Portable headphone amp to smartphone w/ mic passthrough?

Discussion in 'Portable Headphone Amps' started by halcyon, Oct 18, 2017.
  1. halcyon
    Let's face it, many of us use smartphones as the source and don't want to lug around three items. My smartphones are not powerful enough to drive all the headphones I want to use, hence the need for an external amp.
    Then again, I want to speak to my headphone/IEMs inline microphone, not to the mic.

    Thus, the question: does any manufacturer make a headphone amp with either USB-C or analog 3.5mm input such that it passes through the microphone signal through itself from the headset to the phone?

    Perhaps this has been covered, but I could not find by searching.
     
  2. DDDYKI
    Hmm. My Creative Sound Blaster E1 has it's own mic and two 3.5mm inputs; one labeled for headphone/mic, the other just headphone. I know that the first jack passes mic duties from the headphone to the E1, but I don't know if the second jack does that (or if it just disables mic entirely). I don't have it on me at the moment.
     
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  3. halcyon
    Hey, I have Creative. Didn't even think of that. It's a bit bulky, but why not. Thanks!
     
  4. DanWiggins
    Our upcoming Nickel has a TRRS input and output and passes the microphone through.
     
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  5. halcyon
    Thanks for the heads up on Nickel! I'll keep it on my radar. I'm within the EU, so it'd be considerably more expensive for me here, but you never know.
     
  6. Wiljen
    So, you'll be doing a review tour for the Nickel right?
     
  7. DanWiggins
    Dunno - we usually send out several all at once to senior members/reviewers and be done with it...
     
  8. Wiljen
    Would love to see the Nickel as the mic pass through is interesting, but doesn't that make it impossible to use balanced headphones since both use trrs plugs for different purposes or is it switchable?
     
  9. DanWiggins
    Yes, it does. However looking at the market, the vast majority of amplifiers are used with normal (not balanced) headphones. In the pursuit of the smallest bundle of power on the market (this thing is tiny - 1.25" wide, 2" long, 0.5" thick, about 0.7 ounces) we simply chose to support the majority of the market. And since most people like balanced headphones in an effort to get more power delivered to the unit - we built in 3VRMS of output drive voltage from the beginning, so you can drive just about any headphone out there single ended.
     
  10. Wiljen
    Sounds very interesting indeed. I'd love to be able to get balanced type performance from a single ended amp. I'll have to see which resllers have them and which meets they end up at.
     
  11. DanWiggins
    We'll be showing the final pilot-production Nickel amps at the Captial AudioFest this coming weekend. 3VRMS output, 200 mA output, lots of power available! Yes, a truly balanced and matched amp has theoretically less THD than a single ended unit, but given we're already around 0.0005% THD at 1 kHz, and if your blaanced sides are NOT perfectly matched you actually increase THD relative to a single ended, well...

    You do need a real power supply for a single ended, though, to get the outputs We have a full separate power stage that generates +/- 5VDC rails, independently regulated, off the battery. So we get a lot more voltage range than most who run off a single 4V battery rail and a floating ground. Also means we do not capacitively couple our outputs, so we have a LF extension down to ~4 Hz (set via film cap coupling on the input to AC couple your source).
     
  12. halcyon
    Periodic Audio Nickel seems like the best choice so far (that I've been able to found). Of course, I need to listen to it first to form an opinion.

    Now, if somebody would make a similar device with built-in DAC / ADC and USB-C digital audio in/out, it would be great.

    Because it looks like that year 2017 will be the last year when major smartphone flagships will feature a 3.5mm analog audio jack, if the rumours about 2018 flagships are anything to go by.

    Personally I dislike the USB-C connector, it is finicky and even more prone to breaking than the sturdy 3.5mm jack, but apparently the manufacturers want to go all digital input/outputs (even though USB-C spec allows for analog audio connections as well).
     
  13. DanWiggins
    LG and Samsung just released new phones with 3.5mm jacks - and they are the flagship units, too. So I think that connector is safe for at least 1 more year. My guess is quite a few more to come. Yes, Apple this and Apple that - but in reality, they are 12% of the market and falling. They won't wield the influence they had in the past.
     
  14. DanWiggins
    Quick update, final PCBAs are in hand. Initial measurements look even better than before and the web page will be updated. Output impedance measures in at 0.21 Ohms, quite low.
     
  15. halcyon
    I agree with Apple being what it is, 100%,

    But the trend is clear: Oppo, Oneplus, Huawei, Xiaomi, many others are giving up the 3.5mm. Even supposed Nokia flagship for 2018 is USB-C only. Let's see for Samsung and LG.

    Now, I'd hate this to happen and I don't like it myself, as I really love 3.5mm jack (and it is MUCH sturdier to mechanical stress than USB-C), but loss of 3.5mm looks like where the industry is heading, now and in 2018.
     

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