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The oversized LCD display shows big digits for track number and time, symbols for start, stop and pause as well as a bar to indicate how much of the playing track remains. The earlier concept renderings showed an LED display which is least noisy whilst LCD variants disperse much HF noise. Here Loit needed counter measures in their power supply.
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Beneath the display sit small metal buttons to operate the transport including one to open the massive motorized cover with its integral puck. This aspect of the design was the only one to seem less suave as the motor operating the lid was very loud, similar to the Gryphon Mikado I reviewed for Audio a while back.
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On top are the tubes protruding through holes of the carbon fiber cover. These 6H30 bottles are NOS issue from the Russian Reflector factory and from a time when they weren’t available outside the country because the army used them for radar and geophones. The first export permission was granted to Victor Khomenko, co-owner of BAT. Khomenko dubbed it a super tube and labeled it Balanced Audio Technology. Today it is freely available to all from Sovtek. The ones in the Passeri however still date from the Cold War.
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Here the bulbs are harnessed for the entire analog stage. The signal exits the DAC chip in balanced form whence it encounters two valves in the I/V converter before proceeding to the voltage gain stage which operates in trans-impedance mode. All tubes are biased in class A without negative feedback. Anode current is conditioned by discrete Mosfet stabilizers bolted to the aluminium base.
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There is no traditional back plate. Connectors—XLR and RCA—are sourced from Neutrik and WBT Next-Gen respectively. Unfortunately there is no digital input, a pity! I think that contemporary digital players ought to operate as transport/DAC combination where each half is accessible directly to connect with a file player or computer. I wasn’t the only one to be surprised by this omission. When Srajan was solicited for a review and asked Kam Lup Yoong about it, he learnt that “I fully agree that the trend is towards the media player, USB DACs etc. I saw lots of USB-enabled products over the past few years but only a few with asynchronous USB to know that results weren't optimized. I think the market now sells features instead of returning to our roots of superior sound. As an audiophile manufacturer we wanted to design something really unique, excellent and not just good whose value would last for many years after the customer's initial investment. That's the main reason we didn’t include a USB input when we developed the product. We focused more on getting the sound right. It took us five years of full-time effort to develop our Passeri and its patented active I/V technology breakthrough which shortens the audio signal path to one single stage unlike others which use either passive or opamp IV and mostly need 2 to 3 stages (I/V stage, filter and buffer). But streaming technology is maturing and easier to adapt. We will study the possibility of developing a media player or USB DAC in the future."
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The Passeri’s thick central aluminium plate creates upstairs and downstairs layers, the former for the audio circuitry, the latter for the power supply. The bottom layer has a central toroidal power transformer for the drive and digital section. It connects to four integrated heat-sinked voltage stabilizers and four filter capacitors. In front of them we can see a beautiful big word clock canister from Vectron. Next to it sat the circuit repaired in Holland. The sides house the power supplies for the left/right channel tubes. These supplies are very sizable and exceed those of many power amps. They run on toroidal Plitron power and Hammond chokes. Their voltage is rectified by high-speed diodes and apparently each tube enjoys its very own rectification/stabilization circuit. Close to the front sit four Mosfets as part of the anode and heater voltage supply stabilization. Overall there are many high-quality capacitors and also a DSP NPC SM5847 IC. That's a multi-function digital filter which probably works with the word clock and as an upsampler. Here also is the digital output board with small but quality isolation transformers.
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On the upper storey we get two boards for the audio circuits to reduce cross talk to a claimed -115dB. Each PCB has Teflon sockets with gold-plated tube contacts. The outputs are coupled with two very big custom capacitors per side. The I/V circuit exhibits Wima capacitors and Dale precision resistors. Most active parts have their markings removed including the two DAC chips. The only remaining markings were on the big Burr-Brown ISO154 chips. Those are high-class optical isolators to separate the drive from the DAC chips. The DACs are 24-bit eight-times oversampling parts of unspecified identity. Because the NPC digital filter is often used in conjunction with Burr-Brown's PCM1704 this also could be the case here. Either way this circuit appears to be very well executed.
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The center is reserved for the Philips CD-Pro2 LH transport, one of the best Redbook-dedicated parts remaining (CEC makes an equally good one). This drive mounts to a solid stable substrate via four AlphaGel soft silicone washers to decouple vibrations, similar to how Nagra did it for their CDC. Although the original Lebedev concept envisioned a custom metal remote, what ships now is the same standard wand Ancient Audio supplies.
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opinia @ highfidelity.pl |
Technical Data (according to manufacturer):
Output voltage: 2/4Vrms (RCA/XLR – 2=hot)
Channel separation: 115dB (1kHz)
SNR: >100dB (‘A’weighted
Total harmonic distortion:0.008%
Power consumption: 170W
Dimensions: 495 x 398 x 146mm
Weight: 16kg |
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