noisy cricket gain led

[markrocknroll]

Going to build the noisy cricket.  how do you wire up that dpdt grit switch to the grit led?  is a standard on-on dpdt switch the correct one.

[awdman]

Mark,

yes a standard DPDT switch will work, think of it has two seperate switches put together.

Hook your LED + lead to one side of the switch and the other side other side and the switch to voltage then the Led - goes to ground.

make sure the led turns on when the gain is enganged.

Anthony

[Slimbo]

I saw that on the instructions, and they didnt mention a series resistor. I'd look at putting one with the LED.

[markrocknroll]

I built the noisy cricket in a cigar box with a 4 inch speaker.  Used the RadioShack IC.  I powered it up and no output.  It's dead quiet, no hum.  Power LED works.  I checked the voltage at pin 5 of the LM386 and got ~8.6VDC.  Adjusted the volume all the way down and got ~7.9 VDC.  I have checked the build against the schematic several times and can't see a mistake.  Is there some troubleshooting steps I should take.  Help.

[J M Fahey]

Hi, what does your "  ~ " sign  mean?

[markrocknroll]

approximately

[tonyharker]

You definitely have something wrong.  Varying the volume should not change the output DC voltage. 
The voltage at pin 5 should be about half of the supply voltage (eg 4.5 volts if you are running it from a 9V battery). 
Are you building it on the Radio Shack board?  Have you tried swapping the IC as you may have a dud one - it does happen.  You did use a socket didn't you??   I dont know what else to suggest.

[markrocknroll]

Yeah I built it on a RS IC.  What could go wrong with it.  The traces look good.  I could swap the board because that would force me to redo it and mybe find where I messed it up.

Of course I didn't use sockets.  That would make this too easy. 

I think I may have measured wrong before.  The voltage at pin 6 is 8.9VDC and at pin 5 is 8.0VDC.  Adjusting the volume does changes nothing.  Still this is not working correctly.  When I measure across the speaker I get nothing.  I expected the same reading as pin 5.

I'm starting to think I have no idea what I'm doing.  (I've successfully build 2 tube amps and several stomp boxes)

[phatt]

Hello markRRoll
You don't just *LOOK* at a soldered circuit,, as even with good eye sight you will not see a (thinner than hair) strand of copper from a striped wire.
They fall off as you strip and can get soldered across tracks and it will drive you mad till you find it.  (Yes I'm speaking from experience)

Scub the track side of boards with a stiff brush*After* you solder them.

If you use sockets for opamps,, makes life a lot harder as it's just another place for a bad connection, (Personal Experience again) IMO they are trouble waiting to happen.
Phil.

[markrocknroll]

OK, I rebuilt this thing from the ground up.  Did it on a perf board (was on the Radio Shack Board).  Did it real slow and checked each solder as I did it.  I still have a problem.  When the Tone is turned all the way up it kind of sputters.  Kinda like there's a loose connection somewhere (intermitant).  However with the Tone all the way off, it sounds better.  You can get a real sweet spot with the Tone all the way down, Gain rolled off about 50%, Grit swithch on and Volume all the way up.  Also, I don't think it's as loud as it should be.  I have changed out the Tone switch, cap on the Tone pot and retouched every solder joint.  I have also checked continutity of all gound connections.  I have changed out the amp and transistor.  I have check, double checked and triple checked the layout.  I checked everything I can think of. Can someone help?

[vividlucidity]

i am planning on building one soon myself.  according to one build write up, the visual image of the mpf102 (half moon shaped) (on the radioshack build) is wrong.  apparently the g-s-d are labeled right, but the item isn't labeled and should visually be flat side to the left. 

[daveh]

I just looked at the schematic and the transistor is installed correctly on the Radio Shack build pdf.
http://www.beavisaudio.com/Projects/NoisyCricket/MarkII/NoisyCricketMarkII_RadioShack_Rev2.pdf

My suggestion is to try a different speaker. If you have a guitar speaker around, it will make a huge difference. Others are hit or miss, mostly miss.