| Hi-Fi Choice issue No 186 January1999 Review by Jason Kennedy |
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| Novices to the valve amp scene may not be
aware that all tubes were not created equal, and that the 300B
triode power tube had a legendary reputation that seemed way
beyond the potential of an audio component. That was until this
'30s tube returned to production a few years back- the Chinese
started making them first; then the Russians and finally Western
Electric, the American company whose original tubes had created
the legend, re-joined the game. In the meantime there have been more than a few amplifiers created that use the 300B and its meagre seven and a half Watt output, most of them single- ended designs like the Border Patrol where one tube drives one channel. This is the least powerful yet also least compromised way of operating a triode tube. What marks out the BorderPatrol 300B SE is the attention that its maker Gary Dews has paid to power supply design and the resulting neutrality of the amplifier. Virtually every single-ended amp I've encountered creates a slightly rose-tinted view of the music it reproduces, and often it's this euphony that turns regular music lovers into tube fetishists. It's a very appealing sound. However, very few SE's have the bandwidth, power and transparency of a good transistor design. Bass and treble extension is often compromised, the designer apparently blinded by the irresistible midrange. However, unless you listen to solely acoustic music the lack of bass grunt can be a significant shortcoming. By going to town on the power supply, however, the Border Patrol puts pay to the notion that SE's can't play bass. The secret lies in the hefty black box that accompanies the solid-wood framed BP chassis. This contains three separate choke input filter power supplies for the high voltage, negative bias and heaters. Which leaves only signal amplifying tubes on the main chassis. This is not the BP's only USP -even rarer is the use of inter-stage driver transformers which are designed to enable large voltage "If I hadn't used this amp I would still be wondering where the 300B tube got its reputation from." swings with low distortion, and present a very low impedance to the output tubes. Having heard SE's with serious PSU's before I suspect that it's this latter aspect which gives the BP its surprising low frequency grunt. SOUND QUALITY |
Having heard the BP a few times in the past I was not
surprised
by its nimbleness, speed, agility and grunt- quietly enthralled
would be a more appropriate description. I was, however, shocked
to hear that it could cope with the N802s. These fine speakers
have proved more difficult to drive properly than most I have
encountered, so to find an amp whose output is claimed to be
nine Watts at best producing rockin' beats through them was quite
a surprise. It couldn't reproduce the level that the 200 Watt
Sirius achieved but it did a more convincing job than amps with
five times its output. But being an SE design, the BP isn't just about power, it's about the ability to reproduce music with its timbral and dynamic elements fully intact. You tend to take good tone for granted with tubes
but when it's created with so little coloration, as it is here,
you can fully appreciate its beauty and richness. Instruments
are created for their tonal character, yet so little audio equipment
can reproduce this in its full glory. Irannie amps usually dry
it up, while most tube amps add extra lushness. The 300B, when
used with this much attention to detail, appears to add no colour
of its own and combines the skill with lightening speed, removing
any sense of electronic intervention. In some respects the lack
of tube-type colorations make this an extremely difficult amplifier
to get a handle on the broad bandwidth means there's a lack of
euphony. The BP has a more honest, bare-bones style that rewards
improvements in source material to a far greater degree. It makes
a lot of trannie amps sound thick and earth-bound with its superb
transparency and fleetness of foot. It doesn't quite match good
trannie bass but does a far better job than any other SE I've
heard. What's more you get the purity of midrange and treble that
such amps are renowned for, say goodbye to grain forever. Add
to this superb high frequency extension and you've got some idea
of its prodigious capabilities.
VERDICT |
| Hi-Fi
Choice
Issue No 174 January1998 Review by Paul Messenger |
|
PERSONAL MESSAGES
| When, like most
ll-year-olds,
I started listening to music seriously, hi-fi wasn't part of
the vocabulary. By my late teens, however, I'd become aware of
a world beyond the transistor radio, tape-recorder and record- player.
I converted the (mono) Dansette to stereo operation, and found
myself starting down the rocky road towards hi-fi nirvana. My ambition wasn't too great at first, but some lucky second- hand purchases helped me assemble a pretty decent system over the next couple of years, and it wasn't long before the hi-fi bug had dug in its claws. The desire to blend business with pleasure was one of my principal reasons for joining the hi-fi industry in the mid '70s. It wasn't long before I started dreaming of a truly great system, and the prospect of assembling it became all the more feasible when I moved from making speakers with Spendor, to working for one of the hi-fi magazines. Contacts were made, and there seemed a real chance of my dream becoming reality. Not just a great system, but The Best. Some 20 years down the road, hi-fi has given me enormous pleasure and satisfaction. But two decades of accumulated experience has made it necessary to revise the ambition. Quite simply, there is no 'The Best'. It may be The Best for me- I'm not looking at changing anything right now- but it isn't perfect, and does involve compromises. Back in the '70s I used Radford valve amps, but changed to Nairn transistor electronics. I can still recall the trade-off involved, between the delicious midrange transparency of the valves, and the full-bandwidth slam of the solid-state devices. I took the transistor route back then, and have stuck with it ever since, but I do get the chance to try valve gear from time to time. (Briefly, I even grappled with the legendary Ongaku from Audio Note.) Such experiences only serve to remind of a hi-fi dimension I normally do without, and never more obviously than during the few weeks I spent recently with a Border Patrol 300B SE power amp. The plan was to try for a completely feedback- free chain, but it's is taking a bit longer to organise than I expected. The single- ended triode power amp is only the third link in my electronics chain, yet swapping to it from my regular NAP I35 power amps still had much greater impact than I'd imagined.
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Quantitatively it was much greater, but qualitatively it was similar to my earlier experiences. This, I presume, has to do with the steadily-improving resolving power of my system. Inserting the Border Patrol brought forth a gush of enthusiasm for rich mid-band lucidity, which is the valve amp's stock in trade, and reaches its peak with a high-class single-ended design. Because it sounds so effortlessly natural and beautiful, basking seems more appropriate than nit picking; to take a critical stance seems churlish.
After days of tubular basking, I went back to my transistors.
I missed the
mid-band clarity; instead there was a congested quality,
as though the system had picked up sinusitis. But there was a
return to the full, wide-bandwidth sound I'd been missing, especially
in deeper and much more authoritative bass. |
