mA, not mAh. Divide milliamps into milliamp-hours to get hours. That tells you in this case that you'd expect 10 hours of runtime, which is enlightening because it means your amp isn't draining the battery fully, since you're only getting half that runtime. You probably can't fix it with a...

I think I found the listing you mean. It gives the brand name as PSTQE, not NatSemi or TI. A search for that brand on AliExpress suggests they're a maker of knock-off electronics. Another red flag is that there are only two votes on the product, neither with commentary. You might give this...

I'm glad to hear it. Care to name-and-shame the retailer who sold you those bogus buffers, so others can avoid them?

As far as I'm aware, you can't buy an actual SOIC-8 version of the LMH6321. You have a choice of the PowerPad/PSOP version or the DDPAK version, that's it. I think there's an excellent chance those aren't actually LMH6321MRs. It'd explain everything.

What it looks like is that someone took my EAGLE files and ran their own hand-rolled CAM processor against it instead of running the included CAM processor, so that all of the DRC rules have potentially changed. You didn't, by chance, send the EAGLE files to your board house, too? As a rule...

Do you mean that you found a store selling simple copies of my board, against my wishes, or that you took my Gerbers and had a board house make some for you, in accord with my wishes? If the latter, did you tell them it needs to be a 4-layer board? If you made it as a 2-layer copper board...

https://tangentsoft.com/audio/pimeta2/history.html Not according to TI. Maybe you're looking at the old non-RoHS version, which is obsolete, whereas the NOPB variant is still active?

They're telling you not to connect the resistor divider to either the GND or Vcl pins because they require a low impedance input. If you replace the TLE2426 in the PIMETA with a resistor divider, you will need to make other modifications, such as to remove the input resistor on the ground...

That doesn't matter. You configure the buffer the same way. Replace the TLE2426 with a resistor divider, and you get the same effect.

See the first page of the PIMETA v2 schematic and the documentation of its R11 resistor.

The implication is that if it wasn't for the resistor, the LED would be brighter. That's true, but only very briefly. LEDs have very little inherent current-limiting ability. Contrast an incandescent lamp, which is a type of resistor, which is a current-limiting device. Specifically, a modern...

If it's a plain old red, amber/yellow, or green LED, many DMMs' diode test functions are capable of lighting the LED safely. Chances are decent that you just have it soldered in backwards, and the resistor may have protected it from damage. (Unlike a normal diode, LEDs are not very good at...

Indeed it will not. Ask me how I know. :) The short answer is that both configurations can work. The long answer is that it depends on matters discussed in other articles on my site. You may find these most immediately helpful: Virtual Ground Circuits Op-Amp Power Supply Quality...

You're...a unicorn? :)

  He's clearly doing the test with a 2-wire meter, which makes such low-resistance measurements nearly matters of opinion. :)   This needs to be done with a 4-wire meter, or something sufficiently close, like the 2x4 feature on Tek's DMM4020.

  Nope. It appears that Panasonic have completely discontinued film-and-foil caps, now offering only metalized film.   Metalized polypropylene isn't bad, just not the best. If you don't mind, then use the parametric search to find a cap with the correct lead spacing. That's the biggest...

  Yes, RN55D-F series.  Which also answers your other question about them.   Note that the LED resistor is a cheap 5% carbon...no point using anything better here.     All of the caps I didn't bother to provide a voltage for are in the audio signal path, so you basically cannot buy caps...

  Then you should be able to prove it with a reproducible test.   Science is hard, but we've had several hundred years of practice doing it well, so we have a whole list of things required to pull off a good test of this sort:   Specify the products to be tested precisely, so that others...

Here's a populated Hansen board:     And here are the part values I used:     For the most part, any experience you have with similar amps tells you how to build this. It's basically a glorified CMoy pocket amp with a buffered crossfeed circuit built in.   The only tricky bit is the...

Yes, that appears to be the case. So, 100× too small.

  .233 what? Picofarads? Megafarads? Always give units.   .233 is also probably the wrong value, since that is not one of the common capacitor values. You could have one custom-made, but off the shelf? No.   It's also not likely to be a capacitance value code, since that would mean "23" for...

  Those input caps you've got there don't look any bigger than 0.1 µF. The originals are 0.22 µF, and that's on the small side, IMHO. I'd like to see 0.47 to 1.0 µF here.   If you have more of those caps, you can simply solder-tack another one or two in parallel with the ones you already...

  ...or if it is, I want to know how you got the solder to 1,749°C.  

  That's the first question in my CMoy Pocket Amplifier tutorial FAQ:     My guide is about 15 years old now, and the original project even older, and my guide has received many updates over that time. You should therefore start with the assumption that your question has already been...

Teflon-insulated wire is pretty stiff, in my experience. The primary tradeoff is that it's much tougher than PVC.   Teflon is also "marine grade" in terms of waterproofing, though that's only likely to matter if you live near the ocean and find that salt in the air keeps corroding the copper...