Cypher Labs’ Theorem 720 is the Sony A7/r of portable amp/DACs. It’s for the dude and dudet that want the best sound on the go, but don’t necessarily want to shove a mains-level battery, a separate DAC and a desktop amp into their p/murses. In fact, if you’re in cargos, Theorem 720 will fit in your pockets along with your iDevice/Android portable source of choice. It just so happens to work nicely with your computer, too. Possibly its biggest asset is its big-arse battery that needs charging about twice a week even during that everyday-multiple-times post-purchase honeymoon phase.
• High quality battery powered headphone amplifier
• Auto-source detect from computers, Android devices and Apple devices
• USB audio resolution up to 16/48 from Apple devices
• USB audio resolution on Mac (natively) or PC (with included driver) up to 24/192
• USB audio resolution on Android devices (using USB Audio Recorder Pro app) up to 24/192
• Larger capacity battery delivers long play time, up to 18 hours while charging Apple devices
• Fully balanced headphone output (4 pin)
• Single ended headphone output
• Single ended analog line-level output (2.1vrms)
• USB mini-A input allows input from computers (USB A to USB mini-B) or Apple devices (use our 30 pin to USB mini-a cable) • High capacity lithium-polymer battery - 8700mAh - isolated AC switching
• Three volume gain settings for all headphone types
• Dimensions 120mm (136 incl volume knob) x 29mm x 64mm
• Weight: 10 oz / 0.3 kg
• The headphone outs have as close to 0 ohm impedance as possible (less than 1ohm). The headphone output levels themselves depend upon the gain settings. With the volume pot set to 100%:
• Single Ended output = 11.3 dB
• Balanced Output = 5.5 dB
• Mid Gain
Single Ended Output = 3.5 dB
• Balanced Output = -2.3 dB
• Low Gain
• Single Ended Output = -9 dB
Balanced Output = -14.8 dB
All outputs are the same for single ended and balanced:
• 32 ohm = 205 mW
• 50 ohm = 320 mW
• 300 ohm = 68 mW
• 600 ohm = 34 mW
Cypher Labs Theorem 720: 899$ USD
ohmage and porridge: haptics
Traditionally, Cypher Labs’ products have eschewed works good for sounds good. Ins and outs have splayed randomly from aft to bow, making pocket/holster usage unwieldy. In portable stacks, they handle like toasters. No more, my precious. No more. Theorem 720 largely corrects the faults of its forebears. Its singular USB input sits next the dual-function volume pot/power switch.
The volume pot travels from 0% to 100% like a Nikkor Ai/S lens. Smooth, yes, but damped like a Leica, no. The final 40-50% of its travel yields a mere 5-10% increase in volume; essential volume control is spread over an insanely small portion of the volume pot. Earphone listeners, be careful; it is all too easy for the volume to travel up up and away. Theorem 720, like the Vorzüge VorzAMPduo and VorzAMPpure, needs to spread volume control over the entire travel of the volume pot.
To the left of the volume pot are the two headphone outs, balanced in the middle and single-ended on the left. In practise, you never have to flip or move anything abaft the amp’s face. All necessary controls and cables splice into the front, meaning very little cable mess. Meaning decent big-pocket use. This is way good.
The Theorem also comes with a plethora (I hate that word, I really do) of cables to fit a plethora of devices from Android to iOS in almost a plethora of forms. By the way, one of Theorem’s 720 best features is that it charges your iDevice. Not only does it act like an external battery, it lasts forever from a single charge. If you tend to listen to music for 6 or 7 hours at a time, you will still get two to three days worth of music, if not more.
The only pidgin-slaying yes but in all of this is the USB input’s somewhat close proximity to the volume pot. Trolls, ex-cons, and big fingered blokes everywhere will decry the close proximity as fiddly for their toe-fingers. Oh the proximity! And like the Sony A7r-dectracting “Full frame has to be big because we is big and we demand big big big. Have you seen my penis? It is big” crowd that can’t trace their photo experience back to the day when 35mm film cameras were small and compact, the Theorem’s biggest (ahem) selling point is its repleteness in the singular. Plug in a source, a cable and your favourite phones. That’s it.
That leaves room in your pockets for chapstick and bonbons and your copy of The Hobbit and Orgy Obligations.
But I think they won’t stew on it for too long. Not when we gots music to get listening to.
Are you kidding me? This is designed and built in the USA. It even does that whole MADE IN USA brick thing quite well- I mean, look at it from any angle and you will be hard pressed to guess which is its profile and which is face.
ohmage and porridge: build quality and finish
Bricks build great walled gardens. And judging by the sturdy way way iPod nano dangles from Cypher’s robust IC cable, bricks are keen building blocks in great portable systems. The sad part is that my Nano no longer does music from the headphone output. One of my Profoto stands fell on it. Lights out.
Theorem connects through lightning or 30-pin on an iDevice. Add one of Cypher’s elastic bands and voila! the Nano is back up and running as the dangling member of a pretty rocking portable music system.
The only plastic on the Theorem it is LED or that ALO-style 4-pin balanced output. The case isn’t prone to flex and the seams are fit. That said, its paint job is a big step down from the CLAS dB. It feels like a group of randy teenage dust balls had an orgy and settled on the aluminium chassis. It also feels pretty prone to rubbing. Continuously pulling the brick in and out of your cargos will probably rub the the ex-orgy off.
Like an orgy, the Theorem is where you want to be. It boasts the resolution of the ALO Rx, the power of the National and the low/high range control of the Vorzüge. Three gain levels allow control and power over any conceivable portable headphone and earphone. There is enough voltage out of either headphone out to power most if not all current production headphones. As with all amps, however, ample voltage alone does not a good headphone amp make. The low Ω output allows even the most sensitive, least resistive earphones to supply wondrous resolution to your ears. This is a first in an all-in-one headphone amp. Sony, Fostex, Venturecraft make all-in-ones, but not a one does low Ω earphones well. In fact, the Theorem 720 stands alone as the only all-in-one that doesn’t need an outboard amp.
NOTE: The following data should not be compared directly to other sources. Measurements were taken by a decibel meter placed haphazardly at the headphone cup. The Theorem 720 was set to maximum volume settings for each gain level. The song is Airwave’s “Denial” from DJ Tiësto’s In Search of Sunrise 7: Asia. Louder songs exist but overpower my wimpy decibel meter. The point of this section is to reference differences in the 720’s output when coupled to headphones typical to home and portable use.
Beyerdynamic DT800/600: no distortion detected at any volume/gain setting
- LG: 73dB with peaks over 82dB
- MG: 88dB with peaks over 92dB
- HG: 94dB with peaks over 105dB (and beyond the limits of the dB meter)
Audio Technica ES10: no distortion detected at any volume/gain setting
- LG: 83dB with peaks up to 95dB
- MG: 91dB with peaks over 105dB (and beyond the limits of the dB meter)
- HG: 98dB with peaks over 105dB (and beyond the limits of the dB meter)
From typical to insane volumes, the Theorem outputs excellent current levels into each gain setting, yielding completely stable sound at any volume setting for almost any headphone out there.
The 720’s line out is as powerful as main mains sources, and as clean or cleaner. It is the cleanest line out of any all-in-one device I’ve tested and is fully ready for outboard amps of any price and echelon.
As with most good-measuring amps, Theorem 720 outputs a very balanced sound to a wide variety of headphones. The highest signal quality is retained in low and medium gain modes, where stereo width in particular is friggin’ outta this world. There is very little distortion at any gain and volume setting though signal noise may be an issue for sensitive earphone and portable headphone users.
Theorum 720 boasts incredibly wide spatial rendering of your favourite music. It renders a square stage, with fast rise and falls. Bass and treble travel the same plane and extend quite a distance outward from the ear. Neither overcomes the other. Clarity is strongest in lows and highs. Mids, while full and detailed, are less forward in space than either highs or lows.
The majority of Theorem’s volume is affected by a mere 90 degrees of rotation of the volume pot. That makes its use with certain, sensitive earphones, precarious. Fortunately, differences in gain levels are dramatic. Low gain easily handles most IEMs and portable headphones perfectly.
Balance between highs, lows and mids is achieved after around a 25 degree turn. Before that, highs are tizzy. Lows and mids slowly filter in from around 22-23 degrees. If you are using high-tilted or mid-detailed IEMs, what you will hear is an explosion of high frequency energy. After 25 degrees, each frequency is perfectly balanced. And what a sound it is- if your earphones aren’t too sensitive. If they are, the volume level may be rather high. Again, I am reminded of Vorzüge’s amps.
Cypher Labs: when the Theorem achieves perfect left/right balance and low/mid/high equality, it sounds truly amazing. Unfortunately, users of sensitive earphones, especially customers of high-end balanced earphones, may find Theorem 720 sounds best only AFTER its output is has become too loud.
Bass vs. Mids
Theorem 720 is all about the details. Bass and treble are the most detailed. Neither has any distortion at all until volume is cranked well beyond what is safe for your ears. Bass is completely fleshed out no matter the resolution or frequency of the file. Details are chalky and honest. Headphonics’ marcusd called it ‘slightly warm to neutral’. The last part is certainly true. But 720 neither measures warm nor delivers any of the typical telltale signs of even a slightly warm amp.
Despite mids kicking out slightly less sound pressure than bass or treble, vocals, guitars, percussion- you name it, are rendered in good contrast and detail. Mids are only slightly smooth next to Theorem’s detail-laden low and high range. It is perfect for live, folk, jazz, contemporary classical, trance, IDM, etc. The only genre that may be somewhat iffy is thrash metal and for the singular reason that highs are bitingly sharp.
At typical medium to loud listening levels there simply isn’t enough distortion in the 720’s signal to warm things up anywhere. If anything, the wide stereo image and incredible bass detail render chipper transitions and clean edges. Bass isn’t dredged up, it is fleshed out. Every small nuance blushes forward, and with an incredible stereo image to boot. All the way to low mids, that bass drives the 720’s output.
Stereo width is massive in both low and mid frequencies. It is wider than ALO’s Rx series and second to no amp I’ve tested.
Bass vs. Highs
Like bass, highs are devoid of distortion. Bass stereo imaging is wider than treble stereo imaging, but not by much. Both are off the charts. There is no noise at all in either frequency. At extreme volume levels, however, bass distortion is slightly higher than treble distortion is.
At the ear, both frequencies are equal. Each equally fleshes out pertinent details. Bass throbs where it should throb and treble shimmers exactly where it should shimmer. Space between instruments is huge and so is stereo spread. It is so wide, in fact, that it can at times be disorienting. Typically, the left/right throws from portable amps are much much narrower. Narrower throws can be easier for the ear to place. But if you are into truly wide stereo images, Theorem 720 has no equal.
The level of detail in both frequencies is guiltily obscene. But after a few minutes, the guilt disappears. It is replaced by awe. And pleasure. That said, some genres mate better with cloudier, warmer output devices. Theorem is edgy and unapologetic in its rendering of fine detail in both low and high frequencies.
Theorem 720’s low impedance output drives everything perfectly. I have yet to find an earphone that causes this amp to trip in even the slightest way. Signal quality is stable and detailed from the most sensitive, low-impedance earphone out there up to the least sensitive, high-impedance headphone.
The fly in the ointment is Theorem’s rather high noise floor and use of a rather imprecise volume pot. The latter is the more poignant issue. Fix the volume pot and Theorem will be my all-time best recommendation for IEM users who want the absolute best. The noise floor is constant. Even during music playback noise is evident, but it can be pushed to the back. ALO’s Rx MKIII has similar levels of noise. Even with portable headphones like the Audio Technica ES10, noise is evident during music playback in low gain.
porridge + 1
Theorem kicks out a lot of voltage, too. It is loud and detailed into headphones with low sensitivity ratings. Users of typical 300-600 Ω Beyers and Senns have no need to look anywhere else. Theorem spits controlled, full detail into those favourites. Notoriously insensitive phones like the HE-6 are good matches providing you listen at normal to slightly loud levels. Head-banging levels with frequent peaks above 95+ decibels is where Theorem 720 piddles out with the HE-6. Having listened to the stock volume of a number of headfiers, I can say with confidence that most people are on the way to serious hearing loss. For that massive cohort, the 720 may not be considered loud enough with the HE-6. I would argue that that isn’t true. For safe listening levels with peaks above 85dB, the 720 outputs a fully stable signal with low distortion and high levels of control in all frequencies.
There are few if any battery powered amps that establish such mature control over such a wide range of headphones.
ohmage: Balanced vs. single-ended
Assuming your balanced armature earphones are properly wired and poled for balanced operation, hold onto your hat. That crazy stereo separation jumps up by several decibels, almost to the limits of the audio format you are listening to. I still don’t recommend balanced wiring for typical off-the-shelf customs and high end balanced armature earphones as the drivers are typically poled for single ended operation. Both dynamic driver earphones and headphones gain noticeably wider images and cleaner midranges.
A number of Japanese headphone fanatics have begun swearing by balanced everything. Theorem 720 is the favourite among them for re-wired IE800 and other dynamic earphones.
I’ve clocked about a month of listening time on the Theorem 720. In these thirty odd days, it has been charged charged fewer times my iPod typically is charged. It works flawlessly with every iDevice I plug it into, and when I’m home, it works flawlessly with my iMac. Its combination of amazing battery life and strong resolution is obscenely good. Distortion levels across the audible spectrum trump even ALO’s Rx MKIII, an amp that until now has been my go-to reference. As long as your earphones or headphones are of middling sensitivity, the 720 is impossible not to recommend. Used with sensitive earphones the 720 loses its edge over the Rx, whose low-gain output is better matched to your FitEar and Jerry Harvey phones. Background noise levels are high, and 100% even left-right balance is achieved beyond safe and/or comfortable listening levels.
But then again, this isn’t just an amp. It is a fully capable 24/192 DAC with a great line out. Its headphone output is pretty much creme of the crop. It requires fewer cables, less pocket room, and a lot less mains time than your typical stack does. If Cypher Labs can fix the low volume headphone out balance, the 720 will be device to bar out every single device from the competition.