Transcript
“On many levels, I found the sound of the Rega DAC more akin to that of their flagship turntable, the P9 (which has been a long term component in my reference system). It shares the P9ʼs quick and open presentation with a healthy dose of pace and timing.” TONE AUDIO 12/10
Rega DAC Retailers Guide Like Asynchronous:
The USB input is not asynchronous per se, but there are similar attributes, which make the USB input a high-quality input, The Rega DAC incorporates a PLL based clock for low jitter audio signal recovery. This recovered audio data is then passed through the WM8805 PLL based receiver, so It can be said the USB audio data has been re-clocked and cleaned up by the Wolfson 8805 receiver. Phase is preserved, helping with bass, imaging and perfect timing.
Unique Filters:
99% of D to A converters today use brick wall filters to remove music robbing phase anomalies. The problem with this type of “phase linear” filter is that it creates time smearing echos (Preringing). Like with more expensive DAC’s (think Esoteric, Ayre, DCS, Meridian) Rega gives you a more advanced system of filtration. A total of 10 filters are available, each one changing how sharply or softly the filter performs. “Soft Knee,” “Brickwall” and even three cutting edge Apodizing filters help create a greater sense of musical naturalness. Differences are small but the results of your experimentation will be greatly improved sound quality.
24/192 Playback:
A pair of TOSLINK and Coax inputs will accept up to 24/192, the highest native resolution currently available.
Mission Critical Electronics:
Careful attention has been paid to the power supplies, grounding, analog amplifiers (Class A biased) and use of fast acting Nichicon as well as low conductive polymer capacitors in critical areas. The control code, the part the tells the IC’s and power what to do, is designed in house by Rega.
Special Power Supplies:
The heart of the power supply is a generously rated Toroidal transformer with separate windings for the digital and analog audio and the micro controller. There are total of 9 separate power supplies using audio grade and low impedance capacitors throughout. Super fast diodes are used in the rectifiers to help keep the switching noise down. Isolated audio ground for SPDIF and USB connections. Dirty power from the computer is completely eradicated.
Entirely built in the UK.
“How can this retail for $995?” “Simplicity - as I wanted to keep the signal path to a minimum. I know itʼs a bit of a traditionalist approach, but I felt the inclusion of an up sampler would over complicate the unit. The WM8805 and WM8742 running at the incoming sample rate do a good job on their own, along with a nice drop of old school audio mojo in the discrete post DAC analogue circuitry keep things straightforward.” “Itʼs worth bearing in mind that both the Saturn and the Isis donʼt use up sampling either, and I wanted the DAC to follow the same sprit of these units.” “itʼs worth remembering 192K is on the high end of what the TOSLINK can handle, so the quality of the optical cable has to be taken into account for reliable operation. Iʼve had the DAC working reliably at 192K with a 2 Meter commercial grade optical cable being driven from both a Xonar ASUS Essence and Prodigy HD2 sound cards.” “The PCB uses ground planes to ensure low impedance earth paths, which keeps earth induced noise in the digital and analogue domains to a minimum. The micro-controller has Itʼs own ground and power supply.”
INSIDE STORY pt1
Huge toroidal transformer. One set of windings for DAC and all things analog.
Another set of windings for the digital micro controller.
The included C5 AC cable connection simply saves space. Itʼs tight in there. Use a C5 to C15 adaptor if you want to use more expensive AC cables.
The co-axial and USB digital inputs are electrically isolated from the audio ground, which is floating with respect to the electrical ground, this helps reduce noise and hum loops when used in large multi-input system. The PCB uses ground planes to ensure low impedance earth paths, which keeps earth induced noise in the digital and analogue domains to a minimum. The microcontroller has Itʼs own ground and power supply. DAC also features a set of TOSLINK and Coax outputs.
INSIDE STORY pt2 High quality I2S pipeline transmits 5 a super4 low jitter clock and data signal.
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TED Saturn DAC (Using WM8742)
Note - SPDIF Data
WM8742 DAC
Analog Filter & Amp
D
USB I/P
RCA
WM8805 DIR Daisy Chain..??
LED=RA1)
RX0 (LED=RA0)
ISO_TRANS
RELAY I2S
I2S Digital O/P
LED=RA2) Inputs
ANALOG OUT Analog Filter & Amp
LED=RA3)
RELAY DIR 3V3 (ANALOG)
TX0 SPI For Future Use
RC3, 4 & 5
Micro (PIC)
SPI
Open Collector NAND..?
3V3 ANALOG..?
Mute RA5 De-emphasis
RCA WM8742 DAC
DIR 3V3 (DIGITAL)
LED=RA4)
C
I2S
Power Up Delay
RB5
5V ANALOG & 3V3 DIGITAL (DAC)
RC2
RD7
RLA/MUTE/HOLD-OFF
Wolfson RC6 WM8805 PLL Receiver time adjusts on RC7the fly which is a form of Tracked Tore WM8805 & WM8742 clocking. Includes a a hardware buffer. Results RA2 RA3 RA4similar to using Asynchronous technique. Input Spare I/O's
+/- 12.7V ANALOG
VCC
B
DIR Supply Source
phase and the output phase is referencing the Digital I/P #2 matched Digital I/P #3 by Digital I/P #4 frequency and if all that is RD2 RD3 RD4 RD5 RD6 matched up the timing will be correct. Bass is improved, better soundstage/imaging, pacing is 44.1K 48K 88.2K 96K 192K..?? more accurate. RE1 RB0 RB1 RB2 RB3 RB4
Analog Pair of parallel connected pro level Wolfson WM8742 DACʼs. Each DAC is DAC & to Analog connected its PSU very own POWER ClassINA biased discrete output. Digital
Power
3V3 (MICRO) A
Digital PSU
Filter #1 Filter #2 Filter #3
Title
Filter #4 Filter #5
Size
Block Diagram For D/A Converter v03 Number
Date: File: 3
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Revision
ISS2/01/10
A3
29-Dec-2010 Sheet of C:\Documents and Settings\A User\My Documents\Mikes Drawn By: Stuff\DAC_Project.ddb 7
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TSOʼs RECOMMENDED APPROACH TO SAFE AUDIO COMPUTING For the non audiophile music lover who values quantity over quality try to use the least amount of compression. 320k. is better than 128k. Use a quality optical, coax and/or USB cable For the best rip consider using an external CD or DVD burner. Dedicated power supply and a bigger memory buffer make for better sound. Go into your midi or sound card setting and select the external DAC you want to use. Use an external HD to store your music files. You get a bigger memory buffer and an external power supply. Audiophiles should consider using a dedicated media specific computer Rip your files at the highest setting possible. AIFF and WAV feature no compression whatsoever. FLAC and Apple Lossless zap empty space cutting file size down by around 50%. Lossless files are bit perfect but take more processor power to sound good. Make sure to have your internal computer soundcard handle all system noises, beeps, etc. Try using a passive power conditioner to see if it makes things sound better Even see if your computer takes an upgraded C15 power cable. You might be surprised.
Computer based volume controls are convenient but they trim bit resolution. Try avoiding this when seriously listening. If you using iTunes choose Apple Lossless, WAV or AIFF. Make sure to check the “use error correction” box. Turn off all available EQ settings. Make sure your sound card is set to the native sample rate of your source. Otherwise your computer will resample. Both iTunes and Windows Media Player are perfectly fine for digital music file storage and playback. If you are doing lots of 44.1-199k listening on your machine you may want to consider a third party bit perfect overlay. If you are not using a dedicated computer you will want to prevent a ton of services from loading into your task bar or menu bar. Background processes can potentially create sonic degradation. You donʼt want programs hijacking your music specific resources. You want your file to be completely intact before it reaches the DAC. If your DAC works harder it will create more music killing jitter. We recommend at least 2 gigabytes of RAM. However, 4 gigabytes will create more headroom to process data intensive lossless or lossy files. RAM is cheap. FLAC and Apple Lossless are similar. Remember that FLAC is not a native iTunes file type. However, you can use programs like MAX, FLUKE, etc to convert your FLAC files to AIFF or Quicktime. Transcoding is what makes this possible. You can also down-convert AIFF and WAVE files to lossless within iTunes.
