Orpheum Fuzz Squeal

[Jamforthelamb]

I ended up fixing it by putting a .01 cap from the input of the circuit to ground. I'm sure this effects the tone of the pedal a little, but it did the trick. As I said I put it on the ciruit's input, so that it won't color the bypassed signal.

thanks for all the help!
-jftl

[pingjockey]

Hey all,

great thread, and very helpful.  The .01 uf cap to eliminate squeal was a great solution; I'm using it in mine, too.

My issue: I gutted the box to paint it, and after re-inserting the circuit and hardware, the thing won't work.  It was glorious before removal.

Some questions:

- What should the voltage be at the input and output jack?
- What should the voltage be where R1 and C1 connect according to this layout:
http://www.aronnelson.com/gallery/main.php/v/DRAGONFLY-LAYOUTS_0/album18/album144/album109/ORPHEUM_FUZZ_VERO.gif.html

- Are there other key leads where I should check voltages to assit in isolation?

Voltages at the transistors are satisfactory.

Other info: I am using a 3P3T switch.  Also using BC109 transistors.

Voltages at the battery read positive, but they read in the negative at the transistors.  Can't remember this from before when it worked.

Thanks to anyone who wants to chime in and help this noob!

Al

[LucifersTrip]

>Voltages at the transistors are satisfactory.

If this is true, then the problem most likely lies in the external wiring...jacks, switch, etc...or the ultimate classic: something is grounding against the inside metal of the enclosure

[LucifersTrip]

I have to make some notes after reading this thread, since The Orpheum is one of my favorites....

1) IMO the germanium version absolutely destroys the silicon version, just like with any Fuzz Rite variant. Notice the .005 pair is larger that the .001/.002 combo, giving it more thickness.
http://www.luciferstrip.com/fuzz/orpheum.jpg

2) It's kinda crazy to remove the "gain" control (tone?) since it's a blend of the clean and distortion and gives tons of tones that you can't get out of a standard fuzz with "gain"

3) It's also kinda crazy to use a .01 at the input since that tames the highs and taming a fuzz is sacrilege

4) Fuzz Rites are actually one of the quieter topologies of fuzzes. I've built a ton and only 1 had any problem with oscillation, and that was actually when the tone was turned way down. I fixed it with a 2K in series with the .01. This is my 2nd fave Fuzz Rite variant; the Fuzz section from a rare Fuzz Rite amp. Again, notice the .0047/.01 combo. Here's my final version with voltages.
http://www.luciferstrip.com/fuzz/fuzzrite-in-amp-final.jpg

5) After loads of transistor swaps, I've never gotten one to sound better with higher gain transistors than with ones in the 70-150 range. Higher gains just add harshness and gives less thick buzz.

6) They sound great with Q2 lower hfe than Q1. For the ge version, you can actually use a Fuzz Face pair backwards, Q1 100-120, Q2 70-100.

7) A simple, and my favorite mod is to just replace the 47K (ge version) with a 50K pot. It's also a great test to hear if you have the right transistor pair. It should sound cool thru the WHOLE sweep. The amount of buzz and treble response will change throughout.

[pingjockey]

LT, it was the input jack, grounded to chassis  thanks very much as always.

i may try a hybrid that incorporates the extra pot with a germanium orpheum using ac128's.

[LucifersTrip]

LT, it was the input jack, grounded to chassis  thanks very much as always.

Sounds great...and as always, play it loud.It's Friday night!

i may try a hybrid that incorporates the extra pot with a germanium orpheum using ac128's.

you can't lose

[pingjockey]

LT, I'm thinking it may be as easy as throwing in a 100K pot in series above the 47K resistor above Q2.

I'll post a schematic that incorporates AC128's for an idiot check.

Al

[LucifersTrip]

LT, I'm thinking it may be as easy as throwing in a 100K pot in series above the 47K resistor above Q2.

Sounds good...though, it sounds great with a 50K (or possibly 100K) instead of the 47K.

If you don't want to de-solder and remove the 47K from the board, you can hear what it sounds like by just shorting it out (clip a lead from one side to the other)...and if you want to make it permanent, do the same with a solder bridge.

edit:

the reason I used a 200K in series w/ the 47K in the schematic above is that the original had a 100K in there. the 200K puts the original tone at 12 o' clock.

http://www.luciferstrip.com/fuzz/fuzzrite-in-amp-final.jpg
http://www.luciferstrip.com/fuzz/fuzzrite-in-amp.jpg

the original amp ver was also silicon, so there is a 220pf on the 1st Q to tame the highs