The RSA Intruder Headphone Amp/DAC Review

RSA Intruder Headphone DAC and Amplifier combo

When it comes to portable audio, nothing begs the reviewer’s eyes/ears to “come play with me” more than a plethora of inputs, outputs and switches. The larger real estate of full-size component enables the hiding of the less-esthetically-pleasing side of hifi audio and allows the elegance of creative design to get a firm foothold, while portable audio can rarely spare such luxury.   Versatility becomes a premium when mobility has its foot on the gas peddle. Can/will portable audio ever be able to produce the same auditory grandeur of its bigger brothers? Headphone amplifier designer Ray Samuels is certainly pushing toward that end with his latest all-in-one portable USB DAC and headphone amplifier called the Intruder ($700).

As it stands today, what makes the RSA Emmeline Intruder truly unique is the inclusion of balanced outputs and inputs in a small form factor.  While Ray’s SR-71b is based around the same concept, the Intruder now includes a USB DAC to boot.  While this DAC tops out at 16/48 according to my Audirvana Plus player, it has both benefits and some drawbacks, which I will address a little later.  Balanced outputs are usually reserved for higher price brackets and larger cases, but the idea has trickled down to the personal audio landing.

Ray Samuels Intruder Front

Balanced input/output with headphones

Balanced connections can be tricky.  The quantifiable benefit to sound quality over short distances (like distances utilized in headphone rigs) is arguable.  However, many swear to hear sonic advantages in soundstaging, instrument separation etc.  One thing that most advocates agree on is this translation varies from headphone to headphone.  Of those advocates I’ve spoken to, many claim the Audeze LCD line shows a lot of balanced potential.

Going balanced in your headphone rig requires a bit more commitment than single ended connections.  While a balanced source may not necessarily be needed to hear the benefits from amp to headphone, the cables involved are harder to come by than your average trip to  Many of the mini balanced connecters (like the ones used in the Intruder) are exclusive to a few manufactures.  Luckily many of the main designers in the headphone amplification market are playing nice in this regard.  ALO, Cypherlabs Algorhythm Solo and Ray Samuel’s products all utilize the same balanced connectors.  Even so, low-cost versions of the connectors are practically non-existent.  The cables have to be custom-made and usually start around the $100+ range.  When all is said and done, you could easily spend over $500 dollars connecting two headphones in a balanced configuration to a $700 amp.  Like so many elements of this wonderful hobby, headphone cables can be taken to the extreme if you want to spend the money. There is an entire community based around cables on

In the case of RSA Intruder, the balanced connections are completely separated from end-to-end through the device.  Individual channel switches are used both for the USB input selector in the back, and the gain setting in the front.  I did notice a higher power output from the balanced connection over the single-ended.

Ray Samuels Intruder Back

The Build

The Intruder shares much of the same design as the rest of the Ray Samuels line. The casing is simple and functional.  The switches are a bit recessed and might not be the easiest to navigate for dexterity-challenged, but their design helps prevent any accidental activations, which could be a particularly unpleasant experience with the gain switches located on the front panel.  The unit feels solid and is a bit lighter than some of its like-sized competition.  The internal battery is charged via a separate wall wart and does not charge through the DACs mini USB port.

RSA Intruder with CypherLabs Algorhythm Solo dB


As I said before, the internal DAC of the Intruder tops out at 16/48, which is a little unusual given the current state of DACs in this price range usually pushes into the HD audio realm.  The good news is that it does not sound cheap, in fact, I found that it outperformed the fan favorite AudioQuest Dragonfly DAC (albeit 1/3 the cost).  I found the Intruder DAC to have better high-end detail retrieval.  Even though it was subtle, the DragonFly had a hair more presence in the mid to mid bass frequencies.  In terms of detail however, the Intruder package overall sounded more accurate and pleasing even though the DAC couldn’t match the Dragonfly’s 24/96 ceiling.  For the best high fidelity experience I would recommend pairing the Intruder with the CypherLabs Algorhythm Solo –dB though the balanced connection.  This dynamic duo won out for best sound out of all the combinations I had on hand. Perhaps one of the most interesting (and lesser known) benefits of the Intruder’s DAC is its compatibility with the Galaxy S III android phone.  Out of all the DACs I have tested in the past few months, the Intruder was the least glitchy DAC to use with the phone.  The connection did require an $8 USB adapter, but once that was secured the experience was seamless.

Samsung Galaxy S III with RSA Intruder

The Amp

The Intruder has power in spades.  The high gain setting claims a gain of +21 dB according to Ray’s website.  It had plenty of juice to power my pair of Audeze LCD-3 to deafening levels, especially in a balanced configuration. The low gain setting was set blissfully appropriate for sensitive in-ears. There was no notice of any back ground hum or hiss with sensitive IEM or headphones.  I always appreciate it when the volume knob has a gradual sweep set for IEMs rather than a sharp low to concert-level change.  I really liked the way the sound of vocals rested in the sonic presentation.  Compared to ALO’s Pan Am, they seemed a bit further back, but clear and lifelike all the same.  I also found the Intruder to have slightly more bass impact and slam than the Pan Am, which is quite a feat considering the Pan Am’s sultry low-end.  Listening to the RadioHead track You And Who’s Army Thom Yorke’s vocals danced around with the guitar and piano though the Intruder with a nice wide soundstage and appropriate separation between the key elements of the mix.

The Summary

Quite a bit of connectivity comes with the Intruder for its $700 price.  Balanced input and output, an internal DAC and an amp powerful enough to drive even very insensitive headphones are all stuffed into a tidy little package that can also connect to your Galaxy III phone without a hitch.  You may want to check it out if you are interested in upgrading your headphone cables, as it is one of the very few portable Headphone/DACs in this size and range to sport balanced connections.

Special thanks to Justin from JE Audio Designs for the loan of his superb custom-made headphone cables for this review.  Check out his site for more information on his balanced and specialty cables.


11 thoughts on “The RSA Intruder Headphone Amp/DAC Review

  • When used with the Galaxy S phone, how much does the DAC drain the phone’s battery?

    • I didn’t notice the battery depleting any faster. The Intruder charges off of a wall wart so I would assume it would be nominal, if any.

    • I didn’t notice the battery depleting any faster. The Intruder charges off of a wall wart so I would assume it would be nominal, if any.

      • Thanks

        The DAC draws its power through the USB, I believe. Not noticing a change in power consumption is a good feature.

        • Yes, that would make sense. When the battery is depleted the amplification stops but the DAC maintains a connection.

  • I was a little confused with your otherwise excellent video and review. I cannot go digital out with my iPod to an Intruder, ie, dock to usb mini?

    • I just retested it again, that is correct.  You cannot go digitally from the 30 pin apple connector from an iPod directly to the the USB mini on the Intruder.  You can however, run it directly from a Galaxy S III phone.  

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  • The balanced connector for the RSA Proctector are available from doublehelixcables I believe its the same as the one for the RSA Intruder, about $6 each.

    • Thanks for the heads up Chris!  It looks like the right connector.  You would still have to have access to a soldering kit as it is not a full cable, but that could be great for a DYI-er looking to save some $$.

  • if you use the balance connector between the intruder and the cypher labs clas db, does the balanced output connection override the DAC in the intruder and thus use the DAC in the cypher labs clas db?

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