#1
So, I decided to try building a Big Muff, the one at tonepad. I finished it up earlier today, but it's not nearly as loud as it should be. I have to crank my amp up over half way to be able to hear it decently. I double checked my connections, and everything seems to be ok. Does anyone who's built one have an idea where I could start with the trouble shooting?
MG Free At Last
#3
When you ask for transistor voltages, are you recommending measuring them as a means of testing it?
MG Free At Last
#4
I mean measure their voltages. Connect the power source, set the multimeter to Voltage, attach the black multimeter lead to ground, and connect the red multimeter to the different legs of the transisors and post what you get for each. Label the legs.
#5
Transistor 1:
Collector ~ 3.75 V
Base ~ 0.60 V
Emitter ~ 25 mV

Transistor 2:
Collector ~ 3.7 V
Base ~ 0.60 V
Emitter ~ 27 mV

Transistor 3:
Collector ~ 3.9 V
Base ~ 0.60 V
Emitter ~ 27 mV

Transistor 4:
Collector ~ 8 V
Base ~ 1.6 V
Emitter ~ 8 V

If I were a betting man I'd say it was in the last one somewhere.
MG Free At Last
#6
Yea. Looks like the last transistor is a bit high on the Collector. Everything else looks like it should be good. I like biases of the high 3v and medium 4v so they look fine. So check the 4th trannie.
#7
Awesome. I had a short from the emmiter to my +9v rail. Works like a charm now. Thanks for the help guys!

EDIT: Anyone have any tips on how to enclose it?
MG Free At Last
Last edited by ljplum12 at Jan 19, 2007,
#8
Yeah, the 8v on the emitter stuck out to me. Cool.

Read the stickies for a whole mess of links relating to pedals.
I'm not very active here on UG currently.
I'm a retired Supermod off to the greener pastures of the real world.
#9
does it sound muffy? and describe its muffy sound? i might want to build one.
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#11
Well, I screwed something up. Like a dumbass I tried adding the millenium true bypass and now it's kinda the opposite, when the volume knob is really low it works ok, but if I turn it at all it starts sounding like someone is sodomising a cow. Transistor one two and three are the same, but that last one looks like this now:

Collector ~ 4.3 V
Base ~ 1.6 V
Emitter ~ .95 V

When I was putting together the other circuit I accidently had power short directly to ground. Could that have fried my transistor or something?
MG Free At Last
#12
Well, I'm back to the original problem of not enough volume. Also, there's a really high pitched whistle if I turn my amp up beyond a certain point.
MG Free At Last
#13
The squeal is just feedback, that's normal and not a product of the pedal.

Check for shorts and stuff, and more transistor voltages are good.
I'm not very active here on UG currently.
I'm a retired Supermod off to the greener pastures of the real world.
#14
This thing is driving me crazy. Went back over the circuit again. Checked transistor voltages again:

Transistor 1:
Collector ~ 3.75 V
Base ~ 0.60 V
Emitter ~ 25 mV

Transistor 2:
Collector ~ 3.7 V
Base ~ 0.60 V
Emitter ~ 27 mV

Transistor 3:
Collector ~ 3.9 V
Base ~ 0.60 V
Emitter ~ 27 mV

Transistor 4:
Collector ~ 4.1 V
Base ~ 1.6 V
Emitter ~ 1 V
MG Free At Last
#16
Finally found the problem. I had a tiny spec of solder across two of the pads, one of them into the emitter of the fourth transistor, and fixed it, so it works again. Now if only I can get it into an enclosure without messing anything else up. Thanks for the help pink, call and others.
MG Free At Last
#17
make an enclosure out of a frying pan. get a small one and cut the handle off, and get like a cookie sheet or sumtni. it will look like a fuzz face.
My Blog
New bands you wish you knew about!

Check This Band:As Blood Runs Black
Guitarist of the month: Quorthon


Got a good band that you want to share with the world? PM me and I'll write them a review.