Luxury & Precision EA4 Portable Tube AMP

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The Luxury & Precision EA4 is a Nutube-based portable amplifier which is packed with a ton of options that allow you to fine-tune the sound to your taste.

I have been using the EA4 for close to four weeks now, letting it burn in and getting familiar with the many functions and settings.

My review below is solely based on IEM use with the EA4 as I am not a headphone user, so keep that in mind before reading on. While I haven’t tested it with any headphones, I can certainly state this is the most powerful portable amp I have come across to date, and I have no doubt it will be able to drive many headphones well.

Like everything in this hobby, what you are going to read are just my opinions based on my hearing, tastes, and previous experience. You may disagree with them, and that’s fine, but just treat them as one data point, as there are no guarantees you will hear things the same.

What’s in the Box​

The EA4 comes in a simple but nice wooden box. Open the lid and you are presented with the amp. Underneath, there is some paperwork and a bag, which includes a USB-C chainring cable, a 4.4mm and 3.5mm interconnect and some adhesive rubber feet. The interconnects are a nice inclusion if this is your first foray into portable amps. One less purchase, for now!



I attached 4 of the rubber feet to my unit. They work well and stop the unit from sliding around your desk while also preventing scraping on the bottom.

Features​

As you can see in the pictures, the front of the device is where most of the action takes place. The power button, battery indicator and charging port are located on the back.

Holding the power button for 3 seconds turns the device on, but it is also used for selecting some settings/ modes using a series of clicks. A quick press of the button shows your current charge level in 25% increments.

The amp has 6 x 18650 battery cells, which L&P states adds up to nearly 20,000mAh of capacity. The device is charged via USB-C and it has been really easy and fast to charge with any of the chargers I have in my home or office. I know some of the L&P DAPs can be a little picky about what cables and chargers are used but that hasn’t been the case here for me.

On the left side of the device, you find a large volume wheel. It is nice to use, and it is possible to make very fine adjustments with a soft touch. Personally, I would have liked there to be even more resistance in the wheel as the amp is so powerful and it is easy to hit off it if you are not being careful. Things can get very loud very quickly!

There are 4.4mm and 3.5mm inputs and outputs on the front face, with all of the buttons for making sound changes sitting between them.



There is a lot to take in when you start using the EA4 first. While the amount of different options may seem a little overwhelming initially, once you get used to it, you find you use the same set of settings with each of your IEMs, so it is just a case of trying them at the start to see which you prefer.

There is a dial which has 11 positions, allowing you to choose from fully Class A to fully Class AB or a combination of both. There is High and Low gain. A selector for 13V or 15V operation. There is a setting for Constant Current or Constant Voltage being supplied to the Nutubes, followed by a selector for ILH or ILA.

The gain and the voltage switches have a similar effect and will be selected based on how hard the set is you are trying to drive, while the combination of the CV/CC and ILH/ILA can be used to finetune how much of a tube sound you want from the amp.

So, in total, you have 176 (2x2x2x2x11) different choices if my maths is correct, which is a lot, but as I mentioned already, in normal use, you find a combination of settings that work and then only change them when you are swapping to a different set or source. And, in most cases for me, that has been just changing one switch at most.

While the number of choices may turn some people off, I hope it doesn’t, as you can find a combination that works for you quickly.

The top of the device has a window allowing you to see the Nutubes illuminating. To prevent them from needlessly being powered, they will only come on when both an input and output are connected.

I measured the amp to be 180mm x 100mm x 33mm. The amp can produce 6800mW @ 32omhs, up from the original 6500mW stated after L&P chose to upgrade the units before making them available for retail.

You can find a full rundown of EA4’s specs in the first post of the official thread, along with many other helpful and informative posts by @Kiats. Needless to say, it is packed full of some of the best audio components available, which have been hand-matched for each unit by L&P.

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Sound​

I have always had an interest in pairing DAPs with external amps to see how the sound could be changed or improved and have been lucky enough to own or demo most of the main ones over the last number of years.

Like everything in this hobby, nothing stands still and listening to the EA4 for the first time felt like a generational step forward. It sounds significantly better to my ears than any of the portable amps I have heard, and it really competes with desktop amps now rather than the mobile/ portable amps that have gone before.

Rather than the fact it is a Nutube-based amp, the first things that hit you when you listen to EA4 are its technical abilities and the level of power that is on offer for a portable device.

Note definition, control, detail and authority are the terms that come to mind when describing EA4. With all of the IEMs I have tested with it so far, it is able to extract and deliver the tiniest of details while still delivering head-rattling bass that is beautifully controlled and textured. It can really make your IEMs slam if they are capable and deliver a visceral sub-bass you can feel in your body, but it is no less capable with any other part of the frequency range.

After giving your head some time to adjust to all the additional detail and sounds you are now noticing in your music, you then notice the vast soundstage the music is being delivered in. Even music that doesn’t necessarily benefit from a large soundstage is improved by the perception of it being less cluttered or congested. However, when you have an IEM and music that takes full advantage of this, it is something special.

The Nutube effect is very subtly done. As mentioned, there are settings to adjust how much of a “tube” sound you get, but it is never a case of it being overly warm or approaching the levels we have seen with some other Nutube-based devices. To my ears, it has enough of an effect on the sound up to the point just before where any more would affect note definition. If you plan to demo the device, it is worth noting that it takes some time for the device to warm up and to me, there is a difference between the cold and warmed-up sound.

I have found the differences between Class A and Class AB to be source and IEM-dependent. It will be a case of testing with your own gear, but I cover it a little below in my impressions when I noticed there was a discernible difference.

With the power that is on tap with EA4, picking the correct source and IEM is important. Clearly, easy-to-drive earphones are not going to use EA4 at anywhere near its full potential, and likewise, if you choose a source with a higher voltage fixed output, it leaves you a lot less room to play with on the volume dial.

I have noticed a drop in dynamics when the volume wheel on the EA4 is below 10, so you need to be able to operate it comfortably for your ears and equipment above that point. My Hiby RS8 is really on the limit of what I can use as it has no adjustment on the line out so it is worth keeping this in mind. It may not be suitable for your current DAPs, or it may end up enticing you to buy another source that is more suitable

It is a pretty straightforward deal with EA4 - feed it good-quality music from a good-quality source, and it will make it better.

Combinations and Comparisons​

In my impressions below, I have compared the EA4 against the Mass Kobo 475, another popular portable amp, using a number of different DAPs as sources for both. I use the Amoma Audio Fei Wan and Campfire Audio Astrolith to test each combo.



I listened to each track using the source DAP first to get a baseline and then listened again with each amp to compare.

Using the Hiby RS8 as the Source​

Arude - Nocturne (Original Mix)

Aroma Audio Fei Wan with L&P EA4


(Settings: Hiby RS8 using Neutron Player. EA4: Full Class A/Low Gain/13V/CC/ILA/ Volume 15)

Out of all the different combos of amps, DAPs and IEMs I have tried for this review, the most impressive has been this chain of RS8>EA4>Fei Wan. It is capable of producing some stunning results, and that probably shines through in my writing.

Listening to Nocturne, the opening drum sequence from about 15 seconds in hits hard and builds nicely as more drums and synths are introduced building the tension. The mid-bass quality, texture and control during this sequence are exceptional with Fei Wan.

When the track breaks around the 02:06 mark, the same heavy bass line is maintained as the track adds more layers with synths and vocals. Everything from the finest detail to the hardest slam is perfectly presented and clear to hear. It is a Tour de Force of control and note definition, presented in a vast soundstage. Swapping back to RS8, notes have a softer edge, and while it is impressive in its own right, it doesn’t wow in the same way it does when combined with EA4.

Aroma Audio Fei Wan with Mass Kobo 475

(Settings - MK475 in Low Gain and volume adjusted to suit track)

Before EA4 arrived, this was my go-to chain for Fei Wan and even though EA4 has really impressed me, it is still clear to see why I loved the MK475 so much when I swap over to listen to this track with it.

The biggest difference I hear after going back and forth a few times is that you just don’t get every drop of detail from Fei Wan that you can get when paired with EA4. Some of the busier parts of the track blend together a little and aren't as clearly defined. With EA4, the whole track feels effortless, as if it handles everything with ease and has plenty still to give, which leaves you feeling like MK475 is coming up a little short in comparison.

I could happily listen to the track with either amp from an enjoyment point of view, but when you hear the extra EA4 has to offer, you notice it when it is missing.



DJ Merlon - Lavitate

Campfire Audio Astrolith with L&P EA4


(Settings: Hiby RS8 using Neutron Player. EA4: Full Class A/Low Gain/13V/CC/ILA/ Volume 15)

I really enjoy this track using RS8 on its own. It is rhythmic and builds nicely, and RS8 does an excellent job of creating a great listening experience with it but there are significant improvements when you compare it with EA4. The whole track is presented in a far grander stage with EA4. When I swap back to listen with RS8, everything feels closed in, even though that was not my perception before I compared. There is a great sense of space between all of the sounds. Transients are quicker, and the background is blacker, so sounds just appear out of the space.

Sub bass is more apparent, and there is a greater sense of feeling the bass kicks. Mid bass is tighter, more defined and better controlled than with RS8, but it spreads across the whole frequency range as everything seems clearer, more intense and layered really impressively.

It takes a little time to adjust to the track with EA4 as it feels like everything is dialled up in detail, resolution and clarity, and when called for, notes hit harder. Still, it is a very engaging and enjoyable experience.

Campfire Audio Astrolith with Mass Kobo 475

(Settings - MK475 in Low Gain and volume adjusted to suit track)

The MK475 creates a slightly more V-shaped listening experience. Mid bass certainly hits harder than with RS8, but it is not as tightly controlled as it is with EA4, which is a recurring theme across all of my comparisons.

The overall presentation is more dominated by the increased mid bass levels too as the stage does not stretch as far, so you have more intensity in a smaller space, and it can sound a little congested in comparison. The higher frequencies cut through a little more but are detailed and easy to hear.

On a basic level, the more V-shaped result with MK475 is less preferable a pairing with Astrolith, with what the EA4 offers being much more complementary. Astrolith doesn’t really need any more mid bass emphasis and doesn’t benefit from more presence in the higher frequencies, but it definitely benefits from the great control, note definition and larger stage the EA4 can provide.

Using the Nipo N2 as the Source​

The Nipo N2 is the new kid on the block in the DAP world at the moment, and I have been trying it out over the last few weeks. It is a very powerful DAP, and you could certainly argue that it doesn’t need the help of an external amp, but it does benefit from some of the other advantages they can bring.

The N2 has what I would describe as a more reference tuning with a bass boost. Compared to my RS8 and N3 Ultra, which I am also using in this review, it adds the least colour to the mid-range out of the three, which makes it more of a blank canvas when listening with the EA4 and assessing the changes in sound it delivers.

In line-out mode, the N2 outputs a fixed 2 volts.

I listened to each track using the Nipo N2 first to get a baseline and then listened again with each amp to compare. I used UAPP as a music player with local high-res FLAC files for testing.



Argy - Sierra

Aroma Audio Fei Wan with L&P EA4


(Settings - EA4: Full Class A/Low Gain/13V/CC/ILA/ Volume 19)

The N2 and Fei Wan wouldn’t be my first choice to pair together, as I find the mids sound a little hollow at times with this combo. When paired with the EA4, though, it transforms everything. The quality of the drums and bassline at the start of the track is absolutely superb. As the synths and vocals enter, they are highly resolving and fill out a huge 3D space around you.

From start to finish of the track, every sound, instrument and vocal is presented with authority and clarity, and it is incredibly impressive. EA4 allows Fei Wan’s technical chops to be fully displayed, and it takes a less optimal DAP and IEM pairing and turns it into something pretty great.

Aroma Audio Fei Wan with Mass Kobo 475

(Settings - MK475 in Low Gain and volume adjusted to suit track)

Going back and forth between MK475 and EA4, there are a couple of things that you notice. The soundstage is narrower, but I would say that this is only really noticeable when compared. I wasn’t listening to the track with MK475, thinking it sounded congested, far from it in fact, but when you swap to EA4, it opens out further, and you get a greater sense of air/ space.

Some of the harder-hitting notes in the track are a little less well-defined, but it is another case of only noticing due to comparisons. Both amps do a great job when paired with this DAP and IEM. There are just a number of small but noticeable improvements that you can pick up in the track when you A/B them with EA4 coming out ahead.



Massive Attack - Angel

While it is often a track that is mentioned for testing bass, it is not often one I use, as so many IEMs do such a bad job with Angel. Astrolith handles it really well, though and with how spoiled I am at the moment for sources, it seemed the perfect track for this test.

Campfire Audio Astrolith with L&P EA4


(Settings - EA4: Full Class A/Low Gain/13V/CC/ILH/ Volume 17)

With such a heavy bassline in this track, on its own, the N2 already has as much mid-bass emphasis as you would want with Astrolith. It certainly dominates when listening, pushing the vocals back in the mix. When paired with the EA4, it balances this back out a little, moving the now clearer vocals more forward. It also gives the track more room to breathe and the smaller details in the track are easier to pick up.

Possibly because of the more reference input, I find the different settings available on EA4 have a more pronounced effect on the sound when using N2 as a source compared to RS8. The difference between Class AB and A is quite clear with A sounding more analog and engaging versus the cleaner sounding notes of AB. The other settings, too, such as ILA and ILH, all impact the sound more meaningfully and I find I adjust them a little more often when using the N2 as the source.

With Astrolith and this song, I preferred using full Class A, which gave the guitars a grittier and more tactile presentation. This, coupled with the visceral thump you get from the bass drum makes the track seem more like a live performance and this was a very impressive combo overall.

N2 combined with the all the available settings on EA4, really allows you to finetune the sound to your tastes and for the IEMs you are using, making this a very versatile set-up.

Campfire Audio Astrolith with Mass Kobo 475

(Settings - MK475 in Low Gain and volume adjusted to suit track)

Swapping to the MK475, there is a very noticeable drop in sub bass. While you could feel the vibrations of the track in your boots with EA4, it is much less visceral with the Mass Kobo. That’s not to say the MK475 doesn’t pack a punch, it certainly does with mid bass but it can’t match the overall bass package that EA4 delivers.

I find the N2 & MK475 pairing to be very enjoyable and loved listening to Angel with them but EA4 is technically another level up with clearer details, a more encompassing sound and a much larger stage in all directions.

MK475 is a very impressive amp, but EA4 just has more in its locker to offer on all fronts and it is very evident with complex or busy tracks which require a lot of control and authority.

Using the Cayin N3 Ultra as the source​

The Cayin N3 has a lot to offer considering its price but that I think has gotten largely overlooked due to it not having streaming of any description. The Classic Tube timbre produces a lovely warm and analog tone, and it is a great option to have when you are in the mood for that type of sound. It is not the most technical DAP, though, and the details in a track can get lost behind the warmth sometimes, so it was very interesting to see how it performed.

The Cayin N3 has a dedicated line out with a variable output, which is very handy for pairing with the amps. It also functions with the tubes turned on in line out, which isn’t found on too many devices.



Skunk Anansie - Charlie Big Potato from the An Acoustic Skunk Anansie Live in London Album

Aroma Audio Fei Wan with L&P EA4


(Settings: N3U Classic Tube timbre. EA4: Full Class A/Low Gain/13V/CC/ILA/ Volume 19)

Going from listening on the N3 Ultra to listening with EA4 is a very different listening experience. With N3 Ultra, the bass guitar is quite prominent in the track and the vocals are pushed behind it. With EA4 everything comes into line. The bass guitar is much tighter but all of the instruments also sound like they got a detail boost.

The soundstage isn’t huge with N3 Ultra, and while it stretches a little more with EA4, the main difference is that it feels much less congested, and every instrument, along with the amazing vocals, can be enjoyed.

If you blindfolded me and played this to me, there is zero chance I would pick the N3 Ultra as being the source, there is that much of a step up in the sound quality.

The opening track of the album, “Brazen (weep)”, and their cover of Paul Weller’s “You Do Something to Me” were absolutely superb with this combo too.

Aroma Audio Fei Wan with Mass Kobo 475

(Settings - MK475 in Low Gain and volume adjusted to suit track)

Both of these amps do a great job with N3 Ultra and you would enjoy the track with either of them. MK475, like in previous impressions, has a slightly more V-shaped effect on the sound compared to EA4. The bass guitar has a warmer tone, and its notes linger longer, while at the other end, the higher notes hit by the singer are a little more shrill at times, so you have to balance the volume a little more carefully.

There isn’t quite the finesse of the EA4, and notes are not as clearly defined, but it’s very enjoyable nonetheless.

I have mainly used my N3 Ultra when I have been on the move up to this point, but after this review, I am going to be spending a lot more time listening to it with my amps.



Kerala Dust - Moonbeam, Midnight, Howl

Campfire Audio Astrolith with L&P EA4


(Settings: N3U Classic Tube timbre. EA4: Full Class A/Low Gain/13V/CC/ILA/ Volume 20)

Astrolith is a little more difficult to drive than Fei Wan so it opens up more settings to be used on EA4. You can go full “head-shaking bass” by clicking on ILH, and everything hits a little harder or you can maintain the same settings as Fei Wan and make use of more volume control. Either way, it is vastly different than listening to the track on N3 Ultra on its own.

With this track, there is a noticeably larger soundstage in all directions. With N3 Ultra, the track was mainly focused on the pounding bass line that comes into the track, and while that is still very much present when listening with EA4, all the other sounds in the track grab your attention and feel like they are positioned all around you. With the intimate vocals, you have the sense of being surrounded by the music.

Similar to my impressions with Fei Wan, there is a huge step up here in just about every aspect and it is hard to compare with the DAP alone as it almost seems unfair.

Campfire Audio Astrolith with Mass Kobo 475

(Settings - MK475 in Low Gain and volume adjusted to suit track)

It has been interesting to see how different IEMs react to different amps during these comparisons. While there are some similarities between sets with each amp, there have also been a lot of unexpected differences, and Atrolith with MK475 was probably the most different.

With this combo, the vocals sound quite different. While they were a little ethereal sounding with EA4, they are very detailed and precise with MK475. They cut through the music much more and stand out rather than being part of the whole.

What was similar, though, was the change in mid bass impact and the bass line hits you hard all through the track. It is very much a mid bass emphasis, though, and sub bass levels are reduced.

MK475 feels like an evolution of the N3 Ultra sound. More of everything but still quite analog sounding. EA4 adds some technical magic that is captivating, though, and you just want more!

Conclusion​

To wrap things up, this is a very technically accomplished amp which has a wealth of settings for adjusting the sound to your taste. It elevates every source that you connect to it, and it stands head and shoulders above the rest of the mobile or portable amps I have tried to date.

It is technically portable, but it will be on the limit for most people I think, and I am not sure how the Nutubes will hold up if they are bouncing around in your laptop bag. Also, all the sharp edges may look nice from a design point of view but it makes it more difficult to handle and more likely to cause damage if it isn’t properly protected when transporting it. On that front, there is no official case launched for it so far.

I am sure it is pretty evident from my review that I am a big fan of EA4. From a sound perspective, it is an extremely impressive amp which excites and can produce some stunning listening experiences. When everything clicks, you will just want to sit back and keep listening to track after track after track……

The L&P EA4 is available to purchase from Musicteck here.