noisycricket amp for my mother

[Xerxes]

first of al, i love guitar but eh....i can't play it. it's a long story but i have tried...

But during my try-outs i managed to get my dear mother so far to pick up the guitar and....success!
I am a nooby at this but i wanted to give a her nice present for christmas a travel amp... so after much reading i built an noisy cricket for her.

here the specs and modding..
noisy cricket amp from beavis
dtpd switch between 9 volt / off / 12 volt
dtpd switch between internal speaker and external speaker/output

now i have a problem...when i switch it on it all seems to work until i turn the volume, i get a real noisy trumpet sound..
i realy dont get it.... mabye it is the extra switch between the speakers, the grounding or a faulty chip (but this is the third one with this problem)

it is almost christmas so i anyone could help i would be very thankfull.

here are the pics

https://picasaweb.google.com/Xerxes75/NoisyCricketAmp

[markeebee]

When I saw the title of this thread I thought it should be in the For Trade section.

That's a nice idea, I reckon your mum will be really pleased.

Couple of thoughts......those wires look pretty long, and sometimes that can cause oscillation. I'd suggest that you make the interconnecting wires shorter. Also, it can help sometimes to increase the amount of filtering....other threads have suggested a 220uf electrolytic between pins 3 and 6 of the chip. Give that a try first.

[Xerxes]

Ah thanks!

THE long wires are THE groundwires connected to à starground. This is because i from THE hifiworld and my diffulcity to transform THE schematic into THE real thing. Using à starground with wires is THE easy Way to go...

But i Will give it à try.... I Will post my results.

[Jorge_S]

...when i switch it on it all seems to work until i turn the volume, i get a real noisy trumpet

That "trumpet sound you talk about reminds me the sound of the amp when the two poles of a guitar cable  get connected.

Check the input jack and the input cables for any shorts.

If it's correct, check all your cables and switches, they look chaotic and a probable place for some kind of short.

good luck!

[dano12]

Willing to bet a six pack of beer that the problem is oscillations from the long leads.

I would reorient the pcb to be up right next to the switches, pots, and have wire lengths no more than 2-3 inches.

Hope it works, and hope mom likes it!