Q: My headphones with built-in mic works but produce strange sound with 9038D, what is the reason of that?
A: 9038D uses OMTP(without Mic support!) pinout for the best crosstalk i.e. stereo-stage performance, your HP seems uses CTIA pinout.
Q: Can I use PDv2/#9038S with my 3.5mm(3wire) cable or adapter?
A: Sorry, no way. Only 2.5mm TRRS balanced(4wire!!!) cable should be used. I.e. One side of the cable 2.5mm jack(A&K-Fiio pinout) for PDv2/#9038S, another side with two specific connectors for your left headphone's cap and right cap.
Q: What means "standard 2.5mm jack" which you recommend to use with PDv2?
A: Two types of 2.5mm jack available today on the market:
1) standard one with 5mm shaft-stopper, the most popular and no problem for PDv2
2) thick one aka "barrel" with no 5mm shaft-stopper, don't use with PDv2 but ok for #9038S
Q: Can I get HPtoy app for Window/Mac/Linux?
A: No, oh god, no! LoL, the main idea of PDv2 is the power DAC with built-in DSP controllable by iOS/Android device from your pocket. Whatever you connect it to, PC/Mac/Linux/iOS or Android as the source of USB high-res audio, the DSP will be controlled by your iPhone/iPad/Android wirelessly. Any USB audio source will play 100.00% the same quality level with the same DSP settings(just keep neutral settings for music players for all platforms). To obtain that level of versatility we added Bluetooth Low Energy interface into PowerDAC v2, your phone controls all PDv2 parameters via BT connection, USB left for high-res audio data exclusively.
Q: USB OTG Y-splitter, what a hell is that? Why I would like it?
A: You may need that piece of tech ONLY if your Android doesn't start with PDv2/#9038S tied to its USB-C. You can see BGGAR video about PDv2, his Samsung is fine without Y-splitter at all. Problem is that not all Androids are the same, and your Huawei may need to separate USB OTG(USB-C) vs USB power(USB-A to power-bank). Fortunately, PC/Mac/Linux don't need such a luxary accessory. iOS device may require similar Y-splitter but "special" one as usual for Apple inc. They call it "camera adapter" and the cost is around $50, no idea why but that adapter doesn't allow max power, unlike USB OTG Y-splitter for $5. I know, no one reading a text >50 words and I've prepared the picture about the splitter.
Q: can HPtoy app control #9038S as well?
A: No, #9038S is an uncompromising top-performance DAC+HPA and has no DSP, no BT interface. However, I built-in 3 modes in that model.
1) Normal mode
2) Performance mode, high order harmonics level is reduced
3) SE mode, intend to emulate tube amps harmonics distribution, 2nd harmonic dominate at the level .25%
How to switch modes please refer to the product page.
Q: Why you always repeat to me, be careful with E1DA DACs if I using IEM?
A: I worry about your ears! Both my DACs has about 600mW of the output power at 15-16ohm. Typical IEMs impedance also 15-20ohm, and the sensitivity about 105db/1mW(thanks IEMs so close to ears). log(10)(600mW/1mW)*10 = 55.56db, hence, IEM may produces 112db+27db = 139db of Sound Pressure Level. It is overkill, dangerously loud - be careful! My Hifiman HE400i has over 120db with my DACs, and it is loud to me, Thieaudio Phantom the same 120db, Audeze LCD4 >130db, just as an example.
Q: What about Bluetooth connection range for PDv2?
A: That range isn't big, the full metal jacket of PDv2 doesn't let to connect iPhone/Android further than 2..4m. It is fine for such kind of application, because of your headphone is wired to PDv2 with cable 1-1.5m so the distance between PDv2 and your smartphone never exceed 2m. If PDv2 losing connection to the smartphone, the sound isn't interrupted because audio data goes thru the USB.
Q: PDv2's front and back caps look mirror-like finishing, is that solution practical?
A: No, my god, of course, no! It is bloody impractical and 20 times more expensive vs ugly plastic case, but how it is stunning! A perfectionist can find hair-like scratches and laser-work dust on the mirror surface but he'll not kill himself because the cost of the whole machine is the same as average balanced cable. If I'll offer plastic PDv2 with $5 discount, I believe angels would shed a tear in heaven.
Q: Which DAC sounds better, PDv2 either #9038S?
A: If you have 2 kids, which one you like better? I wish you'll decide which is better for you. In my life I rather prefer PDv2, #9038S has too analytical sound, perhaps too precise for me. SE mod(tube-like emulation) makes a bit "more body" in vocals, this one I like about #9038S.
Q: Why you insist PDv2 isn't DAC+HPA combo, and why "no feedback" is good?
A: That practice wasn't started by me. Companies which produced Fully Digital power Amps(FDA) from about 2000, began to call their products PowerDAC or FDA either Pure Digital Amps. You can read about it here and here.
I simply scaled down the out power and cost 200 times and offered the same idea for headfiers as well, that's why my PowerDAC is "v2" = we too. Regarding a feedback-less feature, I'm not against of feedback itself as an instrument for improving formal specs and finally to reduce device cost as well but I remember many DIY discussions around this topic. Usually, audiophiles believe that less feedback amount makes a more pleasant sound, however, only PowerDAC can provide true open loop topology with no feedback at all, that is practically impossible to implement in an analog-linear amp with a decent level of distortion and for $50.
Q: Could you sale 2.5mm TRRS balanced cable for my headphone?
A: Not yet but already thinking about it, too many guys asking me about that and I gonna check how to order a few types of cables decent quality and chifi price simultaneously.
Q: Your logo reminds me Atari + Pac-man, is this a message?
A: You played too much Atari, my friend )) I just tried to search by image my logo in TinEye and got the following result: Your image may be unique, and doesn't appear anywhere on the web. This happens with personal photographs, artwork, or other original images.
I do respect Atari Inc., 1990 I used their Atari SE130 to control my handmake sampler and recorded lots of tracks with it until I bought Ensoniq ASR10. However, my life taught me to see a msg in any kinda signals ;)
Q: Why my PDv2 running very warm if not to say hot, is it normal?
A: Yes, it is fine. Only one single part getting hot over there it is TAS5558 Ti 8 channels digital PWM modulator. I placed this IC close to the front mirror-cap and filled the gap with silicone for a better thermal interface. So if you feel that cap is hot, it means TAS5558 is safe because dumps its heat to the universe ;)