Description: Remote-controlled line-stage preamplifier. Maximum gain: 18dB. Output impedance: 150 ohms balanced, 49 ohms unbalanced. Input impedance: 10k ohms unbalanced, 20k ohms balanced. Frequency response: DC–100kHz ±0.05dB. Distortion: <0.002%. Signal/noise ratio: –118dB. Maximum output: 24V RMS. Sensitivity: 350mV for 3V output at 1kHz.
Dimensions: 17.6" W by 14" D by 3.5" H (preamp); 8.75" W by 12" D by 4" H (power-supply).
Serial numbers of units reviewed: 11389 (preamp), 11379 (power supply).
Prices: $5250 in black, $5350 in "silver pewter" (…
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Sidebar 1: Specifications
Sidebar 2: System
Analog sources in my large room included the Fanfare FT-1 and Magnum Dynalab Etude tuners; VPI TNT Jr. turntable with Power Line Conditioner, tripod pulley system, and an outboard flywheel on a Bright Star base mounted with the Graham 1.5-T and Clearaudio/Souther TQ-1 tonearms. The VPI HW-19 Mk.IV with Stand-Alone Motor Assembly on a Bright Star J-7 base mounted with a Clearaudio/Souther TQ-1 resides in my small room. Cartridges included the van den Hul MC-1 Super, Dynavector XX-1L low-output MC, Benz L04, Fidelity Research/van den Hul FR-1, Denon 103/van den Hul, and a…
Sidebar 3: Measurements
A full set of measurements was run on the Threshold T2 in its balanced mode, with selected measurements repeated in the unbalanced configuration. Unless otherwise noted, the results below are for the balanced mode.
The output impedance of the T2 at its line outputs measured 314 ohms (70 ohms unbalanced). Its (line) input impedance measured 10.6k ohms (just a little less unbalanced at 10.2k ohms). The above figures are for the left channel at the maximum setting of the gain control; the right-channel results were not significantly different, nor were the…
The Krell KPS-20i (KPS stands for "Krell Playback System") is essentially a CD transport and digital processor in one chassis. What make the KPS-20i different from a CD player are the unit's five digital inputs, which allow the KPS-20i to function as a digital/analog converter for external digital sources.
A CD player offers the potential of giving a similar sound quality for less than the price of a transport and outboard processor combination: with only one chassis, packing carton, power cord, and other items, a CD player costs less to build than a comparable pair of…
The DSP56002 is clocked at a blazing 66MHz, and has more computing horsepower than the DSP56001 used in previous Krell processors. Consequently, a single DSP56002 does the work of two DSP56001s. The digital filter section is located on the main printed circuit board, with the DAC and analog output stages mounted on a board stacked above the main pcb.
The digital-filter output is converted to an analog audio signal by four Burr-Brown PCM63 DAC chips. Four DACs are used for true differential operation: the digital signal is split into positive and negative phases in the digital domain,…
Sidebar 1: RH's System
I put the Krell KPS-20i at the front of my playback system, playing discs on the KPS-20i's integral transport. The KPS-20i also saw time driven by the Mark Levinson No.31 transport via AES/EBU cable, using the KPS-20i as a digital processor. Further, I drove the Mark Levinson No.30.5 (fitted with the HDCD decoder/filter) and the Sonic Frontiers SFD-2 Mk.II from the Krell's digital output to assess the KPS-20i as a transport. Of course, having these superb Class A processors on hand made them natural points of comparison for the KPS-20i.
I found that the KPS…
Sidebar 2: RH's Measurements
The KPS-20i had a maximum output level of 6.6V from the balanced outputs, and 3.3V from the unbalanced jacks. Output impedance was a very low 16 ohms (unbalanced) and 32 ohms (balanced) at any audio frequency. This combination of low output impedance and high output voltage means that the KPS-20i should have no trouble driving any preamplifier or even a power amplifier directly through a passive level control. The review sample had no trouble locking to 32kHz and 48kHz datastreams. The balanced outputs conform to the pin-2–hot standard, meaning that the KPS-…
Martin Colloms reviewed the KPS-20iL in October 1995 (Vol.18 No.10):
The High End is dead? Don't believe a word of it! The High End is alive and kicking—long live the High End! Larry Archibald had it right last January (Stereophile, Vol.18 No.1, p.274) when he said that a worldwide recession does not mean that the High End is in trouble.
It's always been true that fashionable entertainments—from video to computer games, multimedia computers to Home Theater—capture huge slices of disposable incomes. High-fidelity manufacturers may well eye such sales with envy and reminisce about…
Sidebar 3: MC's System
My longstanding one-box reference CD player, the Accuphase DP70-V, was on hand for this evaluation, as was my new reference, the Wadia 16. I also had access to a Krell MD-10/Reference 64 combination and PS Audio's Reference Link driven by the Lambda transport. Other recent digital visitors to my system included the Sonic Frontiers SFD-2, the Theta Generation V/Data Basic 2 combination, and the Audio Research CD1.
Control preamplifier references included the Mark Levinson No.38, Krell KRC-2, Audio Research LS5 Mk.II, Audio Synthesis Balanced Passion passive…
Sidebar 4: MC's Measurements
As a CD player, the KPS-20iL performed very well. It's non-inverting—pin 2 is wired to be positive on the balanced outputs—and has essentially linear phase and zero interchannel phase difference. The Krell's frequency response (fig.1) was essentially flat, lacking the premature HF rolloff of some earlier DSP implementations. With de-emphasis, there was a mild loss of –0.5dB by 16kHz. This will not be very audible.
Fig.1 Krell KPS-20iL, frequency response without de-emphasis (solid line) and with (dashed) (0.5dB/vertical div.).
Channel…