Once I get a real LM3886 into the XY board, I am sure mine will show lower THD due to the better routing of the feedback and input grounds. The fact that I use a solid ground plane rather than a pour should make a difference also.
Well, thanks I appreciate that.
I'm both. I did not force XY to deliver fake components. They claimed to deliver an LM3886 amplifier kit and I took their word for it. The argument that I should buy their kit, throw the parts away, and buy new parts to have a valid comparison is absurd. I'm simply comparing what you get when you order an LM3886DR from me versus one of XY's kits.
Depends. It seems most people here assumes that I'm comparing Layout A vs Layout B, when I'm really comparing Kit A versus Kit B.
How do you explain that the lot code printed on the front of the LM3886 from XY is not in TI's system then?
As mentioned in Post #1, I used a pair of HP 6643A power supplies.
I'm not in touch with the design team - assuming any of them are left with TI. But I do have a connection with TI who is able to get the chip decapsulated so we can see which die is inside. I'm trying to get some X-rays of the IC as well. In order for this to happen, I need to ship him the part, though.
Tom
Some of that cheap stuff has to be bogus. There sure is a lot of it out there. But people do buy it and mod it, or they use the board and install quality parts.
Parts Express has started selling Juan-Jing products.Yuan-Jing -- DIY hi-fi audio products at the lowest possible price, helping everyone learn the art of audio and build their own audio system. I saw these on FleaBay before PE started carrying them. There's no way I could build this stuff that cheap without using a bunch of scavenged parts. Plus my time = not worth it for $50 or whatever. I was going to buy one of the modules and check it out until I read some reviews. I still might buy one and see if it's useful or whatever. I have built some good stuff with salvaged components but I would never represent it as new or sell it without complete disclosure.
But your kit comes with genuine parts, technical support, and real engineering behind it. One of the complaints about the Juan-Jing products is lack of documentation and technical support.
I'm very interested in what a good/less good pcb layout can do although I know it's very important for a high current device like the LM3886.
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I wonder if China is capable of copying that good but the lot code could reveal something
I don't think they copied the chip. I think it's a factory reject that's been rebadged. Basically, an LM3886 that failed the final test on the production line because it didn't meet the specifications listed in the data sheet. The parameters that are listed with Min/Max specs in the data sheet table are tested in production.
It could also be an entirely different die. Maybe an LM1875 or something. That's been done before too.
Tom
It could also be an entirely different die. Maybe an LM1875 or something. That's been done before too.
Tom
I'm both. I did not force XY to deliver fake components. They claimed to deliver an LM3886 amplifier kit and I took their word for it. The argument that I should buy their kit, throw the parts away, and buy new parts to have a valid comparison is absurd. I'm simply comparing what you get when you order an LM3886DR from me versus one of XY's kits.
Not all true as you can buy PCB only and populate with quality parts.
I bought power supply PCB and two xy amp PCBs as I didn't want the cheap chines junk parts.
Not all true as you can buy PCB only and populate with quality parts.
I bought power supply PCB and two xy amp PCBs as I didn't want the cheap chines junk parts.
I too bought a pair of the XY things a year or 2 back.Less than 10$ to my doorstep... simple curiosity.
Eyes wide open though , as I had a few Chi-Fi clone chip amps previously, which ..when.. they worked, were Poor indeed.
Clearly a sucker for almost free,
As soon as I saw the included Lm3886 chip, it was clear this was fake. Odd labelings, odd casting even. No Sherlock Hemlock work required.
I have not even bothered to power the thing up.. What for ?
Have a couple of decent US made (likely not of Modulus level, but still v nice..) Lm3886 amps
Some curiosity as to what these might work/sound like with Mouser sourced Lm3886 chips.. One day.. maybe.
Curiously I don't understand Why? some think that China cannot build copies.
Hell.. they have successfully copied F35's !
A low value Audio chip is hardly a stretch.
What is always a source of amusement for me are the bleatings (Likely from owners) of how this talk of fakes is all inaccurate... or misleading.
PT Barnum would be proud.
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Thanks for eye opener, you have replicated scenario of new Diyer as when I also started didn't had much options but to go for Chinese LM kits, thanks to your kit now people have much better option in $35+.
I'm happy that now we have more options for Diyer's with better sound quality, serious engineering and research.
I hope you will come up with a lot of kits for us with great specs like Mod86.
All the best
I'm happy that now we have more options for Diyer's with better sound quality, serious engineering and research.
I hope you will come up with a lot of kits for us with great specs like Mod86.
All the best
I removed your racial slur.
I worked for National Semiconductor from 2005 until TI acquired National in 2012 and three years for TI after that. Neither National nor TI would deliver 11000 parts on a 10000 order. They would deliver 10000 units on a 10000 order. Both companies were very focused on profit margins and the bottom line. TI even more so than National.
Tom
Thank you. I do plan to be around for a while to come and will continue to deliver well engineered circuits. It's good to hear that some people still value good quality.
Tom
OK thanks for removing.
I too have been working with a certain chinese company (I hope that did not sound too racist) for the past 20 years.
I know it is very easy to just leave the machine on after the order quantity met.
Anyways,
I suggested in the rest of the removed post (and i deserved the penalty points, i admit, sorry for that), a capacitor change in the XY board.
But I understand this is not about the XY board and how it can be improved, so lets just leave it.
If you'd want to improve the XY board, it would take more than a capacitor change.
If you'd like to know what should be changed, I suggest reading the LM3886 data sheet thoroughly. I also suggest reading my Taming the LM3886 pages, in particular the supply bypassing and grounding pages. To implement the changes and unleash the best performance possible from the LM3886, you will realize that you need a circuit that is exactly what I have implemented in the LM3886DR. Those who would like me to do the work for them can buy my boards. Those who would rather go through the learning process themselves are free to do so. I'm happy to nudge you along the way, but you will have to learn and understand the material rather than just follow my directions.
Tom
Catering to DIYers should mean documentation and technical support.
What makes me suspect is the prices. What kind of parts are in it?
When I read the comments it was not always clear to me whether the product was defective or whether the customer was unable to figure out how to hook it up properly. Complaints like "hum in one channel" could very well be customer error.
Some of the prices are too good to be true. I might get one of his products and see for myself whether they live up to the hype. I'm sure I can reverse engineer it and I'd be surprised if any of the circuits are anything unconventional. We'll see where it goes from there; I might try a little turd polishing if it's halfway up to snuff.
I'd rather pay $12 for a halfway decent "budget" chip amp board and populate it myself than pay $20 for a complete board with questionable components. I don't see how anybody could sell a complete board with genuine parts for less than $35 or $40 and still turn a profit.
You could purchase two XY LM3886 boards plus a PSU board for less than $7.00 on EBAY. The parts for the set will cost you about $40.
HiFi LM3886 Power Amplifier PCB 2pcs Rectifier Filter Power Supply Board PCB | eBay
It will be interesting to see if the XY amp performs better with genuine/better parts installed.
HiFi LM3886 Power Amplifier PCB 2pcs Rectifier Filter Power Supply Board PCB | eBay
It will be interesting to see if the XY amp performs better with genuine/better parts installed.
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Interesting. I don't do flea bay though , they have a 100% fraud rate with me. I ordered ONCE and they took $700 from me and never shipped me anything. About 3 years later I got $150 of it back. That's not my idea of kosher.
Sure it's only $7.00 but I will not share my financial info with a den of thieves. What's stopping them from taking all the $$$ out of my account?
Sure it's only $7.00 but I will not share my financial info with a den of thieves. What's stopping them from taking all the $$$ out of my account?
After all these years I do not remember how to access my account. Playmepal did not do a very good job of protecting me as a buyer. After losing my money I still had to go to a reputable vendor and cough up around $1000. I will not use paypal again.
I will use Parts Express again. I use Digikey and sometimes Mouser. I don't like to be played.
I would suspect that the cheap boards would perform better with good parts.
Buyers on eBay have a lot of rights, sellers not so much. As a buyer you can complain about a lot of things , true or not, eBay will not try to investigate the situation , seller needs to come with a plan to fix the situation, most of the time to pay the buyer a portion of the initial value of the item. I'm talking up to 75% of the initial agreement.
That sucks for seller ....
Mouser, digikey are the best.
Parts express not so much, even they have the price match policy, they don't do it, I was buying stuff from them and I wanted to price match some coils with erse.com.... Well , they did not do it, even thought the coils were erse , not other brand.
Fast Eddie, you will still need the PayPal account to buy from tom anyway.....
Where do I sign up for that beer, buffalo grove or Skokie?
That sucks for seller ....
Mouser, digikey are the best.
Parts express not so much, even they have the price match policy, they don't do it, I was buying stuff from them and I wanted to price match some coils with erse.com.... Well , they did not do it, even thought the coils were erse , not other brand.
Fast Eddie, you will still need the PayPal account to buy from tom anyway.....
Where do I sign up for that beer, buffalo grove or Skokie?