Debug my first build! (Bazz Fuss)

DerHoggz · February 10, 2010, 09:30:12 PM

Decided to try my hand at a simple project for the day off, so I went with this (the top one).

http://www.home-wrecker.com/bazz.html

It says you can use any NPN Darlington so I went with the only one Radioshack had, a TIP120.

Built it and, nothing. no sound.

Voltages by points in this pic:

0 = >9v
1 = <2v
2 = <2v
3 = 0v
4 = 1v
5 = 0v
6 = 1v
7 = 1v
8 = <2v

Oh, I'm using an active bass, newish battery.

glops · February 10, 2010, 11:24:03 PM

Go back to Radio Shack and get 2N3904 or 2N5089 and build the BF from the first schematic on this link, http://www.home-wrecker.com/bazz.html The schematic is almost identical to the 2nd schematic using the Darlington, which is what you are building from via the link you posted. If you notice, the only difference in the schematic is the value of the collector resistor. 100k via 2N3904/5089 and 10k via the Darlington version. Build the first one if you can't find MPSA13 at R Shack.

Don't think the transistor you are using will work (I could be wrong) For Darlingtons the in the Bazz Fuss, people tend to use MPSA13.

Did you solder a board or do you have it on breadboard?

DerHoggz · February 10, 2010, 11:33:56 PM

Alright, will I need to swap out the resistor?

It is soldered, couldn't find my breadboard.

glops · February 11, 2010, 12:13:09 AM

Yeah, if you go with 2N3904 or 2N5088, swap the 10k you have soldered with a 100k. At my closest radio shacks they only have 3904s. Try those and you will get sound if your solder connections are good and your switch and jacks wiring are correct. That circuit is great to play with on a breadboard, switching out components for different sounds, etc. My favorite pedal that I've built (only 4 so far....) is that circuit. I tried variations ala the link I posted, but ended up with 3 in series with a lot of tweaks to get it to sound great and used uncommon diodes I picked up from a local surplus electronics store. Stayed on the breadboard for a long time but I ended up with a sound that seems unique, but who knows, maybe it's not. I need to go back to the circuit because although it sounds great as a standalone effect, it works horribly with my other pedals. I think some impedance issues.

Anyway, the link I sent you is a good read, and if you follow the instructions you will get sound. Personally, I always breadboard a circuit first before going to perf just so I can experiment.....

Good luck, the BF is awesome. I you want another low parts, easy to build fuzz, I highly recommend the Colorsound One Knob Fuzz. Do it on breadboard, and test different transistors, etc. It has tons of gain and is incredible, I wish that one was my first.

DerHoggz · February 11, 2010, 09:40:35 PM

Alright, got a 2N3904 and a 100K resistor swapped in... nothing.

I'm not reading any voltage to the collector on my (analog) voltmeter.

Now what?

DerHoggz · February 12, 2010, 08:43:34 PM

Bump to the first page, any ideas here?

glops · February 12, 2010, 11:25:36 PM

double check your wiring for the jacks and the switch and make sure the transistor is oriented the right way according to the pinout. Is this your first build? Making sure all the wiring was proper was really tough for me on my first build. It is a pretty easy circuit. Make sure you soldered connections are good....

DerHoggz · February 13, 2010, 10:09:12 AM

Quote from: glops on February 12, 2010, 11:25:36 PMMake sure you soldered connections are good....

Hehe, just noticed there wasn't a path for my input after the cap, must have come undone when I soldered in the new transistor. The soldering is real ugly.

DerHoggz · February 13, 2010, 10:48:59 AM

Ugh, I realized there was no voltage on the collector because the input resistor had come loose, resoldered it and now it isn't passing anything. Heat damage possibly? I did rip this resistor out of an old TV. Can't find any others, I lost this big bag of random components.

flintstoned · February 13, 2010, 11:09:45 AM

If you use a borrowed resistor from an old component, use an ohmmeter on it first to see if its still good. I've burnt up a lot of trannies swapping em out like that too! Always buy extra!

DerHoggz · February 13, 2010, 01:56:59 PM

Put a new transistor in and nothing, but there is voltage on the collector now!

flintstoned · February 13, 2010, 03:05:18 PM

Whats your voltage readings now?

DerHoggz · February 13, 2010, 03:11:37 PM

Fixed it, turns out I had grounded the negative side of the input cap. Doh!

What if I did the second stage, but with a 10K resistor?

Kearns892 · February 13, 2010, 06:08:30 PM

If by second stage you mean turning it into a buzz box (second schematic), that should give you a slight octave up effect

DerHoggz · February 13, 2010, 06:52:14 PM

Yeah, could I just use two 10Ks as in the schematic?

glops · February 13, 2010, 10:38:26 PM

Yes, follow the schematic. Otherwise, you might not get anything.

bluelang · February 13, 2010, 10:42:47 PM

Did you find your breadboard yet...?

That might be the first right step..

DerHoggz · February 14, 2010, 12:54:47 AM

This build is a mix of two schematics, so I'm not all that sure.

Last time I used that breadboard was a couple of months ago, who knows where it could be.

walker · February 18, 2010, 12:37:44 AM

which direction do the two Capacitors go... because I've seen several conflicting schematics, including the beavisboard project one.

DerHoggz · February 20, 2010, 04:16:23 PM

I have the caps so that the negative side points to either the output or input.

One problem though, the volume pot also controls the bypassed volume, this shouldn't happen right?

Should I have the switch (SPDT) at the input or output?

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Debug my first build! (Bazz Fuss)