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The German company AQVOX Audio Devices has produced an innovative moving-coil/moving-magnet solid-state phono preamplifier, the Phono 2Ci, that's as intriguing for its technology and performance as it is for its relatively low price: $1400. The zero-feedback, op-amp–free circuit uses a compact switch-mode power supply that's built into the chassis and features conventional voltage gain for moving-magnet cartridges via its RCA jacks, and current gain for moving-coil cartridges through the balanced XLR inputs. Rear-panel switches select between RCA or XLR inputs and offer a convenient ground…
Sidebar 1: Specifications
Description: Solid-state MM/MC phono preamplifier with voltage-gain and current-gain inputs and switchable subsonic filter. Gain: 49–68dB (RCA input), 55–75dB (XLR input). Input loading: 100 ohms, 1k ohms, 47k ohms in paralle with 47pF, 94pF, 147pF, 267pF, or 515pF (RCA input); 10 ohms (XLR input). THD+ Noise at 1V output: 0.009% at min. 0.04% at max. (MM, RCA input); 0.019% at min. 0.09% at max. (MC, RCA input). S/N Ratio (ref. 1V output): 76dB unweighted/84dBA at mininimum gain, 63dB unweighted/71dBA at maximum gain (MM, RCA input); 69dB unweighted/78dBA at…
The last time I was in England, I happened to be rummaging through some boxes in my mother's garage, boxes containing photographs, my old school books, concert programs, diaries, postcards—all the bric-a-brac you collect throughout your life that you'll never have a need for and can never discard. If anything, such rubbish is perhaps the nearest thing to roots that anyone can have these days. Among the boxes was an amplifier that had been an everyday companion of mine for many years, the vintage Vox AC100 I had used to amplify my Fender bass when on the road.
Nowadays, musical…
Regarding the output transformer itself, rather than supply a number of secondary taps, for example labeled "2," "4," "8," and "16" ohms, VTL's David Manley prefers to provide the 100W mono with just one, hardwired to the output terminals and set to a nominal 7.5 ohms impedance (footnote 5). The reason is eminently sensible: with conventional multiple taps, the negative feedback taken from the secondary will only be optimum for one tap; for the others, a small series impedance will exist between the amplifier's output terminal and the point where the feedback signal is derived. The back EMF…
Sidebar 1: Specifications
Description: Monoblock tube power amplifier: nominal rating: 100W RMS into 8 ohms. Output impedance: 1.1 ohms at 1kHz (standard factory output transformer tap). Distortion at rated power: 0.1% Harmonic, 0.1% IM. Input impedance: 137k ohms. Sensitivity: 775mV RMS for rated output. S/N ratio: 90dB (unweighted), 96.5dB (A-weighted). Tube complement: 12AT7/ECC81/6201 input, 12AT7/ECC81/6201 phase splitter, 4xEL34 output.
Dimensions: 13" W by 9" D by 7" H. Weight: 42 lbs.
Price: $2650/pair (protective cover grids cost $60 each), 1988; no longer available, 2008…
Sidebar 2: Review System
The preamplifier used with the VTL Compact Monos was mainly the Krell KRS2 but also the Van Alstine Super PAS; loudspeakers were the Celestion SL600s and Celestion SL700s, used on their appropriate stands, and the Acoustic Energy AE1s; source components included my stock Revox A77 for master tape replay, CD players from Sonographe, Precision Audio, and Meridian, and the fully loaded Linn LP player (Sondek/Ittok/Troika) sitting on a Sound Organisation table.
My reference power amplifier was a 1986-vintage Krell KSA-50, it proving impossible to wrest the…
Sidebar 3: Measurements
On the test bench, you could have been forgiven at first for thinking that this VTL was a solid-state design, the small-signal frequency response (1V into 4 ohms) extending from 2.2Hz to 77kHz (–3dB). Noise levels, too, were impressively low, measuring –90dB, unweighted, with the input shorted, this improving by just over 6dB when an A-weighting network was switched in circuit ahead of the meter.
Looking at the output impedance, however, revealed the amplifier's thermionic nature, with a value around 1.1 ohms at 20Hz and 1kHz rising slightly to 1.25 ohms…
Recently, I got an e-mail from a colleague at another audio magazine complaining about the paucity of new SACD hardware. We've been hearing about the slowing pace of new SACD releases, and about Sony's neglect of a format they themselves developed, but I now realize that, apart from the High End (footnote 1), machines that can play SACDs have been fast disappearing from the middle of the market. When the battle of SACD vs DVD-Audio was raging, universal players that could play both formats were available from almost every major manufacturer. Even John Atkinson jumped on the bandwagon,…
With its more substantial construction, superior analog outputs, and reasonable price of $499, the Pioneer DV-58AV is an outstanding candidate for a keeper legacy universal player. Others will have to comment definitively on the values of its video performance, but I found it no slouch in that department either.
Bag End E-Trap
Although acoustically treating your listening room may the most important thing you can do to make your system sound its best, everyone seems to have a reason not to do it. I understand. Décor and significant others usually stand in the way, but also imposing…
Sidebar 1: Contacts
Bag End Loudspeakers, 22N272 Pepper Road, Lake Barrington, IL 60010. Tel: (847) 382-4550. Fax: (847) 382-4551. Web: www.bagend.com.
Oppo Digital, Inc., 2629B Terminal Boulevard, Mountain View, CA 94043. Tel: (650) 961-1118. Web: www.oppodigital.com.
Pioneer Electronics USA, P.O. Box 1540, Long Beach, CA 90810. Tel: (800) 746-6337. Web: www.pioneerelectronics.com.