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PW-10.
Since the Tripath chipset is 90% energy efficient, it’s logical to invest a little more in the power supply. Trends fulfills their commitment to complete solutions by offering the PW-10 power supply that can be connected to a basic 3-unit Trends combo i.e. the TA-10, PA-10, UD-10 USB/SPDIF interface (and the future DA-10 DAC). The transformer-based linear power supply is built with the following features according to Trends:
  • Ultra-fast speed ON Semiconductor MUR420 and MUR120 rectifiers to provide the fastest response
  • Rubycon’s top MCZ series and Sanyo OS-CON capacitors for high frequency digital and Nippon Chem’s high-end capacitors for analog
  • High-end National Semiconductor LM-317A (higher precision than LM317) and LM1084 linear power regulators
  • High quality EMI noise filter for high frequency noise induced from the global electricity network

The three supported units can be individually switched on/off from the back and relevant LED indicators will light up on the front where the master power on/off switch is situated. DC voltage is delivered through 20” wires: 12V/3.3A to the TA-10, 5V/0.2A to the UD-10 and 24V/0.42A to the PA-10. Although the three factory-supplied wires are color-coded white, red and yellow, the coax connectors are the same size. It would have been nice to size them differently. Make sure you don’t absentmindedly misconnect any of them. I’d encourage users to formulate their own identification methods or mark the connectors. Better safe than sorry.


Bi-amp assignment.
The new Trends line-up offers huge opportunities to mix & match. I of course couldn’t refuse bi-amping. You could say that it's mandatory for all my Tripath amps. I have a KingRex preamp + T20U bi-amping Klipsch Synergy F2; a Restek Sector preamp + Winsome Labs Mouse bi-amping Mark & Daniel Sapphire; and a Virtue Two bi-amping Mark & Daniel Diamond+. As for the Trends TA-10, I have two bi-amped systems: one with Micromega VarioDrive MicroDAC as preamp driving Loth-X BS1 in D’Appolito array; and another on my daughter’s desktop with a KingRex HQ-1 as preamp driving Mark & Daniel Maximus-Mini. While these systems have their own merits and personalities, the most incredible is the last. Driving Maximus-Minis at 82.5dB/4ohm low efficiency with 15wpc is no laughing matter. But the TA-10s have been doing just that for years gushing out solid bass and high definition sound without coughing or choking. Naturally I volunteered to upgrade this review to become a bi-amp assignment with the new TA-10.2P power amps. But first let’s look at the PA-10 preamp alone.


QC.
It took quite a few months to get a PA-10 that was working properly. The first three units all had problems of a similar kind. The first PA-10 had no sound in the right channel. The second had a very loud hum in the right channel. The PA-10.1D after it had very low output on the left and none on the right. Two were dead on arrival, one developed the symptom after a month. Sometimes its problem could be rectified by switching the input selector back and forth but that cure would only last a few minutes. That raised genuine concerns over quality control. I put that straight to David Ho of Trends Audio. I also mentioned that I’d heard of QC problems with the TA-10 from his Canadian importer who was out of business a few years ago and the fact that I myself had one TA-10 that would only work with its jumpers set to bypass the volume control. David Ho’s swift answer was not just tightening their QC procedure but as a sign of confidence to increase the warranty on all Trends products to 2 years. He shipped me a new TA-10 PCB to replace the one in my malfunctioning amp plus the two preamps he personally checked.


For this review I finally ended up with one PA-10, one PA-10.1D and a bagful of tubes ranging from the Chinese 6N11 and Russian 6H23n to American GE 12AU7 and Japanese HP Toshiba 5963 (12AU7). None of these preamps had off-centre volume knobs. That issue seems to have been licked. The two TA-10.2 P and PW-10 were delivered well before and exhibited no problems whatsoever.


PA-10 + TA-10.2P.
The ceremonial run-in and subsequent audition of the pre/power combo first took place on my desktop displacing the old TA-10 integrated. Even though the preamp was fitted with the basic 6N11, the petite JohnBlue JB3 speakers sounded fuller and broader as though power had doubled. Did it give me that valve bloom like tube amps though? No. The JB3 has always been musical and warm. I simply didn’t get that extra bloom I was enticed to expect. Would the GE 12AU7 add some magic?


The task of rolling tubes proved tedious even for a serious hifi lover like me. I first had to reset the mini jumpers (from 6DJ8/6922 to 12AU7). Then I had to adjust the bias voltage with a digital multimeter. The positive probing point on the PCB is so tiny and slippery that I had to apply just the right pressure and hold the two probes steady with one hand (the negative probe must touch a grounding point like the outer ring of the RCA socket or the metal ring of the power switch neither of which provide for secure anchoring) while the other hand had to hold a mini screw driver to turn the mini screw on the blue mini trimmers. No easy task if you have big hands. And there’s not much space on the board around the probing points. I had to negotiate the best angle to stick the red probe in. The mini trimmers were unpredictable and slow to react too. When the amps first arrived, I had to turn more than a full turn to start getting any response. I wish the bias adjust was automatic. [Special note: the PA-10.1D inherits its user manual from the PA-10 without edit to the bias setting page to correlate with the actual changed PCB silk-screen: potentiometers R3/R13 (L/R channels) of the PA-10 were changed to R5/R6 (L/R channels) on the PA-10.1D].


The GE 12AU7 installed in the PA-10 didn’t exactly turn tables. After ten days of run in and repeat tube rolling that really put my patience to the test, it seemed that the tubes sounded almost if not completely identical. Partly frustrated I decided to let the tubes and myself cool off before I jumped to any conclusion. Regardless the pre/power combo was a warm and musical setup with more potency and resolution than the integrated. It’s definitely not a cold amp. The warmth is basically from the Mosfet in the PA-10 and the Tripath 2024 in the TA-10.2P. The IRF610 Mosfet is largely favored by headphone amp DIYers for its "soft and musical" characteristics. The MJE15030 bipolars I believe are used as tuning devices to blend in a good measure of HF speed and punch. Trends have achieved a very fine nuance and the sound is nicely balanced. Yet the role of the tube is not critical enough to exert any audible effect even though it’s been applied to active voltage gain rather than as unity-gain buffer where you’d perhaps not expect as much.