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I used DRA Labs' MLSSA system and a calibrated DPA 4006 microphone to measure the Triangle Signature Delta's frequency response in the farfield, and an Earthworks QTC-40 for the nearfield and spatially averaged room responses. My estimate of the Signature Delta's voltage sensitivity was 91.8dB(B)/2.83V/m, which is both much higher than average and basically agrees with the manufacturer's specification of 92dB. The Triangle's electrical impedance and electrical phase angle are shown in fig.1 (solid and dashed traces, respectively). The Delta is a much kinder load…

The original Tempest, produced through the end of 1986, was reviewed by John Atkinson in Vol.9 No.6. As a result of using Mike Moffat as a consultant, however, CAL introduced some changes in early 1987, mainly relating to improvements to waveshapes and to power-supply noise levels in the digital sections. The new Tempest is not designated differently from the original, and costs $2095. An upgrade from original to current can be had for the difference in their prices ($200). CAL has also introduced a less-expensive, 16-bit…

The bulk of the test data relates to the original Tempest. As regards frequency response (fig.1), this deck was less flat than most; not only does it have the usual Philips 14-bit system HF ripple, which imparts a subtle but identifiable sonic signature, it also showed a hint of treble lift (+0.2dB) by 20kHz, coupled with a 1dB droop in output by 20Hz (into the 11k chart recorder load) due to the finite size of its output capacitors. In consequence, input impedances in the 50k–100k ohm range are recommended to help maintain good bass extension. 100k loading…

When I reviewed the VTL 225W Deluxe Monoblocks in January 1990, I concluded that they were the most musically satisfying amplifiers I had ever heard. Despite the intervening years and products, the 225s still do it for me. They have an unparalleled midrange liquidity, harmonic rightness, and a detailed yet unfatiguing presentation. After reviewing other amplifiers—many superb in their own rights—it is always a joy to return to the special qualities that make the 225s so musically compelling.

With the…

I'll begin the measurements with the EL34'd 225s, and save any comparisons with the KT90 version for the KT90 measurements section.

The EL34'd 225's output impedance was just under an ohm across the band, measuring 0.97 ohms at 20Hz, 0.89 ohms at 1kHz, and 0.79 ohms at 20kHz. This is a moderate value for a tube amplifier, but high in relation to most solid-state amplifiers. For comparison, the VTL Compact 160 reviewed in August had a very high output impedance of about 1.5 ohms at 1kHz in triode mode and 2.2 ohms in pentode mode. The 225's high…

Looking next at the 225's behavior with the KT90 output tubes (a different amplifier sample), there were a few differences compared to the EL34 version. I'll note these differences when they are significant.

Output impedance with the KT90s was virtually identical, measuring 0.95 ohms at 20Hz and 1kHz, decreasing to 0.87 ohms at 20kHz. Input impedance, though still fairly high, was much lower than the EL34'd 225's input impedance of 129k ohms at 74.5k ohms. Input sensitivity was 1.63V, about half a volt more being required than the EL34 version to be driven to clipping. Since the…

If anyone is still around who hasn't been reading their back issues of Stereophile religiously, the California Audio CD player ($1895) uses tubes—without overall negative feedback—for all of the analog circuitry. It uses triode class-A tube stages, operating in dual mono, for current-to-voltage conversion rather than IC op-amps. It also uses passive filtering for output-waveform reconstruction within the tube analog section, instead of the active low-pass networks used in other players, and uses passive de-…

With the Cambridge Audio CD-1 ($2500), one never knows if one is hearing the final version of this elite and nearly total rebuild of the Philips Model 104, or even if there ever will be a final version of this player. I should point out, however, that Cambridge is now being imported by Sumiko—one of the best and most demanding importers—and hopefully will now be both consistently reliable and available in the form of a stable and finished product.

The two units I have heard so far avoid the treble edge and…

After prolonged listening, I've concluded that there is simply too much bass on the MCD Pro. This is a problem that's not immediately evident, and will affect you differently depending on your system. For systems with true low-bass response, such as the RS-1Bs or Quads with Janis subwoofers, there will be a definite problem. Not only that, the quality of that bass is somewhat loose, though not nearly as uncontrolled as the bass on the original Meridian MCD. In spite of its other virtues, I must modify my…

The new 16-bit-with-oversampling version of the $999 Mission CD player is more dynamic, with better bass, and a deeper, more open soundstage. Nevertheless, in my opinion the better modifications of the machines using the original Philips 14-bit process are still better-sounding in virtually every respect, the Mission having a touch of the 16-bit sound problems encountered in the Philips CD-650.—Anthony H. Cordesman