BorderPatrol power amplifiers

Border Patrol valve amplifiers combine superb sound quality with clean retro visuals. The elegant hardwood plinths house state of the art triode valve circuitry that use the latest high performance components. Valves are used not because of nostalgia but because they are still the most linear amplification devices and have tonal and resolution capabilities that continue to elude the solid-state alternatives.
It is often commented that valve amplifiers have wonderfully communicative midrange and sound tonally rich and warm but have poor bass performance and dynamics and are incapable of capturing the drama and tension in music. Our intensive research into power supply design has overcome these dynamic problems. With a Border Patrol amplifier you can enjoy the smoothness, clarity and tonal realism that valve amplifiers are renowned for together with good bass bass and dynamics. All the drama and tension is effortlessly portrayed.
All Border Patrol amplifiers feature triode valves, the simplest and most accurate amplification devices of them all. Each circuit is designed to be as simple as possible to maintain signal integrity and each component is critically evaluated to make sure it blends into the whole. All the amplifiers are point to point hard wired and constructed from non-magnetic materials to minimize the effects of electric fields on the audio signal. Inter-stage transformers are used to couple the small signal valves to the large output triodes. Something of a lost technology, inter-stage transformers were abandoned by amplifier manufacturers for reasons of cost and size despite their technical and sonic benefits.
And, all Border Patrol amplifiers feature heavy duty external power supply units, one each for the SE300B and P21 stereo amplifiers, and two, one for each channel, for the P20, S10 and S20 dual mono designs. Each power supply unit contains three independent valve rectified choke input filter high voltage power supplies that feed different parts of the amplifier circuit with clean filtered voltage.
More than anything the award winning power supplies are responsible for the combination of dynamics, bass performance, clarity and resolution that set Border Patrol triode amplifiers apart from other valve amplifier brands.

 

Border Patrol SE300B and S10 single-ended amplifiers.

The 1st Border Patrol amplifier, the SE300B was introduced in 1995 and quickly redefined the capabilities of 9watt/channel amplifiers. Using a single 300B output triode for each channel, the amplifier surprised critics, not just with its resolution but with its dynamics and control which were thought to be beyond low powered single-ended amplifiers. The poor bass and weak dynamics that had been associated with designs of this type were removed by the sophisticated external power supply unit and the amplifier is a model of sweetness, clarity and vibrancy with fine, extended bass and dynamics.

The SE300B features a single ended output stage which is the simplest and purest circuit topology available.
An external power supply unit feeds both channels and each power supply unit contains three independent valve rectified high voltage supplies that feed different parts of the amplifier together with additional supplies for the valve heaters. The internal components were selected after exhaustive empirical testing. Different brands of 300B output valves are also offered which subtly tailor the sound of the amplifier.
clarity, resolution and tonality are outstanding and the amplifier excels on all types of music.

The SE300B is often seen at hi-fi shows driving large horn-loaded loudspeaker systems but the amplifier is equally comfortable driving more real world designs. The recommended efficiency for partnering loudspeakers to extract the maximum performance needs to be greater than 93dB/watt but in smaller rooms loudspeakers with efficiency down to 89dB (8ohms) can be used. One reviewer was staggered to find the SE300B driving a loudspeaker (B&W Nautilus) that had defeated everything but his 400W channel transistor amplifier though this is not something we generally recommend .

The BorderPatrol S10 takes the SE300B design to another level by the addition of an other PSU and re-configuration to dual mono. Stereo separation, dynamics, stability, headroom and control are all improved compared to the SE300B. Any owner of a high efficiency loudspeaker system should strongly consider this amplifier.

'There are no rose tinted specs, slurred and rolled off frequency extremes or over stuffed harmonics here.  In fact, for the first time in my experience, I'm listening to an amplifier with the linearity and directness that are supposed to be single-ended's great virtues.'
Roy Gregory Hi-Fi+ issue 8

'...the Border Patrol might have dipped out on the syrupy sweetness part of the single-ended deal, but it delivers the “real sense of power” with consummate ease, another area in which most of its compatriots fail to live up to their billing.  Instead of lush and overblown, the 300B SE (WE) is wonderfully (and correctly) rich.  Instruments have a natural weight and colour, and voices, especially tenors, have tremendous authority and a real sense of substance.
Roy Gregory Hi-Fi+ issue 8

'Passion, grace and fire.'  Jason Kennedy Hi-Fi Choice Jan 99 Hi-Fi Choice  EDITORS CHOICE

'Uncommonly capable single-ended design with less colouration and more grunt than any of the alternatives- resolution guaranteed.'  Jason Kennedy Hi-Fi Choice Jan 99 EDITORS CHOICE

' ....., I went back to my transistors. ....there was a congested quality, as though the system had picked up sinusitis.'
Paul Messenger Hi-Fi Choice Jan 98

 

Border Patrol S20 parallel single-ended amplifier.

Originally conceived as a single-ended amplifier to drive more difficult loudspeaker loads, the S20 has shown it has far more to offer than just that and is now the most popular Border Patrol power amplifier. The winner of a prestigious 2004 Hi-Fi+ Product of the Year Award the S20 gives 18 Class A watts per channel from the parallel pair of single-ended 300B output valves and can drive a wide variety of loudspeakers. The combination of extended bandwidth married to excellent dynamics and a magic midrange make the S20 both capable and musically communicative. With the improved sound staging, headroom and tonal body that come from having double the power and a separate power supply for each channel the S20 is a fine musical transportation device. Clear, clean, fluid, extended, tonally rich and natural are all adjectives used to describe the performance of this fine amplifier.
Recommended loudspeaker efficiency <89dB/watt for best performance.

'Another atypical aspect of this amp is its response. Valves are famous for having a glorious mid-band and a tendency to emphasise this above all else. The S20 while phenomenally transparent in the mid-band has a remarkably flat response. You don’t miss out of the frequency extremes with it This is a wide band amplifier!'

'The mid-band is proper SET stuff though, voices are superb and you can hear all the words all of the time. This is a fluid and revealing amp that combines a delicacy that lets you hear micro dynamics clearly with an ability to swing real energy when it’s required.'
Jason Kennedy HI-Fi Choice Collectors Edition Summer 2004

'At first glance it looks to be of a similar build quality to many other small brand amplifiers; in other words fine but nothing to write home about. But look a little closer and use the product for a while and you realise that this is a fully finished well thought out component that will stand the test of time as well if not better than machine made audio electronics. Look under the lid at the way components are connected up and held in place and it inspires a confidence that can sometimes be lacking in the valve world. Standard of finish is high
throughout, but stops just short of slick while the paintwork is perfect and the screen printing professional. This is a solid product make no mistake.'
Jason Kennedy Hi-Fi+ issue 35.

Recommended loudspeaker efficiency >87dB/watt.

 

Border Patrol P20 and P21 push-pull amplifiers

The subject of two recent reviews in the hi-fi press, both of them unequivocally complimentary, the Border Patrol P20 has carved a solid reputation for fine sound quality, serious musical enjoyment and ability to drive loudspeakers that were thought to be beyond the capability of 20W valve amplifiers. Featuring two 300B output triodes per channel, this time in a push-pull configuration giving 20W/channel the P20 handles all music with finesse and aplomb and injects a serious dose of energy and excitement. The natural timbres of instruments are superbly portrayed with fine resolution and detail retrieval whilst floor-shaking bass can be delivered should the music demand it. Once again, the external power supply units are in evidence providing a super quiet, black background and a solid bass foundation. Single ended all the way up to the inter-stage transformer the P20 takes advantage of this supposedly antiquated technology to split the phase in a more accurate and time consistent way than the much more common active phase splitters resulting in a much purer sound with better resolution and leading edge definition. Described by one hi-fi reviewer as ‘one of the finest musical enjoyment devices available’ the Border Patrol is sure to illuminate and extract maximum enjoyment from any music collection.

Superb amplifier with bags of power and genuine resolution, one of the best music appreciation devices available.'

'In the right company this amp delivers transparency, fluidity of timing and grunt like few others out there...... if it's the musical essence you're after it's a tough act to follow.' 
 Jason Kennedy Hi-Fi Choice Summer 2002
Hi-Fi Choice  EDITORS CHOICE

'Here, the authority shape, pacing and tactile presence that the P20 brought to the nether regions of these physically modest speakers (Reference 3A and Living Voice Avatar OBx-R) imbued them with a scale and sheer unflappable stability totally at odds with expectations. Tonal colour and separation were superb, with none of the qualitative sameness that collapses the individual character and texture of instruments (and performers).'

'The P20 is a mightily impressive amplifier and one that explodes the triode myth. Once again, it proves that it's not what you use but how you use it that counts. Good engineering will win out. I've listened long and hard to the push-pull Border Patrol and still haven't got its full measure.'
Roy Gregory Hi-Fi+ Issue No 25 August/September 2003.

The BorderPatrol P21 has the same audio circuit as the BorderPatrol P20 but uses a single power supply. It is not a poor relation. It has all the trademark Border Patrol sound qualities; clarity, dynamics, bass and tone in abundance with capability almost matching the P20. The P21 can be upgraded to dual mono P20 specification.

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