Fosgate Signature Phonostage Preamplifier & Fozgometer Azimuth Range Meter
I first became aware of the Fosgate Signature Phonostage when I visited the Musical Surroundings room at CES 2010 and my eyes came to rest on the beautifully finished and sculpturally attractive all-tube phono preamp. If, at that moment, you had asked me to guess the preamp’s price based on looks alone I would have said in the $4k–$5k range; thus, it came as a pleasant surprise to find that it cost “only” $2500. The Signature Phono Preamp was designed by Jim Fosgate and is manufactured and distributed by Musical Surroundings (leveraging the firm’s successful efforts at building its own Musical Surroundings-branded series of phonostages).
Still, $2500 is a major sum to invest in any audio component where I come from, which raises a key question. Is the Fosgate significantly better than today’s best phonostages in the $1k price range (a product category I know well and deeply appreciate)? The short answer is that it is, and in ways that are satisfyingly self-evident from the moment your stylus first touches the record grooves. Before talking about the Fosgate’s sound, though, let me explain some of the technical highlights of the preamp.
In the Signature One’s Owner’s Manual, Fosgate says that, “all amplification is accomplished with the SRPP (push-pull) configuration for the best possible linearity, lowest noise, and distortion. No solid-state devices are placed in the signal path and a tube is used for the high voltage rectifier.” The acronym SRPP stands for Shunt Regulated Push Pull—a circuit topology that, according to Garth Leerer of Musical Surroundings, “was first patented in 1940 by Henry Clough of Marconi,” and has appeared in many forms and under many different names since.
Leerer says the SRPP configuration has at times been used for small power amplifiers and is known for its ability to deliver current “into heavy capacitive loads.” One noteworthy aspect of the SRPP configuration is its elegant symmetry, which Fosgate describes by saying that the circuit “uses two triodes, (where) each triode is biased the same. The lower triode acts as a common-cathode gain stage with an active load, and the upper triodes acts as a common-anode gain stage with an identical active load. This is about as close to a complementary transistor pair as valves get!”
The Fosgate Signature is a “dual mono” design, with the preamplifier channels “located on opposite sides of the circuit board in near mirror images with dual triodes in a row down the center.” The preamplifier consists of three gain stages arranged as three complementary pairs of dual triodes. The first stage, says Fosgate, “has no NFB (negative feedback) to interact with the cartridge,” while “the second and third stages are enclosed in a single feedback loop incorporating both positive and negative feedback.” The preamp provides gain switches with settings that “provide a gain of 60dB or 42dB,” while a cartridge-loading knob provides settings from 100 ohms to 100k ohms. Input capacitance is a very low 50pF.
Fosgate says that the preamplifier’s RIAA network “is divided into two sections, one passive and one active.” The high frequency RIAA EQ (above 1kHz) “is accomplished with a passive network between stage one and two.” In turn, the lower frequency RIAA EQ (below 1kHz) “is accomplished with an active network around stage two and three.”
The preamplifier’s power supply is very special, too, though it uses no regulated power supplies at all. Instead, Fosgate has designed the circuit so that “each tube stage is powered by a separate storage capacitor which acts like a battery.” By design the storage capacitors are very large—10 to 20 times “oversize,” says Fosgate—so that the preamp’s power supply “simply holds the voltage across the capacitors like a ‘trickle charger.’” According to Fosgate, “there is absolutely no way for signals to leak from one stage to another through the supply, and the supply voltage on the tubes is rock solid.”
While the technology embodied in the Signature Phonostage is interesting in its own right, what’s even more interesting is its sound.
Let’s begin by noting that the Fosgate offers plenty of gain (60dB) for use with most moving-coil cartridges, yet is also very quiet—exceptionally so for a tube-powered phonostage. Indeed, Fosgate thinks he may have set “the world record for lowest noise with an all tube front end”—a claim I couldn’t verify, of course, but that makes sense given the Signature’s very high apparent signal-to-noise ratio. Low noise buys you several things. First, you’ll note a general sense of, well, lower noise, and second, you’ll enjoy concomitantly greater amounts of low-level sonic information. Thus, through the Fosgate, subtle textural and timbral details suddenly become more whole, complete, and well-integrated.
To appreciate what I mean by this, try listening to Pinchas Zukerman’s violin (and also viola) on Claude Bolling’s Suite for Violin and Jazz Piano [Columbia]. When played at moderate volume levels, Zukerman’s violin exhibits warm sonorities touched with sweetness, with the attack at the beginning of bowed notes sounding crisp and decisive, yet never edgy or “glassy,” as some phonostages tend to render them. And when notes end, you can easily hear the reverberant interplay of each note’s decay fading to silence within the relatively live-sounding recording space. But when Zukerman bears down for a moment of virtuosic flourish, you’ll hear his violin sound become the sonic equivalent of a shooting star—leaving behind a glorious, showering trail of high harmonics and evanescent overtones. In this and thousands of other ways, the Fosgate invites you to fall more deeply under the music’s spell, making complete those details that might have gotten lost with less revealing equipment.
Next, let me say a word or two about the Fosgate’s gain characteristics. Above, I’ve quoted Fosgate’s 60dB maximum gain specification, which is a figure many other phono preamps claim to meet or exceed. But what Fosgate’s number can’t tell you is how much more authoritative and dynamically unconstrained this phonostage sounds, so that it subjectively seems to play louder and with less apparent strain than some phonostages with higher gain specifications (e.g., the PS Audio GCPH). Where some phonostages sound constricted or congested when dynamics become challenging, the Fosgate simply throws back its head and sings at full voice without skipping a beat. Indeed, one almost gets the sense that the Fosgate makes a generous, open-ended offer with respect to high-powered dynamic passages, as if saying to phono cartridges, “If you can track it, I can amplify it, so let’s give this a try…” And lo, the Fosgate makes good on this offer—a quality that may be attributable to the Fosgate’s relative freedom from input overload (with many phonostages, as gain goes up, so too does sensitivity to overload).
I don’t think I fully appreciated the Fosgate’s dynamic power and agility until I played the Frederick Fennell/Eastman Wind Ensemble recording of Hindemith’s Symphony in B Flat (for concert band) [Mercury], where bold timbral contrasts and abrupt shifts in dynamic levels are the order of the day. In the symphony’s opening movement, I found the Fosgate could wade into full-on trumpet and percussion swells at one moment, yet shift gears in an eye-blink to cover delicate woodwind and low brass passages. The beautiful part was that, even at full throttle, the Fosgate always managed to preserve the burnished golden sound of the trumpets, the sounds of sharp mallet strikes and skin sounds from the drums, and the initial “ping” and lingering shimmer of high percussion instruments. What came as a revelation was the Fosgate’s remarkable ability to handle large-scale variations in dynamics and overall musical complexity, while maintaining consistently high levels of nuance and detail.
Let me expand on this point. With many components one has the sense of playing music within the constraints of a “zero-sum” game. In other words, detail levels can be terrific, provided that the demands of musical complexity and dynamic are low. Or, dynamics can be impressive, provided that the demands for sonic detail are modest and there are not too many musical voices at play at once. But with Fosgate you finally have the opportunity to hear dynamics, details, and graceful handling of complex passages all optimized at once—just as when you hear live music. Together, these qualities give a wonderful sense of freedom, letting you choose whatever music you wish, secure in the knowledge that the Fosgate will neither stumble nor become flustered no matter how complex or demanding the material might be.
Three other positive qualities worthy of mention are the Fosgate’s purity of timbre, its effortless soundstaging, and its neutral (yet thoroughly musical) tonal balance. For a good example of all three in action, try Bill Frisell’s Good Dog, Happy Man [Nonesuch, pressing from Pallas Diepholz, Germany], which offers a lovely marriage of traditional folk/bluegrass instrumentation and Frisell’s “acoustic and electric guitars, loops and music boxes”—all tilted in the direction of gentle, exploratory jazz. I’m particularly fond of the track “Shenandoah (for Jimmy Smith),” which features Frisell on acoustic guitar, guest artist Ry Cooder on electric guitar and Ripley guitar, Viktor Krauss on bass, and Jim Keltner on drums. This is, quite simply, one of those tracks so exquisitely beautiful and intricate you can get lost in it (in a good way), over and over again.
The Fosgate captures the at times very subtle voicing differences between Frisell and Cooder’s guitars (and playing styles), so that there’s never a moment’s doubt as to which player is which. More importantly, it effortlessly nails the ethereal and almost otherworldly lilt of Frisell’s guitar lines, setting them free from loudspeakers to float within the boundaries of an enormous 3-D soundstage. At the same time, the Signature tracks Keltner’s delicate and tastefully restrained percussion work, which gives the song its measured pulse. Down low, Krauss’ acoustic bass lines put a solid yet organic-sounding low-frequency foundation beneath the song, with notes that are appropriately dark, sonorous, and woody, yet taut when they need to be and that bloom in a deep and expansive way. On all of the instruments, you can hear inner details galore, so that the resulting ensemble sound is very accurately balanced, though in no way sterile, antiseptic, or “shrink-wrapped.” On the contrary, the Fosgate is vibrant and full of tonal colors—not because it has euphonic colorations, but because it sounds so utterly natural.
Like many of you, I’m intrigued by the idea—first put forward by our own Jonathan Valin—of using a “truth-to-beauty” continuum to characterize the personalities of fine audio components. Where does the Fosgate Signature fall on this continuum? I’m tempted to say it comes tantalizingly close (much as does Shelter’s magnificent Harmony MC phono cartridge) to landing smack-dab in the middle of the scale. If you twisted my arm a bit, I suppose I would say that it shades (but only just barely so) toward the “beauty” end of the spectrum, which to my way of thinking is almost always the smart way to compromise. But audiophiles seeking that extra “nth degree” of treble resolution that makes “truth-oriented” components sound so accurate should note that the Fosgate ships with “an extra 12AT7 tube that can be used in place of the 12AX7 in position three (V3) to give a slightly more detailed top end.” Personally, I found the Signature’s standard tube complement almost ideal for my purposes, but I encourage you to try the alternate tube to see how its sound matches up with your own tastes.
Is the Fosgate Signature the best phonostage ever? Probably not, given that there are many, many talented designers looking to push the envelope of what’s possible with analog sound, many of whom are developing phonostages more than twice the Fosgate’s price. But is the Fosgate one of the strongest performers available at the $2500 price point? It’s certainly the best one I’ve heard thus far, and by a not-subtle margin—meaning the Fosgate will offer all the performance some listeners will ever need or want. If you’ve wondered, as I sometimes have, if it is really worth the effort and cost to step up from a phonostage in the $1000 range to one at this higher level, the Fosgate provides great sounding answers that add up to a resounding, “Yes.”
Sidebar: The Fozgometer Azimuth Range Meter—A Delightful Accessory for Vinyl Enthusiasts
As many of you will already have discovered, getting the azimuth (or axial tilt) adjustment of your phono cartridge just right is one of the keys to achieving spectacular 3-D soundstages. But how do you know when the settings are right? In the past, you had two basic options: You could check settings by eye and hope for the best, or you could buy a good test record and expensive test gear and go to work. Now, Fosgate’s new Fozgometer provides an ingenious and not too expensive ($250) solution, which is designed to be used in conjunction with The Ultimate Analogue Test Disc [Analogue Productions, AAPT 1].
The Fozgometer is very simple to use. You first go through your normal cartridge set-up routines, making adjustment as needed for overhang and horizontal cartridge alignment, tracking force, vertical tracking angle, and anti-skating (if any). After giving the cartridge about 40 hours of initial run-in time, you are ready to bring the Fozgometer into play.
Begin by plugging your phono leads into the Fozgometer and turning the Fozgometer on, and then play Track 2, Side 1 of The Ultimate Analogue Test Disc, which provides a 1kHz left channel test tone, and observe results. The left (red) signal direction light should come on, and the meter needle should swing upwards on the scale (which is arbitrarily numbered from 0 to 40). Note the readout value. Now repeat the process playing Track 3, Side 1 of the test disk (which provides a 1 kHz right channel test tone) and compare results. This time, the right (red) signal direction light should come on, and, ideally, the meter needle should provide the same readout value as the left channel did. If the readouts don’t match, azimuth adjustment is required.
If the right channel reading is higher than the left, then gently rotate the cartridge clockwise as viewed from the front; or, rotate the cartridge counter-clockwise if the right channel reading is lower than the left. Make very small adjustments and retest until you get readings that are identical—or very nearly so. Voilà, your azimuth settings are now spot on.
SPECS & PRICING
Fosgate Signature Phonostage Preamplifier
Type: Vacuum tube-powered phone preamplifier
Tube complement: Two 6DDJ8, two 12AX7, two 12AT7, and one 6X4 (also includes a spare 12AT7 tube that can be substituted for the 12AX7
Inputs and outputs: One stereo phono signal in (RCA), one stereo analog out (RCA)
Gain: 42 or 60dB
Loading options: 100 ohms, 300 ohms, 500 ohms, 1k ohm, 47k ohm, and 100k ohm
Dimensions: 5.625” x 13.187” x 10.75”
Weight: 10 lbs.
Fozgometer Azimuth Range Meter
Type: Analog azimuth adjustment meter
Inputs: Stereo phono signal in (RCA)
Indicators and controls: On/off switch, analog meter (needle type), signal direction lights (left/center/right)
Dimensions: 3.25” x 6.5” x 2.375”
Weight: Not specified
5662 Shattuck Ave.
Oakland, CA 94609
Analog: Nottingham Analogue System Ace-Space 294 tonearm/Space 294 turntable; PS Audio GCPH and Sutherland Ph3D phonostages.
Digital: Musical Fidelity kW SACD player, Rega Isis CD player.
Amplification: Musical Fidelity kW500 and Rega Isis integrated amplifiers; NuForce P-9 preamplifier and Reference 9 v.3 Special Edition monoblock amplifiers
Speakers: YG Acoustics Carmel loudspeakers.
Headphones, etc.: HiFiMAN EF-5 headphone amplifier; Beyerdynamic DT-990, HiFiMAN HE-5LE planar magnetic, and Shure SRH-840 full-size headphones.
Cables: Furutech Alpha Reference and NuForce Focused-Field signal and interconnect cables; Furutech Alpha Reference power cables.
Power Conditioner & Acoustic Treatments: PS Audio Power Plant Premier power regenerator and Soloist in-wall power conditioner, RGPC 1200 power conditioner; Auralex Studiofoam and RPG B.A.D. (binary amplitude diffsorber) acoustic treatment panels.
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