Bazz Fuss Debugging - PLEASE HELP!!!

Started by mr.adambeck, June 16, 2009, 09:35:42 PM

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mr.adambeck

Hi, so I built a Bazz Fuss for my friend (who paid for all the parts, so I really want to get this working properly), with a Battery Sag and BMP tone control that I found on beavisaudio.com
I'm going to try to remember all the little details, but honestly, I'm not completely sure about the order and timing of a few things.
The night I built it, it sounded good, but there was a really, really high pitch ringing in it on most settings.  Even though it was running off of a battery, I wasn't sure if it had to do with my house or not (I've noticed grounding buzz on almost all of my audio equipment, and the bass amp was plugged into the wall), so I took it to practice and ran it through her rig.  The tone was GREAT, but the high pitch noise was there, so we took it out, and went through with our regular practice.  Afterwards, I wanted to mess around with it again, so we plugged it into her ac adapter (I'm not sure if it was plugged into that or running off of battery the first time), and this time it made a CRAZY high pitched screetch.  I noticed that the screetch had something to do with the bass's volume being all the way down.  The screetch only happened if the volume on the bass was all the way down, but when the bass had it's volume on it was fine.  However, shortly after that I noticed that the pedals fuzz/distortion was gone.  It just sounded pretty much like the pedal was bypassed or something.

Upon taking it home, I traded out some parts and got the fuzz to work via battery, but when plugging it into an AC adapter, the fuzz went away.  I now can't get it to work again, even through the battery power.  I don't know what I did exactly but here are some things I remember.
In my trouble shooting I have switched the transistor pins as well as the electrolytic caps orientations a couple times.  Could I have friend them or something?
One thing that's also not supposed to happen is that if the AC Adapter is plugged in the pedal will activate even if there's nothing plugged into it (I thought I wired it so that it would only drain battery if a cord was plugged in the input).  If the ac adapter isn't, the LED lights up a little, but not as much. I wasn't 100% sure of how the diode was supposed to be oriented, I put the side with the black line "Up" (according to the layout).  Also I socketed the caps and the transistor, (...I don't know what info is helpful and what's not, so I'm just trying to be as thorough as possible!) and used an "Ultra-bright" Blue LED (I don't remember the resistor value I used on the LED, but it does seem to be a bit too bright, if that means anything).

so here's the layout I used for the PCB (I didn't use the wiring though):


When it was working, I had 10uf Electrolytic caps with the negative side facing the top of the layout (I think, but honestly I've switched them around a bunch at this point, so I'm not 100% positive). 

I used this tone filter:


I used this "Voltage sag":


And I used this wiring:

--One this I had done different about the wiring was that I had connected the grounds from the input and output to each other.  While trying to troubleshoot I cut that wire though.  So it's they're longer connected.

...I might be able to send pictures later if that would help, but my camera's battery is recharging.

PLEASE help.  This was one of a very small few boxes that I had actually gotten to work and I was really excited about it!

mr.adambeck

okay, so I took a break, ate some dinner and decided to have a go at it again.  I figured from the fact that a battery would work, but the power supply wouldn't, that it was something to do with the power wiring.  I put in a fresh pair of caps (not the values I'd like, but just top be sure, I grabbed a couple that hadn't been used.).  Then I carefully cut the heat shrink off of the connection that goes from the DC jack to the board and LED.
All of the sudden, it's now making fuzz, both with the battery as well as an adapter, however, there are two odd changes between the two:

1) With the battery, the tone is GREAT, exactly what we were looking for, just like the sound clips I've heard, but once again, there's that really high pitched noise (it sounds like my ears ringing after a loud concert, but maybe an octave lower than that).  The high pitch stays there even when the effect is bypassed.
2) with the AC adapter, there's no longer the high pitched noise, but the tone of the fuzz has far less high end, and doesn't sound too good at all.

I noticed that on my it jack looks a little like there's a part of it coming off.  Not the wiring, but an actual part of the jack looks like it's coming apart.  I can't find any extra jacks right now (I SWEAR that I have one somewhere, ARGH!), so I think I gotta wait and swing by Radioshack tomorrow or something.

I hope this is the problem, but if anyone has any other ideas, I have a tendency to overlook painfully obvious issues with circuits!

mr.adambeck

Okay, so, I do realize I'm just talking to myself here, but I replaced the power jack, and that DID get rid of the high frequency background noise!  However, the fuzz still doesn't sound as clear and bright through the adapter as it does with a battery... 
My adapter I keep at home isn't necessarily made for pedals, could that be the problem?  I don't know if there's such a thing as a bad sounding adapter...  I won't be heading out to my practice space until Thursday night (and I can try it through my OneSpot then.), so in the meantime, I gues I'm just left wondering.

Also - I'm still having the problem where when I turn the volume of the bass all the way down to mute it, theres a really odd high screechy note, but it only happens with battery power, and not the adapter. - I'm so confused!

mr.adambeck

Err... wait, no.
Oddly enough, using battery power the high freq. noise is there when the pedal is bypassed, but not when the pedal is engaged.  However there sees to be a bit of grounding hum with the battery power that could be covering it up.

Okay, I realize how many times I've posted.  I promise I'll stop soon.  :icon_redface:

JOHNO

do you have a volt meter? Check the voltages at the transistor. I'm pretty sure the caps should be oriented like this. C1+ to base of transistor and C2+ to collector.

mr.adambeck

I don't have a voltmeter yet...   :icon_rolleyes:
Hopefully soon.  I'll double check the cap orientations!  Thanks!

mr.adambeck

Okay, so I'm not great at reading schematics (I usually stick to pictures of layouts) - however, from this schematic:

It looks to me like the layout I used up there ^^^ might have the diode backwards.

Am I right?

I'm going to try this - I can't permanently fry any components trying this, right???

I hope not!

JOHNO

#7
I just threw this circuit on the breadboard and it works fine. If i turn the diode around it doesnt work at all. I would check all your wiring and the circuit
for mistakes and or shorts. I think the rog schemo is incorrect

mr.adambeck

crap.  So it's definitely not the diode?  Because  just spent twenty minutes getting that tiny thing off of the board!   :icon_cry:

mr.adambeck

f-ing sh!t

I took the diode out, now I can't get it back in and get the pedal working.  II think I might need to rebuild this whole thing as everythings just coming unsoldered during the "debugging" process and falling apart.  ARGGGGGHHHHHH  :icon_evil:

mr.adambeck

Okay, so sorry to keep posting over and over and over and over.  I have a question RE: diodes.
The diode in this is a very small red piece with a black line on one end.
I found this picture on the net which says which way the diode is to be oriented:


so, according to this layout, which is the one I used, the black line should be facing the top of the board, connecting to R1 and the C pin of the transistor:


However, according to this layout, it looks like the black line should be attaching to the B pin of the transistor:


Then, according to this eyelet layout, it looks like the black line connects to the B pin again:


Sorry to simplify it so much and refer to it constantly as the "black line", but I think it will make me get this correctly if I keep the terms as such.  I could easily be getting things confused, as I am really new to all this.  However, are you sure the black line of the diode needs to connect to the C pin and not the B pin?  Thanks!

Br4d13y

yes. my bazz fuss did not work, i used the same layout, then i flipped the diode and BAM!!! fuzz
freedom is the freedom to say 2+2=4

JOHNO

The black line "cathode" of the diode goes to the collector "C" of the transistor. It still works even with the diode removed. I'm not sure what that diode even does perhaps some could enlighten us. Its a crappy sounding fuzz any way IMO just build a big muff.

duckpow

Sry to disagree with you Johno but I think it's a great fuzz!

And Mr.adam: Please keep us posted! You might think that you're just talking to yourself, but I have learned a lot from your troubleshooting!
I have Bass fuzz of my own that sometimes work and sometimes doesn't!
Banders Duckpow

Derringer



You're right. The diode in this layout is incorrect for the used transistors. My guess is that whoever made the diagram, did so with a (BCE) darlington tranny in mind but then accidentally labeled it as (CBE) ... which is the pinout of the MPSA13.

Check all of your solder joints too.


Keep at it. You'll get it!

mr.adambeck

Thanks for the feedback, help and encouragement.  I'm going to be too busy the next couple days to get much work done, but I'm not going to give up on this!

mr.adambeck

Okay, so...
I took the original schematic and a breadboard layout from Beavis and came up with an entirely new stripboard layout for this:


I have it up and running!  I think it'll work out great, but I'm hesitant to say it's actually working until I've given it the full run around at our practice space through a real amp and all that.

Definitely none of the weird bugs I was having before though!

This was exciting for me, as I've never put together my own layout before.

slacker

#17
That looks good, except C1 is the wrong way round, the positive end should go towards the base of the transistor. Flip that and hopefully you'll have it working.

Congratulations on your first layout :)

mr.adambeck

Slacker-- You're right!  :icon_redface:
Thanks!

Here's an updated layout if anyone wants to ever use it:


JOHNO

It seems i screwed this circuit up and Ive missled you Adam. My apologies. I don't know what went wrong the first time i stuck it on the bread board but the lay out you came up with works ace. And the diode does indeed change the sound of the circuit. And now that its working correctly i must admit that its not a bad sounding fuzz at all. Glad you stuck with it a got it working, sorry for the confusion.   Johno