Vinyl Asylum: REVIEW: Balanced Audio Technology (BAT) P5 Phono Preamp by Bruce from DC

Model:	P5
Category:	Phono Preamp
Suggested Retail Price:	$2000
Description:	vacuum tube phonostage
Manufacturer URL:	Balanced Audio Technology (BAT)
Manufacturer URL:	Balanced Audio Technology (BAT)

Review by Bruce from DC ( B ) on November 01, 2002 at 07:58:14
IP Address: 207.91.86.5

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for the P5

If you measure value in electronics by weight or by the numbers of tubes, this is a screaming value. It also happens to sound very, very good.

What it is

The VK-P5 is a vacuum tube phonostage that is fully balanced and uses 10 -- count 'em, 10 -- vacuum tubes to do its job. It appears to be dual mono construction, from the power cord input forward. It has one pair of XLR outputs and a pair of RCA inputs. On the circuit board are a number of handy features: switchable gain, DIP switches for adjustable resistive and capacitive loading, trim pots to compensate for uneven L-R cartridge output and a handy plug and pin arrangement that allows you to place varying amounts of inductance in series with the input and capacitance to ground to make your own RFI filter by trial and error, if you need that. The plug and pin arrangment involves soldering the leads of the inductors or capacitors to small gold pins; then you plug the pins into corresponding "sockets" on the circuit board. This way, soldering is done away from the board. Build quality is exemplary; the unit is big and heavy. Despite the large number of tubes, the P5 does not produce as much heat as my Krell KAV-300i transistor amp when it's working at moderately loud levels. The P5 has a soft-start circuit that means you wait about a minute between to get sound after you turn on the power. When the unit has been running 1/2 hour or more it seems to sound a bit more "liquid" than when first powered up; the difference is very subtle.
Recently, I bought an Equitech balanced power supply/isolation transformer. This seems to increase the already excellent "dimensionality" of the P5's playback; but the effect is subtle.

Sound

With the Beta S MM cartridge, the sound is excellent. I would characterize it as neutral, so if you're looking for a "golden glow" quality commonly associated with classic tubes, this is probably not for you. To the extent that the P5 has a sound, I would say it delivers the full impact of transients, both large and small; it has very extended, but controlled bass; and it "reaches in" and brings you the smallest nuances of the recording, in that sense, giving you more "detail." The sonic presentation is not like a canvas stretched between your two speakers, but more like a 3-dimensional model where instruments and voices have distinct placements, both left and right and front to back.

In my system, this replaced the venerable and well-known Lehman Black Cube. While the 'Cube has no apologies to make at its price point, the P5 is a definite step up. Here are the differences: (1) while their octave-to-octave balances is otherwise indistinguishable, compared to the 'Cube, the P5 appears to have a bass "lift" of 2-3 dB below about 40 Hz; (2) the P5 delivers more low-level detail that is simply lost to the 'Cube, (3) with this cartridge (3.5 mv output), the 'Cube, even though it has less gain (at its low setting), can be audibly overdriven into distortion by record passages that do not cause a similar distortion with the P5, (4) the 'Cube delivers more than a 2D soundstage, but conveys only an approximate sense of depth; the P5 is a more precise, 3D rendering, (5) the P5 is, overall, more dynamic sounding than the 'Cube.

As some of you may recall from earlier posts, I live in a very high RFI environment; about 1 Km or less from a TV transmitter tower. This affects all kinds of electronics in my house, and has made phono playback a real challenge. With the inductors and capacitors supplied by BAT, I was able, through trial and error, to make an input filter that removed the TV stations' audio from my phono playback. This is the first phonostage that I've had that has managed to do this. On the lower gain setting, with the volume set for loud playback in my room (85 dB average), noise is audible only with your ear within less than a foot of the speaker.

There still seems to be some "self-noise," with inputs shorted, that may have something to do with an interaction between the P5 and the Krell KAV-300i, because it is independent of the P5 gain setting (the 'Cube suffered from the same problem, which is why I possibly attribute the problem to the Krell). However, with the Beta S MM cartridge, this "self-noise" is not an issue.

The only caution that I would mention is that my attempt to run this with a low output moving coil (Dynavector Te Kaitora; 0.25 mv) was unsatisfactory, despite being able to switch select the right cartridge loading. With only 58 dB of maximum gain from the P5, the result was not acceptable. Even though, using the volume control on the Krell, I could get sufficient loudness, the sound was anemic -- and there also was the noise (60/120 hz hum/buzz) issue. So, my suggestion would be to get a step up transformer or head amp if you want to use a low-output moving coil cartridge with this preamp. Given the difficult RFI environment that I have (and the reputation of some step up transformers as "hum magnets") and given how wonderful this sounds with the Clearaudio MM cartridge, I decided not to throw more money into this effort; but, rather, to sell the Dynavector (which I had bought used anyway). With over $1000 invested in the Dynavector, increasing that by 50% or more to get a good head amp or step up transformer, just seemed disproportionate compared to the level of expenditure on other components in my sytem.

The P5 occupies a middle place in the price structure of phonostages. It's too expensive to be in the sub-$1000 "giant killer" category with such products as the Black Cube and the Phenomena. But it's too cheap to be in the "statement product" category. (BAT's P10SE, at more than twice the price is that company's "statement product" for vinyl) This is a very musical-sounding combination. In my case, I was looking for a definite step up from the 'Cube and the P5 is most definitely that. And, in the event that this review comes off as too clinical, I think the entire vinyl setup now sounds really good as good or better as any I've heard in my limited experience. I know that moving coils are supposed to have that "special magic" but I would very highly recommend this Clearaudio Aurum Beta S (MM)/ P5 combintation.

Product Weakness: not enough gain for low output moving coil cartridges (.25 mv)
Product Strengths: macro and micro dynamics; bass; 3-D soundstage; "natural" presentation; flexible and adjustable

Associated Equipment for this Review:
Amplifier:	Krell KAV-300i (integrated)
Preamplifier (or None if Integrated):	none
Sources (CDP/Turntable):	VPI HW-19 Mk 3; JMW-10; Clearaudio Aurum Beta S
Speakers:	Joseph RM-7si signatures; Mirage BPS-150 sub
Cables/Interconnects:	Goertz Triode quartz; micropurl AG; DH Labs speaker wire
Music Used (Genre/Selections):	classical, jazz, rock, musical theater
Room Size (LxWxH):	15 x 20 x 11
Room Comments/Treatments:	bookshelves on 2 walls; rug, upholstered furniture
Time Period/Length of Audition:	10 months
Other (Power Conditioner etc.):	Equitech -ET2RQ
Type of Audition/Review:	Product Owner

Product Weakness:	not enough gain for low output moving coil cartridges (.25 mv)
Product Strengths:	macro and micro dynamics; bass; 3-D soundstage; "natural" presentation; flexible and adjustable