Classé's new CP-800 preamp is less expensive, yet significantly more well featured than its predecessor the CP-700. In fact, it has more features than any dedicated two-channel preamp we have ever encountered!
For starters, it has digital, as well as analogue inputs and, of these, two are USB connections; one in the front panel for your Apple device and another on the back for a computer. Then it has five output channels with which to incorporate a second system or extra power amps and subwoofer(s) and that's only the connections.
Inside the sleek aluminium casework it's stacked with technological firepower, including bass management, so that you can optimise low-frequency performance almost regardless of where speakers are placed and parametric EQ.
If that weren't enough it also has something we've not seen on a high end preamp since the seventies; tone controls. All this with barely a button in sight thanks to a 16:9 touch screen.
The most controversial thing about the CP-800 however, is that Classé head of sales, Dave Nauber, claims that his iPhone sounds better through it than any CD transport. The front USB extracts a digital stream from your iDevice but that is fighting talk in our books.
When HFC met Alan Clark, the Scotsman who designed it (and the rest of the Classé range), he wasn't quite so bullish but did claim that the USB input could outperform the S/PDIF – which is pretty controversial itself. Alan has come up with a variation on the USB receiver, which he claims is superior to all the alternatives on the market.
He accepts that the asynchronous route chosen by increasing numbers of serious USB DAC-makers is better than the synchronous approach found in more affordable convertors, but has added a twist which is said to make the CP-800 a world-beater with this computer audio link.
Clark calls regular asynchronous USB interfaces 'non-optimal' because the ground noise that is inevitable with computer sources pollutes the clock and the DAC in the receiver. His solution to this has been to add an FPGA (field programmable gate array) between the USB microcontroller/receiver and the DAC, as a means of isolating both it and the audio clocks within the preamp.
The USB receiver has its own clock but it's impossible to fully isolate this because the noise levels are very high within the chip, The FPGA recovers only the data from the incoming signal and uses the precision clock within the CP-800 in order to minimise jitter.
The preamp also has an unusual power supply (PSU). One reason why it costs less than its predecessor is that the PSU is onboard rather than being in a separate box, but that's not the only difference. The CP-800 has a switched-mode PSU that operates at very high frequencies, which its claimed makes it less noisy than traditional linear supplies. It also makes it more efficient (as is usually the case) and this product hits the EU target of sub single-watt power consumption in standby.
Classé also uses power factor correction, which maintains a constant load on the mains. As a result it should benefit other components in the system, because they are not having to deal with a fluctuating mains supply. We would expect a power amp to modulate the mains, but were surprised that this is also considered an issue with preamps where power requirements cannot be that great.
Unusually for such a complex product, PCB layout is done by a lady called Cheng, who Clark describes as the world's most patient electronics designer, because she does it all by hand. This is because auto-routing cannot achieve the results that are possible when the effects of each component in a multi-layer board are taken into account.
As a result the motherboard on the CP-800 does not look as neat as you might expect, rather it has an organic appearance because signal paths need to be kept away from the noisier elements in the circuit.
The CP-800 is superbly built; Classé knows how to put a product together and how to finish it better than most. Many build heavier, shinier and more bolt-laden products, but few highend companies are able to execute their products to this standard.
It is also replete with inputs, 15 in total including balanced and unbalanced analogue in and outputs, all the usual variations of digital input and the 12-volt trigger outputs beloved of North American manufacturers. There's even an RJ45 Ethernet socket which will allow the preamp to stream content directly when a future software update is made available.
No comments:
Post a Comment