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BorderPatrol SE-i USB/SPDIF Digital to Analogue Converter Review

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David’s Q&A with Gary Dews of BorderPatrol

Q: How is the SE-i different from the SE? And how do these differences play out both socially and operationally?

A: The first SE DACs used UptoneMusicap polypropylene film and foil coupling capacitors on the output. New SE-i DACs use Jupiter cryo Beeswax caps which give it a richer, more full-bodied sound with a more organic, natural timbre.

The value of the capacitors is also higher which reduces the output impedance and enables the DAC to work with a wider range of pre-amps than before.

The upgrade is available to owners of pre-2020 DACs.


Q: With all the technical advances that have been made by manufacturers in the interim, the years between the SE and SE-i, how does BorderPatrol answer those hungering for these advances? What is the argument for being the purist? And how do they respond once they’ve been enlightened?

A: That’s an interesting question to ask a designer who also makes a range of amplifiers that use a 1938 electron tube!

Technological advancements don’t necessarily translate into better audio. There are many examples where the reverse has been the case. Is it better to have a DAC with the latest tech or one that produces a sound that you like? Which sounds best: a relaxed sounding R-2R DAC playing a 16/44 or 24/96 file or an edgy delta-sigma DAC playing a 24/192 file?

I make products that I like to listen to rather than following industry trends to make sales. The DAC is a reflection of this. I was told that a lack of hi-res would be a serious disadvantage and that I would be crazy to release a DAC that couldn’t do 24/192 or above. But when I prototyped hi-res delta-sigma chips from ESS, Wolfson, Texas et al I never liked the sound. I will go further and say I positively disliked the sound. I found the smooth relaxed sound of R2R chips when used without over-sampling and digital filtering to be much more lifelike and easier on the ear than the over-analytical, edgy, artificial sound of the delta-sigma chips.

I understand some customers must have the very latest technology and assume that hi-res/MQA etc must mean better sound and that’s fine; there are plenty of companies that cater to that, but the response by reviewers to the BorderPatrol DAC (many of whom have bought the DAC for their use) and BorderPatrol DAC owners suggest there are just as many that are more interested in listenability and musicality. As far as sales are concerned, the lack of hi-res hasn’t been a problem. Most music servers can easily be configured to down-sample to 24/96 and the DAC is fine with that.

Interestingly, Steve Guttenberg, aka, “The Audiophiliac” recently posted a YouTube video about this.


Q: What is the profile of the Border Patrol DAC customer? What is it that they are looking for in a DAC when they come to you?

A: Many of the DAC buyers complain about their previous experiences with digital sound and how they have been unable to relax with it and enjoy their music. They are looking for listenability, musicality and the ability to listen for long periods without becoming fatigued. Once they receive the DAC, not only are they pleased by how easy on the ear it sounds but also by how open and vibrant it is. Maybe they were expecting something that sounded thick and dull, like a vintage tube amp, but it’s not like that.

Updates to the following Q&A between Doug Schroeder and Gary Dews from his Review:

Doug Schroeder: The DAC SE uses copper for chassis. Why?

Gary Dews: The use of copper for the casework was a spin-off from the Border Patrol amplifier designs. Early BorderPatrol amps were made with steel and aluminium chassis. There was a noticeable difference in sound between the two. Steel imparted a glare and grainy character to the sound. Aluminium, by comparison, sounded lighter, freer and airier but was also somewhat frenetic and unruly by comparison. I was lucky enough to hear amplifiers made by Audio Note Japan and to meet the legendary late Mr. Kondo several times. We discussed amplifier design and I asked him why he used copper for the chassis of his amplifiers. He told me it was not for looks and that copper sounded better than steel and aluminium. He spoke about calmness, tone colour, the quietness of background, noise floor (audible, not measurable) and freedom from grain. I had a copper chassis made for my amplifier and the difference was clear. When I realized I could use copper casework for the DAC and still make it relatively affordable it seemed like an obvious thing to do. Anyone that thinks the chassis material does not play a part in the sound of a product hasn’t done the work.


DS: The DAC SE uses a ladder DAC in a tube circuit. Why?

GD: I was aiming to make an affordable DAC that sounds refined, clean, relaxed, fluid, colorful and human and free from the artificial ‘hi-fi’ sound that characterizes so many sub $3k designs. Lots of DACs have dazzling specs but sound machine-like and digital. Information is one thing, but it needs to be presented naturally with recognizable timbre and tone. Not many DAC’s achieve that. I found that ladder DACs used without over-sampling and digital filtering sounded much more natural and listenable than delta-sigma oversampling/digital filtering types which sound processed, unnatural and synthetic.

I have been designing high-end 300B tube amplifiers for over 25 years. The amplifiers are notable for their elaborate power supplies, component quality, casework materials and for not using negative feedback (NFB). Much of the knowledge I have accumulated designing SET amps went into designing the Border Patrol DAC. In many ways, the DAC resembles a BorderPatrol 300B power amp in that it uses a minimalist audio circuit surrounded by high-quality passive components and fed from a very high-quality linear power supply. There is no over-sampling (NOS) or digital filtering so, much like a triode tube amplifier that does not use negative feedback (NFB), what goes in at one end comes out at the other with minimal manipulation of the signal. The tube is in the power supply, not the audio circuit.


DS: The DAC SE uses a linear choke input filter in its power supply. Please explain.

GD: The power supply borrows heavily from the BorderPatrol power amplifiers and pre-amps. It is a linear choke input filter design, not a switch mode. Rectification is a hybrid tube/solid-state design that uses an EZ80 tube rectifier in parallel with low noise high-speed diodes snubbed by resistors and capacitors. The DAC will work with the tube turned ON or OFF. The supply topology is a choke input filter in which the rectifiers feed directly into a high inductance choke. An ELNA Cerafine reservoir capacitor is used and each of the digital chips has its voltage regulator.

Switch-mode supplies are great for computers and laptops but have no place powering audio circuits. Switch-mode supplies are equally responsible for the artificial, unnatural sound that characterizes so many digital products.

The sound of any product is a sum of the circuitry, parts, materials and the power supply. Everything has a sonic signature. There are many notable features in the DAC: the NOS R2R DAC circuit, the high-quality output and power supply capacitors, the copper chassis, but if there is such a thing as the ‘star of the show’ it’s the power supply which is significantly more sophisticated than the supplies usually found in other DACs, regardless of price. During development, the power supply began as a solid-state, choke input filter design. It sounded very good from day one but it gradually evolved with the addition of snubbing techniques and the addition of the tube rectifier. Each step made the DAC sound more refined, less edgy, less ‘digital’ and more natural and musical.

Border Patrol is still the only company to my knowledge that applies tube rectified, choke input filter power supplies to digital circuits and before anyone shouts ‘Lampizator’ there are two crucial differences. One: Lampizator use chokes in the power supplies to the output tubes, which is an analogue application, not digital. Two: Lampizator supplies are capacitor input filter designs, not choke input filter.

Audiophiles know that the quality of the power supply matters: The market for power chords and power conditioners is large yet lots of equipment is equipped with low-quality power supplies like switch mode or low-cost linear types because the designers would rather spend the money somewhere else. That’s a mistake in my book.


DS: The DAC SE does not support DSD. Why?

GD: I am not opposed to hi-res: I think my desert island DAC (that’s the DAC you want with you when marooned on a desert island with no chance of rescue) would be a high-res NOS R2R design with great power supply etc. but that would probably be very expensive.

Designing affordable products in many ways is much more challenging than designing statement products. Choices have to be made. Given the choice between a good NOS Redbook R2R DAC with great power supply etc. and a hi-res delta-sigma design with all singing, all dancing specs and a ‘just enough to make it work’ power supply I’d go with the NOS Redbook DAC every time. Interestingly, the lack of Hi-res hasn’t been an issue. Some people (like me) never threw away their CDs and even if they copied them to a hard drive, the files are still Redbook quality. Only a tiny fraction of the music available is in hi-res and it is likely to stay that way for a long time.


Copy editor: Dan Rubin


3 Responses to BorderPatrol SE-i USB/SPDIF Digital to Analogue Converter Review

  1. ric escalante says:

    I do not have the updated version, but at some point will consider upgrading. I do recommend changing the fuse to Synergistic’s Orange, using IsoAcoustic’s underneath–love the sound. Still not up to vinyl quality, but getting closer.

  2. DJS says:

    I have this dac and I love the open and natural and relaxed qualities it exhibits… presently listening for hours with my Bakoon HPA-21 and Sennheiser HD820’s, while reading on the internet. Beautiful little dac.

  3. Greg B says:

    Which SW1X dac do you have and how it compares to Border Patrol ?
    I’ll be using it connected to Marantz Nd8006 via spdif cable and then to Line Magnetic 845ia with rca cables.

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