I've been looking at ways to improve the little cmoy I've got. Reading about putting bigger caps to improve bass, metallized polypropylene film caps to improve overall sound quality. So I've done what I thought was the improved upgrades. Now its not working. Unsure why. I changed the NE5532 for the OPA2134PA, this didn't have the usual notch to line up with on the DIP. So I used the circle on the chip as a reference. Unsure if this is correct, or if the chip is the issue.
Have I gone to big in terms of caps, electro and polypropylene? Looking on line about this is a minefield, after trying to search on line, it gave me more questions than it did answers. Any help, advice would be much appreciated.
Have I gone to big in terms of caps, electro and polypropylene? Looking on line about this is a minefield, after trying to search on line, it gave me more questions than it did answers. Any help, advice would be much appreciated.
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The circle is pin 1. The notch is between pins 1 and 8. The polarity is correct given the orientation of the LED.
If the OPA2134 isn't working its junk/fake - these days you would never expect a valid semiconductor part unless purchased from a reputable electronics supplier, its hopeless out there in random-vendor land.
If the OPA2134 isn't working its junk/fake - these days you would never expect a valid semiconductor part unless purchased from a reputable electronics supplier, its hopeless out there in random-vendor land.
There are no good deals on chips, unless you buy in bulk
Decent chips cost money
Get your money back, unless you've been sitting on this "bargain" for too long.
I've had fakes from "suppliers" who normally (and historically) have a good rep.
Even "suppliers" can get conned, but most of these shonky "suppliers" know exactly what they're selling.
I'm not talking about big name distributors, you can rely on them for genuine product.
It's the tip of the cotton bud that will reveal things, if it's gone black/dark it's odds on fake.
The depth of the mould circle is telling, the ones in your photo look quite variable depth.
And lastly this is a PDIP moulded IC the top shouldn't show striations of sanding
The IC will always have a orientation mark (not to be confused with that mould circle) , either a nice sharp indent or a sloped long side top edge.
The depth of the mould circle is telling, the ones in your photo look quite variable depth.
And lastly this is a PDIP moulded IC the top shouldn't show striations of sanding
The IC will always have a orientation mark (not to be confused with that mould circle) , either a nice sharp indent or a sloped long side top edge.
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Are they totally useless, I know this maybe a silly question..But It feels like such a waste binning them, I've been stocking up on bits as the months have gone by. Boxes of caps, PCBs, Cables, Op-amps, resistors, diodes, pots, battery snaps. The op-amps are one of the first purchases, so cant return.
That's what they were hoping you would do
There's no better place for these once confirmed fake than the bin
As someone else said the market is rammed with fake semi's
Take a look at this Burr Brown chip https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=pcm1704&_sacat=0
Long discontinued by the original manufacturer, but there's reels and reels of them out there, all going for big money ... 99% of these (and I'm not joking) are fake.
A couple of years ago I bought sequentially from 3 different chinese suppliers, every single one started to pull the supply down (dead short) - I got my money back on every one, some without argument, some with one! lol
I eventually found a supplier in the UK that had genuine ones (because they simply worked when fitted!) and he said he'd been seriously burned with a large quantity. (prob a reel) and he didn't get his money back
Take a look at this Burr Brown chip https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=pcm1704&_sacat=0
Long discontinued by the original manufacturer, but there's reels and reels of them out there, all going for big money ... 99% of these (and I'm not joking) are fake.
A couple of years ago I bought sequentially from 3 different chinese suppliers, every single one started to pull the supply down (dead short) - I got my money back on every one, some without argument, some with one! lol
I eventually found a supplier in the UK that had genuine ones (because they simply worked when fitted!) and he said he'd been seriously burned with a large quantity. (prob a reel) and he didn't get his money back
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They are surely not the OpAmps you paid for but it may be worth investigating what they are. For example if they are 741s, they would not work as a replacement for a dual opamp but there are places where a 741 could be used (admitedly not in the audio path).
Do not bin them, rather do what I do. I have a quarantine box where I keep suspect devices until I have time to test them.
Do not bin them, rather do what I do. I have a quarantine box where I keep suspect devices until I have time to test them.
Hoping these bit are all OK. This is just the bits I've got here now, I've got a box full of bits to. I didn't intend to buy this much stuff. I just ended up with a lot of bits, and I'm still looking at more bits. The wife is getting on my case, so I need to stop.
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Its taken the wind out of my sails a bit now, I've been learning to read and design electronics schematics. I've been playing around with Kicad, I was going to use these op-amps for a few different projects. I've also got a few things in my basket on ebay to build a power supply. All bits from china, like the bits I've found out are all mostly knock offs.
Any advice on a good place to look for transformers, power supply parts?
Any advice on a good place to look for transformers, power supply parts?
If you are really interested then you could take voltage reading on all 8 pins and see what that shows.
If the project uses a dual rail supply then measure them all from ground.
If it uses a virtual ground then measure all from that point.
If it is single rail AC coupled then measure them all from the zero volt line.
If the project uses a dual rail supply then measure them all from ground.
If it uses a virtual ground then measure all from that point.
If it is single rail AC coupled then measure them all from the zero volt line.