POLK AUDIO SWA 500 Dedicated Digital Power Amplifier For CSW Series 800W/4Ω 250W/8Ω

Driver Complement
Electrical
Dimensions
Cabinet Size     3-1/2" H x 17" W x 12-5/8" D
(8.89cm H x 43.18cm W x 32.07cm D)
Shipping/Other     
Shipping unit:     each
Total Shipping Weight     14.00 lbs. (6.35kgs)

The 851W has class XD amplification at 200W into 8 Ohms in stereo mode or 500W RMS per amp in mono bridged mode, separate toroidal transformers for the power amp and input/other circuitry, and terrapin impedance buffering modules. All in all it\'s the best sounding amplifier we have ever made.

         Our proprietary Class XD amplification
        Separate toroidal transformers for power amp and input/other circuitry
        Our bespoke Terrapin impedance buffering modules – separating amplifier and signal impedance
        200W into 8 Ohms stereo mode or 500W RMS per amp mono bridged mode
        CAP5 protection from DC spikes, overheating and clipping
                All metal chassis with premium components
        Remote Control – Compatible with the entire 851 range

 Power output – stereo/mono    200W per channel into 8 Ohms
350W per channel into 4 Ohms
Power output – bridged mono    500W 8 Ohms
800W 4 Ohms
THD (unweighted)    < 0.001% 1 kHz
< 0.005% 20 Hz - 20 kHz
Frequency response    5Hz – 80kHz
S/N ratio (ref 1W / 8 Ohn)    >90dB (unweighted)
Sensitivity – stereo or mono    1.5V rms unbalanced
1.5 + 1.5V rms balanced
Sensitivity – bridged mono    0.775V rms unbalanced
0.775V + 0.775V rms balanced
Input impedances    Balanced input 38 kOhm
Unbalanced input 68 kOhm
Power amp damping factor    > 110 at 1 kHz
Max. power consumption    2400W
Standby power consumption    Standby

• MusicCast expands entertainment possibilities
• Streaming services offer a huge range of listening choices
• Enjoy the entire spectrum of all your favorite modern music sources
• 5.6MHz DSD Native and AIFF 192kHz/24bit reproduction with high performance 24-bit D/A converter
• MusicCast CONTROLLER lets you operate from your smartphone or tablet
• Wireless music streaming via Bluetooth® or AirPlay
• Bluetooth Output for convenient music streaming
• USB digital connection for iPod, iPhone, and USB devices
• Pure Direct Mode for greater sound purity
• Digital audio input for TV or Blu-ray player
• Eco Mode and Auto Power Standby

Choosing the DAC

Both our CXA60 and CXA80 amplifiers employ the same Wolfson WM8740 DAC, and thereʼs a very good reason for that: it sounds superb! There are more recent Wolfson DACs in circulation, however none sound quite as great as the WM8740 in our view. Which is why, time and again, we choose them.

The CXA80 utilises two separate windings on the oversize toroidal transformer. In effect, this is like having two toroidal transformers wound onto one chassis, providing separate windings for each amplification module. If you get a huge transient in the right channel, it wonʼt unsettle whatʼs going on in the left. The current is being drawn from a different path, rather than a common path, so the output is stable and remains unflustered, whether your liking is for Little Richard or Lamb of God.

The transistors used by the CXA80 are not your usual common or garden offerings. They come with an integrated Dynamic Thermal Tracking System. So what does this mean? Normally a Power Output transistor utilises a thermo-coupler attached directly to the heat sink of the amp; this informs the system so that it can rebias when key temperatures are reached. However, using Integrated Dynamic Thermal tracking provides a far more accurate reading of the real temperature of a transistor, and relays it faster too because itʼs not a delayed heating effect. This enables us to bias the amplifier more accurately and in almost real time. Which means your CXA80 is always running at optimum performance.

If you want to use a subwoofer as part of your speaker complement, the CXA80 doesnʼt penalise you for it. Because we want to ensure thereʼs no unnecessary high frequency noise affecting the subwoofer, weʼve put the output filter at 3KHz. This is high enough to prevent any phase shift associated with the low pass filter affecting what happens below 200Hz. The result is a phase linear subwoofer output signal which is clean and musical.

The CX range represents a step change in the way our engineers have approached signal path design, and the result is one of our most musical and entertaining amplifiers yet.

Previously, we went to almost surgical lengths to minimise distortion in order to get the best results. This invariably meant 46 components sat in the signal path. For the CX Series, we wanted to dramatically reduce that component count. The CXA80 now has only 24 components in the signal path. The big difference is that there are now 500 support components as well. Their job is to guarantee those 24 key components are absolutely optimal all the time, regardless of mains fluctuations and other influences.

This has made a big difference when it comes to tuning. Previously, tweaking one of the 46 components only made a small difference and it was sometimes difficult to quantify exactly what difference any change made. With the CX series, those 24 components have now actually become quite critical. Changing just one affects the character of the amplifier.We can hear very clearly what each of those components is doing.

This revision has fundamentally changed the character of the amplifier. Listening to a CX series amplifier is fun, engaging and exciting.

In order to offer 24-bit 192kHz resolution via asynchronous USB we use a specialist XMOS device dedicated to the USB input. Weʼve also written a custom driver to allow PC users to access the higher sample rates available in USB Audio 2 mode. This bespoke code allows us to stream audio files at the highest possible resolution.

If you want to use your CXA80 with a Bluetooth source, we offer an optional BT100 audio receiver. To ensure that this does not interfere with other components in the amplifier, itʼs isolated internally on the digital input board. From the ground up, this is an audiophile Bluetooth device. All the coding for the BT100, including the aptX implementation, is done in-house. We even include an extension cable which enables you get the best Bluetooth range.

Sometimes thereʼs a good reason to keep things uncomplicated. The CXA80 features a high-quality damped metal chassis, designed to ensure that nothing rattles or interferes with the electronics. Weʼve also kept volume control simple. The CXA80 uses a logarithmic ALPS pot. And when it comes to switching inputs, the CXA80 uses relay switching with silver plated contacts. This classic approach is still the best way to move signals around, rather than with transistors or electronic switches.

• Power output:80W RMS into 8 Ohms, 120W RMS into 4 Ohms
• DAC:Wolfson WM8740
• Frequency Response:

High rigidity metal frame
Shielded high current power supply
• 500VA toroidal transformer
• 80.000uF capacitor bank
• Rubber insulated aluminium feet
• WBT connector on unbalanced input
• Neutrik connector on balanced input
• Fully discrete analogue design
• Onsemi MJL1302/3281 power transistor
• Low overall feedback
• High stability on capacitive loads
• White Gold cable on output connection
• 100W/8Ohm power unit and double the
power on 4 Ohm until 390W on 2Ohm; a
big power reserve that allows to drive any loudspeakers even in a big room.