S9 Pro Plus Martha HiFi Balanced Dongle DAC & AMP, 768kHz/32Bit, DSD512 Portable Audio Decoding Amplifier for iPod Android PC with Windows/Mac OS/iOS/iPad OS System (Black)

I mostly use bluetooth headphones on both my desktop PC and my phone these days, but still have plenty of traditional wired headphones and IEM's around, especially for more analytical listening, in and out of my studio.I have no idea who Martha is, but what I can confirm is that this DAC is tiny and has a USB-C interface, so it's easily versatile enough to just stick in when I need it. It has both a balanced and a standard 3.5mm port, so it's very versatile when it comes to headphone/cable support, too. Many DACs offer just one or the other, so having both, particularly at this price point, is a big win.It's all metal/aluminium, and looks way more premium than the price-point might otherwise suggest. It also has volume dials, too! Way too many portable DAC's seem to skip this now, and put all the work on the app instead. This doesn't even have an app, which is a good thing, IMO. I control the EQ from my own software, so I don't need any additional processing inside the unit itself. Just give me that clean sound stream, baby!I'd say it has a slightly warm sound profile. Very pleasant to listen to, with a wide, engrossing soundstage. Probably not something I'd use for mixing purposes in my studio, where a flatter sound is preferred, but it's definitely very enjoyable to actually listen to music with. Bass was deep, mids rich, and highs slightly laid back. No hiss or annoying noise-floor. A very clean, warm sound.For the price, this is a great buy. It has everything I need in a tiny package, and has the versatility to be used both inside my home, and outside. If all you want is a great sounding upgrade for the audio on your phone, then this is as good as it gets for the amount you'll be paying. Even as a desktop DAC, it's better than most of the competition in this price bracket.

I wasn’t sure how much of a difference something like this would make, but I’m genuinely impressed. The sound quality is noticeably clearer, with more detail and separation than I’ve ever gotten from my phone or laptop alone. It drives my headphones effortlessly, even the more demanding ones, and adds a sense of depth to the music that’s hard to go without once you hear it. Build quality is excellent—it feels solid and premium in the hand. It also worked right out of the box with both my phone and computer, no hassle at all. If you care about your audio experience, this is a great little upgrade.

HIDIZS S9 Pro Plus Martha HiFi Balanced Dongle DAC & AMP:Basically a more affordable way to improve your sound output without buying expensive equipment.It is smaller than you might think and it is lightweight, so it's unlikely to get in the way when plugged in.I think this is the sort of thing that won't be of interest to most unless you have specific audiophile needs. Like if you are looking for crispier sound from your audio output.You get 5 to 6 settings to adjust the sound to your requirements and you can tweak them to your hearts content.I think it is a cool device that might cause confusion until you actually use it.

The HIDIZS S9 Pro Plus Martha DAC/AMP is an excellent DAC and headphone amp for the money.It's a small device, and looks to be a high quality build, constructed from aviation-grade aluminium alloy and weighing just 17g!It offers a USB-C interface, and two outputs - 3.5mm and balanced 4.4mm. It has 138mW output at 32Ω for the 3.5mm single-ended connection and 180mW at 32Ω for the 4.4mm balanced output.The performance is good - it provides a much cleaner sound output than my computer sound card alone and sufficient power to drive the Sennheisers.An interesting fact - the reason they are called Martha, is in honor of the last surviving female Passenger Pigeon, the largest flocking bird species ever to have existed, that became extinct 109 years ago.Control options are limited to the two buttons on the device - these control volume and the filter options which are:Default - Vocals are slightly forward, and high frequencies are extended with reduced resonance. (GREEN)Linear phase fast roll-off - Enhanced analytical capabilities, delivering a clean and crisp sound (RED)Linear phase slow roll-off - Enriched harmonics, full low frequencies, and natural reverb. (BLUE)Mimimum phase fast roll-off - Balanced and moderate sound. (YELLOW)Minimum phase slow roll-off - Clean sound with a forward position. (PURPLE)Hybrid fast roll-off - Soft and smooth with enhanced detail. (WHITE)The selected filter is indicated by a coloured light.A shame that there isn't also smart phone support for configuration, but you can't have everything I guess!In summary, this is a feature rich, and performance headphone amp that delivers exceptional performance without breaking the bank.

Ordered the HIDIZS S9 Pro Plus Martha HiFi Dongle DAC & AMP, and it’s an amazing little gadget. It does exactly what it’s meant to do, delivering outstanding audio quality. The 32-bit HyperStream QUADDAC architecture and time-domain jitter eliminator technology ensure precise, high-quality sound with a signal-to-noise ratio of 128 dB and distortion as low as -120 dB.It’s incredibly easy to install – it worked straight out of the box with my Windows 11 PC without needing any drivers or additional software. The device is compact, lightweight, and sleek, making it portable and practical for on-the-go audio.I’m thoroughly impressed with the performance and would highly recommend this DAC & AMP to anyone looking to enhance their audio experience. Great value for such top-tier sound quality.

The HIDIZS S9 Pro Plus DAC & Amp is incredible! 🔥 It brings out so much detail and richness in my music, especially paired with decent headphones. Smooth, balanced sound with plenty of power. Build quality feels premium, and it's super compact — easy to travel with. A real upgrade for any serious music lover! 🎼