#1
well, i'm building this mini amp here:
http://runoffgroove.com/littlegem.html
it's almost finished, however, i have 3 questions i need to answer befoer i finish:
1.- No store in my area hgas a 25 ohm pot. the smallest i could get was 220 ohms, and i went to every electronics store here. Is there someway to put resistors to make the 220 pot act like a 25 ohm pot?
2.- the speaker is wired to the 25 ohm pot and a 0.047mF capacitor, but where do the positive and negative wires from the peaker go? more importantly, how can i recognise the speaker cables? the one on the right has a little writing, but it's just some numbers, so i think this has nothing to do.
3.- i checked this PDF too:
http://runoffgroove.com/lg-pcb.pdf
and along with the pics, it helped me to understand some stuff i couldn't make up from the diagram. as i made the part to the master volume pot, i found in the PCB that it appeared like having 4 connectors instead of 3 (somewhere it said it was a rheostat, so i would understand if it had only 2, ¿but 4?), and the other diagrams dont specify anything either, so can someone explain WTF does that mean?

sorry if you dont understand my english. any help will be appreciated
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Last edited by ldnovelo at Jul 7, 2009,
#2
1. RadioShack carries 25 ohm rheostats. If you don't have one locally, you can order online.

2. Speaker terminals are almost always marked + for positive (hot) and - for negative (ground). The - lug is grounded and the + lug is connected to the wiper (middle lug) of the rheostat.

3. Three of those 4 holes on the "out" of the pcb are for the rheostat and there's an extra pad for a wire, so it would look more professional than soldering directly to the component.

That PDF is just for etching printed circuit boards.
#3
Quote by Invader Jim
1. RadioShack carries 25 ohm rheostats. If you don't have one locally, you can order online.

2. Speaker terminals are almost always marked + for positive (hot) and - for negative (ground). The - lug is grounded and the + lug is connected to the wiper (middle lug) of the rheostat.

3. Three of those 4 holes on the "out" of the pcb are for the rheostat and there's an extra pad for a wire, so it would look more professional than soldering directly to the component.

That PDF is just for etching printed circuit boards.

thanks for the help
i know that was for PCB, but i still used like somewhat of a guideline to check some conections.
no i have it ready
except for the rheostat. I'm in mexico, so it's not possible to order online from radio shack because of the expensive shipping, but i just remember a store that probably has it

thanks again
EDIT: just checked online. the biggest electronics store doesn't have 25 ohm pots. the smallest pot is 220 ohms. can you help with this?
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Last edited by ldnovelo at Jul 8, 2009,
#5
Quote by Invader Jim
Good luck, man.

tnxs but something happened (i edited my post right before you answered :S)
the smallest pot avaible from the biggest store is just 220 ohm. any possible solution for this? or should i try with that?
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#6
No way around it, you'll just have to make due.

I have one of those 25 ohm rheostats though. If it's not too much, we could split the shipping cost and I could try and send it to you. Never sent anything outside the US though.
#7
Quote by Invader Jim
No way around it, you'll just have to make due.

I have one of those 25 ohm rheostats though. If it's not too much, we could split the shipping cost and I could try and send it to you. Never sent anything outside the US though.

i dunno. i'll PM you tomorrow about it. If it's done, it will probably be in about a month, because i'm going on vacation next week, and i wont retunr until august. i'll pay the shipping
consider this thread closed, that was the only question left
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