Beavis Breakout Box Woes

[Jdansti]

Well, the jack issue needed to be corrected, but it might have been a coincidental problem. No offense, but we are assuming that the correction is correct.

Maybe another set of photos would help. If possible, include shots showing the wiring between the breadboard and the box and also the wiring to any offboard components. It would be good to know the color bands on the resistor as well.

[slacker]

I'd start with a much simpler circuit, once that works you know the box works, until you know that you're trying to debug two things at once.

Starting with Beavis's bazzfuss pdf remove everything except the top 10uf cap and the in wire. Then connect the 10k resistor from A7 to ground and connect the out wire to d7.

The box should now pass sound when bypassed and on, if it doesn't you still have a problem with the wiring in the box.

[audiolife]

Ok! I tried what slacker suggested, and it did pass audio. It was noticeably quieter when the stomp was engaged, but it worked!

So...now the issue would be the circuit?

[davent]

Took me for what seemed like forever to successfully breadboard a circuit, i find it pretty easy to screw up even the simplist of circuits and screwed up is still a given for me, failed connections because leads are plugged into the wrong row, transistors wrong way 'round... Like most things with this hobby it took lots of practice to start seeing success.

Now that you've sorted out your board and box... stick with those Beavis examples, follow them exactly and things will fall into place.

dave

[Jdansti]

Ok! I tried what slacker suggested, and it did pass audio. It was noticeably quieter when the stomp was engaged, but it worked!

So...now the issue would be the circuit?

Maybe. If it were me, I would split the problem in two at this point. There are two ways to do this.

Option 1) Disconnect all of the wires between the box and the breadboard. Hook up a 9V battery or PS to the breadboard. Connect two spare jacks to the in/out wires of the effect and ground the jacks to the breadboard. Watch your tips and sleeves. Plug the guitar and amp into the appropriate jacks and see what you get. If you get the same low volume, then the problem is the effect. This assumes that the guitar, cables, amp, and your ears are all functioning properly. If it sounds like it's supposed to, then you have a problem with the box.

Option 2) The other option is to take a working stompbox and connect the in/out to the terminal strip in/out (there are at least a couple of ways to do this). Use a known good power source for the stompbox and make sure the stomp switch is in the "effect on" position. Connect the guitar and amp to the Beavis box. Play and cycle the Beavis Box bypass switch a few times. If the "effect on" switch position has low volume, then you have a problem with the Beavis box.

[audiolife]

Nothing is EVER easy with this stuff! 

So there's no chance that the slight volume drop could be due to the signal traveling through the cap and resistor, with nothing to bring the gain back up (like a transistor)? Could be a totally noobish question but I figured I'd ask.

[slacker]

Yes it could be, the 10k resistor will cause tonesuck and some volume loss, remove the resistor leaving just the cap connected and your volume should go up to normal.
If that works then I'd say your box is working. The only other thing I would check is that you are getting power from the box to the breadboard.

[audiolife]

SUCCESS!!!

Removing the resistor made it unity when bypassed and on. Just to be sure I popped the res back in the circuit and got the original result. So the problem was the circuit all along. I'll take a crack at it again.

Thanks so much for all of the help!

[audiolife]

So after taking a nice break from building these things I came back to it today. I threw up another of the Beavis projects (love this guy), the LPB1 Booster.

http://www.beavisaudio.com/bboard/projects/bbp_LPB1.pdf

I have the same issue with this circuit. Bypasses fine, nothing when on. The board is getting power, and I'm very confident that the problem isn't the breakout box. I even tried slacker's suggestion again to success. I've narrowed down the point in the LPB circuit where audio is lost. It is right at B and C on the transistor. Everything after C passes signal, everything before B is nothing. I've tried swapping transistors, same thing.

Just wondering if any of you might have any advice on this?

[Jdansti]

If it were me, I would first triple check all of your component values, placement, and polarity.  Then thoroughly recheck offboard connections again.

If I didn't find anything, I would temporarily remove all connections to the breakout box and connect the jacks and power directly to the breadboard. If it still didn't work (assuming the power and jacks were properly connected), then I would continue troubleshooting the circuit.

[slacker]

Can you post a good quality photo of how you have the LPB on the breadboard, if possible showing the connection to the Beavis box. I've just noticed in your earlier bass fuzz photo you don't appear to have ground connected, so perhaps you have a similar problem.

[audiolife]

I'll post a pic as soon as I can. In the photo mentioned the ground is connect out of the GR terminal and into the bottom-most breadboard ground rail in the picture. It is then jumpered across to the other ground rail.

[Pyr0]

Just a thought, I've got a couple of different bread boards, and some of them do not have a continuous ground and power rails, on one of mine there is a break every 10 points, so I have to jumper the ground/power rails between segments to get stuff working, so it might be worth checking the continuity of those top and bottom rails on your breadboard.

[deadastronaut]

^ yep good call,  i wired up a new breadboard for true bypass earlier.

the grounds were ALL connected...but the V (red) rail had to be jumpered every 2 blocks/lots of 6....


blocks of 5 in your case...

[audiolife]

After yet another reprieve and since trying 3 different Beavis projects, there still is something wrong with the breakoutbox setup. I feel I've narrowed it down to either a power or ground issue, as when I test the power rail while grounded to ground rail it measures approx. 3.5v, but when I touch the ground probe of the DMM to the metal enclosure the power rail reads around 12v.

Still no sound when effect is engaged.

This is the main project I was testing with due to low parts count:

http://www.beavisaudio.com/bboard/projects/bbp_BazzFuss.pdf

I built it from scratch and tested signal flow every step of the way and it only cut out when the transistor was added, that would be a power thing right?

I'll test the power rail continuity when I get home from work.

Cheers!

[deadastronaut]

so your breakout box is fine when bypassed.

but not when in/outs/grounds are connected on breadboard..(no circuit just in/out connected on breadboard..) try that as a test.

if no sound when on , then sounds like your switch wiring....

[slacker]

He's already tried that Rob, the switching part appears to work fine.

Does sound like a power issue with those readings, I would try the following:
Disconnect the bread board and measure the voltage right at the DC jack, if your power supply is 12 volts you should get 12 volts. Switch the pedal between bypass and on the voltage shouldn't change, if it does you've probably wired the LED wrong.
Then measure the voltage at the V+ and Ground screws on the connector block, you should get the same voltages.
Then connect wires from V+ to one of the strips on the breadboard and Ground to another one, measure the voltages between those strips, you should get 12 volts, if not there's something wrong with the breadboard or with the connections on the connector block.

To be honest at this point I would follow John's earlier advice and buy a couple of jacks and test the circuit on breadboard completely independently, you're still potentially trying to debug two things at once.

[audiolife]

Ok so I pulled and tested the V+ and ground and everything measures as it should, rails included. For some reason...still nothing when engaged.

[deadastronaut]

@ian: okey dokey..

well just for the hell of it, heres how i have each of  my breadboards setup..

i just have the jacks/switch/ led/dc socket  on a back panel.....same as your breakout box really , ....and wired as this...i never have any problems, true bypass etc....its the same as having the pedal boxed. (no sheilding obviously)

but a great tool for trying stuff out...




blue in/ grey out...



a bit messy , but i put this one together xmas day ....after a few whskies..

[audiolife]

This morning I tried as suggested - I wired up other 1/4" jacks and powered the breadboard with a battery, totally independent from the breakout box. The project I had on there was this one:

http://beavisaudio.com/bboard/projects/bbp_MuffFuzz.pdf

While it did pass audio there really wasn't much "fuzz" and I wasn't sure if it sounded right as I don't really know how it's supposed to sound.

I was encouraged by this and proceeded to try the bazz fuss again, due to the low parts count it's been the circuit I've been using mostly to troubleshoot this.

Same result as usual, no audio.

That's where I am now, still as confused as ever