Heartfield R1

General Information

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About R2R Technology​

For those seeking precise sound reproduction and authentic analog signal conversion, R2R technology is the ideal choice. R2R DACs convert digital signals into true analog signals through a resistor network. Unlike the widely used Delta-Sigma (Δ-Σ) and 1-bit technologies, which approximate analog signals by modulating digital data into sequences of 0s and 1s, R2R DACs avoid these inherent errors and can accurately reproduce even DC signals.

Proprietary R2R Architecture​

Our design features 32 ultra-high-precision resistors per channel, totaling 64 resistors, to form a fully discrete R-2R DAC circuit. With 64 resistors each offering a 0.1% tolerance, this uncompromising precision ensures unmatched audio fidelity.

Meticulous Sound Tuning​

At HeartField, we believe the essence of any HiFi product is in its tuning. Advanced technology alone isn't enough—without careful sound craftsmanship, the result is lifeless. Exceptional tuning brings music to life, making every note resonate. HeartField—Experience a world where every note is full of vitality.

Wide Range of Applications​

Android Phones & Tablets: Plug and play, enhancing your audio experience.
iPhone & iPad: Perfect compatibility for high-fidelity sound.
Apple Mac & Windows PC: Seamless connectivity, balancing work and entertainment effortlessly.
Portable Music Players (with USB Audio Output): Unlock a new level of musical enjoyment.

Only 19.8g Lightweight Design​

It won’t add extra strain to your cables or USB ports on devices like smartphones. Its near-weightless design ensures easy portability, allowing you to enjoy high-fidelity sound wherever you go.
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Latest reviews

vandung2510

100+ Head-Fier
Heartfield R1 - A new R2R dongle contender
Pros: - Good build quality
- Glass panel so that you can see all the individual electrical component
- The volume wheel is nice to use
- Analog-ish timbre yet not excessively warm sounding
- Cool to the touch after long using period
Cons: - Sound closer to a Delta-Sigma dongle dac than a R2R dac
- Noise floor from the EMI
- Bass crackling/crashing/distortion at high volume with certain type of iem which makes them unlistenable
- Not as tight bass
- Lack of features
- Expensive for the performance it gives
- Average stock cable
 Introduction
Dongle is not an unfamiliar object to many of us audiophiles, especially in 2024. But in case you don't know, it's a miniature DAC/AMP device that lets you plug into your phone to decode and play high quality music through your iem/earbuds/headphone with ease.

Heartfield is a newly established Chi-Fi audio brand that starts producing interesting audio products in mainland China. The R1 is the first dongle from Heartfield, featuring a 16-bit R2R DAC architecture.

You can find out more about the R1 here: linsoul.com/products/heartfield-r1

Disclaimer: I would like to thank Linsoul for providing this iem in exchange for an honest review and impression. Everything I said in this review is my subjective opinion only.

Unboxing
The R1 comes in a small and minimal box. Opening it up will reveal the dongle itself. Under it is the C-to-C otg cable along with some paperwork.

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The R1 doesn’t have any case coming with it.

Design/Build quality
The R1 has a full aluminum body with a matte, anodized finish. The top side of the dongle is a clear acrylic plate that will let you see all the individual components that made up the R1. On one end of the dongle are the 3.5mm and 4.4mm port, while the other side has the female type-C port. On its side is a plastic rotating volume wheel, along with the marking to show you which way will increase or decrease the volume.

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Features:
Or lack-there-of. The R1 is a pretty straight forward dongle with a minimal amount of features. There’s no screen on the R1, no gain switch, no app support. You can only control the volume, as well as having a small LED light to show you if the dongle’s working or not.

Using experience
To use the R1 is a pretty simple operation. Just plug it into your device of choice, be it your phone or PC, plug in your iem/earbuds/headphones and you can start playing music through it.

When using the R1 with Window’s laptop, you can’t control the volume by the laptop’s volume slider. Whether you slide it down to 0 or all the way to 100, the volume output remains constant. You can only control the volume by scrolling the volume wheel.

The volume wheel feels very smooth to scroll/turn. It doesn’t have any clicky, snappy feedback, just a smooth rolling experience from Min-Max volume setting

The potentiometer in the R1 works perfectly fine, as there’s no channel imbalance even when listen to the dongle at low volume

Noise floor?
The R1 is a VERY noisy dongle. Noisy in the meaning that whenever you connect to a source that is connecting to wifi or using data – so your phone and laptop – then listen to stream music, you’d clearly hear a constant humming, buzzing noise from the dongle due to the EMI. Or when you sit near a wifi router, you’d hear it as well. Those noises get very annoying the longer you hear it. Only by turning on airplane mode or disconnecting from wifi + data AND doesn’t put near any source of signal, should you stop hearing those noises.

During the listening period of this dongle, I have to turn on my phone’s airplane mode most of the time and can only listen to offline music to not be interrupted by the noise floor.

Bigger problem
The R1 also have a big problem is that, with many of my iem, specifically being hybrids, whenever I turn up the volume pass 50% and listen to tracks that have big bass thumps/rumbles playing, the bass driver would get clipping HEAVILY, which is absolutely unlistenable. The bass driver sounds like it is crackling and crashing on itself. When I turn down the volume, this clipping noise phenomenon doesn’t happen anymore.

Synergy
Why did I mention hybrids? Because with other iems type like 1DD iem or multi BA iem, i didn’t encounter it as much. I have no problem when listening to the Simgot EA1000 or the Tanchjim Oxygen, or the Heartfield Blanc (5BA).
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One interesting matchup is the Penon Conductor, a hybrid earbud with 1 DD and 1 BCD. If I turn the BCD OFF – so only the DD is working, I won't hear those clipping noises when I turn the volume of the R1 up. But when I turn the BCD ON, even slightly, those clipping noises start happening again.

What does this mean? This means that the R1 has a serious synergy/match up problem, where you can’t use some specific type of iem with it, especially when you’re a mid-to-high volume listener.

Sound impression
Despite being an R2R dongle, the R1 doesn’t have the typical warm-ish sound signature that many are familiar with. Instead, the R1 has a neutral-ish sound signature, one that sounds surprisingly similar to many Delta-sigma dongles out there. It’s like a non-R2R, R2R dongle if that makes sense.

For the overall “timbre” signature, the R1 leans more over the analog side than the hi-fi side.

The bass of the R1 is around neutral level, not heavily boosted but still has decent subbass extension. The bass doesn’t feel sluggish at all, but the texture does feel a bit soft and average in tightness as well as the impact it provides.

Mids are smooth and organic, but not overly warm and thick. Noteweight is around “normal” level, not heavy or light. It definitely doesn't sound thin. Midrange instruments have good center stage presence and texture to them.

Treble is smooth and not harsh. I wouldn’t say the R1 has the most sparkles, clarity and details in the top end. It feels very safe here.

Stage is decently open staging with above average imaging and layering.

For a more relative context of how the R1 performs, please continue reading till the comparison parts.

Driving power
The R1 has an above average amount of power. Judging by volume level only, I can reach my Letshuoer S12 and ZiiGaat Estrella to well above 80db.
However, like i said, you’d likely run into the the bass crackling issue before you even reach your desire volume

Sound comparison
1/ EPZ TP50


The TP50 is a dongle with 2x Cirrus Logic CS43198 DAC chips. It has a dedicated screen with a lot more features, like gain control, changing filters and such. The TP50 also has a 3.5mm and 4.4mm port. It used dedicated buttons to control the volume and settings.

Sound wise, the TP50 is like a tier or two above the R1. The bass sounds tighter, more distinct and well defined. The midrange is relatively neutral with greater transparency. Instruments have better texture and breathing room here. Treble is undoubtedly more extended, more energetic, crisper with more sparkles and details on the TP50. The TP50 is not an overly harsh or bright dongle to begin with btw. Soundstage is also bigger on the TP50 with improved imaging, layering and separation.

All of that for the price of 113$ on Aliexpress , which is cheaper than the R1.

2/ Hiby FC6

The FC6 is an R2R dongle from Hiby. It has a dedicated screen and a control button to let you change the filters of the FC6, as well as choosing the OS or NOS option. The FC6 only has a 3.5mm single ended port as opposed to a 3.5mm and 4.4mm ports on the R1.

The FC6 is selling for 299$ on online retail stores, almost double the price of the R1.

Sound wise, the FC6 sounds way warmer, closer to that of a classic R2R signature.

The bass on the FC6 is more impactful, but it also feels more sluggish. The mids are warmer, noteweight is heavier on the FC6. Vocals are more forward on the FC6. Male vocals sound lusher on the FC6. The treble is more extended despite still sounding smooth.

Soundstage wise, the FC6 feel more intimate due to a more vocal forward presentation. Imaging is better on the FC6, but the separation and layering is similar, as it can only do so much with such a small stage. Timbre is more natural on the FC6.

Conclusion
In and of itself, the Heartfield R1 is a decently performed dongle. But sadly it has WAY too many caveats, too little features and therefore too expensive for what it is. For the first ever dongle from Heartfield, it’s certainly praiseworthy. It does have potential. However, the R1 still needs to be improved a lot more to stand a chance against the many dongle competitors in the market, either through adding more features, improving the sound performance or decreasing the price. I’m looking forward to seeing what Heartfield has to offer in the future.
That’s it for my review and thank you for reading.

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Redcarmoose

Headphoneus Supremus
Pros: Not all Dongles sound the same
Warm, smooth analog tone with every IEM, though the R1 seems to excel with all BA IEMs
Even after used for hours on end the R1 barely gets above human body temperature
Cons: Has different output power from various styles of TypeC USB connection protocol
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HeartField R1 R2R Ladder Dac/Amp Dongle
Redcarmoose Labs October 28th, 2024

Executive summary:

This has really been a story to tell, and I will try and keep it short. The HeartField R1 is like no other Dongle I have experience with. Later in this review I will explain how Ladder DACs are different from regular decoder DAC chips in use and in sound personality. While I have only heard 10 Dongles I have used them enough to make some fairly broad statements concerning the R1. Overall the sound is less detailed than with pretty much any Dongle, yet that is not what the R1 is about. Being R1 tops off at 16bit, it is going for warmth and an uncanny texture that seems to be the 1st Dongle to really make BA driver IEMs shine. This is accomplished by two aspects of the R1 personality.

1) Great bass that is maybe not the most detailed, but warm, full and outreaching into the stage position.

2) Thicker realizations of treble and midrange fall-out, enabling a treatment fully against any stridence, even with your temperamental all BA sets.

End of summary:

HeartField also makes besides the R1:
The $1999.00 Astella IEM
The $799.00 Galaxy Pro IEM
The $389.00 Orange IEM
The $399.00 Silberia IEM
The $499.00 SilverSmith IEM
The $169.00 Acoustic Deer IEM
The $249.00 BLANC IEM

With such examples of IEM construction do you really think HeartField would come-up with a less than stellar R2R Ladder DAC/Amp?

What are R2R ladder DACs?


R2R DACs
From the 1990s, such resistor ladder DACs can do 16bit, even 18bit……still never (can they do) 24bit or 32bit. So no R2R DSD playback in correct resolution. The word is explained as such……

16-bit word results in 96dB
24-bit word results in 144dB
32-bit word 192dB

PCM DACs with a 16bit word:
The signal word header says what to do. Then the actual word shows the above 16 bit counts using on or off 2-4-6-16-32.

R2R DACs:
On and off 16 switches, each switch has to be joined to a precision resistor. These are precision resistors therefor even better than good resisters that have 1% accuracy.


Why different?
R2R resistors have greater accuracy are put into row of switches and resistors on a board.

R2R resistors have .0001 accuracy resistors, typically obtained and used in R2R DACs. These on and off signals are 44,000 times a second, more current higher voltage, less current lesser voltage thus a signal. Current to voltage converter is then used to make music by up and down voltage. Regular DACs Sigma Delta modulator 1 bit, 2 bit, and 3bit does DSD and is needed for conversion to PCM. Though there are DSD DACs which don’t do the PCM conversion and leave the signal in DSD. Here with R2R we see an analog volume knob, and the R1 does not get super loud, but is more about a smooth quality with a glow.

The HearField R1:
I was sent an R1, then upon using it a while I noticed some peculiar aspects. Thus in an attempt at being complete I asked for a second review sample to be sent over. I simply wanted to confirm that the artifacts were the same on both units and they were. No big deal, and if you love the HeartField R1 like I do you will overlook such personality traits. As talked about in prior reviews the R1 has a volume threshold that at a certain point creates static or a pop. Not a big deal, except there were also other festivities at hand here, like the volume never turning to complete zero, being able to hear a faint sound of the music playing always, yet only under certain conditions and not always with every IEM. But remember there are a few variables to creating this. Meaning the R1 will respond in various ways to the different USB protocols.

Meaning TypeC 3.1 like what the HiBy R3 II puts out creates such amplifier power to the R1 that you can’t even turn the volume wheel past 1.5 (almost only 1/10th) of the power capabilities without hearing static. Though all this also depends on the draw of your IEM. From regular 1.0 TypeC (like a Samsung Phone) things were way more manageable, yet there was a slight ghosting of distortion only when the song ended out to the right channel. So you could see why I needed two units to verify if it was normal. Plus the customs department from my friendly mail service opened the 1st R1 and who knows what they did with it. Lol

You see, I have been a member of Head-Fi since 2008, reading here at this place since 2006…….and I know there is a section of the populace that is very close to expecting perfection from the sound output, regardless of sound quality. So I could not do a review with broad accolades without at least understanding what we have. To me these small sonic artifacts never affect the enjoyment of music, but depending on which device I use, can remind me that the R1 is in place at the tail-end of songs.

Volume/power:
The R1 may be my least powerful Dongle. Yet it gets loud enough for any of my uses. The only other low power Dongle I have is the Shanling UA3. And while the two are still very much different ideas of what a Dongle could sound like, the Shanling UA3 also has a very full analog sounding bass, but that is where similarities end in sound. As such upon first trying the R1 out I thought maybe it would not power full-size headphones well, or Planar IEMs. And in practice really both full-size headphones were listenable, yet maybe not their best in Dongle Land. Same as Planar IEMs, that while they got loud enough, the bass didn’t hold the definition and detail that other random Dongles offered to the Planar type of IEMs. But still it worked to use the R1 with Planar IEMs, and the more time I spent listening the more I liked the R1 even with Planar IEMs. You start to over look any technicality drawbacks, with the musicality taking over.

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Personality: :relaxed::relaxed::relaxed::relaxed:
The HeartField R1 has personality……that is the best way to describe it. I have never had a Dongle that inspired me to take out 6 boxes of IEMs……6 cases of IEMs. Multiple cables and trying it with multiple digital sources, as each one was very different in both how they affected power on the volume wheel and even those small almost unnoticeable sonic artifacts. While using an easy to drive all BA IEM I hooked the R1 to my MacBook Air and found the song still playing even with the volume turned all the way down. Yet in-spite of these issues the R1 climbed to the top of the Dongle ladder. Pardon my expression, but after trying countless IEMs, after trying a number of cables, even my most expensive $799.00 cables, and most expensive (all BA) IEMs together I started to realize that the R1 was showing me a new vista. Maybe don’t call it detail but different stage sizes filled with textures? This let me know the R1 was a keeper. Plus it made the KZ AS24 Pro some of the best I ever heard it. You see there is no wonder I was sent the R1 and HeartFiend all BA BLANC IEM together. And in the range of examples some all BA IEM examples are less BA sounding than others………..still the R1 got rid of any of that tell-tale BA sound. And just as manufacturers moved forward to try and down-tune the BA characteristics out of some BA examples, the R1 was also moving forward to un-digitalize parts of the sound. The side effect of this is extra long listening times. And maybe this is normal for reviewers, but for me when I get done testing IEMs for a review I put them away. Though in the case of the R1 and prior KZ AS24 Pro review, I had the AS24 Pro in my ears and even after the review was completed I simply kept listening because the tone was so enjoyable, smooth and fun. Plus I couldn’t get over the fact about how they made the KZs easy to gain synergy with all genres of music. If this is not an endorsement for a product, I don’t know what is?

Sure the R1 isn’t everything, the stage is not quite as big as the enormous WM1Z, nor is the bass quite as thick or as physical, but remember we are talking about a Dongle barely larger than a box of matches and costs only $159.00! Sure it doesn’t contain the WM1Z details, especially in the treble, but the R1 doesn't cost $3200.00 either. What the R1 does is provide much of the same linear warmth throughout the signal, a style of warmth that seems to coat each and every note and make it both more accessible and organic.

Comparisons in daily use:

ifi GO blu:
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Probably the most fun can be had by purposely not using the HeartField R1 for a day or two, then hearing the contrasts from previously used devices. Obviously this use practice is silly as why would you spend $159.00 on a DAC/Amp Dongle and not use it. But coming back to the R1 holds a little of that magic moment when you first hear it. An example would be me using the ifi GO blu Bluetooth device for a morning with the SIMGOT AUDIO LC7 cable in 4.4mm, and putting the KZ AS24 Pro all BA IEM to use, then switching over the the R1 for a taste of glory. The GO blu is sold typically for $199.00. The Go blu can be used as a wired Dongle or a Bluetooth device. One reason I used the GO blu is it is one of my warmest examples of a source. People could even say the ifi sound is very analog at times. Also the GO blu, just like the HeartField R1 seems to offer synergy with the 12 BA tuning of the KZ AS24. In 2 bass switches up mode the AS24 Pro is both resolving but still slightly offering that KZ tone…….this tone maybe due to using custom BA drivers, I mean us audiophiles often talk about the expense and rarity in installation of both Sonion and Knowles procurement. While custom made BA units are on the decline as far as individual asking price, this fact enables the massive IEM output company named Knowledge Zenith to provide 24 BAs at only $115.99 (switchless) to $131.99 (switched model). And in a way here everyone wins as the consumer and manufacturer join forces to partake of what 12 BAs a side can do. Later in the review we will get into the HeartField BLANC 5BA IEM. At $249.00 the 5BA BLANC shows how we can do more with 7 less BA drivers a side. If this sonic success is from utilization methods or the actual quality of HeartField’s BA drivers, who knows? Whatever it is, the GO blu and R1 Dongle makes these two IEMs sound great!

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Go blu:
Just so you know I have had the R1 banging around here at Redcarmoose Labs for a month. During this time I have taken a few days off from its tone and used it for a few days straight. The GO blu has digital filters, which noticeably affect sound, the GO blu accepts up to 96Hz - 24bit. The GO blu has XBass and XSpace plus XBass/XSpace settings. And finally the GO blu and the R1 are roughly the same size, with the blu not quite as long. Though the GO blu has a battery, and weighs 27 grams on my humble kitchen scale, the R1 weighs just 20 grams. Such a difference is actually noticeable in hand. While sure all of the settings on the GO blu do change the tone, you still have the basic stage and overall sound, even though of course the XSpace does do something. After going back and forth about 5 times I figure I have a good idea between the two. As such this change from wired GO blu to wired R1 is as simple as a switch of the 2 cables.

The GO blu v the R1:
With switches #1 and #2 up on the KZ AS24 Pro IEM we are kinda in the zone as far as tone goes……………….when switching to GO blu XBass you would think this would cause the desired tone to change, and it does a little, though here in this set-up the GO blu XSpace seems to truly enlarge the stage. This XSpace is really the desired GO blu effect. So we will use that setting. The truth to be told this stage of the R1 is simply more spread out and holding farther actualizations of sounds, when the bass comes in it is rounded, smoother and deeper with the R1. To try and further study the differences it is arguable that there is a lesser quality of resolve, but yes at times and with unique places in the song we find the R1 to clump information together where the GO blu (in wired mode) goes ahead and carefully takes stuff farther apart. Though what is taken apart shows as more GO blu digital sounding even though more detailed. There is a noticeable thinner and forward style of the GO blu stage. Where sure the R1 has a slight timing blur, yet instruments are encased in fluidity and a wider deeper stage. I have spent two days comparing the GO blu and R1 with the AS24 Pro, which means I could probably write a paragraph or two regarding the source character, but I figure the above is clear enough to make this review less long. Yet I just wanted to point out that the GO blu due to its warmness, as well as the R1 are both wonderful sources for the AS24 Pro. And even in Bluetooth mode the SIMGOT AUDIO LC7 cable in 4.4mm is showcasing the GO blu smoother (then some Dongles) personality which takes away the digital edge of the 12BAs a side of the AS24 Pro. It’s just that while some may view the Bluetooth as a sonic limiter, really I found that Bluetooth with its lesser stage and lesser bass and vividness to actually be almost preferred with other IEMs, as a way to make them less drastic in tone. Sure though in wired mode both the GO blu and the R1 become closer to the same function, and wildly they look a lot like they ultimately are. Meaning the GO blu with all the lights and details of construction (detail sounding), and the R1 more simplistic and stark in user buttons, as actually there are none! Lol Only a single volume control and a LED light under the clear/amber window to let you know you have power. But in use the two GO blu and R1 Dongles become complementary with one offering Bluetooth as an extra route to go, plus a warm sound, and the other (R1) offering a very different change of pace making having both really a win-win.

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Side-by-sides:
Left to right top: KZ AS24 PRO, SIMGOT AUDIO SuperMix4
Left to right bottom: HeartField BLANC, TANGZU Wu Zetian

1) SIMGOT AUDIO SuperMix4 1DD+1BA+1Planar+ 1PZT $149.99 (6 grams each)
2) TANGZU Wu Zetian 14.5mm Planar $149.00 (4 grams each)
3) Knowledge Zenith AS24 PRO 12BA (switchable version) $130.99 (8 grams each)
4) HearField BLANC 5BA $249.00 (4 grams each)

Side-by-side preamble:

So this grouping of side-by-sides I have used before. Yet such comparisons of four IEMs were used recently to justify the praise to the HeartField BLANC. Coincidentally the 5 BA BLANC has perfect synergy with the R1. Maybe this was planned in the making by HeartField? Maybe it is just the analog personality of the R1 having smooth peaks and making the BA character less digital and stark? Yet the other striking plus has to do with the soundstage enlargement of the R1 taking the BLANC BA character and not only smoothing it out, but pushing details into formation arriving at even a larger stage than the last 9 previous Dongles I tested? That stage is bigger in width, front-to-back and top-to-bottom!

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SIMGOT AUDIO SuperMix4:
So word on the street is that a few listeners out there even find the treble/upper-midrange slightly too much with the SuperMix4. Yet that in many ways could be the combination of their source and the SuperMix4? Let’s find out how this works-out! Well after trying out the TANGZU Wu Zetian in the following comparison I can realistically say the SuperMix4 is brighter, bright in that it holds an upper midrange energy that while subdued by the smoothness of the R1, is still there. This is a doorway into the detail world, that it comes with both ways to work and ways to accept that this extra detail is created by a tuning. I mean I don’t even remember a thing I said in the SuperMix4 review, and it doesn’t matter, because that was then and this is now. Still this works, offering a heightened set of audio components that is of an airy upper midrange while still consumable and fun, I just want to express that after hearing the TANGZU Wu Zetian we are truly in a different part of town, sure some call this floaty and a shelf of information that makes personality character statements as to what SIMGOT was doing proclaiming ultimately a form of upper midrange detail! Though SuperMix4 is also combining a fun kind-of rolling bass matrix to add to the party. These vocal ideas are up-there and while still smoothed out by the R1 character, are unique in this price point, and sure the analog style of R1 source here helps with the perception of such attitudes, where there is a spice of musicality offered in addition to what the SuperMix4 does by the R1!

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TANGZU Wu Zetian
The truth about the Wu Zetian is that it actually took me a few days of testing to do this particular IEM. To where when IEMs shine brightly they can get talked about in a review………and everything is wagging puppy dog tails and sunshine. And when we are ever dealing with perception there is always a chance of that perception changing. Here the TANGZU Wu Zetian is one of my most favorite and on the very first day of testing, it seems that the R1 was not up to controlling the Planar bass? Yet after taking a day off then coming back to the R1 and Wu Zetian combo, it wasn’t really that bad. The most important aspect here is to take time to come to conclusions. As reviewers we jump to conclusions and even when testing groups of IEMs it is hard not to do such things. To where the R1 is adding smoothness to an already smooth IEM. And sure it works and the R1 bass added to the Wu Zetian is not bad at all, it just seems the digital phosphorescence added by other Dongles could add a little to the Wu Zetian, maybe not, maybe tis still of sound is what you want? It is almost a song by song level of great and slightly less great than I remember the Wu Zetian always being? Though again the longer I hear this combo it starts to draw me in, especially with certain songs! Where the Wu Zetian is somehow activating the stage of the R1 and grabbing hold of imaging and taking charge, taking charge of my entertainment, and I like that. Some drum beats are truly big and amazing, OK…………OK disregard the first half of the Wu Zetian comparisons, this is getting good, maybe it is the song, maybe it is my brain being told it is OK to rock-out with this combo………I’m totally confused, but that’s OK as it is only in this one combination. There IS a joining of both effortless of the Wu Zetian and effortless of the HeartField R1. Magic, maybe? Yes, this is good! :) Still it may just be my music, because I say this is the songs have slowed down and there is not that obscurification of planar bass! Yes, slower songs are the magic here! Slow is sexy, it really is!

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Here the KZ AS24 Pro with LC7 cable in 4.4mm with used medium bore ear-tips.

Knowledge Zenith AS24 PRO (from the AS24 Pro review)
Here we are gifted with just what the AS24 Pro was always waiting for. Yep, pure fun. In truth the HeartField R1 is way different sounding than any Dongle I have ever used. With the R1 analog volume control and overall demeanor we are taking a warm bath. As such what makes this experience so very different is the stage has the same images, but they are placed in different locations than the rest of the regular digital Dongle output. Not only different locations but holding warmer and mellow fluid textures than regularly found in Dongle Land. This new style of bass actually sounds like more, meaning it makes up for any loss of bass physicality to a point, adding what we always dreamed of for the KZ AS24 Pro! There are many different analog volume settings for each and every TypeC device output. Meaning get the R1 your phone and depending which model the volume knob may be at 5 out of 10. But get the R1 the powerful 3.1 TypeC output from a mini-DAP like the HiBy R3 II and note all the volume loudness needed at even level 2 out of 10. A smoother set of trebles and midrange AS24 personality. More like sheets of sound than finite digital details. To where there becomes endearing imaging personalities about how somehow the stage just seems larger with what the R1 does, but more than that there is distance between music elements which seems to de-clutter the AS24 Pro sound. It is this warm inviting KZ AS24 PRO personality that extends listening times, gaining audio ground by showing you that a sound like old 1960s and 1970s audio gear can still be found in 2024 from a new style of Dongle/IEM combo! Cheers!

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Here the HeartField BLANC with included cable in 4.4mm with used medium bore ear-tips.

HearField BLANC:
This BLANC is the shining example of all this review is about. Why? Well there is a joining of many combinations of things going on. In fact I rebelled and am using the BLANC’s included cable, where the rest of the reviews were using the SIMGOT AUDIO LC7. So here the furnished cable in 4.4mm is upping the detail over the LC7. Yep an aftermarket cable as second to the included BLANC cable. Plus we are in a much better neighborhood sonic wise than the KZ AS24 Pro. Now sure that is a $115.99 to $130.99 12BA a side KZ IEM being compared to the $249.00 BLANC. Still there is a synergy found here that is recognizable right off. The fact that the R1 makes the most of the stage, better sounding and a bigger stage than any Dongle I have tried. Next there is a fluid vibrancy and a smoothness of images that stuff like guitar streams out to the side of the stage with the vocals placed into the center hold both a clarity and a separation. Sure I talked about this in my KZ AS24 Pro review that the BLANC is doing more with less drivers, holding a more realistic rendition of all music played with less background clutter getting in the way. But more than that there is a sexy fast bass that shows up at the most unexpected times to seal the love deal here. I don’t need to say anymore, except you know I will be using this combo way after the review is over, you can bet your sweet behind on that!


For once the timestamps match the video, a first here at Redcarmoose Labs!

Using the R1 with a tablet:
While probably the best part was how with the HeartField BLANC and the YouTube videos I chose blended a sound personality that was marvelous. Here any digital starkness or even thinness was counteracted. We are left with the FKA twigs video being both smooth sounding and well executed into how the sound effects were introduced right before the beat starts at 00:03! When the beat starts we are left with the speed of digital sound effects as example of the vocal samples at 01:46………but an amazing experience of involvement! At exactly 02:20 the bass hits and it is a different fast yet not super low bass that rumbles onward and takes its own placement into the stage. Even the breakdown at 03:17 is well experienced and fun, with those side sound effects taking a deep seat out at the edges of the stage. All and all this lower quality YouTube video takes the cake as being pretty much perfect in so many ways. When Tahliah Debrett Barnett’s (AKA FKA twigs) vocals start up again at 03:43 they are shown out-front in the perfect place, heard in the middle to the sound effects like reverse echos off to the side. The various overlays are exquisite! At 04:41 we are witness to very good stage separation and reverb placements into the multitrack take on her fairly excessive effect production in design.

Though it is the warm bass and the imaging and smoothness that really makes this, the very opposite of stark and gritty too bright of normal Dongle playback! Sure the BLANC are partially responsible, but I truly feel the BLANC and R1 were meant to be a team! Using a Galaxy Tab A8 has never been so fluid and easily digestible on many levels, with no cut-outs, or even fiddling at the start. The R1 was instantly recognized and procured into action……not one question asked!

The HeartField R1 v the Sony WM1Z stage:
Here I was curious about the stage. As here I am on my soapbox always talking about how big the R1 stage was. But in doing side-by-sides the two things I noticed is the Sony WM1Z has a slightly lower bass tone and a slightly bigger stage. A bigger stage in every direction, where on its own the R1 beat-out my regular Dongles 100% of the time with added stage offerings. I won’t go further into comparisons as it is slightly ridiculous to compare a $3200 DAP to a $159.00 Dongle. But I will say there was added treble detail with the WM1Z. Though in truth it is the tone of both the R1 and the WM1Z that I hold so dear. The fact is both devices hold this smooth warmth that keeps me coming back for more!

BA IEMs in general:
All BA sound is unique in that it offers a few very special ideas.

Plus:
1) Speedy attacks and transients
2) Focused pin-points of detail
3) BAs are small and fit in small areas
4) As a rule BAs don’t need to be always vented, but they are at times (can you find the vents in the picture?)
5) Super quick decays (can be good or bad)
6) A special BA detail quality to the bass that DDs can't match
7) Detailed and accurate sound
8) Clarity boost over DDs
9) Typically use 1/2 the power of DDs

Minus:
1) Often promote BA timbre (though not here)
2) Can be prone to distortion at times (though not here)
3) Super quick decays (can be good or bad)
4) Can sound unnatural and steely (though not here)
5) DDs displace more air, offering richer bass physicality

USB-C power delivery:
https://en.wikipedia.org/wiki/USB-C

Every normal USB-C cable must support at least 3 amps of current and up to 20 volts for up to 60 watts of power according to the USB PD specification. Cables are also allowed to support up to 5 A (with 20 V limit up to 100 W of power). However, the 20 V limit for 5 A cables has been deprecated in favor of 50 V. The combination of higher voltage support and 5 A current support is called EPR and allows for up to 240 W (48 V, 5 A) of power according to the USB PD specification.

Packaging:
The packaging is fairly elaborate with a sticker to show if anyone has ever opened the package before. Inside there are three pieces of foam and a TypeC to TypeC cable, and a manual. The manual that explains how the device needs at least 4.5V to operate. There is also a slight risk of volume imbalance at low volumes due to the potentiometer volume control. It also explains how some devices need to be switched off USB exclusive mode so that files that happen to be larger than 16bit can be recognized and decoded into 16bit.

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Construction:
Glass finds itself installed on the clear window side, and there is a very brisk feel to both the 3.5mm plug and the 4.4mm plug which comes-off reassuring. The TypeC USB cable insert plug has a wobbly (side-to-side) action which I confirmed was identical to both R1 units I had. There is an amber LED which goes to showing there is power, and no other features except the volume wheel. The nice part of the volume wheel is there is no static like super old audio equipment. The other neat feature is your ability to guess volume levels by how many brushes of your finger-tip across the top. I found simply a single “rub” took the volume into the 2.5 zone which was perfect for phone use. Remember each device you own may put out a slightly different amount of current which would mean maybe going up to 4 or staying on 1 on the numbers............you can see through the top amber glass.

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Full-size headphones:
Interestingly enough the R1 did power the Sony MDR-Z1R to fairly good volume levels. This is most likely going to be a person to person question to if sufficient volume and damping is achieved? I would guess though that if you had only full-size in use that the R1 would be questionable as your only Dongle. Maybe, maybe not. The great part was the analog goodness of tone was fully recognizable inside the MacBook and Sony MDR-Z1R headphone sound. Especially how the stage went out to the sides, that was enchanting and better than a few side-by-side Dongles I used at the time. Though remember the R1 only has so much output ability to power full-size, but if you get to a place you like, well............consider yourself lucky with your favorite headphone, and just remember the MDR-Z1R is very, very easy to drive. Plus the extra lower midrange and bass seem to make low power listening work-out.

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Conclusion:
What more can I say? Here the R1 worked to become one of my most favorite Dongles ever. While holding many quirky personality traits, such abilities in sound make it one of a kind! Sure HeartField would not release any Dongle like everyone else, they had to be different. With the ability to make YouTube videos smooth and listenable, well paced/detailed …………..here was nothing at all to complain about. The R1 stayed connected and never put-up a fuss, even joining to my Galaxy Tab A8 consistently and uninterruptedly. Really anyway you chose to use the R1 it is simple and easy going, but changes its output according to the power of each individual TypeC USB you choose. At only 16bit it's not the detail monster of thousand dollar DAPs, but the warmth and charm is one of the standout features that will have you showing the R1 to friends. If they borrow the R1 there is a good chance you will not see it for a while as the R1 is lovable and charming. Get one today!

$159.00

https://www.linsoul.com/products/heartfield-r1

Disclaimer:

I have had the HeartField R1 for a month.

Disclaimer:
I would like to thank Kaitlyn Wu of Linsoul for the love and HeartField R1 review sample X2.

Disclaimer:
These are one person's ideas and concepts, your results may vary.

Linsoul website: https://www.linsoul.com/
Linsoul Aliexpress Store: https://ddaudio.aliexpress.com/store/2894006
Linsoul USA Amazon Store link: https://www.amazon.com/s?i=merchant-items&me=A267P2DT104U3C

Equipment Used:
Sony WM1A Walkman DAP MrWalkman Firmware 4.4mm balanced
Sony WM1Z Walkman DAP MrWalkman Firmware 4.4mm balanced
HiBy R3 II DAP 4.4mm balanced
Assorted Dongles too many to list
Galaxy Tab A8 Tablet TypeC USB

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Bonus IEM, the qdc Anole V3 3BA Universal:
When writing reviews I’m always at question as to how long or short to make them. So at times I will attach a last mini-test at the end. Here I’m using my humble phone with the R1 at only level 2 with an uncommon occurrence here. It seems normally it is a combo of the R1 source TypeC output power ability and the IEM which results in audio clipping when pushed. Again…..but not here……..meaning with this highly efficient qdc Anole V3 we have no clipping even to level 6 or 7 or even 8 on the volume wheel. These loudness levels (really not usable above only 3) are too loud to use with this IEM. And yes it may start to showcase distortion into the 7,8,9 and 10 levels, but those (levels) are never going to be utilized by humans anyway as they are just too loud. :)

With both IEM switches off we are viewing a less contrasty, even less bass idea of where qdc were going with the Anole V3 normally with any source. Yet here probably the greatest attribute to start off with is the giant stage. Here the humble 3BA Anole V3 is not known for a giant stage. Surprisingly I found switching the two switches to the both-on position seemed to add to the contrast and improve pace at hand? Really it is maybe the contrasts and imaging found into the stage along with the overall deep warmth that made these 3BAs a side sound some of the best I have heard from any DAP or Dongle. Now it should be noted that while super-fun and cool sounding, here is another example of the R1 getting slightly jumbled-up in regards to pace.

It may be the jumbling ability of the IEM combined with the jumbling of the R1 that leads to this perception? Where here there are more composite sheets of information with while still offering cool cymbal crashes off to the very sides, the center information could be looked at as almost congested? It was almost like the Anole V3 was too smooth even for a 3BA IEM, as the switch over to the 5BA BLANC still had that smear of pace, but so many attributes of the stage where pushed outward and enlightened into positive focus, thus increasing perception of both pace and clarity.

And even though this review today has come to a close, I’m still very curious to try the R1 with even more IEMs to witness what the outcome may be! Cheers!
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bithalver
bithalver
Thank you ! You made me curious about this DAC.
Redcarmoose
Redcarmoose
Thank-you, @bithalver,
It was my pleasure to write.........yet that is probably all I can disclose at this point in time? Other than today I’m using the R1 with the BLANC and Galaxy Tab A8 as a way to make music videos exciting and fun!

Ianbanz

New Head-Fier
Heartfield R1 Review: Sonic Bliss, Feature Miss
Pros: 1. Excellent, analog-like sound with warm, smooth tonality.

2. Impressive power for such a small device.

3. Simple, tactile design with an analog volume potentiometer.
Cons: 1. Doesn’t support high-res files beyond 16-bit.

2. Loud popping sound when pushing the volume to higher levels.

3. Lack of modern features for the price.

4. Steep price tag for what’s on offer.
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The Heartfield R1 is a simple, straightforward DAC amp that stands out for its analog warmth and impressive sound performance, but it comes with its share of quirks. At $150, it's positioned as a premium dongle, but does it offer enough value to justify the price?
Whats in the box :

Design and Features

First off, let's dive into the physical design—minimalist is the perfect description. The Heartfield R1 embraces a vintage vibe with its analog volume potentiometer, which adds a tactile charm to the experience. What’s great is that it avoids the usual annoyance of volume channel imbalance, something I often notice at lower volume levels with my other amps that uses analog pots. Here, you get precise, smooth volume control, which will please those who love fine-tuning their sound. However, feature-wise, it’s pretty barebones. It doesn’t support high-res audio beyond 16-bit, which feels limiting for a device in this price range. Also, if you’re using a bit-perfect source, you’ll have to turn off bit-perfect mode for it to function properly—an extra step that could frustrate users.

While the lack of digital display, buttons, or higher resolution support could be forgiven if the performance compensates for it, this missing functionality does seem like a drawback for modern users who expect more versatility from a $150 dongle.

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Power and Usability

The Heartfield R1 packs a punch—more than you'd expect for its compact size. Its volume control ramps up quickly, meaning you'll likely keep it under halfway for most listening sessions. Even at a modest setting of 5, there's plenty of volume. But here’s where things start to unravel: push it to 7, and not only is it painfully loud, but you also start hearing a loud popping piercing sound, its so piercing that you might think it gonna tear and damage your iem driver. This is clearly a technical issue and could be a deal-breaker for some who uses hard to drive Planar IEMS and Headphones. A device like this priced at $150 should handle its power output smoothly, and this quirk does take away from the overall experience.
Sound Quality

Now, here’s where the Heartfield R1 redeems itself, the sound. Despite its functional limitations, this dongle delivers an incredibly smooth, natural, and warm sound signature, which feels very reminiscent of tube amps. The analog nature of the sound is palpable, making it a standout for those who appreciate a rich, organic listening experience. There’s a sense of weight and smoothness to the mids and lows that will particularly appeal to users like me who prefer more musical, less clinical presentations.

The treble is controlled and never harsh, the midrange feels full and emotive, and the bass is present without overwhelming the rest of the frequency range. It’s an impressive sonic performance, no doubt. In fact, I’d go as far as to say it’s one of the best analog-sounding dongle I’ve tried to date—its soundstage and tonality have that relaxed warmth that can almost trick you into thinking you’re using a well-tuned tube amp.

But this quality sound also begs the question: how much are you willing to overlook in terms of features and quirks to get that sound?

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Value and Verdict

At $150, the Heartfield R1 is priced in a range where expectations naturally rise. For a dongle DAC amp that doesn’t decode high-res files beyond 16-bit and has technical issues with volume at higher levels, the price feels steep. If this was priced under $100, it would easily be a strong recommendation for those who prioritize pure, analog-like sound over features. But at its current price, the lack of modern conveniences and some serious usability issues give pause.

That said, if you’re someone who can live without high-res support, can work around the volume quirks, and prioritize sound quality above all else, this could be an intriguing option. The Heartfield R1 may not check all the boxes, but it delivers a sonic experience that’s hard to find in this format.

Heartfield R1 link: https://www.linsoul.com/products/heartfield-r1
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daijobudes
daijobudes
Question is, how does it compare to FC6 Hiby????
Thx

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