8pin DIPS, mine all seem to suck

[Saint Frank]

Hey, all. Just started back doing electronics after a couple year layoff to get a coupla EPs out. I really like making nice little chip amps but seem to have a real issue finding chips that work consistently. Now, I'm more than willing to admit that my soldering skills could be the culprit but when I build stuff that doesn't require a chip they always seem to work fine. Also, I've built a coupla LM386 amps and just replaced chips when they didn't immediately work and they started working. I've just tried a TDA7052a amp with just the minimal parts on breadboard and can't for the life of me get it to work through all 5 chips sent to me. Is it just me or are all chips flaky...or am I just buying cheap crap from irreputable places. Thanks and looking forward to doing some projects off of here!!

[MrStab]

hi Frank,

welcome aboard! where did you buy these chips? i have some dodgy-looking power amp chips from eBay which didn't cost a lot, but i sure as hell wouldn't use based on how they look and how they were packaged.

[Saint Frank]

Amazon but I don't actually remember the company that supplied them. It was something kinda like Jameco but not them. They came in a plastic cylinder.

[Mark Hammer]

It takes serious quality control to make sure that EVERY chip you sell is bad.    When people buy from less-than-conscientious vendors, typically less attention is paid to verifying the quality of the parts, so some turn out good and some not so much.

If you can't seem to get anything to work, then I would start out by confirming the following:
1) The power connections to the circuit are as assumed, with V+ showing up where it should, and Gnd showing up where it should.
2) That any derived Vref is as expected (i.e., half of V+) and is showing up where it should.
3) That there is continuity from the guitar (or other signal source) to the first stage of the circuit.

[anotherjim]

I'd look for something common to you and or your setup.

The breadboard is my first suspect. You may have one of those where the power rails are deliberately not fully interconnected unless you put links in.

Because you have done some of this stuff in the past, it's easy to misremember some basic things and end up assuming you have something right (because it's very, very basic) like reading resistor codes or the number order on the chip pins or which lugs are which on a jack socket. Anyone can get caught out this way.

If you are still struggling, breadboard a basic 386 amp and show us photos and voltage readings on the chip pins.

[bean]

Yeah, I think jim has got it. Breadboards can wear out over time. They can also have some resistance on the rails, I think. I've had a couple where I had to connect both the top AND bottom portion of the same vertical rail to ground.