon trannies.
Thanks to all involved in sharing the info on this circuit, I ended up really enjoying this one!!!

[electrobuster]

Bluesdevil,  Tried some ge trans last night and went back with the silicons! Sounds more together with them, if this nasty piece of work can be considered together sounding.
I think it needs some value adjustment to work with ge's and I don't have the knowledge to do that yet. They did tame the high end but the lows were just a mess, a bias issue I guess. With the silicons I can just roll back the guitar tone if need be.
Really dig the dual sound of this circuit, with the the mushy lows and blistering highs it can be very powerfull.

[bluesdevil]

Always worth a shot trying different combinations and letting your ears be the judge. I might have just got lucky with the right germs because I didn't have to rebias anything.

[electrobuster]

You mentioned you used the same hfe for the germs that Dragonfly suggested for silicons, maybe thats it?
The ones I tried were either too low at 80hfe or too high at around 200hfe(leaky?).
Tried combinations and pulled some from my FF and TB ranging from 80 to140 but it was just too cheesey.

[bluesdevil]

   I actually spent the whole night trying different gains of germs after that post..... the best I came up with out of the batch of Japanese 2sb176 trannies I had were actually in the 160 - 175 hfe ballpark. This is with leakage accounted for as well.
       In comparison the lower hfe ones that I originally raved about were a bit too weak. The slightly higher gain got me the smooth saturated fuzz with lots of sustain that I really like.... it just comes down to personal taste, no absolute wrong or right. Also with the 3904's I tried I got oscillation with volume and tone maxed and the germs didn't do this.
       I probably should've just waited after going through all those trannies before posting anything, but it's just fun to post progress while someone else is also experimenting with the same build .   

[electrobuster]

I also noticed the oscilation disapeared with the germs. Didnt have much time last night and had to play low volume.
I will definately give it another go over the weekend. I was using some Toshiba 2sb56. Sure is fun.

[tcobretti]

I also noticed the oscilation disapeared with the germs. Didnt have much time last night and had to play low volume.
I will definately give it another go over the weekend. I was using some Toshiba 2sb56. Sure is fun.

This makes sense - Ge transistors are usually lower gain than Si transistors are.

[doug deeper]

i played the 3 knob version of this years ago (at black market music in hollywood)
from what i recall it was really saturated buzzy.
almost in superfuzz territory.

[Yun]

ummmmm, not to be Too controversial here, but......

this schematic is from my OLD book on amp service.  "the field guide to amplification" is on the (ripped up) cover. 

The biasing is a tad bit different though.  Let me flip through the book here.......


all caps (except the tone "stack") are .05uf

-10 meg is really 2.2Meg
-22K is really 100K
-47K is really 100K
-Ommit the 100k resistor going across the 22K and 47K
-1meg is really 2.2Meg

That's what the book calls for anyway.  And i have built it (the book version) and to my ears is a bit more nastier than the orpheum fuzz.  Has a different tonality though.  It's more along the lines of a Maestro fuzz-Tone than the super-fuzz, companion FY-2, etc.