umi buzztone and expander

[pinkjimiphoton]

this was my second fuzzbox, always intended to build one again, finally got around to it...
this thing sounds just like my original pretty much..not a fuzz, but a BUZZ...different animal...
anyways, here's a vero of it, which i verified...if someone else feels like making one, and it works, please let me know, i never trust my own verification. 



here's the schem:



i used russian mp16b's, hfe of around 90 and 130. neat sounding box.

where it says no connection necessary, it means it...the buzz/vol expander switch can be spst even if you want. or...you may wanna just connect the buzz to the ground rail so it's always on...the volume expander is nothing but a very slight, and kinda muddy, boost.

rock on!

[LucifersTrip]

It's about time you built that bastard!  It has quickly become one of my favorite fuzzes (which is why I built it for the 1000 comp) and has to be one of the most underrated germanium ones...

It really doesn't sound like any other....and doesn't look like a direct knock off of any common fuzz... and judging by the lack of hits, it looks like hardly anyone here has built it.

I did experiment with a ton of transistors for this one and I always wind up with lower leak ones (so you've chosen wisely with the Russians) in the 70 - 80 hfe range for both.

As you noted, the "expander" is not a big deal, but I did leave it in there on my first one. For the 1000 comp, I have the fuzz/buzz full on.

In certain positions with the "buzz" and "contour", you should be able to get some hints of octave at the 12th fret and beyond...

I'm sure you saw the Conrad Buzz Box and Vol Expander, which is basically the same without the tone control
http://tonebender.webs.com/CONRAD%20BUZZ.GIF

[pinkjimiphoton]

i love the tone knob on this thing, really is effective at finding a good tonal notch for any guitar you throw at it.

this was my second pedal, always wanted another...so yah, was time to build one. it really does sound different from other fuzzes and even other buzztones...this has a really smooth decay, and like you said, a hint of octave (which a starve control with really hot trannys gives more of...it's cool, you can get octave up AND down at some settings).

i guess we share great taste in weird boxes bro...lol!!

[mac]

Let's play with it this weekend!

Do you have voltage readings?

mac

[pinkjimiphoton]

nope, sorry, didn't really think of it.

i just kinda kept subbing transistors til i found some that i liked together.

but the hotter ones...maybe leakier ones..  ....with higher hfe's were definitely getting a little octave stuff happening.
could have been the battery in my ruby dieing too, tho...so i better check.

[LucifersTrip]

Let's play with it this weekend!

Do you have voltage readings?

mac

Here's from the first one I made...a killer:

[bluesdevil]

Looking forward to another "Stupid Pedal Tricks" video.
I've been on a fuzz kick for the last month, will have to slap this on my breadboard after I hammer out the tweaks on my current Heathkit Fuzz build..... thanks again for the inspiration!

[pinkjimiphoton]

you can never be too rich,
have too many guitars,
or too many fuzzes...

stupid pedal tricks to come...lol. one of these days.
it's funny, some hoser left a comment on one of them videos today that i was baked outta my mind.
lol.

i don't need to get baked to be like that.   

[bluesdevil]

Got it built up with the diode fixed to ground to get rid of the switch.
Just have a question:
The "buzz" control seems to be acting like a volume control (wired backwards), is this right or did I screw up somewhere?

[pinkjimiphoton]

reverse the connections to pins one and three. i always forget which is which, and i've seen it backwards so many times i have no idea which is which...sorry bro, probably my bad.

the switch is hip tho, cuz you can get a nice clean boost OR the buzz

[bluesdevil]

Thanks Jimi..... btw, what is the purpose of the "Buzz" control?
Should probably just hard wire it for full on the way it sounds, I guess.
 

[LucifersTrip]

Thanks Jimi..... btw, what is the purpose of the "Buzz" control?
Should probably just hard wire it for full on the way it sounds, I guess.
 

you get good tones throughout most of the sweep. it's definitely worth keeping.

[bluesdevil]

Yeah, I'm playing around with it more and hearing some smoother tones on the pot range, but the volume drops too much for my taste below a 1/4 full up.... maybe fine with weaker output single coils to keep it at unity gain. Maybe I got a mistake somewhere too.
   I don't know, I just finished up the Heathkit fuzz build a few days ago and probably just has me spoiled.
Hey Jimi: Build the Fuzz-Rite next!!

[pinkjimiphoton]

hey bill, my buzztone gets more distorted, not really louder...if anything, more compressed (= sounds louder) the last quarter turn or so.

that heathkit does sound nice, doesn't it?

can't do the fuzzrite yet, mark got me sucked into a harmonic percolator project which i have fail'd at epically

[bluesdevil]

Thanks, man. Mine is the opposite it seems, the more compression the lower the volume.
I think it may be that I use a lot of bass on my amp and the circuit cuts a lot of low end so the perception is lower volume compared to bypass.

[mac]

I played with it today. As suggested in the above schem I chose a pair of Hitachi 2SB77, both around 80 & 160ua, and a non-leaky new 1N60 diode.
Nice buzz, although some contour settings are too bright for me, even with these high internal capicitance germs.
The Buzz pot mixes both outputs, in a way that completely overrides the second transistor when the wiper is at the battery side. Cool!
I'll try this way in a Fuzzrite.
The expander is ok, but as I prefer treble boosters, I'd add a double switch to decrease the input cap when the expander is engaged.

mac

[pinkjimiphoton]

mac, that's a great idea, cuz imho the volume expander is a little "dull" sounding.
i'd love to know how that works out, so please let us know!!

[bluesdevil]

I think I'll try a DPDT. One side for taken out the diode/emitter to ground and the other side to switch between different caps. You can wire one lead of each cap together and then take the other individual leads to each leftover lug of the switch. The middle lug of the switch (cap side) goes to offboard input wire. Then solder a wire from the connected cap leads to where the input cap goes onboard.

[mac]

I think I'll try a DPDT. One side for taken out the diode/emitter to ground and the other side to switch between different caps. You can wire one lead of each cap together and then take the other individual leads to each leftover lug of the switch. The middle lug of the switch (cap side) goes to offboard input wire. Then solder a wire from the connected cap leads to where the input cap goes onboard.

"double switch"  = DPDT

mac

[bluesdevil]

Just tried it with everything from .0068 to .047uf. Still sounds like shiiitt no matter what I you put in there..... to hell with the expander, I'm going to hard wire it out.
Man, I'm sorry for stinking up this thread with my posts.... I think that's it for me!