TP 8.0
Tube Phono Preamplifier
"IMO, the [Audio Horizons TP] 8.0 [sMCpn] is the best phono stage that I have used and I have used a number of them from Audio Research [PH3], CJ [Conrad Johnson PV12], Mod Squad [phono drive], Curcio Sarah and [other fine phono stages]."
-Scifi
TP 8.0 Tube Phono Preamplifier

Audio Horizons Superb Tube Phone Stage, the TP 8.13Sc

If you have read the reviews of the Audio Horizons TP 8.0sMCpn in 10 Audio, 6 Moons, and StereoMojo in our Reviews sec tion, then you know it got rave reviews. Now, Joseph Chow introduces an even finer phono preamp, the finest he’s ever designed, the new Audio Horizons TP 8.13Sc, available single ended or in balanced output mode.

TECHNICAL SPECIFICATIONS

RIAA Frequency Response +/- 1dB

Total Harmonic distortion 0.08 %

Signal to noise ratio 85 dB

Channel separation 73 dB

Output impedance 390 ohms

MM gain 40 dB

MC gain 60/66 dB

Power consumption 30 Watts

Tube complement 3 Tesla PCC 88 (6922 type)

Fuse Audio Horizons Platinum Reference 1 amp.

Dimensions 17.5”x 10”x 3 ¾”

Weight 10 Lbs

How good are the Audio Horizons TP 8.13Sc tube phono stage specs? Let’s compare them to two well known phono stages, one a solid state phono stage with a MSRP of $7500 (two and three quarter times that of the TP 8.13Sc) and the second a tube phono stage with a MSRP of $5400 (twice that of the TP 8.13Sc):

Example model: ss Model X tube Model Y TP 8.13Sc

$7,500 $5,400 $2,750

RIAA: +0.5/-0.3 20-20kHz Passive +/- 1 dB

Gain: 50, 55, 60, 65 dB 68 dB 40/ 60/ 66 dB

THD: 0.0042% 0.03% 0.08%

S/N: 65 dB 70 db 76 dB

DESIGN FEATURES

   • All inner wiring uses Teflon silver coated wiring to provide optimum performance for many years, and to protect those who live in environments with high humidity. All gold plated Teflon RCA jacks insure low connector loss and much high signal transfer.

   • RF shielded balance/XLR connectors option eliminates contact impedance, insuring the lowest possible noise floor.

   • A Furutech gold plated IEC.

   • Film caps in the power supply.

   • Choke loaded power supply, smooth out the ripple noise.

   • Choke loaded high transfer ratio, smooth out the ripple noise.

   • Point to point hot wiring in the signal paths.

   • No feedback overall signal path.

   • Selectable 2 tone arms or cartridges in MM/MC by toggle switch in fly

   • RC dampen plug to optimize cartridge frequency response

   • Constant current filament supply and soft start to extend tube life time

   • Silver plated tube socket, tight contact for trouble free operation

Upgrade options:

Mono switch can be add on for mono cartridge.

Available in XLR balanced output mode for an additional cost of $ 450.

DESIGN PHILOSOPHY

Some reviewers have said the TP 8.0sMCpn compared favorably to the much more expensive Manley Steelhead ($7500), arguably one of the finest phono stages around. If that’s true, then given the improvements to the 8.0sMCpn manifest in the TP 8.13Sc we have reason to believe the 8.13Sc is among the very finest phono stages presently built.

The TP 8.13Sc price for the moving magnet (MM) version begins at $ 2,195, and the TP 8.13Sc moving coil (MC) version begins at a surprisingly modest $ 2,750.

Add $239 for the performance chassis, performance feet and rosewood wood sides.

DESIGN PHILOSOPHY

The 8.13 boasts a new improved power supply and an added tube buffer stage with a third tube for added smoothness, textural richness and body and brand new, hadsome slim line cosmetics.

Like the newly designed Audio Horizons TP 2.3 tube preamplifier, the TP 8.13Sc is a superb phono stage at prices a fraction of comparable units. But don’t let our affordable prices deceive you.

Like all of Joseph Chow’s zero feedback designs, these phono stages are very sensitive to cabling and tube complement. Because they are so transparent, different tubes and cables will alter its sonic signature significantly. Obviously, the finer the tube and cable the more the TPS 8.1 and 8.13 will show to advantage.

Specifications, as we all know, are no guarantee of a component’s performance excellence. For example, decay time is difficult to measure and yet clearly it is a significant factor in whether a component captures the slow, evolving lingering notes of a musical phase or not—too fast and the swiftness of the decay dries out the music and robs it of its intangible musical flow, that which defines the intangible superior musicianship of one musician over another; too slow and the music begins to lose its clear edges and the micro-detail that permits us to distinguish one instrument from another. Here, we know that tubes have a slower decay time than solid state equipment, which is why, in some intangible way, for many listeners they provide more musical satisfaction.

Similarly, our instruments for measuring the ability of a component to capture harmonic texture is poor, and yet we know that the ability of a component to capture harmonics—that is, the reedy quality of a clarinet, the brassy blare of horns, or the resinous quality of a cello is indispensable to our musical enjoyment. Again, we know that tubes do a better job of capturing harmonics than solid state equipment, but again, if we could measure this superiority in a satisfactory fashion, solid state manufacturers could have a means by which to know whether they are approaching closer to the goal of excellent harmonics.

For more information on this subject, visit our link to the TP 2.3.

But having said that much that increases our musical enjoyment is hard to measure is not the same as saying that specifications are not good indicators of performance in many areas. Because they are, some manufacturers, even high end manufacturers, will not supply you with these specifications, or they will report the measurement in an unconventional way that confuses the reader and leads him to believe that the performance is better than it is.

For example, we know that signal to noise (S/N) levels are almost infallible measurements of the quietness of a component, of whether the sound comes out of a black silence or not, and hence of its ability to reach in and capture those subtle micro-details that allow us to differentiate one instrument from another in an ensemble. Here, the numbers not only do not lie, they expose nakedly the limitations of the component, which is why they are often omitted by reviewers. For this reason also, many manufacturers do not report these numbers.

You can visit the websites of any number of Stereophile’s A rated phono preamps and search in vain for a S/N spec presented according to a simple standard. When they do show up, they often frame the measurement in language which is indecipherable to a lay person by using an input figure, for example, or that are vague and unclear by not specifying the output voltage. For example, the standard S/N measurement is reported in decibels (dB) taken at 1 volt output (v), so a S/N of -90 dB at 1 volt, could be reported that way or as -90 dBv. Should a manufacturer take the measurement at say 3 volts output, he will gain an additional 9 dB over the figure he would have achieved at 1 volt. For example, -90 dB at 3 volts output is equivalent to -81 dBv. If someone reports -80dB but supplies no other information, we really do not know what that voltage is when measured at 1 volt output.

There are a number of other specifications whose translation into a sonic equivalent is clear enough to be comparative, and thus evaluative--for example, Channel Separation or Crosstalk, Dynamic Range, Total Harmonic Distortion. And these, too, will often remain unreported even in components costing thousands of dollars. Instead a host of other measurements will be reported that are less sonically critical or that have less value to a prospective buyer in making his evaluation.

We at Audio Horizons believe you ought to have all the key specifications presented in a clear and intelligible form so you can compare Audio Horizons components with other components, at least with respect to the sonic and musical performance delivered by that specific parameter.

Let us say a few words about specifications and what they mean:

RIAA is the standard curve used by recording companies when recording, and it is the ability to track this frequency response curve that is critical in capturing the balance inherent in the live recording. Since few transducers—cartridges and loudspeakers--do a very good job above 20,000 Hz, and since below 20 Hz, subsonic noise, such as rumble and other resonances, may show up, phono designers often construct their designs to filter out frequencies below 20 Hz. Thus the frequencies between 20 Hz and 20,000 Hz are most critical. Many tube phono preamplifier manufacturers, even in the Stereophile Class A, do not report this figure. The Manley Steelhead priced at $7500 does and we cite those figures above.

Signal to Noise is one of the areas where tubes are hard pressed to match solid state equipment because of the inherent residual noise level of tubes. In doing a little research for this ad, I reviewed four of Stereophile’s Class A rated tube phono preamplifiers ranging in price from $5000 and up. Here’s what I found: Not one of them reported their S/N figures in a way that included the voltage out or in a way that would permit informed comparison with other phono preamplifiers. Despite that limitation, not one of them reported an S/N figure higher than -85 dB. The most expensive unit reported their S/N to be -83dB. The lowest reported S/N was -80 dB. I also researched a highly regarded Class B unit costing under $1500. Again, the dB figure of -80 was reported without elaboration.

The S/N for the TPS 8.1 and 8.13 in all versions is very high. Compared to a DAC, these specs are nothing to write home about, but for a tube phono preamplifier they are remarkable and audible, delivering a low noise floor rarely found in tube phono preamplifiers. This high S/N figure translates into an extremely quiet, highly resolved and richly textured sound.

Like all of Joseph Chow’s designs, the sound is spacious because the soundstage is wide and deep. This is to be expected given that the figures for channel separation, rarely reported in tube phono preamps, are extremely good. As a result, this phono preamplifier captures some of the superior spaciousness we thought reserved only for digital sources.

In listening to a Joseph Chow design, one is always struck by the lack of compression and the ability of the component to capture the extraordinary dynamic contrasts of live music. Much of this is due to Joseph Chow’s refusal to use feedback. Like his TP 2.3 tube preamplifier and his TD 3.1 tube DAC, this is a zero feedback design. As a result the dynamic range figures approach those found in the TP 2.3, praised so often for its extraordinary dynamic range.

Finally, and this is something someone will notice within a couple of minutes of listening to one of these phono stages, they are all very articulate, with clean, clear but soft musical edges and with a transparency of reproduction rare in any component, let alone a tube phono preamplifier. Again, this is due to Joseph Chow’s ability to coax stellar performance worthy of a solid state design out of tubes and to translate this into low distortion for a tube design.

If you are one of those people like me, with a large collection of LP’s but who finds himself listening to them less because his solid state phono stage sounds compressed and lacking in all those wonderful intangibles that define digital sources, then you really should audition one of these phono stages. It won’t give you everything a digital source will, but it will give you enough of them not to be disappointed by the contrast. And it will preserve all those wonderful analog virtues—soft musical edges, a tendency to caress the notes instead of clip them, and an intangible musical flow that just makes even a dramatic work easier listening than the same piece played over a digital source.