BorderPatrol P21 EXD 300B Amplifier | REVIEW

This one is a bit of a convoluted story, let me tell ya. One sunny day in the early pre-COVID winter, Gary Dews, the head guy at BorderPatrol Audio (website), paid me a visit bearing gifts. While Gary was not exactly appearing as one of the Magi, these were fine gifts indeed: a pair of Living Voice IBX-R3 Auditorium Series speakers, as well as one of his own creations, the BorderPatrol P21 EXD push-pull 300B amplifier.

Together, we enjoyed a bright afternoon of lunch, audio banter, and all-around good cheer. When it came time to leave, Gary told me to enjoy the bounty, as he wouldn’t need these back for awhile. And enjoy I have as the months ticked by…

First off, I feel negligent having taken so long to get pen to paper about these fine products, but other projects intervened, including my own adaptation to remote teaching at the collegiate level thanks to the ever-enduring bug. Talk about a sea change! Perhaps, also, there was something of a hidden desire to hang on to this combo as long as possible once it had encircled me in its subtle, yet solicitous, grasp. Yeah, I’m going with that.

Let me be clear: this review focuses on the attributes and characteristics of the BorderPatrol P21 EXD amp, but the Living Voice speakers also play an important role. Why? Well, because the two components play so nicely together. Like a well-conjoined set of Siamese twins, they are hard to separate from one another.

Bits ‘n’ Bobs

BorderPatrol is one of those audio companies that has been around for a long time (1993 in fact). It’s also my understanding that it got its start alongside speaker manufacturer Living Voice, both in Merry Olde England. I’ve also been told that each company used the other’s goods for development of its own products. If that’s the case, there’s no wonder there’s some serious harmony evident between the two companies’ offerings.

Somewhere along the way, Dews decided to cross the pond, as it were, while the Living Voice folks stayed put in the Old Country. There are lots of low-powered vacuum tube amplifiers out there for enthusiasts like me to ponder over and admire. What is it that makes BorderPatrol amps unique?

First off, there’s that exquisitely overbuilt external power supply. My back tells me the thing weighs a ton, and it’s fully tube rectified. It’s been said that this attention to detail at the power supply level has allowed Mr. Dews to wring more bandwidth out of the ancient 300B tube than previously possible. Want seriously taut and punchy bass from a 300B amp? Well, this one delivers it.

The thing that struck me most odd when the amp was unboxed, however, was the quartet of 300B tubes standing at attention in the middle of the amp’s chassis like guardhouse sentries. In SET (that’s single-ended triode) world, you’d normally see only a pair of output tubes, one per channel. That’s because in SET mode, a single output device handles the whole signal. It’s a sweet deal sonically (and price-wise), but the
downside is limited power, control, and heft. 300B-based SET amps most definitely sound sweetly beguiling, but often give up bass resolution and extension, for example.

Such deficiencies therefore greatly limit the range of speakers that can be effectively used with these amps. The alternative chosen for the  BorderPatrol P21 model is to use the quartet of tubes in a push-pull configuration, now assigning a pair of 300Bs per channel. A big advantage is that now one can design an amp with roughly twice the power of the equivalent SET design. Ostensibly, we can now have the traditional 300B tonality coupled with increased power output, definition, and grunt. Additionally the BorderPatrol P21 operates in Class A, meaning that it is therefore free of the so-called “notch” distortion that occurs in typical push-pull designs such as typical 6550/KT88 designs that operate in Class A-B. The absence of “notch” distortion and the low internal impedance of the 300B tubes allow the P21 to operate without negative feedback. These characteristics lead to improved leading edge definition and image precision, according to Mr. Dews.

What else does the BorderPatrol P21 EXD have to offer? Well, the lucky owner gets a completely hand-built, point-to-point wired amplification device constructed by Gary Dews himself. Incidentally, one could save a few bucks by considering the standard (non-EXD) version of the P21. Differences? The EXD option offers copper chassis parts on the amp, as well as upgraded internal components and full cryo-treatment of the amp and power supply unit. The standard version costs $9325, or $3825 less than the EXD model. (That ends up being $13,150 for the unit I reviewed, excluding tubes.)

Enough about the design; time to get on to sound quality and performance of the BorderPatrol P21 EXD.


The BorderPatrol P21 EXD spent most of its time in two system configurations, though I put it through its paces with every speaker setup I have in my room. These main systems consisted of the following:

System 1: Crane Song Solaris DAC (usb) feeding my ancient, but totally re-built, Cary Audio Design SLP-70 preamplifier, tossing signal to the P21 EXD, which in turn drove a pair of Living Voice IBX-R3 Auditorium Series speakers.

System 2: BorderPatrol DAC (coaxial input fed via my Sound Devices USBPre 2 usb-to-S/PDIF converter) sending signal to a Linear Tube Audio MicroZOTL preamplifier driving the BorderPatrol P21 EXD, which in turn powered a pair of Quad ESL-63 electrostatic speakers (rebuilt by Electrostatic Solutions).

System 1 Impressions

Given that the BorderPatrol P21 EXD showed up here just prior to our COVID shutdowns, I’ve spent a lot of time with it, both in serious listening sessions and countless hours of background listening while I worked and accomplished other tasks. I’ve thus got a pretty good handle on how it sounds, especially coupled with the Living Voice IBX-R3 speakers.

Gary Dews told me when he dropped that amp off that many folks tell him that it doesn’t sound all that much like a tube amp. He himself disagrees. Me? I fall somewhere in the middle of these two opinions.

Overall, I’ve found the BorderPatrol P21 EXD to be a master of truthfulness, both sonically and by way of its remarkable resolving power. Indeed, the P21 EXD is neither the wet blanket nor the cup of sweet nectar. It moves fast and doesn’t take prisoners. Kind of like a ninja in the night, methinks. The sheer clarity and neutrality of tone took me awhile to adjust to; it’s a presentation that my brain really had to wrap itself around.

While the BorderPatrol amp disarms with its truth-telling, it’s also easy on the ears. People like it. I had several friends and family members have a listen and then switch over to my reference system, which is housed in the same room. Almost to the person, folks preferred the sound of the P21 EXD/LIving Voice combo. Less “thick” and more “naturally engaging” were typical comments…. and from non-audiophile listeners to boot. One visitor called the combo the “Ferrari of Stereos.” When folks who don’t geek out on audio like what they hear, I take it as a good sign that something positive is going on.

Me? I personally like a system that rewards me over time. We have all experienced the system or component that wows us up-front. It’s exciting and fun at first, but the thrill wears off eventually. Inevitably, something about it starts to grate on us or become less convincing. The BorderPatrol P21 EXD driving the Living Voice IBX R3 speakers has been exactly the opposite. Admittedly, it sounded nice right out of the gate, but maybe a tad unexciting (perhaps due to its intentionally neutral presentation?). Now, nearly a year on, I’ve come to truly appreciate how naturally absorbing the combo really is- I look forward to firing it up every night for an hour or two of quality time. It truly wears well
over time.

Some specifics you ask?

No problem… Let’s start with some female vocals. A great example (recently released) is Simin Tander’s album Unfading (24bit/96 kHz flac file, streamed via Qobuz). Tander is of Turkish/German ancestry and sings with a distinctly Middle Eastern inflection. She also possesses a lovely purity of tone which comes through “clear as a bell” via the BorderPatrol/Living Voice system. It was this sense of reach-out-and-touch-it clarity that truly disarmed me and kept me listening time and time again to this album.

Precision was another term that kept coming forward in my notes. Here, I refer not only to the precision of tone and vocal inflection, but also to the precision of the spatial cues I hear between and around the speakers. It’s this trait that reminds me that the BorderPatrol P21 EXD is truly a vacuum tube amp; the soundstage opens up and blossoms, yet remains totally in check regarding image boundaries in all directions. Just relax, close your eyes, listen, and you’ll see what I mean.

Another album that I often use for evaluation purposes, as well as for my own enjoyment, is Pat Metheny’s solo acoustic outing One Quiet Night (16 bit/44.1 kHz flac file, streamed via Qobuz). I love this album for its sheer simplicity and immediacy. Here’s Pat all alone in a room with a guitar, closely mic’d. It qualifies as a “you are there” recording if ever there was one. I listen for several things: the complex harmonic structure of the plucked notes, the movement and pressure of the strings against the fret, and the movement of fingers over and against the strings themselves. A well-reproduced rendering of this recording highlights lots of squeaks and bumps riding underneath the plucked strings, just as one would expect to hear when in the close company of a master guitarist.

Played back via the BorderPatrol P21 EXD, I have an easier time following the progress of the music, warts and all. I truly hear the little things like squeaks and blemishes that are going on underneath the music; in fact, these all become an integral part of the experience to a degree I don’t normally hear. I chalk all of this up to the BorderPatrol P21 amp’s ability to resolve and flesh out the underlying tonal details that make good music what it is. Once a door to reality like this has been opened up, it’s hard to close it again and remain satisfied with the status quo.

System 2 Impressions

Enter the Quads…

I’m referring here to a pair of rebuilt Quad ESL-63 electrostatic monitors that I recently acquired from Scot Hull. I have multiple pairs of excellent speakers already, so why another? Well, I’d repeatedly heard that these Quads were special, and I’d always wanted to experience them for myself in my own space. I’d heard these, as well as the older ESL-57s at shows, and I’d always come away impressed with how immediate and realistic they could sound, especially for an older design.

One caveat: unlike the ESL-57’s, the 63s reportedly like power; the more the better. Would the 20 watt per channel BorderPatrol amp be up for driving the hungry and somewhat demanding Quads? In short, no problem! At reasonable sound pressure levels at which I enjoy listening, the BorderPatrol P21 EXD amp was a magical combination with the ESL-63s. Everything the amp did well with the Living Voice speakers it did equally well with the Quads. If anything, I heard even more detail and resolution, but always in the service of the music, as
opposed to being gimmicky or showy.

Going back to Pat Metheny’s One Quiet Night, I could more easily discern the squeaks and scratches of fingers moving over and against strings. Again, not in an irritating or overbearing manner, but more as a magnification of the finer details of the recording event. I felt ever closer to the living, breathing human body and his acoustic guitar and thus felt even more the emotion that Metheny was trying to convey.

I’m sure there may well be advantages to driving the Quad ESL-63 speakers with a higher powered amplifier, tubed or solid state, but the BorderPatrol P21 EXD did some real magic with the speakers in my listening arena. A few comparisons…

I can honestly say that I didn’t have anything in-house that could be compared directly to the BorderPatrol P21 EXD, either in terms of price point or design. I therefore decided to see how the 300B amp would stack up against a couple of my own favorites: the First Watt SIT-3 (class A solid state) and my Dennis Had Inspire High Output Single-Ended Triode amplifier (tubed). Interestingly, both the First Watt and Dennis Had amps share similar sonic signatures. Both sound more traditionally “tube-like” with a good dose of second order harmonic distortion intentionally built in. Both are smooth, three-dimensional, and harmonically complex. Both also mated beautifully with the Living Voice IBX R3 speakers, with their high sensitivity and easy impedance load. I’ve tried both amps with the Quads, and neither was up to the task. The ESL 63s are just too inefficient and difficult a load for these amps to drive well.

Via the Living Voice speakers, I found the BorderPatrol P21 EXD amp to be more forthcoming with detail and immediacy. It just seemed more honest, offering a clearer and cleaner window onto the recorded performance. It refused to editorialize; it just gave me what was there on the recording and little else. To be sure, not all music lovers will prefer this level of honesty. Many will be better served and more satisfied by the sweeter tonal color and depth of harmonic structure offered by the SIT-3 and the Inspire amps; the BorderPatrol might come off as a bit threadbare and over-resolving in comparison.

Parting Thoughts on the P21

If nothing else, Gary Dews has effectively shown me that the 300B output tube is still quite a force to be reckoned with. Bass-wise, he’s demonstrated that it can hold its own with the other perfectionist amps in my collection. I never felt less than satisfied in the bass department, especially recalling listening to 300B amps in my distant history where bass suck-out happened as soon as the music got complicated or loud. Not here though, not at all.

Broadly speaking, it’s hard to fault the BorderPatrol P21 EXD amplifier. It’s one of the most beguilingly neutral and honest amplifiers I have ever experienced. As I mentioned before, it took me some time to adjust to its uniquely open presentation and fully learn to appreciate it. It’s still kind of amusing to me that my non-audiophile friends “got it” right away, and yet it took me a long time to fully appreciate what they were trying to tell me!

Yes, the BorderPatrol P21 EXD is expensive. It’s above my pay grade. However, if it sounds like an amp that would check your boxes, I think it’s definitely worth the coin. I’m just pleased that there are talented designers and artisans like Gary out there who remain committed to building gear like this… It’s truly a labor of love to produce these works of art for audio perfectionists to enjoy for a lifetime.

Kudos to you, good sir, for a job well done!

For more information, or to arrange a visit of your own, you can find BorderPatrol Audio Electronics at:

And don’t forget to check out some past coverage here: