Astell&Kern PD5 DAP Review: The SR35's Long-Awaited Redemption
Read Time: Approx. 6 min.
TL;DR
- Octa-DAC architecture with eight Cirrus Logic CS43198 chips and a dual-drive mode that lets you toggle between Quad (efficient, natural) and Octa (powerful, dynamic) sound.
- Up to 28 hours of playback in Quad-DAC mode; a notable jump from the SR35's 20-hour playback, despite housing twice the DAC count
- EnviroTune, a first-of-its-kind real-time ambient noise compensation feature for a DAP
- Compact, ergonomic redesign that's closer in size to the SR35 than the PD10/PD20, with a standard clear TPU case
- Full Android OS with Roon Ready and Qobuz Connect certification, plus fast, lag-free performance that addresses the SR35's biggest weakness
AK's Newest DAP Turning the SR35's Shortcomings Into Strengths
For the longest time, the A&ultima SR35 DAP was the ultimate entry-level player for audiophiles. It was small and compact, easy to use, and delivered that signature Astell&Kern sound. But underneath the praise, the SR35 had a host of problems: sluggish, laggy performance, limiting software, and limited driving power, and those cracks eventually caught up with it. Once the SR35 was relegated to legacy status, a clear gap emerged in Astell&Kern's product catalog. It's rare to find a truly pocket-sized DAP with good power and good battery life, and for years, nothing in AK's lineup quite filled that gap.
Enter the Astell&Kern PD5 Digital Audio Player, the ultra-portable entry-level DAP we've all been missing. While it's technically part of the PD series, it's closer to the SR35 in size and portability than its PD10 and PD20 siblings. It brings an Octa-DAC architecture built on eight CS43198 chips, a dual drive mode that puts you in control of your listening experience, and EnviroTune, a first-of-its-kind feature for a DAP. With 28 hours of playback on a single charge, the PD5 was built for all-day listening.
Call it the SR45, the SR35 MKII, or whatever you want; the internet certainly has. Dubbed by fans and industry alike as the successor to the SR35, the PD5 had a lot to live up to before it ever reached my desk. But despite all the outside noise, the PD5 stands tall on its own. It's not just filling the SR35's shoes; it's fixing what held it back, and in doing so, makes the SR35 feel like old news.
PROS
- Fast, consistent performance that held up under repeated stress testing, unlike the sluggish SR35
- Quad and Octa-DAC modes let you tailor sound signature and battery life to your gear and genre
- Compact, comfortable design with a premium build and a clear case included
CONS
- Octa-DAC mode's superior sound comes at a steep battery life cost (15 hours vs. 28)
- No physical volume lock control on the chassis (software-only)
- Long-term durability of the clear TPU case is uncertain
Design
Move over SP3000M, there's a new pocket-sized king in town! While the PD5 is technically the same size as the SP3000M, it's lighter and easier to hold and carry. The beveled edges and unique shapes of Astell&Kern's A&Ultima series DAPs have become a trademark, but the PD series moves in a different direction. Square, structured shapes with precise corners make up the PD series components–a design reminiscent of early models like the AK100 DAP. When the PD10 and PD20 were released, many audiophiles found the shape and overall size hard to manage. They were larger models that didn't scream "portable," but the PD5 changes that. It's only 1/4" larger than the SR35's dimensions--miniscule differences--but the overall design and user experience couldn't be more opposite.
Those sharp corners that would nick you if you weren't careful are gone. Sure, the volume wheel isn't as recessed as it was before, but that's only because there are no triangular edges to cover it. I've seen many comments and concerns over the volume wheel's placement. Some feel it sits too far out and that it might get snagged and damaged, but I'm here to set the record straight and dispel any worry you may have. It's no bigger than a Smarties candy. It practically feels like one with the recessed center, and I honestly forgot it was even there when I was using it. I think we get so used to a certain design, sound, or experience, that when things change we turn into skeptics, quick to voice any and all possible flaws. I'm the same way, so that's why it's important I address the things I see online as a reviewer. Call it my civic duty or just me looking out for my fellow audiophiles, but the PD5 is a welcome change. I wouldn't want it to replace the SR35 verbatim and steal its thunder, but we have to move forward as an industry and be receptive to new ideas. Astell&Kern has rarely led us astray.
The overall build of the PD5 is awesome. It's small, lightweight, and incredibly easy to hold comfortably in one hand, and that's something I can't say about every AK DAP. The light, almost heather gray finish is beautiful. It's simple enough without feeling bland, and the TPU clear case only elevates the look further. Yes, you read that right. The PD5 comes with a clear TPU case that fits the DAP like a glove. After the years of leather and faux leather cases, I'm happy to see something new. Not that I don't love a leather case, but after wrestling with the PD10's case every time I tried to take it on and off, I'm relieved. You can still purchase a leather case as an aftermarket accessory through Astell&Kern, but all units ship with the clear TPU case. My only qualm is how it may look after a year of use. I have a clear Speck case on my Apple iPhone 13 Mini and after about a year of use, the rubber border that hugs the phone begins to yellow. While a quick Google search confirmed that Speck case uses thermoplastic polyurethane (TPU) like the PD5's case, only time will tell how it withstands wear.
As for functionality, you'll find all the basic physical controls placed around the chassis: a USB-C port and microSD slot on the bottom, the volume wheel on the right side, three playback buttons on the left, and 3.5mm and 4.4mm headphone jacks, a power button, and the built-in microphone for EnviroTune on the top. The only thing I didn't see on the chassis is a physical volume lock control, which is a feature many of us use. It's not a complete oversight on Astell&Kern's part though, because it's included in the software and can be turned on/off through the dropdown menu on the top of the display screen or in the settings.
The User Experience
The PD5 boasts approximately 28 hours of playback on a single charge, which is a noble amount for a DAP of this size. The SR35 was rated at 20 hours of playback on a single charge and had a host of problems that dulled the user experience. Slow, laggy performance became the SR35's Achilles heel, especially when you were using streaming services. Determined to ensure the PD5 wouldn't fall victim to a similar fate, a few of my colleagues and I put the PD5 through its paces, quickly opening and closing apps, pressing play, pause, and skipping tracks after just a few seconds, and so on. Yet, despite our best efforts to find a flaw, the PD5 remained fast and consistent. What was a point of failure in the SR35 is a strength in the PD5.
Sound
Historically, Astell&Kern has done a good job creating products that get out of the way and let the gear you pair it with truly shine. I can think of a few models in their lineup that stray from this, with slightly more warmth and weight, but across the board, their signature sound has been consistent. The SR35 was praised for its smooth, slightly rich, full-bodied sound that never lacked musicality. It supported the low-end impact of a pair of bass-centric IEMs while reproducing the fine details in your favorite pair of planar magnetic headphones. The PD5 echoes the same sound signature as the SR35, partly due to its matching DAC chips, but with four more chips than its predecessor, it does so at a much higher level.
With the PD5's dual drive mode being one of its most enticing sonic features, I knew that's exactly where I needed to start my listening session. I jumped right into A/B testing the Octa and Quad-DAC modes against each other, and the differences aren't subtle; they're night and day. On paper, the Quad-DAC mode is the more efficient option, using significantly less power than Octa mode, and delivers what Astell&Kern's dubbed a balanced, natural, and smooth sound. The Octa-DAC mode maximizes performance, drawing more power than the Quad mode, which in turn significantly reduces the playback time you get. One of the first things I noticed when A/B testing an EDM remix of Ty Dolla $ign's track "Blase" was its efficiency.
Quad-DAC mode is modest. It reproduced the track with enough musicality and dynamic range to do the synth-heavy parts justice, but it's smooth, just like Astell&Kern said. Octa -DAC mode makes its presence immediately known, reproducing the track with fervor and lightning-fast speed. It had more impressive speed and decay than the Quad mode, which was perfect for a fast-paced EDM track like this one. Everything became bigger, bolder, and more immediate. It's fair to say that Octa-DAC mode is the sonically superior choice here, but that level of performance comes at a price. It demands much more from the entire system than the Quad mode does, bumping you down from 28-hour playback to a mere 15 hours.
While the Octa-DAC mode may have been the sonic winner, that doesn't make it inherently better than the Quad-DAC mode. What I realized is that there are clear times when one mode outperforms the other. Throughout my listening session, I found myself switching modes depending on the genre and gear I paired with it. Quad-DAC mode complemented the low-end extension and dynamic range of the Meze Audio ASTRU IEMs better than Octa, which felt almost too powerful at times.
When the PD5 first arrived at my desk, I looked at the dual drive modes as nothing more than a way to save battery life, but in reality, it's a sound-shaping tool–just not in the way you'd think. Regardless of which mode you're using, you're getting Astell&Kern's signature sound. That's evident from the start. But the real gift here is the ability to perfectly match your gear and music to the PD5–much better than any DAC filter can do.
The PD5 stands out as the entry-level DAP that disappears during your listening session. It enhances the sonic strengths of your favorite IEMs and over-ear headphones, while accurately reproducing the fine details and nuances of songs–all the parts you don't know you're missing until you hear them through a high-quality DAP like the PD5.
Compared to previous PD series DAPs, like the PD10 with its surprisingly warm, lush sound signature, the PD5 is natural and authentic. The PD10 stood out in AK's lineup because it strayed so far from the company's signature sound. While it wasn't the first time Astell&Kern released a DAP with warmth and richness, it had certainly been a while, so when the PD20 was debuted shortly after, Astell&Kern put us in control of our sound. The PD20's Personal Sound Studio made us the architects of our listening experience, and the PD5 carries on a similar purpose. There's no Personal Sound Studio, but there's dual drive mode and a natural sound signature–and that's all it needs.
Big Feelings
By Ariana Grande
(Petal)
I Only Have Eyes for You
By The Flamingos
(Flamingo Serenade)
Hang On to Your Love (Long Version)
By Sade
(Diamond Life)
About You
By The 1975
(Being Funny in a Foreign Language)
Features
- Octa-DAC Architecture: Eight CS43198 DACs for wide dynamic range and channel separation
- Dual Drive Mode: Switch between balanced and ultimate sound
- Up to 28 hours of playback
- EnviroTune: Auto-compensates for ambient noise without raising volume
- ESA (Enhanced Signal Alignment): Minimizes group delay for clearer sound
- TERATON ALPHA: AK's tech for noise removal and stable amplification
- Digital Audio Remaster (DAR): Upsamples PCM to 384kHz and DSD to DSD128
- 4 Selectable DAC Filters
- Crossfeed Technology: Speaker-like soundstage with adjustable settings
- ReplayGain: Automatic volume normalization
- Dual-Band Wi-Fi: High-res streaming with Roon Ready support
- Bluetooth Sink: Stream audio wirelessly from external devices
- Roon Ready & Qobuz Connect Certified
- Compact, Ergonomic Design: ~200g, curved 4.1" display, "Grip Control" build
Cirrus CS43198 DAC: The SR35's Legacy Lives On
While Astell&Kern hasn't explicitly said the PD5 is the direct successor to the SR35 DAP, the invisible strings linking the two together are clearer than ever, and it all starts with the Cirrus Logic DAC chip. The PD5 sports the same Cirrus Logic CS43198 DAC chip used in the SR35, but in a slightly different configuration. The PD5 takes the SR35's quad DAC configuration and doubles it to an Octa DAC configuration. The top questions on everyone's mind: How does this impact the sound? Will it still sound similar to the SR35? Why eight Cirrus Logic chips instead of two or four AKM chips? These are all very valid questions that also crossed my mind, and as it turns out, Astell&Kern had already thought them through when designing the PD5.
The PD5 implements a dual drive mode, letting you run all eight DAC chips or scale down to just four. In Quad-DAC mode, you get AK's signature sound: natural and smooth. In Octa-DAC mode, you get the full sonic potential here: expansive dynamic range and exceptional channel separation. Access this mode in the PD5's side panel under "DAC Filters" or in the drop-down menu.
EnviroTune: Astell&Kern's Latest Innovative Feature
EnviroTune is Astell&Kern's latest feature, debuted in the PD5, that makes listening just better. It's an intelligent sound-tuning technology that uses the built-in microphone on the DAP's top panel to detect changes in ambient noise in real time, then analyzes the input sound by frequency band to automatically compensate for frequencies masked by noise.
Sony has a similar feature they've been using in their wireless noise-canceling headphones for years, but this is the first time I've seen anything like it in a DAP. Skeptics have wasted no time voicing their opinions and concerns, questioning whether this is even a necessary feature in a DAP or just another component slowing the system down, and while I don't have all the answers, I will tell you this: If it's not a feature you're interested in using, you can turn the microphone on/off in the device's settings. Don't let this minuscule feature be what holds you back from owning the PD5.
Other notable features include ESA (Enhanced Signal Alignment) technology, DAR (Digital Audio Remaster) technology, four distinct DAC filters, crossfeed, and ReplayGain.
Dragon Cables
There are a lot of reasons why you need to make sure your audio cables are not afterthoughts.
Our HiFi Audio Dragon Cables bring out more of what you love in your music and audio gear. If you love your headphones but wish they had a bit more top-end sparkle - a Silver Dragon Headphone Cable would be a great option. If your USB cables keep dying - as many stock cables do - then check out our quality USB Audio Cables. We say time and time again that materials matter, and our audio cables and custom geometries actually help to bring out those desired properties in your gear and music. We make tons of custom options for our customers so that you can get the right HiFi Audio cable for your exact needs. If you have any questions feel free to Contact Us and we'll be more than happy to help.
Generally, stock audio cables are manufactured with subpar materials, metals with impurities, poor geometries, and an overabundance of layers to make them look and feel like a fire hose. Inconsistency and lack of quality control in stock cables can lead to poor sound quality and a veiled sound vs. what the musician intended for you to hear and feel from the music. Dragon Audio Cables are handcrafted with the highest standards and made to order according to your specific needs. At Moon Audio, we create a custom cable for you using the highest quality UP-OCC silver or copper conductors that can be manufactured. UP-OCC metals are void of impurities and are optimized for signal transfer and sound quality. We have one of the largest collections of audio and headphone connection options available online and we create limitless audio cable options depending on your specific gear and needs.
Why Dragon Cables?
You’ve heard the saying that a chain is only as strong as its weakest link, right? Well, the same applies to your brand new audiophile-grade headphone or other audio components. The weakest link, in this case, is your stock audio cable or the cheap interconnects the manufacturer threw in the box just to get you up and running. Why is the audio cable always an afterthought, when it’s just as important as the rest of your system? At Moon Audio, we use the purest and best raw materials in our cables to unveil your music. We believe that materials matter and your audio cables should have the same care and craftsmanship that manufacturers put into their audio components and headphones. Audio cables are ultimately the connection to your music. The fact remains that cabling is often considered the last priority to that of the main product and a means to cut down the overall production costs. It’s as simple as that. Dragon Cables elevate every note - as if you were hearing your favorite music for the very first time.
Verdict
Over the last few years, Astell&Kern has made huge strides in product development, breaking out of what once felt like a statement of marginal, back-to-back upgrades. The SP3000 DAP marked the turning point, debuting a new UI alongside industry firsts like a stainless steel body. Momentum built quickly from there: the SP3000T DAP combined tube and solid-state amplification in one chassis, while the SP3000M brought a compact, pocket-friendly size reminiscent of AK's legacy models. Then came the SP4000 DAP, and the industry shook once more. It was Astell&Kern's first DAP to run a full Android OS–a feature audiophiles wanted for years, and one that had left AK trailing behind competitors.
A few more releases later, we arrive at the PD5: a pocket-sized music player blending heritage and innovation into an affordable entry point for audiophiles and music lovers alike. The Astell&Kern PD5 Digital Audio Player isn't trying to be everything to everyone, and that's never been AK's goal. In a way, they've answered years of fans asking for an SR45–just on their own terms. Whether it's the SR35's de facto successor or not, what matters is what's inside, not the product name: a full Android OS, Octa-DAC architecture built on eight CS43198 chips, EnviroTune's real-time noise compensation, and the battery life that outlasts the SR35 despite doubling its DAC count. The PD5 doesn't need a new name to prove itself; it just needs you to press play.
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What's in the Box
- PD5 Digital Audio Player
- USB-C Charging Cable
- Warranty and Manual
Specifications
Model: PD5
Body Color: Silver
Body Material: Aluminum
Supported OS: Windows 8, 10, 11 (32/64-bit) MAC OS
Dimensions: 2.74" (69.7mm) [W] x 4.71" (119.7mm) [H], 0.63" (16.1mm) [D]
Weight: about 6.98 oz (198g)
Display: 4.1-inch 720 x 1280 touchscreen
Built-In Memory: 64GB [NAND]
External Memory: microSD x1 (Max. 1.5TB)
Battery: 4,000mAh 3.8V Li-Polymer
Charging Time: Approximately 2.5 hours (PD3.0 charging)
Continuous Playback Time: Approx. 28 hours (Standard: FLAC, 16-bit, 44.1kHz, Vol.50, Quad-DAC, LCD Off)
CPU: Octa-core
Wi-Fi: 802.11 a/b/g/n/ac (2.4/5GHz)
Bluetooth: V5.3 (A2DP, AVRCP, Qualcomm® aptX™ HD, LDAC, LHDC, SBC, AAC)
Operating Temperature: 0℃ ~ + 40℃ (32℉~ 104℉)
Feature Enhancements: Firmware upgrade supported (OTA)
DAC: Cirrus Logic CS43198 x8 (Octa-DAC)
Input: USB Type-C Input (for charging, PC & MAC)
Outputs: Unbalanced Out (3.5mm), Balanced Out (4.4mm, only 5-pole supported)
Supported Audio Formats: WAV, FLAC, WMA, MP3, OGG, APE, AAC, ALAC, AIFF, DFF, DSF
Sample Rate:
- PCM: 8kHz ~ 384kHz (8/16/24/32-bits per sample)
- DSD Native: DSD64 (1-bit 2.8MHz), Stereo / DSD128 (1-bit 5.6MHz), Stereo, DSD256 (1-bit 11.2MHz), Stereo
Output Level:
- [Quad] Unbalanced 3Vrms │ Balanced 6Vrms (Condition No Load)
- [Octa] Unbalanced 4Vrms │ Balanced 8Vrms (Condition No Load)
Decoding: Support up to 32-bit/384kHz Bit to Bit playback
Frequency Response:
- ±0.011dB (Condition: 20Hz~20kHz) Unbalanced │ ±0.011dB (Condition: 20Hz~20kHz) Balanced
- ±0.130dB (Condition: 20Hz~70kHz) Unbalanced │ ±0.143dB (Condition: 20Hz~70kHz) Balanced
S/N: 125dB @ 1kHz, Unbalanced │ 129dB @ 1kHz, Balanced
Crosstalk: -145dB @ 1kHz, Unbalanced │ -147dB @ 1kHz, Balanced
THD+N: 0.0006% @ 1kHz, Unbalanced │ 0.0006% @ 1kHz, Balanced
IMD SMPTE: 0.0003% 800Hz 10kHz (4:1) Unbalanced │0.0001% 800Hz 10kHz (4:1) Balanced
Output Impedance: Unbalanced Out 3.5mm (0.6 ohm) | Balanced Out 4.4mm (1.2 ohm)
Clock Jitter: 25pS (Typ.)
Reference Clock Jitter: 250 Femto Seconds
