Help recovering volume loss (super fuzz)

[StevenJM]

I just got a Shin-Ei Tr-8 fuzz / wah ... The fuzz is supposed to be the super-fuzz circuit.  The fuzz is amazing, and perfect for what I'm looking for.  The wah is kind of useless though.

My issue is I get such a volume loss when I turn the fuzz on.

Is there a simple fix/mod to help recover volume loss?  Or should I just try running a clean boost after it?  I'm not sure if there's a schematic online but I'll look or maybe post a picture of my pedal (the schematic is on the bottom of the pedal)

[joegagan]

this complaint comes up from time to to time on this circuit.

haven't tried it, but replacing the 1k  E to gd resistor on the last trans with a 1k trimmer so you can turn it lower might give a nice boost. worth a try.

[StevenJM]

I have a ton of resistors to play with... Maybe I should try a 470ohm resistor there and maybe I'll recover volume?  And it won't hurt the transistor?

[joegagan]

yes, this will not hurt anything. you might even like 330, 270, or smaller! use alligator clips and your bypass switch to figure out the optimal volume. please let us know how this works out.

also, can you do me a favor ( not sure if this forum allows modifying the thread title ), can you go back and modify the title to include 'superfuzz'? this way, future pedal people can find it in a search if they have this problem

[StevenJM]

Cool... I changed the subject.  Good point about future searches... I was having a hard time turning up any results through google.  I'll let you know how it goes tonight.  I haven't checked my schematic yet this morning, but hopefully that resistor is easy to find in this circuit.

[joegagan]

in this case, trace it backwards from the switch. there will be very few components between it & the last trans.

[StevenJM]

Thanks, I'll definitely look into it after work.

First im taking it to my bands spot, to test it with my 59 bassman

[StevenJM]

http://www.experimentalistsanonymous.com/diy/Schematics/Fuzz%20and%20Fuzzy%20Noisemakers/Shin-ei%20Fuzz%20Wah.gif

So I found the schematic online... It looks there's a 1.9K ohm resistor coming off of the emitter of the last transistor.  Should be easy enough to find on the circuit board.   I'll post results tonight or tomorrow.

Can anyone confirm that this is the super-fuzz... It looks pretty similar, same transistors, but looks a little different in some spots but I'm still getting used to reading schematics.

[DiscoVlad]

Yeah, it is the same schematic, it's just laid out differently (the Q4/Q5 pair is most obvious), and the 22k input resistor is missing - Ground (0V) is the central horizontal line with the fuzz part above, and the Wah section below.

I believe there were a couple of different revisions of the Fuzz wah, some with separate Superfuzz and Wah boards, and others with both circuits combined on one board.

[StevenJM]

Yea mine has both on one board.  and it has a resistor connected directly to the input jack... Probably the 22k resistor.  I'll have to check.  I was able to find the 1K resistor off of the emitter of the last transistor.

The fuzz sounds amazing i just need more volume to work with. 

[John Lyons]

Bypass the last transistor's 1k with a 10uf cap (cap across the 1k).
Start with the volume lower when you audition it. 

[StevenJM]

I put in a 220ohm resistor in place of the 1K and now it doesn't work, unless i crank my amp, then i can faintly hear the effect.

The original resistors are a tad bit bigger than my 1/4 watt resistors, so i'm wondering if the originals are 1/2 watt resistors.



so your advice is to put a 10uf cap instead of a 1k resistor?  i'm not sure i understand what your suggesting... I d have any spare caps though.

[John Lyons]

Replacing the 1K cap with something smaller will misbias the tranistor somewhat.
Replace the 1K resistor and place a 10uf cap in parallel with it like the transistor just to the left of it.

[DiscoVlad]

I'd check to see if the transistor voltages are in the right ballpark first:
http://www.diystompboxes.com/smfforum/index.php?topic=64068.0

Just in case there's a problem somewhere else - dried out caps maybe?

[StevenJM]

this is going to take me a while to determine which transistor is which.  these old boards aren't the most friendly to navigate through.

[StevenJM]

I'm not 100% positive this right...  but I *THINK* it could be right.  it was confusing because i read that these transistors go Emitter, Collecter, Base (from left to right) rather than E,B,C like I'm used to.

Battery:  8.95

Q1
C=4.87
B=0.69
E=0.08

Q2
C=8.58
B=2.48
E=2.67

Q3
C=6.25
B=2.99
E=2.59

Q4
C=2.75
B=1.52
E=0.92

Q5
C=2.75
B=1.53
E=0.92

Q6
C=0.30
B=8.94
E=0.19

[joegagan]

yes, forgot to mention, in my brief experience with 3 of these, all of them needed the electros replaced.

to find your last trans, it should be the closest one to output. sorry, don't have time to look over your voltages til later.

[joegagan]

now i am confused. i have seen two different configurations of the last transistor on different schematics.

[StevenJM]

all the electro's look old, they're all 10uFs ... maybe i'll just order some and plan on replacing them. 

Not including my readings, i've found 3 different readings now for Q6 on different sites. 

And my Q6 is a 4th different reading... i'm not really sure what the deal is with that...

[StevenJM]

I ordered some 10ufs... Figured why not?  It's an old pedal and it won't hurt.

Also grabbed some 1/2 watt resistors at radio shack this morning.

I'm excited to get this pedal back to full strength!