Recent content by tangent
  1. tangent

    the Pimeta-V2 thread

    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...
  2. tangent

    the Pimeta-V2 thread

    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...
  3. tangent

    the Pimeta-V2 thread

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

    the Pimeta-V2 thread

    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.
  5. tangent

    the Pimeta-V2 thread

    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...
  6. tangent

    the Pimeta-V2 thread

    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...
  7. tangent

    LMH6321 in virtual ground circuit

    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 Maybe you're looking at the old non-RoHS version, which is obsolete, whereas the NOPB variant is still active?
  8. tangent

    LMH6321 in virtual ground circuit

    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...
  9. tangent

    LMH6321 in virtual ground circuit

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

    LMH6321 in virtual ground circuit

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

    Stupid CMoy Question

    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...
  12. tangent

    Stupid CMoy Question

    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...
  13. tangent

    Stupid CMoy Question

    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...
  14. tangent

    OFC vs. OCC wire

    You're...a unicorn? :)
  15. tangent

    OFC vs. OCC wire

      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.
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