BORDERPATROL SE-i DAC – Fully Assessed

The BorderPatrol SE-i DAC is a small black box that produces music in an awe-inspiring, grand scale!

The relatively tiny box you see in the feature image is made and manufactured by CEO and long-time audiophile, Gary Dews. He designs and produces the esoteric BorderPatrol 300B tube amplifiers and non-oversampling DACs, which following a recent move, are now built-in Bristow, Virginia. The DAC, which is handmade and under review here, is the latest incarnation of the BorderPatrol SE-i DAC which has been through a few upgrades since its inception about 5 years ago.

Gary Dews BorderPatrol
Gary Dews CEO BorderPatrol

BorderPatrol electronics, Inc. also imports a few amazing products, one of which is the Living Voice Auditorium series loudspeakers, the latest upgraded model R25A having been fully evaluated by us here at The Sound Advocate.

An internet search on the BorderPatrol SE-i DAC reveals many reviews, all positively praising the sound quality, but also contaning more than a hint of controversy with feuds, complaints, and calls of apostasy for parts, chip selection, and design ideas (no digital filtering or over-sampling). One well-known magazine was so conflicted by the disconnect between sound quality and measured performance it sent the DAC to a second reviewer for a second opinion at which point things got very amusing.

In comparing the BorderPatrol and my reference Audio Note DAC (CD3.1x/2) as an example, both use R-2R DAC chips with no-oversampling and no digital filtering. However, BorderPatrol takes the output directly from the DAC chip whereas Audio Note couples the DAC chip to a tube output stage. Whats more, BorderPatrol places a lot more emphasis on the power supply feeding the digital circuit.

A lack of that “overt” tube lushness seems to be a part of the BorderPatrol house sound. BorderPatrol 300B tube amplifiers are no-negative feedback designs with stiff power supplies and DO NOT have the typical profuse, rose-tinted, overly romantic presentation of most tube amplifiers. This may be more toward your liking or not, but it is a subjective attribute that is the BorderPatrol’s stamp of approval of their equipment as well as the SE-I DAC.

The R-2R, no-oversampling, no digital filtering approach can lead to some similarities in the sound, namely an openness, naturalness, and some freedom from digital nasties but the Audio Note DACs can at times sound more overtly ‘tube” sounding and profuse than the BorderPatrol.

Our Border Patrol uses the Phillips TDA1543 DAC chip which is an R2R chip design and is devoid of any oversampling. This is a chip that was introduced in the late 80s but has never been implemented in such a quality format setting as the Border Patrol SE-I, which became quite obvious within the listening sessions.

While there are delta-sigma chips out there that measure better by today’s standards, delta-sigma chips encode and change the music information into a lower-resolution high sample rate that is then mapped to voltages. These voltages then have to go through analog filtering to smooth the response. While this makes circuit design simpler in delta-sigma DACS, I can conclude that this changing of the input resolution and filtering alters the music and frequency range somewhat making them sound more “digital” in effect. Many newer DAC designs rely on R2R topologies to keep the music information in its native resolution.

BorderPatrol SE-i DAC

When dissecting my Audio Note, we see that it uses the Analogue Devices AD1865, another highly regarded DAC chip from the ’80s. This chip like the Phillips chip does not oversample and is an R2R chip. The main (only) similarity is that both use R-2R (resistor ladder) DAC chips with no-oversampling and no digital reconstruction filtering.

So, in effect, when looking at The BorderPatrol tube amplifiers, for instance, and their DACs, the former are no-negative feedback designs with stiff power supplies. Both their amplifiers and DACs DO NOT have the typical ample, lush and passionate, presentation of most tube amplifiers.

Here is a summary of the BorderPatrol DAC ingredients that make up its particular optimized sound quality:

1. The BP DAC uses a hybrid tube/solid-state choke input filter power supply to power the digital circuit. This is unique as the output is taken directly from the DAC chip via Jupiter beeswax film and foil capacitors with no output buffer or extra amplification stage.

2. The BP is built in a painted copper chassis (except for the faceplate which is aluminum) not normally seen at the price point.

3. It uses an R-2R DAC chip with no-oversampling and no digital reconstruction filter 

The main (only) similarity between the SE-i and the Audio Note DAC is that they both use R-2R (resistor ladder) DAC chips with no-oversampling and no digital reconstruction filters. However, both units produce music with a more typical “analog” style of presentation which I find much more preferable than most Delta-Sigma-designed DACs.

I will be addressing here the top model BorderPatrol SE-I ($1995.00) which has dual inputs and the Jupiter Beeswax PSU upgrade. The model variations contain a top-loaded EZ80 vacuum tube that is visible from an opening on the top portion of the unit. While the copper used inside the chassis is also visible it was definitively chosen for its effect on the sound quality.

Since it serves as a rectifier in the power supply, this tube isn’t technically in the audio path, except that it is. The current that provides the output signal from the DAC chip comes, (quell surprise,) from the power supply. The tube rectifier can be turned ON or OFF via a lighted front panel push-button giving the DAC two different sounds. Eventually, I found the effect of switching the tube ON offers a subtle but significantly better audible quality.

Another interesting thing about the BorderPatrol SE-i DAC is that it only converts PCM (pulse code modulation) digital at sampling frequencies of 44.1K, 48K, 88.2K, and 96K. No ridiculous 192K. No fancy-schmancy DSD. No MQA decoding (thank goodness!). This DAC is for the Audiophile Purist!

I cannot or will not challenge anyone else’s love or acceptance of any of these formats, but I can honestly say that as of late, I am not a huge fan of Delta Sigma, hi-resolution DACs. I have assertively spent precious hours with the most distinct program sources with these DACs and always… find myself preferring the non-oversampling/filtering mode of operation for a more honest, deeply penetrating, and non-arguably, moderately less aggressive sound presentation that they display. Enough said here!


The first order of business was to determine whether that “tricky” tube in the DAC’s rectifier path should be turned on or off. After about 1 hour of auditioning the unit with some good program sources, both pop, and classical music, the initial impressions were a touch confusing. With the tube turned off, the sound was intricate and lovely though a bit distinctively more immediate. The effect was undoubtedly pleasing. However, things changed somewhat dramatically after a longer period of time.

BorderPatrol SE-i DAC

In the end, with the tube set “on” the sound took on a quality that was more in line with the best analog sources, yet still had excellent transient attack, an exuberant but not overtly overdone “blooming” effect in the sound stage as well as a feeling of great, self-effacing musicality. Though the differences were subtle, the sound opened up a bit more and so since then, the tube mode has always been left on. Mind you, because of how the BorderPatrol is engineered, this DAC did not give the full sonic impression of a tubed (valve) unit. This is most definitely the hallmark of the BorderPatrol SE-i.

To be more exact, this exceptional option provided by the designer truly gives the listener the best of both worlds. It is also where the BorderPatrol can at times, jump leaps and bounds beyond what may be offered by other DACs; regardless of price or design implementation.!

The overall sound quality could only be described as unconditionally “natural” in its harmonic quality and instrumental overtones. It displayed a slightly warm delicacy but without that openly “romantic” tube sound. Close to ideal in this area, old recordings and music files were dramatically natural in their caliber of sound. The sound was never “bright” but it was sonically and distinctively embossed in the wrath of outstanding tonality, depth, intricate but never overly etched detail — ravishingly subdued yet wonderfully elegant.

A distinctly huge sound stage was presented, assuming speakers and room acoustics were allowed as such. Never fatiguing in any way, the BorderPatrol SE-i was quite profound in its audible sincerity.

Interestingly, the response was nicely extended yet outstandingly smooth in its highest frequencies while imbuing a fleshy yet natural midrange response. Bass qualities were taught and deep, (remember, that tube is only implemented in its rectifier) and so nothing ever was caught out by surprise by the SE-i.

Not unusually, with most components of such high caliber, DACs included, they require a good amount of break-in time and the BorderPatrol was no exception to this rule. Even after about 50 hours of use, the SE-i kept getting better and better while even becoming a bit smoother in the very highest frequencies. I would say, arguably, that this DAC will come into its full prime after about 70 hours of use.

The cream in the coffee is that even as you keep using it, you realize how a few increments of soundstage width, depth, and overall silkiness emerge while the DAC is in use. The SE-i apparently can sometimes overtake many other rival DAC’s costing MORE than double its price and beyond. It’s a little hard to believe how much this R2R design can run fully ahead of several competitive units I have evaluated.

The Border Patrol DAC is completely devoid of a feeling of being closed in, a feature anyone would appreciate in a DAC more than anything else.  It has a melodious sentiment of subtle transparency which is highly detectable, while easily blending with the music and its frequency extremes without putting one’s ears on notice in any way. In a sense, I am bewildered how Gary imbued these fundamentals into his product — in this case, some of the above rules were made to be broken. One thing is for certain: The BorderPatrol SE-i is a completely different animal from almost most other DACs I have recently auditioned.

Assuming one may have a few caveats around many Delta-sigma DAC’s visas vie high-res support, which may or may not be minor depending on your current digital collection, I can confidently profess that the Border Patrol SE -1 DAC will never make you yearn again for an up sampling digital converter!

As I have been listening to the BP, with Quads, Spendor, Harbeth, and Living Voice loudspeakers, I am thinking that on many recordings with a well-recorded PIANO, the BP design virtues can bring out that actual keyboard tactical “attack” to the piano sound with a touch more naturalness, (essentially clearly defined), while not pushing the sound presentation at all “upfront” in the soundstage. This has to be the result of the rectifier tube that essentially, keeps the sound detailed and fully transient but not at all containing a “cloudy” or sumptuously “bloated” presentation as some DACs with tubes that are administered directly into their output stages.


The first obvious comparison would be with my longstanding reference Audio Note CD3.1x/2 player/DAC. The Audio Note is a purist example of a design that uses its tubes in the output stages which produce its singularly effortless sound quality. While the BorderPatrol has many similarities in its sound quality to the Audio Note, it has that one main attribute in its tube application that will either enthrall your senses or give you some pause to think twice about.

There is no doubt that the SE-1 will encompass less of that “tube” fluorescence in the midrange contained in the Audio Note and after many long hours of comparing the two units, I can say that the BorderPatrol may be a touch more accurate in its midrange response than my Audio Note player, but this was also highly dependent on the program sources employed. Other than that, BorderPatrol still offers small doses of that “tube sound” many of us adore quite adamantly. While the Audio Note presents this in spades, the BorderPatrol gives us a good measure of it without going overboard, by any means!

The Prism Sound Callia is a fully comprehensive DAC and their Prism Sound DA-2 is used by many recording engineers today. The sound is sweet transparent and detailed with no hard edges while exhibiting a full soundstage in its width and depth and a rich-bodied midrange; being quite a natural beauty in its own right.

The BorderPatrol equals the Callia in every way but its presentation gives out a touch more softness with a little more naturalness in its fundamental tonality and harmonic presentation. (Again, that tube is in the input stage). The BP appears to equal or exceed its depth and width perception, but not by much at all!

Wyred4Sound’s 10th Anniversary DAC. This DAC has been (and still is) a terrific performer in my system for the past 4 years. It uses the Delta Sigma up sampling formula (but can be set up with numerous sampling or NOS rates) and has outstanding transparency, detail and musicality throughout. Once again, however, the main differences alongside the BorderPatrol would be a touch more upper-frequency lift in comparison, whereas the BorderPatrol still exudes a more romantic, slightly smoother sound presentation.

The Denafrips Pontus DAC (another R2R design) is currently under evaluation and initial reactions allude to a highly dramatic, fully transient, and detailed overall presentation with a “rich” mid/ bass response, thereby not foregoing any of that natural sound quality of the BorderPatrol SE-1. The full review is progressing nicely–.


The BorderPatrol SE-I, NOS DAC’s brain is the Phillips TDA1543 R-2R DAC chip. It does not use digital filtering, oversampling, or an Op-Amp output buffer, which are further causes of the exaggerated sound that affects the majority of digital to analog converters.

Not surprisingly given that it’s a BorderPatrol design, the power supply also received a lot of attention in its implementation. After Gary Dew’s long development process, his hybrid tube/solid-state design using choke input filtering was found to be the most musical, dynamic, and additive-free. I believe that BorderPatrol is the only company that applies tube rectification and choke input filtering to its digital circuits.

To summarize, the sound quality of the SE-I is quite simple to encapsulate. It is amazingly natural and musical in its overall tonality and full audible presentation. With an exuberant, opulant midrange response and silky high end, this DAC will give the music lover some of the finest reproduction qualities that you may ever experienc in a Digital to Analog converter.

There is no doubt that after living with the SE-1 for a few months, it is hard to switch back to some other DACs that one may have sitting in the dugout. Indeed, the BorderPatrol SE-1 has left an indelible mark on my musical senses and I believe that it may well become a permanent resident of my audio system; this appears to epitomize everything here on a grand scale!

Review System for this component:   Loudspeakers: Living Voice R25A loudspeakers, Spendor BC1, Harbeth Compact 7 ESR/XD, Quad ESL63 ~ Digital: ~ Innuos Zenith Mk.3 server/streamer ~ Wyred4Sound 10th Anniversary DAC ~ Audio Note (UK) CD3.1x/2~ Denefrips Pontus  Analog: Audio Technica LP-7/ZYX Bloom 3  Amplification: ~ Pass Lab XP-12 preamp ~ Pass Labs XA30.8 power amp ~ Cambridge Duo MC/MM ~ PS. Audio M1200 monoblocks / Cables/ Conditioners: Inakustik AC-3500p power station & LS-4004 speaker cables, AC-2404 reference Air Power Cord ~ Audience Studio 1 interconnects, speaker cables, Clarus “Crimson” digital, loudspeaker and Interconnect Cable loom, Audio Art 1 e” AC Power

BorderPatrol SE-i USB+SPDIF $1995

Other prices : S USB $1225

S SPDIF(COAX) $1225 S SPDIF(COAX) X2 $1325

USB + SPDIF(COAX) $1675 SE-i USB $1525

SE-i SPDIF$1525 SE-i SPDIF X2 $1625

BorderPatrol Audio Electronics

9657 Granary Place

Bristow VA 20136

Phone: 301 705 7460


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