Audio makes a low-cost, palm-size, Class-T stereo chip amplifier* (see Enjoy
the Music.com for article at links below Blue Note ratings). "Good things come in small
packages," I said "the TA-10 easily scores four Blue Notes. No, it does not have the lush tube
mid-range that sends Big Ole Horns into the outer orbit of ecstasy. But it does
so many things well, for so little dough, that Trends Audio's TA-10 amplifier is
an excellent value in the right situations." Two years later, I reviewed their
tube and MOSFET hybrid stereo pre and headphone amplifiers, with both Russian
6H23n double-triode and Chinese 6N11 tubes. The pre-amplifier supports either
6DJ8, 6922 or 12AU7 tubes by way of easy-to-make internal jumper switches. More
low-cost, small size, good value success, I proclaimed, the PA-10 "has a
charming coloration that sounds like music and grabs your attention."
Their next move was only logical. Combine their tiny amplifiers for more power. The new Trends bi-amplifier system chains two of their amplifiers together with a special dual power supply and a y-shaped input cable to their tube hybrid pre-amplifier. They combine two sets of the TA-10.2P Class-T power amplifier with the PA-10.1D tube headphone/pre amplifier (with two outputs for each amplifier) by way of their QB-773 cables.
Trends offers several international variations of this kit. Be
sure you order the proper combination kit for your electrical outlet connections
and country line voltage. The SE version is $699 (with the Russian 6H23n tube I
preferred) and GE version is $699 too, but with the typical, well-known 12AU7
tube in the pre-amplifier. Trends doesn't sum up the combined wattage output
of these combined amplifiers. Instead, their bi-amplifier specifications remain
the same low-power ratings as their single stereo amplifier, except times two:
15 Watts at 4 Ohms, 10 Watts at 8 Ohms but with 10% THD.
Enough For Big Ole Horns
For example, I use my Bottlehead 2A3 Paramour* mono-boxes on
the mid and upper horns, connecting directly into the crossover network. I run
my 15" woofers full-range with a solid-state, stereo Pioneer M-22 amplifier,
directly bypassing the dividing network. So I don't bi-amp for power. Not when
delicious sounding amplifiers like Don Garber's 1.5-watt Fi with Tung Sol 46
(single-plate, but double-grid) tube has enough power for all but the loudest
and most complex passages. I do
bi-amp passively because even uber-efficient 15" woofers need powerful
amplifier control to shape their impedance curve into the proper bass frequency
response. In other words, it sounds better. Better bass fills out mid-range
texture and tone. Therefore, I bi-amp for quality,
not quantity of watts. I got into
Big Ole Horn loudspeakers because of their incredibly realistic and therefore
engaging sound. I was hoping to drive them with inexpensive front-end
electronics. (Which I have. See "Stereos as Indoor Sport."*) Turns out
horns are not so simple as that. Uber-efficiency means uber-sensitivity to
front-end qualities, such as cleanliness, Total Harmonic Distortion and noise.
So Lilliputian chip amplifiers, like Sonic Impact's $40 Class T amplifier ("A Straight Wire With Gain"*), have no trouble driving the Big Ole Horn loudspeakers of my bargain basement system. Trends' TA-10 drove them also, not only to some quite respectable levels, but with startlingly good quality in all but the most demanding situations. Their charming amplifier is fairly transparent, exhibits midrange purity and naturalness of timbre, with treble that is neither dull, nor bright.
With bi-amplification, I can match the sonic qualities of the
amplifiers to the type of loudspeaker drivers; tasty tubes on top compression
drivers, solid-state control on cone woofers. Bi-amping opens up the dynamics
and lowers distortion. An audible difference is evident. It works together like
ham and eggs.
Monoblock bi-amplification means one mono amplifier per channel runs both the bass and the treble with a single loudspeaker cable to the bridged binding posts (and crossover) in each single loudspeaker – one amplifier per loudspeaker. This is popular because it uses short loudspeaker cables, but with long interconnects to the pre-amplifier, in order to place the amplifiers near the loudspeakers, which has its own sonic advantages.
Vertical bi-amplification means one stereo amplifier runs both bass and the treble, with separate cables to the unbridged binding posts – again one amplifier per loudspeaker, but the two sides of the stereo amplifier drives one loudspeaker. This is also a popular way to place the amplifiers near the loudspeakers on a short cable run.
Horizontal bi-amplification uses one stereo amplifiers to power the bass drivers in both loudspeakers, and another second stereo amplifier to power the treble drivers in both loudspeakers – two amplifiers per two both loudspeakers, but powering different loudspeaker drivers. This is popular because different amplifier types can be used to power different types of loudspeaker drivers. In this configuration, you can match the sensitivity of horns to the delicacy of tubes. You can match the impact of cones to the control of solid-state amplifiers.
In my configuration, for example, two tube monoblocks power the top horns, but one solid-state stereo amplifier powers the lower cones. Therefore, my ideal set-up is a combination of Monoblock and Horizontal bi-amplification. Sounds complicated in theory, but it is simple in practice. Trends has drawings on their site showing each variation. Even the drawings make it look more complicated than it is. Remember, this is passive bi-amp'ing to the existing loudspeaker cable binding posts, not active bi-amplification, with active crossover units and direct connection to the loudspeaker drivers. The purpose of all these extra amplifiers, connections and wiring is two-fold. First, it gives tweaking audiophiles something more to play with on their systems. Seemingly endless combinations and swaps are possible. Second, especially with tiny Trends amplifiers, it does improve the sound.
Slightly perhaps, but improved nonetheless. Although wattage is doubled (gasp!) with a second 10-Watt tiny chip amplifier, loudness is not. The improvement doesn't make the bi-amplifier and pre-amplifier bundle sound like a very good 30-Watt integrated amplifier, but it does make a very good 10 Watt one.
The low-cost Chinese separates in the Trends bi-amplifier
bundle make this an excellent
starting point for a small tweaking audiophile system, because you can upgrade
your way in pieces to a more powerful and superlative system. Start here, and
then with Horizontal BI-amplification, add a monster solid-state amplifier like
my Pioneer M-22 for thunderous bass. Next sweeten up the mids and highs with a
tube amplifier like the wonderful Garber or solid ASL AQ-1003* values. Finally,
if even the Russian tube version of the Trends PA pre-amplifier is not good
enough for you, you can add a robust pre-amplifier like the Audio Research LS2B
Mark II, the winner in last year's Preamplifier
Bundled Tonality has slightly better definition than a single TA-10 amplifier. Sub-Bass (10 Hz to 60 Hz) was certainly improved enough to make an appearance. Mid-Bass was slightly tighter. Both of these categories helped balance Midrange. Attack did not seem to benefit from the double-wattage, but Decay did. The bi-amplifiers had richer sound and decay. They had richer tonality and more body. Combined, these capabilities seem to add details to the Inner Resolution. Soundscape categories however, on Big Ole Horn loudspeakers about 20 feet apart, seem no different. These improved capabilities lift the Trends pre-amplifier and the dual amplifier combination to a very competitive level with other far-more larger and costly receivers.
In my own category, Enjoyment, the Trends' tiny bi-amplifier bundle is easily four Blue Notes for above-average. It earns five Blue Notes as being the best Value for the Money.