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AP80 - Hidizs next portable Hi-Res music player

Discussion in 'Portable Source Gear' started by IryxBRO, Apr 24, 2018.
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  1. AndySocial
    Yes, because the amplifier is an analog system that produces the actual electrical signals for the headphones. There are some systems on a chip (SOCs) that combine multiple pieces of the chain, but you basically have
    1. File handling (finding a file on the hard drive, an OS function, and queuing it to play which is a player software function)
    2. Digital signal processing (decoding the file into an audio stream, and optionally modifying it at the player software level)
    3. Digital-to-analog conversion (sound card or external DAC)
    4. Amplifier (sound card or external amplifier)
    5. Listening device (headphones or speakers)
    If you use Bluetooth headphones, the DAC/Amp parts are in the headphones, but the above list is the basic process of taking a FLAC/MP3 file and listening to it.

    In the analog days, we'd have three steps: source (LP or tape recorded with analog signals), amplifier, headphones/speakers. The definition of "source" in the digital audio world is less simple.

    I'm sure if I've missed something, the helpful folks here will point it out.
    Last edited: Nov 9, 2019
  2. OmniscientNihilist
    so is it possible for the DSP software to lower the quality or bottleneck the quality befoer it gets to the dac ?

    for example i noticed some settings in windows and various apps etc.. for the quality level of the audio. so if those settings were not turned up and you were playing a high res file would that not bottleneck it down before it sent it out to the high res dac?

    and then the dac would be bottlenecked (limited to upscaling only) due to only receiving a lower quality signal?
    Last edited: Nov 9, 2019
  3. AndySocial
    That is a question with far too many variables to answer with any authority. But, there is a negotiation between the player software and the DAC, via the driver (WASAPI in this case), which defines what specific formats the DAC will accept. A decent audio player on the PC will be able to output a data stream beyond what even the AP80 can process. The bottleneck varies depending on what piece of the chain has the lowest common denominator.

    I'm not sure where your repeated "upscaling only" term is coming from. If WASAPI is set to send the best possible data that the AP80 can handle, that's exactly what it will send. If it's not configured correctly, or if you're using a player that doesn't understand the WASAPI driver and instead uses some other driver that the AP80 understands, all bets are off.

    Basically, using an external DAC on a modern PC is not a beginner-level task. It requires knowledge and specific configuration steps. Once that configuration is done, though - it's done.
  4. OmniscientNihilist
    im downloading some 32BIT 192kHz albums right now. its like 4GB per album and bitrates are showing at 8000kbps
    Last edited: Nov 9, 2019
  5. mandrake50
    This is probably late considering how long ago the above was posted. ANY device will DRAW only what it needs. Anyone could use a 5 volt 100amp charger and be fine. The charger does not PUSH anything related to current. It is a source and allows the target to take what it needs, period.
    Having a higher amperage rated supply only adds capacity to allow destination devices to DRAW what they need. So having an under rated supply on the current side (AH/MAh) will slow the process down. Having one rated higher will ALLOW the destination device to DRAW anything it needs.. up to its max DRAW requirements. Voltage is different. It is the driving force. The PUSH part. So charging with a 10 volt supply would kill the device. Current is just capacity. The PUSH is the voltage, not current.
    Last edited: Nov 9, 2019
    AndySocial likes this.
  6. OmniscientNihilist
    do you confirm that there benefit (battery life) to deliberately charging a battery slower. meaning deliberately using a charger that has lower amps then the battery wants to draw?

    or should a peson always get very high amp chargers so they can make sure they are giving the battery the maximum possible?

    does charging speed reduce battery life?
    Last edited: Nov 9, 2019
  7. mandrake50
    Speed kills... With LION batteries there is a specific charge curve that need to be built into the charging process.
    Read this:

    The advised charge rate of an Energy Cell is between 0.5C and 1C; the complete charge time is about 2–3 hours. Manufacturers of these cells recommend charging at 0.8C or less to prolong battery life.
    In this case "C" is the capacity rating of the battery.

    Now there is an optimum way as above to charge the battery. It can be done faster with quick chargers that do not worry about battery longevity in the interest of speed. There is no free lunch.

    Smart chargers can adjust the current and sometimes the voltage to make things faster. But again, longevity has to suffer.

    But the fast charge algorithms depend on communication between the source and the device being charged. So the charger has to have a chip that talks to the destination chip and manage voltage and current based on that communication.

    So really, if you have the patience a longer slower charge will tend to make your battery last longer.

    (in the context of the LION battery in the AP80)
    Last edited: Nov 9, 2019
  8. OmniscientNihilist
    so quick charging reduces battery life compared to regular charging. but what about regular charging compared to deliberately under charging?

    for example a battery wants to draw 800ma, but you only give it 500ma. does it make the battery last longer?
  9. mandrake50
    No, it just takes longer to charge. As long as the charging circuit follows the recommendations for the battery type. Remember the cycle for ithium batteries is "constant current", followed by a Constant voltage stage. The constant voltage stage is terminated when the current draw falls to a specified level. Speed is changed by how much current is available in the first stage.

    BTW, under charging refers to not fully charging the cell to it's max capacity... not how much current is available.
    Last edited: Nov 9, 2019
  10. OmniscientNihilist
    so since the ap80 has no quick charge available i should charge it with whatever 5v device works the fastest?

    so i should use my 5v2.4a wall charger to charge my ap80 which takes 1hr20min.

    and not use my 5v0.9a usb port to charge it which takes 2hr5min.

    since there is no worry of shortening battery life?
  11. headfirst
    Isn't there a "how batteries work" thread somewhere on this forum for all of this nonsense?
    CactusPete23 and AndySocial like this.
  12. mandrake50
    I assume that the AP80 has a charge algorithm built in. So yes that higher rated charger is preferred. The whole idea of adding battery longevity by tweaking the charge rate is more for people that have large battery packs.
    I know a bit about lithium ion batteries. I use a 6 port charger rated for 2.5 AH . It charges pretty quickly, and I have monitored the current draw. It never actually goes beyond about 1.6 amps. My charge times are close to yours, 1 hour 20 minutes.
    I don't worry about killing the battery early.
  13. OmniscientNihilist
    your saying you measured the draw of the ap80 at 1.6a ? because another guy said he measured it at exactly half that.

    and then to explain why the 900ma usb port was charging slower he said it was only giving 500ma due to the data connection also being present
  14. mandrake50
    I have a cheap USB monitor. I would not trust it for any level of analytic measurements. That was with the AP80 battery FLAT discharged. It would be lower if the battery was only 80%.
  15. OmniscientNihilist
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