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IQ Audio M300 MonoBlock Power Amplifier Conclusion



There is little not to like about a 300 watt amplifier I can literally hold in my palm of my hand.  However at $1500/pair, this gets you into a dangerously competitive price class of some seriously good two-channel amplifiers from the likes of Emotiva and Outlaw Audio.  If you need more power, and have the space for a much larger box, then the alternatives may better suit your needs.  However, if you want truly impressive performance from the smallest and most efficient package I’ve ever seen, the IQ Audio M300 has no equal.

M300 Stack

IQ Audio M300 Stacked


I came into this review wanting to pick apart this little amp as nothing more than a gimmick.  Instead I was pleasantly surprised.  The IQ Audio M300 amplifier is the first Class D amplifier that I’d seriously consider for my own use. It offers better measurable performance than I’ve seen from the Axiom Audio Class D amp and the very popular ICE amplifier modules integrated into some AV receivers and standalone products.  It generates little to no heat making it ideal for stacking multiple units or cramming into tight spaces.

for its size, the M300 amplifier has no equal.

Most importantly, the M300 sounds fabulous, never misbehaving or losing composure.  It is a deceptively great little amplifier. I’d recommend this amplifier for small to medium sized speakers with reasonable sensitivity (>87 dB 2.83V/meter); not goliaths like my 2 ohm dipping $50k reference towers.  The M300 should be able to fill a medium sized room with clean SPL without a hitch.  I foresee the M300 fulfilling many applications splendidly like an office system, personal DJ system or to power speakers from an electric drum kit or digital piano.  This is the only amplifier offering IQ Audio currently produces but I sincerely hope that changes.  I’d love to see a multi-channel amp based on this design as well as a more powerful MonoBlock for power mongers like me.

IQ Audio Corporation
M300 Review
MSRP: 747.50/ea

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

  • StarStarStarStarStar — Excellent
  • StarStarStarStar — Very Good
  • StarStarStar — Good
  • StarStar — Fair
  • Star — Poor
Frequency Response LinearityStarStarStarStarStar
Measured Power (8-ohms)StarStarStarStar
Measured Power (4-ohms)StarStarStarStar
Multi-channel Audio PerformanceStarStarStarStar
Build QualityStarStarStarStarStar
Fit and FinishStarStarStarStarStar
About the author:

Gene manages this organization, establishes relations with manufacturers and keeps Audioholics a well oiled machine. His goal is to educate about home theater and develop more standards in the industry to eliminate consumer confusion clouded by industry snake oil.

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Recent Forum Posts:

jinjuku posts on March 07, 2014 09:40
Lets create another thread as this one is really about the amplifier reviewed.
cutedaddy posts on March 07, 2014 08:35
More on UcD technology by Bruno Putzeys of Hypex, the Netherlands, with a proprietary solution or two implemented to solve traditional class-D drawbacks:
Hypex Electronics BV - UcD
cutedaddy posts on March 04, 2014 07:04
@jinjuku and @haraldo

Thanks for your replies, i am honored.

Whether Hypex's UcD and NCore modules are overhyped i wouldn't know. That's why i would like to see a Class-D comparative testing article, really putting the measurements in perspective, on a nice comparative spreadsheet. Relevant measurements that is, but we can leave that to Gene, or someone else serious about testing.

As far as i can find, there are no serious (meaning “objective”) reviews that doubt the claims Hypex is making about it's own modules, but, on the contrary, several that confirm the stated claims. In other words, Putzeys is NOT overconfident as far as i can judge.

Sure there's more class-D contenders, and sure class-D existed before Putzeys. Carver e.a. are great contributors to audio development. However, the UcD module originally patented by Philips was patented because it was a leap forward. Since, Putzeys has left Philips to join Hypex and has registered a whole number of new patents making even the Philips UcD obsolete by comparison. So yeah, Putzeys is a step ahead IMO.

About Channel Islands Audio: they have a lot to say about Bruno's modules, but the bottom line in my view is: they are USING THESE MODULES for their own products. Why? I'll tell you three good reasons why: 1. The modules are so good; 2. The modules carry a patent CIA would like to own, but they don't; 3. The modules are very competitively priced. So much so, CIA can make a huge profit. Of course they will have to uphold that they do a lot ‘in house’, or else what would be the justification of their pricing?

To me, Channel Islands Audio are too much involved to give any objective comment on the NCore. If it's nothing at all, why do they use it in the first place? If it's not a bother to do all these ‘upgrades’ in house, why don't they do their complete amplifier in house, but use Hypex modules instead? They don't have the right to speak AFAIC, i have yet to see ABX-tested any accomplishment completely their own.

The Hypex modules measure unrivaled and do very well in blind listening trials as well. Output impedance (=cone control)? Industry lowest. Completely discreet signal path, no IC's, who else has that? Regulators measure unrivaled as well. Gain structure, I/O buffering, plenty other features no one else handles so well. Please show me wrong, always curious to learn more.
gene posts on February 28, 2014 11:03
haraldo, post: 1014760
Thx Gene for a great review (as always)

You write:
At 4 ohms, I measured a whopping 371 watts (1% THD+N) and 317 watts (1% THD+N).

Do you mean?
At 4 ohms, I measured a whopping 371 watts (1% THD+N) and 317 watts (0.1% THD+N).

Yes, let me fix that. Thanks.
conanb posts on February 28, 2014 02:45
Audioholics should review one of the D-Sonic class D amps.
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