SPL Auditor~ No marketing gimmick, a very honest amplifier.

How many times have you seen a company making marketing claim or using marketing gimmick when selling audiophile products to a customer?  How many of them are snake oils and false claim based of scientific research and feedbacks which in the end show no added benefit from using such product? Well SPL auditor also did make some marketing claims about their products in their websites. However the difference is that the claims made by SPL are true but just not detailed enough in describing the effect.

Specs

Audio

Frequency Response: ‹5 Hz to ›200 kHz (-3 dB)
CMR:-80 dBu (@1 kHz, 0 dBu input level and unity gain)
Crosstalk: -84 dB (@1kHz)
THD: 0,001 % (@ 1kHz, 0 dBu input level and unity gain)
Noise: -97 dBu (A-weighted)
Dynamic Range: 129 dB (@ 600 Ohms Impedance)

Inputs

(XLR connections, electronically balanced)
Impedance: ca. 20 Ohms balanced/ca. 10 Ohms unbalanced
Maximum Input Level: +24dBu

Outputs

XLR Connections: Input thru, electronically balanced
Headphone Output: 6,35 mm stereo TRS connection
Pin Wiring Tip = left, Ring = right, Shaft = GND
Impedance: 9 Ohms

Power Amplifier

Max. Output Performance:
1,7W (+32,2dBm) @ 1 kHz and 600 Ohms connection
360mW (+25,6dBm) @ 1 kHz and 30 Ohms connection

Power Supply

Voltages: 230V AC, 50Hz/120V AC, 60Hz
Power Consumption:max. 5,6 W/7,9  VA/0,03 A
Fuses (slow blow): 200-240 V AC: 200 mA/100-120 V AC: 400 mA

Dimension and weight

Height x width x depth: 95 x 210 x 315 mm
Height with lifted feet: 127 mm
Depth with volume knob: 335 mm

Weight: 2.65 kg



0dBu = 0,775V. Subject to change without notice.





View From the Back and Instruction For Unbalance Connection



SPL with Stereo Mono Switch and Phono Jack on the Right Side. Look At the Size of the Volume Knobs

Design

They are one of the simplest designs for an amplifier at this price range. You don’t get many things to play with except for the stereo mono dial which have questionable use for audiophiles. For professionals, this should come in handy. And in the middle is a very large volume knob that is very smooth in control and volume adjustment. This headphone runs on 6.35mm or ¼ inch jack. The adapter is not supplied, so you have to use the one that comes with your headphone. Four XLR 3 pin plug at the back of the amplifier with two plug act as output port and two as input. Please note that the two XLR out on the back transmit unaltered signals to the next sources or amplifier in line. So this amplifier does not act as a preamplifier. Then again this is a questionable use in audiophile world but in professional usage is highly appreciated. For audiophile, the biggest benefit of this design is that they allow you to use another headphone amplifier or speaker amplifier for your passive speaker without the needs to unplug and plug back the cable to the next amplifier. The XLR designs allow the use of unbalance connection or RCA and TS/TRS plug by using an adaptor. If you want to DIY your own cable from an unbalanced source (RCA or 3.5mm or 1/8 inch jack), you just have to short the Pin3 to Pin1 inside the plugs with a cable as guided in the instruction at the back of the units.

Left European Power Cable, Right UK Power Cable

The unit comes with a European two pin power cable. If you don’t use this type of socket I urge you to change it to a 3 pin design that your country support. Without the grounding pin/ earth pin on the UK three pin sockets, the grounding is leaked to the casing instead of properly grounding it. The good news is that they use the normal socket for the input on the amplifier unit that is compatible with your desktop pc and monitor. This design allows you to easily purchase them from any hardware store or pc store while at the same time allowing you to upgrade to high end power cable of your choice with ease.

Length and Dimension of SPL Auditor

The amplifier is heavier on the bottom (where all the components are) but very light on top. It’s only about a notebook/laptop weight (2.65 kg), so besides the extremely large size, you can bring it to a TT session/ headphones meet easily as long as you can find a bag big enough for it. It’s very long to fit into most bags, and I think the minimum criteria might be a 17inch notebook backpack if you want to carry them inside a bag. Hand carry might be a bit hard because of the size and unbalance weight distribution. (Top light, Bottom heavy)

The large toroidal transformer does charges up a bit after some use. They can still produce sound for a few seconds even the power is switch off enough for you to play off the last bit of songs. But they will start to distort and produces loud buzzing sound when the power starts to fade. So it is not advisable to use it in this way. Always shut down your source first before shutting down the amplifier. SPL recommend that you either lower down the volume or unplug the headphone from the amplifier to reduce the effect.

Sound Quality

They are a very neutral amp in which they allow your individual headphone to show out its true potential in a natural way. They allow the sound signature of your headphone to be more pronounced than any colored headphone amp could ever achieve. On the other hand the transparency and the colorless sound allow you to show what the original recording intended to be. Just like how head-fi stated in the videos they are not a clinical headphone amplifier at all but still have the ability to reveal subtle details for monitoring used. This unique amplifier is really a safe haven for sound engineer to process and mixing songs while using their favorite headphone. Although it is targeted at professional users the general sound is still far from being a cold and analytical amplifier usually associated with professional equipment, so even if you are an audiophile you will still be able to enjoy the amplifier if you find the sound signature suits your taste.

The amplifier has a mild warm sound to it. But it is more of an added boost in the lower frequency than a complete warm sound that usually associated with increase in lows and mids. The boosted bass gives a slightly more punch factor in it than the other frequency. However when you look back at it as a whole picture again, it still manage to retain its neutral flat sound even if there is a boost at the low end. So in the end even with the added bass you won’t be getting the same type of knockout from the bottom end as those given by the colored amplifier.

The mids no complain here and well rendered with very good amount of mid details so we will just skip here.

The highs would have a bit roll off just like how the frequency graph shown. But the rolls off still have to depend on the headphone as well because on some headphones they actually have a boost in the highs instead of rolling off. This is something that is contributed by the neutral flat frequency response. The extensions on both ends are very good. You can get the rumbling low ends as long as your headphones support them, and the highs are great.

So what you get here is not a very warm sounding (mildly warm) and not a bright headphone amp but a neutral flat amp that is very astounding in its performance. There is another thing that you have to make note of. This amplifier likes to be in control of every headphone that you can place it on. This is one of the reasons that I chose it instead of the graham slee. The boosted lows on the graham slee might push too much bass on my JH16PRO as being noticed in the JH13PRO demo unit in Jaben. But then again it is not only the bass are well managed with this amp. The mids and the highs are well controlled as well. The high are very well defined now with good control on the speed, timing, and well rendered. Try to imagine this. On other headphone amplifier you get a very thick sound on the highs like a thick string but when you use the Auditor, what you get is the very fine thin string that you use for sewing your cloths. That is how well the highs are rendered. Other headphones also show the same amount of control that you get with the JH IEM. It is not about boosting bass or highs, but about the amount of control on the headphone drivers. I’ve never heard this amount of control before.

This amp is definitely a very introvert amp. They don’t have the PRAT factor but yet it is not failing in producing a fast speed for fast paced songs. The neutral flat frequency they produce is too shy in showing its ability to the world. Compared to a colored sounding amp, the auditor just shows you what you should hear and nothing more and nothing less. When you use this amp, don’t expect to get a jaw dropping wow effect. What you brought home is just an honest amplifier that always likes to hide itself at the corner. When challenged, you will know that this is not any ordinary amplifier that you can find anywhere. It is that good for a headphone amplifier.

Fresh out of the box the sound is already this amazing. Great transparency, distortion free sound, zero noise floor, lot of details (they have details but again they are shy). The problem I face during the first few days of use is the diffused soundstaging that overshoot into the far back of your heads. Most headphones are still ok, but for those that did soundstaging very well, you will hear the effects. But after some time of burn-in the effect is gone. The soundstaging is now better and well layered and well placed. 

The soundstage for this amplifier is rather wide and well separated. Each and every headphone that I use shows the same wide soundstage to a certain degree. The crossroads woody 2 really shows a tremendous improvement in the soundstage after using this amplifier. Image positioning on this amplifier is very well done and it sound best with the angled driver headphone designs. There is one problem with this amplifier which is the lack of center image. For example, left side sound come from the left earpiece and less likely to be mixed with the right earpiece and vice versa. This is where I wish they can implement the crossfeed effect just to get a better center image. But don’t get me wrong at all. This effect is very useful when you are using this headphone amplifier for monitoring purpose. On music listening, only few vocals are affected, but most instruments are still well separated and not much affected. If you want to reduce the effect I suggest you getting the Phonitor instead. But at only approximately 47% of the price of Phonitor, it is clearly a winner here if your budget is constraint. Do mind that although 47% is a small figure but when you look at the Phonitor costing at US$ 2150 a piece, an additional 53%+- is a very large amount to consider. With the price you get all the amplifier circuit from Phonitor but minuses all dials and the fancy VU/Peak meter, and voila this is Auditor for you.

SPL Auditor has a very smooth volume control. There is no clicking, distortion, channel imbalances and any problem associated with poor volume potentiometer designs. Best of all is the one gain level fits all headphones. There is no gain level here but with the high amount of room for volume control you don’t get the effect from soft to very loud volume adjustment. This amplifier has enough headroom for you to have a precise small volume adjusment even on very sensitive headphone. This again is something that you cannot get from the graham slee since their volume adjustment is too limited for sensitive IEM.

Marketing Claim by SPL

For this part you can refer to their websites at here to see how they claim the effects.

Acoustic Magnifier

This amplifier really allows you to detect the smallest amount of details by allowing you to detect each individual instrument. This effect has to thanks to their good soundstaging and image separation. Each instrument are so well kept in their place, you can distinct them from the rest of it thus allowing you to magnify into the instruments. Here having a good DAC (Digital to Analogue Converter) is crucial in bringing out the best of the acoustic magnifier effect.

The End of Ear Fatigue

They claim their 120 volt Class A technology can help end the ear fatigue that we always do with the other headphone amplifier. And this 120 volt technology really does delivered what is said in the website. What this does is that they allow you to push your headphone to even ear deafening level while still remaining the smoothness and distortion less sound and the dead quiet zero noise floors. Some amplifier will have a slight hissing or grain in them, but with this amplifier you don’t get to hear any of this. The quiet background, the distortion free sound and the smoothness of the sound allows you to enjoy every bit of your music for a longer time without ear fatigue unless you actually make a fool of yourself and blast the music. I know it is quite addicting with this effect, but blasting your headphone won’t help you go anywhere. So even if you get fatigueless sound please listen at a safe volume.



SPL Auditor With HM-602 as Source DAC/DAP



SPL Auditor on different headphone

Beyerdynamic DT880 250 Ohm Premium Version- This is the headphone that shows the best potential when used with this amplifier. They are the perfect match. This is the first time I’ve heard such good sound from this headphone. It has been long time since I’ve heard anything so good out of this headphone. Even with the JDS Labs Cmoy that can drive it well also couldn’t achieve such level of details and control on the drivers. It is phenomenal. The amount of highs, mids and bass control on this headphone can give you quite a chill down your spine.

Crossroads Woody 2- This is another headphone/IEM that match well with this combo. On other amplifier, the bass is wet, slightly loose and boomy. To get a general idea try to imaging using a multimedia subwoofer, but the high end one. This IEM is not really that poor in the bass because they are still ahead in the performance compared to a multimedia subwoofer. But when used with this headphone amplifier, they changed from a multimedia subwoofer to a high end audiophile subwoofer that can be heard in the KLIAV show. They are more define and less loose. The bass punch also increase a lot. This has to thanks to the ability of SPL Auditor that can bring out the best of each headphone as the bass performance are a strong point of this IEM. However, the decay is slightly shorter than an ideal wet bass from before. Hey who cares? The shorter decay still does not affect your experience to enjoy this great match. Besides the bass performance, the whole frequency range also scales up so well it becomes a high end headphone. Well not really as in high end because they still have some flaws that make it in the lower spectrum but the Crossroads Woody 2 now share the common sound performance of those higher up headphone range. Definitely a good match.

Audio Technica T500- This headphone is borrowed from a friend and used for a while only. While the sound is still far from being an audiophile products but it manages to scale up quite well with this amplifier when so many have failed. These include the JDS Labs CmoyBB V2.03, hippo amplifier and fiio E5. Although the headphone scales up well now but the driver designed for the Audio Technica T500 is still too weak for any audiophile to enjoy. However the angled drivers give it a better front image than any none angled driver headphones that I currently have. Definitely a good buy if you own an angled driver headphone.

Crossroads HR1- This earbud on its own is already super smooth. But when added with the smoothness of transition that this headphone amplifier have, the effect is just straight awesomeness for your ears. And this earbud is rated at 150ohm and also requires some good amplification to shine. And I can tell you this with the SPL Auditor as the amplifier it really shines. It does shine in their details, smoothness and control on the drivers but I still prefer a slightly more forward sound with better center image out of it so that the vocals are well blended.

Shroom EB- The sound with this in-ear monitor changes quite well also. The highs are now more define just like in the case above. The bass also have more control now. You will still get the same light bass as before using SPL Auditor but there is more well define with good control in it. This IEM is not the best match with the Auditor because they will enhance the treble of this already bright sounding IEM.

Superlux HD668B- This headphone can only be used with a Hifiman HM602 as both DAC and DAP. It’s too revealing and show too much flaws when used with lower end products. The added warmth from the hifiman and the SPL Auditor helps it improve the overall tone. But the added highs is a bit of a problem to highly recommend this headphone as a match with the SPL Auditor. As stated before this is not the fault of the amplifier but this headphone itself. On its own, they already have the sibilant and excessive treble but when used with this headphone amplifier, the treble is brought out more than usual. So unless you avoid those pop, rocks and other songs that have lots of treble quantity then I will not recommend you with this match. Jazz and instrumental songs such as OST are great with this match.

Verdict

The SPL Auditor is not a weak amp and in fact they are above the level of Graham Slee Solo Ultra Linear version. Although the auditor doesn’t have the coloration of the graham slee but the transparency level, the smoothness, the zero noise floors really makes this amplifier a special one. To sum it up in three words, I can only say control, control and control. Ok, I know it’s a one words X3 but that is what this amplifier do best.

Will I recommend this headphone amplifier?

Yes I will highly recommend it if you are using this headphone amplifier for professional use. However, if you are an audiophile I will say it depends on your taste/ sound preference and the match with your headphone. A better center imaging will be nice here so a crossfeed will be a good implementation than the stereo/mono switch that are meant for professional use. When you go out to demo this unit please bring your headphone along. In the end this will still be on my highly recommended list.

Note: You will still require a good DAC (Digital to Analogue Converter) to show its best and Hifiman is still not up to the task yet. With Hifiman you will get better sound quality compared to other source that I’ve used in the testing but Hifiman still could not bring out the best of this amplifier yet. The Class A design also does not generate any heat at all. So the user does not have to worry about heat issue usually associated with Class A amplifier.

Price:

Auditor US$1000/ MYR 3999

Phonitor US$2150/MYR ?