Most of the headphones I’ve owned over the past three decades have benefited when paired with a dedicated headphone amp versus being powered by portable devices. There are countless amp options at every price point, but in that crowded field, the Samson QH4 ($70) stands out.
The new QH4 got my attention because I’m familiar with its predecessor, the Samson S-Amp, which I purchased from a local Sam Ash music store about eight years ago. That was back when my wife Danya and I would listen to our matching AKG K-701 headphones together. These days, we each have our own headphone favorites.
I still have that S-Amp (it’s discontinued), but the QH4 is a better design—more power and more features—so I grabbed one to check it out. Let’s see what this affordable amp offers.
Whereas the S-Amp only offered a 1/4″ stereo input, the QH4 provides dual balanced 1/4″ mono inputs, and a 3.5mm stereo input that makes it easy to use with portable devices. There’s even a 3.5mm stereo line out so you can daisy-chain multiple QH4s, allowing even more people to listen.
The QH4 is technically a headphone distribution amp, with four 1/4″ stereo outputs. Each output includes a dedicated volume control, and there’s a master volume control as well. Plus, you get a mute button and a button to switch between mono and stereo listening modes. Samson says the QH4 handles headphones with a rated impedance between 16 and 600 ohms, and it claims you get full power from each stereo channel when you use all four at once.
The rated frequency response of this unit is spec’d from 17 Hz to 47 kHz (-3 dB) and Samson lists the noise floor as -114 dB. Peak output is 282 mW RMS per stereo channel into a 32-ohm load.
That’s not a huge amount of power when compared to some dedicated 2-channel headphone amps, but it’s more than enough to push many cans—including full-sized models—well beyond reasonable listening levels.
The QH4 does not include a battery-powered option—most unfortunate, IMO—but that did not stop me from throwing it in a backpack. An Anker Astro Pro 2 external laptop battery supplied all the 16-volt DC the amp needed. A Sony NWZ-A17 hi-res Walkman provided the audio I heard during numerous walks with a variety of headphones on my head. I’m not saying that’s a practical portable rig, but I got lots of pleasure from it.
Performance & Listening
The QH4 is a simple device, so there’s only so much to discuss. It is a nice headphone amp at a great price. End of review.
The QH4 is sold as a headphone distribution amp for studio use—hence the balanced 1/4″ inputs and four stereo outputs. However, it’s great for driving headphones that present a challenge to the built-in amplification capabilities of portable media players, tablets, laptops, and phones.
Sony A17 Walkman, Anker external battery, Samson QH4 Amp, Pioneer SE-A1000 headphones, Blue Mo-Fi Headphones.
The QH4 is not the most powerful headphone amp around, but if you own esoteric headphones that gobble up power, you will not be in the market for a $70 amp to begin with. In most cases, you’ll find the QH4 has all the clean juice needed to get full concert dynamics out of full-sized headphones and IEMs (in-ear monitors).
It’s fun to have four stereo amps to play with, even if you don’t need ’em. If you own multiple pairs of headphones, you can power them all at once. With a bit of rough level-matching, it’s a great way to compare cans.
The best demonstration of the amp’s abilities came when powering a pair of HiFiMan Edition X V2 planar-magnetic headphones—reviewed here. These over-ear, open-back cans can only achieve modest volume levels when powered by a phone or portable player. An AVR’s headphone jack produced better results, but of course, it’s in no way portable.
Walking around while listening to the external battery-powered Edition X V2 and QH4 combo with the A17 Walkman as a source delivered the highest level of audio fidelity I’ve experienced when strolling through a park. I heard fidelity matching the depth plus dynamics of a great stereo system.
The soundstage and energy of the tracks in Gotan Project’s album Lunatico possessed an uncommon lucidity. I loved how it rendered the female vocals and Spanish guitar strumming in “Arrabal”; the overall presentation had plenty of verve.
You don’t have to use $1300 headphones to get exceptional fidelity out of the QH4. I have several pairs of Pioneer SE-A1000 over-ear open-back dynamic headphones I bought years ago—you can read my review here. Selling for $56 per pair on Amazon, their only “flaw” is a long (20 feet!), yet permanently attached cord.
The value proposition here is amazing. You can hook an SE-A1000 to the Samson QH4, add a Chromecast Audio as the source, and have a home system that sounds amazing for about $160. If you know anyone who would listen to headphones with you, adding another pair of Pioneers is an audiophile bargain.
I turned up Jon Kennedy’s excellent album Corporeal, and found that the volume knob had no sane limit. Bass was thick, cymbals crisp, and everything was loud. The SE-A1000s are sensitive (105 dB/m/W) and able to handle a lot of power (1500 mW). But I found no way I could max out the combo without getting into painful and immediately dangerous volume levels.
Blue Mo-Fi headphones are over-ear, closed-back, dynamic headphones that have served me well for over three years. The QH4 had no issue getting a great performance out of them. When I reviewed the Blue Mo-Fi, I found it to be an excellent performer in the bass region with clean output down to around 16 Hz.
Listening to the Blue Mo-Fi, African Head Charge’s album Vodoo of the Godsent provided a nice dose of dub that demoed the deft handling of the deep stuff Samson’s QH4 delivers.
I was thrilled with how good my Dub King album, Deep Dark Dub, sounded through the Mo-Fis and the QH4. You can check it out here on soundcloud.com. I mastered these tracks using headphones and tweaking the bass on an EQ’d multi-subwoofer stereo. Even the super-deep tones came through clean and clear.
“Profunditty,” the third track on Deep Dark Dub, has layer upon layer of deep sound in the downtempo mix. I twirled the volume knob into uncomfortable territory, fearful of distortion. Instead, the mix came through loud and clear and intense. It was far beyond what a phone could deliver. Plus, mids and highs were crystal clear, and the soundstage came through just as I mixed it.
The next track, “The Minimal Express,” has razor-sharp synth sounds that hurt if your system is not clean and distortion-free. Here, the intensity of those sounds defined them within the abstract audio collage.
Track 13, “Throbberizer Dub,” is the real woofer-buster of the bunch. I cycled through all the full-sized headphones I had at my disposal—Sony’s MDR-1R, Samsung’s Level-On, the HiFiMan Edition X V2, Pioneer SE-A1000, and back to the Blue Mo-Fi. Notably, the Sonys dug deeper and sounded more dynamic than I thought they were capable of. I don’t do it all the time, but it sure is fun to listen to music at concert levels once in a while.
I wanted to see if I could verify Samson’s specs, so I fired up an Emotiva Big Ego DAC/amp and started by connecting the Blue Mo-Fi headphones directly to its line output. I measured the output of the headphones using a miniDSP UMIK-1 USB microphone I placed inside the earcup. I ran multiple sine wave sweeps using REW (Room EQ Wizard) from 16 Hz to 20 kHz, both at -20 dB and at -3 dB.
Then I repeated the procedure with the QH4 connected to the Emotiva’s line out and looked for differences in the response curve between the two setups. The response curve is not linear, but that’s irrelevant—what matters are measurable differences between the source and the amp. What I found was encouraging.
Samson promises a frequency response from 17 Hz to 47 kHz (-3 dB), but my measurements—of actual headphones—reveal it can track the response of the source to within +/-0.3 dB from 30 Hz up to 20 kHz, and +/-0.2 dB from 70 Hz to 20 kHz.
Here are the measurements I used to ascertain if the QH4 is faithful to the source. It did well.
In the deep-bass region, deviation from the source signal is less than the -3 dB spec would lead you to believe. Response was off by only -1 dB at 20 Hz, and -1.3 dB at 17 Hz. Up near 20 kHz, response was within +/-0.1 dB of the source. This amp beats its -3 dB spec within the slice of the audible spectrum that’s meaningful to humans and germane to headphone listening. If the amp’s response is -3 dB at 47 kHz, that’s not something I will sweat.
There’s not much more to say about this affordable gem. The Samson QH4 handles all music and movie genres with ease and provides great fidelity because it is a transparent amp. It’s four great headphones amps in one box!
If that describes something that could serve as a suitable solution for your headphone-amplification needs, give the QH4 a shot. This amp is available from Sam Ash through Amazon, so it’s easy to try and if you don’t like it, you can return it with ease.
Samson’s QH4 predecessor, the S-Amp, served me well for many years. But, in terms of performance, this new amp is an improvement over what came before it. For 70 bucks, this thing is a steal; I look forward to getting years of use out of mine.
Blue Mo-Fi dynamic over-ear closed-back
HiFiMan Edition X V2 planar-magnetic over-ear open-back
Pioneer SE-A1000 dynamic over-ear open-back
Samsung Level-On Pro on-ear closed-back
Sony MDR-1R dynamic over-ear closed-back
Anker Astro Pro 2 multi-voltage 20,000 mAh external battery
Hosa 3.5mm-stereo-to-dual-1/4″ cable (3 feet)