There's a litte Gem on my breadboard...

[Hal]

and it sounds like poo.  Its totally crunchy, and not at all loud.  

things that _might_ be a problem:

1. IC is LM386-1, Radio Shack, says 300mw or 400mw or something.
2. Battery reads 8v
3. Speaker is mini 8 ohm, .5w maybe 3" diameter.
4. amount of resistance between pins 1 and 8 on the 386 does something noticable, but not significant.  It only cleans up slightly between a jumper and nothing across them.
5. voltage divider (I dont have a 25 ohm pot) cleans up slightly, but causes HUGE volume drops, to a barely audible level.  I tried values such as 10ohm-10ohm, and 22ohm-10ohm.

any suggestions ?  I expected much more from everybody's comments on this...

The idea was to put it in a teddy bear.  So its imperative that i get help, and fast :-D :-D

[David]

Hal:

The 386-1 can be flaky.  A couple of things you can do quick:

Try using 6V instead of 9V on the 386-1.

Replace the 386-1 with a 386-3 or -4.  I've never gotten good results with a 386-1, and I know for a fact that a 386-3 sounds good at 9V because I use one in a 9V DIY headphone amp on my breadboard.

[Hal]

Hal:

The 386-1 can be flaky.  A couple of things you can do quick:

Try using 6V instead of 9V on the 386-1.

Replace the 386-1 with a 386-3 or -4.  I've never gotten good results with a 386-1, and I know for a fact that a 386-3 sounds good at 9V because I use one in a 9V DIY headphone amp on my breadboard.

thanks for the suggestion.  I ran it at 5v, and it did seem to clean up quite a bit.  I would switch to a 386-3 or -4, but i only have a -1 at my house .  And its from radio shack.  I think they only have -1's, but on the web page it gives specs for all the types.  Weird...

The volume actually seamed reasonable this time...maybe its one of those illusions, becuase i was listening to loud music the first time i tried it, and this time i wasn't.

I also tried 2 different speakers, and they make quite a differanec in the sound.  I have one flat one that actaully sounds really cool - its very trebley, but cool...

Still, all in all, its poo-ish.  One of the web pages i read (at run off groove, i think) says it should work with radio shack 386's.  Does that mean that rat shack _does_ sell 386-3's, or does that mean that it should be able to work with 386-1's?

[David]

Rat Shack's 386-1 is actually a 386-2. I don't recall the specs for this one, but I know its performance is superior to the 386-1.  Unless you're in the sticks like me, should be easy to find a shop with 386-3s or the JRC386 (which according to the ROG skunkworks, is superior to even the -3.

You might also try the Ruby.  Its JFET front end may help you clean things up.

Are you going to do the possessed "jack-in-the-mouth" teddy bear thing with the amp works up its a**?

[Hal]

yup!

I was actually thinking of doing the AC adapter in the a$$...volume on nose, and red LEDs on the eyes  :twisted:  :twisted:  :twisted:

I actually found out about an electronics story semi-near me.  Maybe now's a good chance to make a trip :-D

[b_rogers]

i run my little gem  with a 18v adaptor believe it or not and its plenty loud with the gain pins jumped. much less overall distortion and way more headroom too.  RATSHACK LM386 is all i have too.  

i have smoked one so far


Brent

[siaoguitar]

i m going to buils this buby amp from rungroove site, so must i use a 4 ohm speaker? any other rating will do?

[David]

Still, all in all, its poo-ish.  

Don't you mean Pooh-ish?   :twisted:  :twisted:

...it is a bear, after all!

[Paul Marossy]

Having my Little Gem done for a few weeks now, I have noticed that what guitar you use with it makes quite a difference in how it sounds. I can get pretty clean sounds with my Strat, but humbucker equipped guitars can make it go over the edge, and sometimes it will sound something less than stellar. I still am enjoying practicing with this amp, though.

BTW, I also have the RadioShack LM386-N1 in mine.

[Hal]

Having my Little Gem done for a few weeks now, I have noticed that what guitar you use with it makes quite a difference in how it sounds. I can get pretty clean sounds with my Strat, but humbucker equipped guitars can make it go over the edge, and sometimes it will sound something less than stellar. I still am enjoying practicing with this amp, though.

BTW, I also have the RadioShack LM386-N1 in mine.

Thats a good point about the guitar.  I was using it with fairly high output, bright humbuckers.  Although my strat is in school, I'll try it with the single coil on my ibanez and see if it works any better.

What voltage are you running it at, paul?  What size/type of speaker?

b_rogers - the package says the chip is rated for 12v, and ABSOLUTE MAX 15v.  Do you heatsink or something to let it take 18v?

I imagine rat shack sells whatever they can get their hands on, and not always the same chip.  Are we all using the same one, or no?

[Paul Marossy]

Hal-

9 volts with two 4" speakers. Believe it or not, it sounds quite good and like a much bigger amp than it really is!

[Peter Snowberg]

I know it won't fit inside a stuffed animal, but try hooking your 386 amp to a 10 or 12 inch speaker.

[Hal]

yea i just tried it again, and it _does_ clean up well with the single coil, but also drops volume.  Its barely audible at this point....

This is kinda frustrating.  I'll try some other speakers, i suppose.

[b_rogers]

Hal ...i checked the voltage on my wall wart and it is 17.6v with no load (unconnected) and i get a 15.65v reading on the power pin..

the chip stays pretty cool when i have the gain low, but it does get warm when i have it at full gain and volume... maybe im just lucky it doesnt catch on fire.... :lol:


Brent