As a final note to the lineup, I shall add that I am aware that some lips may purse at the inclusion of a tatterdemalion T-amp. All I can say is that this tiny tyke was mail ordered all of five years ago as something of a novelty; and that since then it has relentlessly chipped itself into my listening habits to the point that I recently bought it a dedicated KingRex linear power supply. True, the power supply costs as much as the amplifier itself but, hey, we're audiophiles. 

Back to the HPA.The default source for the evaluation was my €14'500 ten-years old still-in-production Nagra CDC spinner (I like to think of it as the Redbook TD 124) which handily doubles as a buffered analogue passive preamp with a separate balance control. In fact, I frequently use it in this configuration. So in the interest of completeness and to avoid the usual sand versus glass face off, I added it to the mix, making this a sand vs. glass vs passive confrontation. Now, as P.G. Wodehouse would have observed, there are many readers so constituted as to scream with excitement at the prospect of blow-by blow-descriptions on some twelve pre/power amp combinations, not counting settings and cable looms. However, since even a serious professional such as Roy Gregory has warned of the burdens involved in preamp comparisons, I shall restrict myself to the setups I actually use: passive on Trends and 300p, hotrod (two tube) PL-P on F5 and 300p, full power (6 tube) PL-P on the TK 2A3. That totaled a manageable five variants in all. Cables were all Van den Hul, unbalanced The First from the CDC's variable output set at 3V, Integration from the PL-P's line or tape outputs and Inspiration power cables biwired to the Tannoy Canterbury HE. The stated Z-out of the HPA is low at some 50Ω, ideally matched to the conventionally high 100kΩ input impedances of all the amps, the partial but unproblematic exception being the Trends' circa 50kΩ while the CDC's and PL-P's outs are equally exemplary at 80Ω and 60Ω respectively. Conveniently, pots on all devices were Alps Blue which neatly eliminated a significant variable. Listening levels were between 75 and (very occasionally) 85dB+, checked by iPhone meter in my large-ish but very reflective room.

As my preferred levels show, I consider low volumes the acid test for any component. This is reflected in the software choices for this particular evaluation: De Rore's archetypal Madrigals and René Jacob's clockwork rendition of the Monteverdi Ulisse while Time and Place by forgotten genius Lee Moses is the exception to the low-level rule. This is a higher volume only grab bag of wonderful R&B tracks and awful recordings, in one instance miked
apparently through a can and piece of string. It's also a powerful testimonial to the ultimate hifi tenet: let the music through and source quality will take care of itself. The first comparison, passive on chip and 300B tube, was hardly perfunctory. In fact these are my default combinations for ease of use and practicality (the CDC's output is remote controlled) and comfort, with winters being cold in Rome and August temperatures altogether unsuited to burning bottles.

It is hardly surprising that the HPA took the Trend's performance to another level though borderline freakish pairings of a €4'000+ upstream component with a €190 amp end up in grotesque mismatches more often than not. Specifically, the HPA gave added grunt to the T-amp while noticeably lessening the Tripath chip's tendency towards simplified tonal shadings and dryish treble. First blood for the HPA over passive then even if in a declaredly less-than-significant combination. On to greater things.