The Platinum Signature DAC IV is the next step above the standard DAC IV building on top of it's technology. 

By referring to the standard Platinum DAC IV page you can get a full understand of this feature rich DAC and then understand how much further MSB have taken it to create this "Signature" version.

The design and goal for the Platinum Signature DAC IV is to target specifically for the ultra high resolution audio requirements.

The four Signature DAC's modules incorporated into this model operate up to twice the speed of the standard Platinum DAC's modules with half the settling time. They have tighter tolerances, lower noise components, and the custom made laser trimmed metal foil resistors allow the Signature DAC's modules to convert precisely with less distortion and lower noise.

However the improvements do not stop there over the standard Platinum DAC IV. Included in the base price for the Platinum Signature DAC IV are:

• The 32x MSB Digital Filter which has been customised for the Signature DAC modules.
• The Signature 384 Upsampler.
• The upgraded Signature Power Base.
• MSB's filter suite.

What is the result from all these improvements? From the MSB Engineers:

"The Signature DAC IV takes your listening experience to a new high.   The lower noise and distortion allow the dynamics to come to life with more room for the music.   The top end is much more open and the bass response is more musical and more resolving.  It may be hard for owners of the Platinum DACs to believe that their Platinum can get much better, but it can.  For me, one of the best improvements are found in the little things, the ring of the cymbal that regardless of how many different instruments are playing, still rings out audibly until it is finished moving, and remains perfectly stable in the soundstage while doing so.  DACs that don't have as much resolution in the low level signals will start to replace a ringing cymbal (or any other low volume audio) with distortion, which quickly starts to sound like white noise within our hearing range."

Specifications:

Inputs:

Outputs:

Specification:

Control Features:

• Remote
• Display dim mode
• Level Trims
• Balance Trims
• Phase Invert
• Input Selection
• Filter Selection
• Clock Selection
• Upsampling on/off
• Dither on/off
• Reclocking on/off
• Input Mode select/auto

Future Upgrades and Expansion Capabilites:

• Unused DSP Headers for digital cross overs.
• Clock Upgrade Headers for future low jitter clocks.
• Input Headers for new input types.

Standard Features Built into the Price: 

Filter Suite

• MSB Filter Suite allowing you to toggle through a range of different filters.
• Provides a filter for every taste and music type.

Signature Power Supply

• Upgraded soft recovery diodes.
• Additional magnetic and electrostatic shielding.
• Upgraded Signature Power link Cable. 
• The Signature MSB Power Base must be used and is already incorporated into the base price if you do not already own one.
• Also includes a digital power supply for the MSB CD Data Transport.
• If you have the Signature Power Base already, select 'None' for both the Signature Power Base and the Digital Power Supply and the base prices drops to $13995.
• You can upgrade to the Diamond power supply and Diamond cable for an additional $1000.
• You can unselect just the digital power supply dropping the price by $499.
• You can also add a second Signature Power supply and Signature Cable for $1295

Upsampler

• Further improves clarity and reduces harshness. 
• Upsamples 44.1, 88.2 and 176.4 to 352.8 kHz with 32 bit resolution.
• Upsamples 48, 96 and 192 to 384 kHz with 32 bit resolution.
• Upgrades S/PDIF inputs from 192 kHZ to 384 kHz.
• Can be toggled on and off.

Optional Upgrades:

Volume Control

• Passive attenuator for shortest possible signal path with least possible degradation.
• 1dB steps from 9dB to -69dB.
• Completely bypassed when set to 0dB.
• Optional Upgrade to the Diamond Volume for improved shielding and isolation.

Analog Input and HT Bypass

• Convert one set of the RCA analog output to an RCA analog input or convert the spare 2 auxillary ports to XLR analog inputs.
• Any of these inputs can be set to bypass the output stage known as HT Bypass, perfect for combining HT and 2 channel setups using a single box solution.

USB Inputs

• Add one or two USB inputs.
• Buffered and optically coupled isolating computer noise and jitter.
• Simply plug in and play with Windows or Apple computers.
• Unbelievably low noise.
• Resolution up to 96 kHz with 24bit.

iLink II iPod Interface

• Works with any Generation 6 iPod or greater, iPod Videos, iPod Touch, iPod Nano's greater than 1Gb, and iPhone.
• Requires no iPod or iPhone modifications, just plug in and play.
• Charges iPod/iPhone while plugged in.
• Uses the iPods/iPhone digital output as a bit perfect digital transport. 
• Integrated iPod/iPhone control built into the DAC IV and it's remote. Play, pause and skip tracks back and forth.
• Upsamples up to 384kHz and 32 bits.

RS232 Interface

• Control the Platinum Signature DAC IV or even the volume from a remote system.

Diamond DACs

• See here for more details on this upgrade option