Hi-end DSP based multi-channel integrated Preamp/Crossover/DAC project

[Tranquility Bass]

Greetings


This is my latest DSP project based around an Analog Devices 4th generation SHARC DSP and ES9028PRO Sabre DAC.

Full details and specs available at Analog-Precision



Detailed Feature Overview (Hardware Rev:B2)

• Four outstanding functions in one: -
  • Reference Standard 2-Channel DSP Preamplifier for Two-Channel sources
  • Reference Standard 8-Channel DSP Preamplifier/Crossover/Signal Processor for Two-Channel sources
  • Direct-DAC (DSP bypass) mode for Two-Channel sources
  • ES9028 Multi-Channel Direct injection mode via a single interface connector handles: -
    • 8 channel I2S mode
    • Single channel 8 to 1 S/PDIF mux
    • 8 channel DSD mode
    • 8 channel DoP mode
• ESSTech ES9028-PRO 2nd generation Sabre Professional Audiophile DAC featuring: -
  • Hyperstream II Technology
  • 64-bit accumulator with 32-bit processing
  • Patented Time Domain Jitter Eliminator
  • -120 dB THD + Noise
  • Precision 32-bit volume control on all channels
  • Precision Gain matching between chips
  • Seven preset reconstruction filter types to suit different applications: -
    • Fast roll-off, linear phase filter
    • Slow roll-off, linear phase filter
    • Fast roll-off, minimum phase filter
    • Slow roll-off, minimum phase filter
    • Apodizing, fast roll-off, linear phase filter
    • Hybrid, fast roll-off, minimum phase filter
    • Brick wall filter
• LM4562 premium audiophile grade opamps used in the post DAC processing
• Multilayer printed circuit board with dedicated ground and power plane layers
• Advanced Analog to Digital Converter featuring: -
  • Balanced inputs for higher noise immunity
  • Built-in Programmable Gain Amplifier (PGA)
  • Clocked by a 49.152 MHz low phase noise master clock not derived from a PLL
• Analog Devices 4th Generation SHARC DSP featuring: -
  • 400 MHz internal clock
  • Harvard architecture with internal 64-bit data paths
  • 40-bit Floating point and 32-bit fixed point processing with 80-bit accumulator
  • 800 MMacs performance and 2.4 Gflops peak performance
  • SIMD instruction set
  • On-chip hardware accelerators
  • 5 Mb of fast on-chip memory and support for 256 Mb of off-chip memory
• Precision 49.152Mhz low phase noise master reference clock from NDK and clock distribution network with impedance controlled traces
• Programmable precision master timing generator featuring: -
  • 192, 96, 48 KHz DSP sample rate processing options
  • 49.152 MHz low phase noise master clock not derived from a PLL
  • Strict I2S standards adherence
  • Master or slave modes
• USB Audio Class 2 interface: -
  • Supports PCM up to 192KHz
  • Supports DSD from DSD64 up to DSD256 or 11.2MHz
  • Galvanically isolated USB Audio interface eliminates injected noise from connecting PC
  • Asynchronous transfer protocol
• Native onboard DSD Processing in real-time with no software pre-processing required!
  • Supports DSD from DSD64 up to DSD256 (2.8-11.2MHz)
  • No DSP intervention
• Precision hardware frequency counter accurately displays sample rate and DSD clock rate even for non-standard sample rates
• Multi-level cascaded regulator design with passive low-Q LC filtering for exceptional noise immunity and regulation,
• Both Balanced/Unbalanced Audio Outputs available to allow mixing of amps with different input requirements
• Audiophile grade capacitors where appropriate
• Premium audiophile grade opamps in the post DAC section
• Relay muting and protection eliminates turn on thumps and clicks with no effect on sound quality
• Bespoke custom logic chip design implements various hardware peripherals
• Perfect-Link dedicated link port featuring: -
  • Ability to piggyback more DSP units for expanding channels or increasing processing capability
  • Proprietary line-lock hardware automatically provides 0-degree phase alignment between multiple boards with no increase in jitter
  • Accurate locking to within one master clock cycle plus cable delay
  • Uses the reference master clock on each board for low phase noise. No PLL re-clocking !
  • Precision gain matching between DAC's on different boards
  • Master and slave DSP boards allows standalone active speakers to be in perfect word sync with each other
• Amplifier control port typically used in standalone active speaker environments to control amplifier modules
• Various Audio I/O options and combinations including S/PDIF Coax, AES/EBU, Toslink, I2S, 12V Trigger
• Advanced user interface console featuring: -
  • Full colored QVGA (320x240 pixels) LCD with backlit display and crisp fast pixel rendered graphics,
  • Stylish full colored bitmap graphics and true-type fonts for that professional appearance,
  • Smooth rotary encoder control for master volume and quick menu changes,
  • Large display of master volume,
  • Seven dimmable status LEDs for real time status reporting namely: -
    • IR receiver activity status
    • DAC Lock status
    • DAC Mute status
    • Plugin active status
    • Line Lock status
  • Full hierarchical intuitive menus and navigation system including: -
    • Tactile buttons for menu navigation
    • Remote control navigation of menus
    • Full color display with context sensitive display
• Standard Apple Remote Control
• User Customization of DSP firmware using drag and drop DSP design software
  • Design complex DSP systems in minutes
  • No complex DSP coding necessary
  • Dynamic instantiation so no additional compilers or linkers needed
  • Precision low noise, high performance filters not limited to low sampling rates
  • Field upgradable
• Field upgradable firmware via USB interface with no unsoldering of chips
• Balance Control facilitates channel matching with up to 10dB difference between channels
• DSP plugins for 2/8 channel preamp modes includes: -
  • Soft-Tube emulates the rich sound of many different tube types and operating points
  • Soft-Clipping emulates the clipping characteristics of a tube amp
  • Distortion less precision 32-bit sinewave generator for test purposes
  • Image focuser adjusts stereo image width
• Typical Applications: -
  • Multi-channel or stereo preamplifier
  • Multi-channel signal processor
  • Multi-way mono or stereo digital crossover
  • Stand-alone stereo DAC
  • Integrated or standalone Active speaker systems
  • Dedicated bass management system
  • Vinyl archiving system

Board Line-up

Analog Audio Input Board

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Digital Audio Input/Output Board

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Power Supply Board

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Eight Channel Un-balanced Output Board

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Eight Channel Balanced Output Board

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User Controls Board

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Amanero isolated USB interface board

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[jcga]

Hi,
this looks incredibly appealing !
Any approximate idea of the price and availability ?

[Tranquility Bass]

It depends on how much interest there is as this board has to built in quantities and can't be built by hand except for one off prototypes but don't expect minidsp prices !!

There are eight other support boards some of which are simple through hole boards and some are more complex surface mount boards.

I will post some of the other boards when I have completed them.

cheers

[amoisis]

Looks interesting should go well with my wire amps in an active setup .

[sumaudioguy]

This is great but is like 10 times more DSP than most people would ever need. But, you know your target buyer better than me! Add up the need for a 5 way crossover, limiters, EQ, time correction for a surround sound system and bet there will be about 90% of the DSP cycle time left over.

Good luck with this though!

[potstip]

Originally Posted by jcga

Hi,
this looks incredibly appealing !
Any approximate idea of the price and availability ?

+++

[Tranquility Bass]

Originally Posted by sumaudioguy

This is great but is like 10 times more DSP than most people would ever need. But, you know your target buyer better than me! Add up the need for a 5 way crossover, limiters, EQ, time correction for a surround sound system and bet there will be about 90% of the DSP cycle time left over.

Good luck with this though!

But the game changes as soon as you start talking about FIR filters or linear phase filters for use in group delay correction or room correction etc. Then every clock cycle counts This is why most of the lightweight DSP's have trouble doing decent size FIR filters and usually they are limited to low sampling rates of 48KHz with not much room for any other processing, because every time the sampling rate doubles the number of taps per sample interval halves !! So at 96KHz or 192KHz all of a sudden you have run out of taps before the next interrupt and your filter can no longer be processed. Then to compound matters you may need an FIR filter for the other stereo channel or 7 channels and then you are in real trouble so you end up have having one dsp board per channel and what you thought was a cheap solution has blown out the budget !!

Even with simple IIR filters you'd be surprised at how many clock cycles are chewed up for even a medium complexity crossover filter so in this case more is better and for the extra $$ of a SHARC DSP over a Sigma DSP it is well worth it

cheers

[Tranquility Bass]

Originally Posted by amoisis

Looks interesting should go well with my wire amps in an active setup .

That is one of its main applications for use in high quality active speakers. It has one S/PDIF output for use with an external DAC to drive subwoofers etc for a total of a 5-way stereo active speaker system

cheers

[tuyen]

Well done on a cool design! I'd possibly be interested in a unit if the opportunity arises

[jcga]

Originally Posted by Tranquility Bass

It depends on how much interest there is as this board has to built in quantities and can't be built by hand except for one off prototypes but don't expect minidsp prices !!

There are eight other support boards some of which are simple through hole boards and some are more complex surface mount boards.

I will post some of the other boards when I have completed them.

cheers

Again, the hardware described here looks to me like the best I've seen so far but I would point that the software/firmware will be as crucial as the hardware to get the benefit(success) of it.

And to answer to someone else, pointing that the power is too much for the home use, I'm running active loudspeakers for the past 20 years or so and yes FIR filters and first room modes corrections need a lot of DSP power.

JC