| Spasticteapot |
My latest attempt at a LM3875 chip-amp still won't work. You can see pictures below. (I'll add the PCB design and notations later.)
Can anyone tell me how I screwed up? |
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| Netlist |
Really hard to tell but I believe you should try to improve your solder skills. :)
If the supply voltages are correct, measure every trace with an ohmmeter to make sure everything is conducting the way it should.
/Hugo |
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| Spasticteapot |
| quote: | Originally posted by Netlist
Really hard to tell but I believe you should try to improve your solder skills. :)
If the supply voltages are correct, measure every trace with an ohmmeter to make sure everything is conducting the way it should.
/Hugo |
I should also probbably get a better soldering iron tip. Or a better soldering iron. (The crappy PCB does'nt much help, either.) |
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| Netlist |
Yes, a good soldering iron is a Diy-er's best friend. You invest once, you have lifetime pleasure. :)
/Hugo |
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| drummer_Dave |
| Just remember if you are measuring the traces with an ohm meter MAKE SURE THE POWER IS OFF!!!!!!!! |
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| Netlist |
Good point; and caps discharged.
/Hugo |
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| v-bro |
| Am I wrong or is one of them two larger electrolites connected the wrong way'round?:confused: |
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| karma |
| it would have been faster to p2p it;) |
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| Spasticteapot |
| quote: | Originally posted by karma
it would have been faster to p2p it;) |
Once I get the @$@$ing PCB worked out, I'm going to have Olimex make me a bunch of 'em. |
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| GG |
| quote: | Originally posted by karma
it would have been faster to p2p it;) |
With the LM3875, P2P is a good choice. This site is shows a simple P2P build in small steps.
http://www.vikash.info/audio/gainclone/
Good luck and don't give up. |
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| Spasticteapot |
After diagnosing the problem to be a fried capacitor, I simply removed the Zobel.
The amp works!
However, there's an odd problem: I think I'm only getting half of the signal (0 - +30 - 0 - (should be -30 ,but is 0) - +30, et cetera.) When I unplugged the amp and it was running off of the power filtering caps, the volume and sound quality doubled, and the nasty distortion disappeared.
I'll be replacing my rectifier, and if it works, I'm off to Olimex! Woohoo! |
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| drummer_Dave |
| Congratulations!!!! Its great to hear you got it working, just a little time and perseverance. way to go |
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