Monoprice Monolith Liquid Spark
Michael Piskor 2019

Monoprice Monolith™ Liquid Spark Review

The Monprice Monolith™ Liquid Spark is a compact transportable headphone amplifier developed by Alex Cavalli for Monoprice.

Disclaimer: The Monprice Monolith™ Liquid Spark sent to us for this review is a paid-for sample. We thank the team at Monoprice for giving us this opportunity.

To read more about Monoprice products we have reviewed on Headfonics click here.

Monoprice Monolith Liquid Spark
Monoprice Monolith™ Liquid Spark
I really enjoy this little amp. It is just right and probably the best generalist small-budget amplifier I've yet reviewed. I love that the pre-amp disables when the headphone RCA is in use, that is a big plus for me because I like to cycle between headphones and speakers and I can use this as a bridge for amps and testing without so much stress.
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The world of small, powerful amplifiers for we chosen audiophiles has only gotten that much more potent over the years. Monoprice has recently come out with a string of new products, each aimed at the ears of a serious fidelity enthusiast…oh, forgot to mention…Alex Cavalli designed this one. Get your wallets and Paypal accounts ready everyone, this is gonna be a show stopper.

Monoprice Monolith Liquid Spark

The Box and Accessories

You don’t get any. You get a power cable and the amplifier itself. Sadly, no RCA cables or headphone adapters are included. The box is nice though, I must admit. Although, still cardboard I suppose it does feel nice.

I have numerous cardboard packages of other products from other companies to review here that I can’t stack on top of each other in the review pile, due to poor quality boxes. So, it might be an oversight on some others parts in design and release, having a nice thick little box feels good.

Beyond that, I am afraid there isn’t much else to say. The experience is very, very basic here and beyond the logos and some text, nothing else was really there to talk about. I know this is a $99 amplifier, but I would have preferred at least one RCA cable since the design allows for RCA input and also RCA output, potentially used as a pre-amp.

Monoprice Monolith Liquid Spark

The Features and Design

I am absolutely in love with the form factor and function of the Liquid Spark design. It looks interesting and could have been so basic rectangle in design, but they opted for some nice curves and edge work. I applaud them for that.

The unit is very small, yet packs a wallop at 1.3w (1300mW) which is excellent for such a small device. Usually, with currents that high and in this price range, you will get a strong sense of distortion and hiss. Yet, the Liquid Spark has virtually no ground noise that I am able to hear.

What’s more, the amp is incorrectly listed at 1.3W into 50Ω, to begin with. It seems some other 3rd parties out there have measured it at more like 1.5+W and even up to 2 or more Watts on High Gain. which is absurd, in a great way.

Sadly, the product only has a ¼ headphone input and I would have absolutely gone crazy for this if it also had a 3.5mm that didn’t make me hunt for those ¼ adapters that we all lose every 5 seconds.

On the front side, you get a nice volume knob that feels very slick and easy on the hand to turn, the gain switch, and the ¼ headphone plug-in. On the rear, an RCA input and an RCA output used for pre-amp needs.

Monoprice Monolith Liquid Spark

The Circuits

Monolith and Cavalli have designed the amplifier with no capacitors between the signal paths, nor any op-amps. That lends some credibility to why the amp is so quiet, at least, in my opinion.

For what it is, at this price range, the experience is something stepping stone audiophiles want and need. Many users don’t want to introduce anything into the sound at all, simply wishing for a true path from start to finish and without any specifically altered anything in the signal.

This is not a neutral-sounding amp to me. It sounds natural. I believe there is a difference there and I will try to explain why now.

Monoprice Monolith Liquid Spark

Sound Impressions


The Liquid Spark is a pleasure to listen to and doesn’t feel harsh, icy, sterile, or what the o2 tends to sound like. Direct comparisons led to the o2 sounding significantly more harsh on the top end and lacking a sense of tonal density, weight, and heft throughout the entire spectrum. This Liquid Spark is more natural sounding to my ears and is more reserved.

If you want full-on neutrality in a brutal sense, then this might only be suited for you if you have a very neutral-sounding headphone or amp in your mix as well. Somewhere in the chain above the Liquid Spark, where the headphone’s very neutral tenancy will not be so apparently dimmed by a more natural approach of the Liquid Spark.

In that regard, I think the Liquid Spark is probably a fantastic little pre-amp and a far, far better generalist amp than the o2’s out there. The reason being is that full-on neutral amps don’t mesh well with warm and fun-sounding gear. It works well with only other neutral products.

Those like this Liquid Spark, something more in the middle, not overly neutral and not overly warm, play to both ends and is the better well-rounded product, at least, in my experience. In regards to tonality, this amp sounds highly desirable.


As mentioned, this is a natural-sounding amplifier, to my ear. Which can sometimes mean that the low end has a very good chance to play nice with moderately bass headphones.

The Liquid Spark does very, very well with my bass king: the JVC SZ2000 headphone. I certainly do enjoy it, but I know that the headphone sounds a bit more prominent on the low end through something like my very warm Heron 5 amplifier from Airist Audio. While I am not going to compare the two on fidelity factors, I will say the Liquid Spark feels less colored on both the top and low end.

The amp is just fine for bassy headphones to start, you’ll be able to EQ up if you need to via your source and achieve a solid +3-4dB before you feel anything getting out of hand, which is great for the price. The Liquid Spark responds to EQ nicely on the bass end, no doubt.

As far as fidelity goes, the Liquid Spark is more about a middle field area, it isn’t the most potent, I think the Schitt Magni has more power. But, I feel like at 1.3W at the very least? What exactly are you powering outside of planar magnetic headphones that are very inefficient?

At 1.3W and more, you can run a 300Ω dynamic headphone without an issue. I feel like the extra power won’t do much for anything but some planar phones that are very difficult to drive, so don’t worry.

Monoprice Monolith Liquid Spark


The Liquid Spark feels of a higher than usual tonal density, it houses a good hefty feel and doesn’t portray a sense of thinness. Combined with the vocal experience, that tonality factor lends a ton of enjoyment and realism for the price and all things considered.

Generally, you don’t hear an amp at this price range sound that solid, and that only enhances the vocal experience by a significant margin. I really enjoy this amplifier with my Audio Technica ESW11LTD’s, which are known for excellent midrange.

I would call this Liquid Spark a moderately forward sound, but not quite into the realm of very forward feeling. It certainly isn’t recessed either. The pure quality factor is excellent at the $99 tier and impressively so.

As mentioned, I think it pairs very nicely with the likes of the SZ2000, 11LTD, and even my newer Beyerdynamic DT17xx. This is a solid, well-rounded amplifier that also has a pension for dishing out excellent tonal midrange density.


The top end of the experience is somewhat reserved. As I was saying earlier, the Liquid Spark sounds toned down in comparison to the o2, as well as my Heron 5. It doesn’t hold a sparkle factor that I find enjoyable and I would consider the entire top end of the product to showcase a flair for just okay tonality.

The treble end isn’t interesting, it is just clean and clear for the price and doesn’t ever sound harsh to me. That is lovely, of course. But, it also means it isn’t lively or engaging. A proper balance for me as a listener is required but I don’t take points off for that. At this price, as mentioned, that is the right step to take. I just subjectively prefer something more interesting and with more sparkle.

I am happy to report that the treble doesn’t hit hard either. The physical strike potential is less than moderate on quantity and that also makes me very happy. That means the amp’s wince factor is enjoyable and not annoying or painful.

As far as quality goes, the top side of the Liquid Spark is just good, but its strengths are not with the fidelity factor. They are in presentation appeal, which is, at least physically, a pleasure to use for hours. I find the experience a stark contrast with my Magni and my older o2, both of which sound more metallic and physically harsher on impact.

Monoprice Monolith Liquid Spark


The Liquid Spark’s width and height factor are just fine, especially so for the price. It isn’t likely anyone with huge-sounding headphones are going to pair with this, but they can.

While the left to right void is just fine, as I put it, the depth factor is the star of the show. I’ve found it to be very engaging and interesting in stage-forward appeal, which means that cavern and reach out and touch the band in the background sense is strong here.

The dynamic potential of the depth of field factor is one of the best in the $99 tier that I’ve heard. Beyond that, the airiness factor, again, only in terms of stage-left and right, is just okay to me. It is neither lacking nor overly extended, which is what I feel most sound stage enthusiasts like me would want. But, for $99, I am not complaining.

The sound stage experience is more than enjoyable enough to be used with your pick of a budget to lower end of the middle tier headphone and not think twice. You probably don’t want to pair it with a Sennheiser HD-800, but those with an older AD-700 from Audio Technica should be more than happy with what it has to offer.

Our Verdict

I really enjoy this little amp. It is just right and probably the best generalist small-budget amplifier I’ve yet reviewed. I love that the pre-amp disables when the headphone RCA is in use, that is a big plus for me because I like to cycle between headphones and speakers and I can use this as a bridge for amps and testing without so much stress.

The unit is punching a bit above its price point, undoubtedly. I’ll certainly recommend it to friends and anyone looking for a $99 or so powerhouse that is neither neutral and sterile nor overly warm in tonality. I really wanted a 3.5mm headphone output on this though. Beyond that, I haven’t a single gripe. The amp sounds great, looks nice, and performs better than the listed specs for power potential.

Monolith™ Liquid Spark Specifications

Model 33304
Signal-to-Noise Ratio 108dB (ref. 1 Vrms input / 2 Vrms output @ 1kHz)
Crosstalk –73dB (ref. 1 Vrms input / 2 Vrms output @ 10kHz)
THD+N (both channels) 1 Vrms (20mW): 0.007% THD+N @ 1kHz
5 Vrms (530mW): 0.035% THD+N @ 1kHz
10 Vrms (2.12W): 0.065% THD @ 1kHz
Output Impedance < 0.1 ohms
Gain +3dB or +6dB
Input Unbalanced stereo RCA
Headphone Output Unbalanced stereo 1/4″ TRS jack
Preamp Output Unbalanced stereo RCA jacks
Output Protection Delay and offset protection
Dimensions 4.6″ x 3.7″ x 1.5″ (117 x 94 x 38 mm)
Weight 9.6 oz. (271g)

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