Gain is required after the DAC because of the custom nature of the UltraAnalog parts used in the VTL converter. A stock UltraAnalog DAC D20400 (as used in the Stax DAC-X1t) puts out 5V at full level,…
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The VTL converter uses two 6201 dual triodes per channel, which is a military version of the 12AT7WA. The four triode elements per channel provide gain after the DAC, perform active de-emphasis, and form an ultra-low–impedance totem-pole cathode-follower output driver. One of the 6201s is also used in the fourth-order Chebyshev anti-imaging filter, of which two poles are passive, two active.
The treble was exquisitely smooth and free of edge. Cymbals had more of the delicate quality of brass being struck, with their harmonic structure intact, rather than sounding superimposed on a layer of whitish grundge. The treble grain that often obscures musical detail in CD playback was noticeably absent, allowing the listener to hear the wealth of nuance at the lowest level of presentation. Similarly, sibilance was not spitty and annoying, as it often tends to be from CD. Instruments' high-frequency harmonic characters seemed natural, utterly free from stridency or edge. The brittle…
Sidebar 1: Specifications
Description: Two-channel, tubed D/A converter. Tube complement: four 6201. Inputs: three S/PDIF on RCA or UHF jacks. Outputs: unbalanced on RCA and XLR jacks. Sample rates handled: 32kHz, 44.1kHz, or 48kHz. Resolution: 20 bits. Dynamic range: 112dB. Filtering: 8x oversampling.
Dimensions: 19" W by 2 5/8" H by 10 3/8" D.
Price: $7000 (1990); no longer available (2009). Approximate number of dealers: 25.
Manufacturer: Vacuum Tube Logic of America, 4774 Murrietta, Suites 9 & 10, Chino, CA 91710. Tel: (909) 627-5944. Fax: (909) 627-6988. Web: www.vtl.com…
Sidebar 2: Review System
The VTL D/A converter was auditioned in my usual reference system: Hales System Two Signature speakers driven by VTL 225W Deluxe monoblocks via 3' runs of bi-wired AudioQuest Clear cable. Level control and matching between processors under audition were through the Electronic Visionary Systems Stepped Attenuator, while interconnects were Expressive Technologies IC-1 (Stepped Attenuator to power amplifiers) and Music Metre (processors to Stepped Attenuator). The VTL was driven by the Esoteric P-2 CD transport (reviewed in this issue) and with a 48kHz signal from a…
Sidebar 3: Measurements
The VTL's output level when decoding a 0dB, 1kHz signal was 3.26V (left channel) and 3.22V (right channel). This is 4.2dB higher than the standard 2V output for a full-scale signal. Frequency response was flat (fig.1), down just 0.2dB at 20kHz. Note also that the right channel is about 0.1dB lower in level than the left. Fig.2 shows the VTL's de-emphasis error. This plot is actually the decoder's frequency response when playing an emphasized test signal, but since the VTL's frequency response was flat, this graph represents only errors in the VTL's de-emphasis…
When I first heard the Eagle 2 at the 1985 Winter CES I knew this amplifier was a winner. I was eager for a chance to get my hands on it, but I also knew that J. Gordon Holt was champing at the bit to do the same. So it came as both a surprise and a delight when ye Gracious Editor gave me first crack at the Eagle 2. I wasn't disappointed; the little Eagle more than lived up to expectations. It's not the best power amplifier I've ever heard, but it's damn good. It is, in fact, better than its big brother, the Eagle 7A, in significant ways; in view of the 2's reasonable price, that's saying a…
J. Gordon Holt commented on the Eagle 2 in August 1985 (Vol.8 No.4):
In view of the fact that I have adopted the Eagle 2 as my current "reference" solid-state amplifier, I feel compelled to comment on several points in Steve's report.
High end: I found this as smooth, open, and airy as that of any amp I have heard, but without the slightly closed-in quality of the better tubed amps.
Middle range: Through even the most revealing and detailed of speakers, I have yet to hear the Eagle 2 sound "electronic." The "up front" quality that SWW observed—a little greater in degree…
Sam Tellig commented on the Eagle 2 in September 1985 (Vol.8 No.5):
This is the John Iverson Electron Kinetics Eagle 2 amplifier—what a mouthful! I gather the amp is already something of a legend, like Iverson himself. Of the many Iverson stories circulated at CES, I like best the one where Iverson walks into a dealer carrying both an Eagle 7A and an Eagle 2 amplifier. He balances the 7A (110 lbs!) on his knee to free up a hand for a shake. Now that's the way to get undivided attention.
This $895 amp is tidy and compact, not bad looking, but a little strange in appearance. I…
Sidebar 1: Specifications
Description: Monophonic tube amplifier with push-pull output stage. Tube complement: two 12AX7, two 12AU7, four KT88. Maximum output power: 40Wpc in triode mode (16dBW into 8 ohms, 70Wpc in ultralinear mode (18.45dBW into 8 ohms), both at 2% THD. Frequency response: 10Hz–100kHz, ±3dB. Input impedance: 100k ohms. Output impedances: 2, 4, 8 ohms. Signal/noise: >84dB unweighted (no reference level given). Total harmonic distortion: <0.25% at 1W, 2% at rated power.
Dimensions: 15.2" (385mm) W by 8.3" (210mm) H by 15.9" (405mm) D. Weight: 63.8 lbs (29kg).…
Sidebar 2: Associated Equipment
Analog Sources: Thorens TD-124 Mk.II turntable; EMT 997 tonearm; Shindo SPU, Ortofon SPU 90th Anniversary, EMT OFD 25 & OFD 65 cartridges.
Digital Sources: Sony SCD-777ES SACD/CD player, HRT Music Streamer+ USB DAC (with Apple iMac).
Preamplification: Auditorium 23 Hommage T1 step-up transformer, Shindo Masseto preamplifier.
Power amplifiers: Shindo Haut-Brion & Corton-Charlemagne monoblocks.
Loudspeakers: Audio Note AN-E/SPe HE, Wilson Audio Specialties Sophia Series 2.
Cables: USB: Belkin Pro. Interconnect: Audio Note AN-vx, Shindo…