Strange LittleGem

SuperGeo · April 20, 2005, 01:20:57 PM

Hello guys

I built the LittleGem MKII, it worked and I thought it very nice amp nice overdrive while driving the 386 with more signal but yesterday I wanted to play guitar but my LittleGem was veery strange! It distorted very easy and it sounded very bad... If you kept letting more signal do the 386 it created a noise like a Bus Horn! Its very unpleasn't sound

Anyone has anyidea of what's going on?

thanks

Paul Marossy · April 20, 2005, 01:28:40 PM

Are you using a 9V battery? You may have drained it to the point where the power supply isn't enough to drive the circuit. It doesn't take too long to eat up a battery with a pair of LM386s...

SuperGeo · April 20, 2005, 01:37:32 PM

i'm using a regulated power supply

I recorded a sample .wav of my problem:

http://s42.yousendit.com/d.aspx?id=0Q07NQKD2P88G21Y4LFHHZPOR8

Paul Marossy · April 20, 2005, 01:47:33 PM

Hmm... that's weird. I don't have any ideas on that right now. What voltage are you running it at? The N4 version has a higher operating voltage capability than the ones that RadioShack sells. Maybe you fried the chip or something?

SuperGeo · April 20, 2005, 01:56:57 PM

just forgot to say, the second part of the clip I was turning the pot

maybe I could fried the chip :S

I'm running it at 9v

Paul Marossy · April 20, 2005, 02:01:00 PM

Strange. Maybe someone has had this strange experience? Anyone?

Pedal love · April 20, 2005, 02:02:52 PM

Check capacitors for short.pl

SuperGeo · April 20, 2005, 04:41:02 PM

I have no DMM here, but I will check for shorts when I get one

Another thing I found. That horn sound that comes from nothing when I turn the volume pot only happens when I touch any metallic part of the potentiometer but the sound continues worse!

ideas?

Paul Marossy · April 20, 2005, 04:56:44 PM

Perhaps a connection to ground has come loose?

Pedal love · April 20, 2005, 07:29:12 PM

Sounds like ground, keep checking the wiring.pl

Pedal love · April 20, 2005, 07:47:08 PM

Something is not connected properly. The chip could have a problem but I'm leaning toward connection trouble.pl

Paul Marossy · April 20, 2005, 07:53:09 PM

I'll bet on a faulty wiring connection as well. :wink:

Pedal love · April 20, 2005, 08:59:42 PM

Probably a connection or one of the components or the power supply. :wink:

SuperGeo · April 22, 2005, 06:23:31 PM

I found the problem!
every single conection to the ground was right
I tried swapping the IC's but nothing changed.
Then swapped the Transistor e voalla! Nice clean sound again!

Something I saw now, when using my Gt-2 made by me with Little Gem, when volume it's like in the middle a noise starts do appear :S

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Strange LittleGem