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Αποτελείτε από δύο βασικά μέρη το γ1 και το γ2.
Για το γ1:
[SIZE=-1]γ1 is a high-performance, full-featured DIY stereo digital-to-analog converter (DAC) for portable and home use. Designed to be housed in a very compact enclosure, its footprint is almost exactly the size of a credit card, and about 0.9" (23mm) thick. Despite the size, a full-configuration γ1 has S/PDIF coaxial and optical digital inputs as well as a USB interface. Ideal for computer audio, CD/DVD players and digital media players, γ1 offers an economical DIY alternative to costly commercial DACs. Its 1.5Vrms analog output provides line-level interface to a stereo preamp, headphone amplifier or other device. The low output impedance and high output current capability allows a long interconnect cable to be used without degradation.
γ1 is also designed to be modular, its two circuit boards can be used together or independently in different configurations, allowing it to suit different usage needs. See below for details.
In conjunction with an off-the-shelf enclosure solution and wire-free board mounting of all components, γ1 is easy and inexpensive to build. The only surface-mount parts are the integrated circuits, all other parts are through-hole. See the Tech highlights section for details.
γ1 is designed by AMB and MisterX with community input. See the History section for details. Basic feature set
Due to γ1's modular nature, there are five main possible configurations:
και για το γ2:
[SIZE=-1]γ2 (gamma2) is an extension and upgrade to the γ1 DIY stereo digital-to-analog converter (DAC). It builds on γ1's modular idea, and pushes the concept far into the high-end. Designed for the compact, attractive and sturdy Box Enclosures B2-080 series extruded aluminum casing, γ2's tightly integrated packaging makes it ideal for home and portable use, such as computer audio, CD/DVD players and digital media players.
The γ1 and γ2 boards plug into each other to form a two-board "sandwich". γ1 provides USB and S/PDIF receiver functionality and feeds the I²S digital audio datastream to the γ2. γ1 also supplies the raw 5V DC power to the γ2, which is then regulated locally on the γ2 board.
The γ1 Full++ (F) configuration is most easily upgraded to γ2, as it uses the same enclosure. The γ1 Full (A), Lite (B), USB-to-I²S (D) and S/PDIF-only (E) configurations may also be upgraded to γ2 by joining the two γ1 board sections back together and changing the enclosure. The only incompatible γ1 configuration is USB-to-S/PDIF (C), because it does not produce an I²S output. See the γ1 website about its various configurations and options.
γ2 could also used standalone as an upgrade DAC for any device that already has an I²S bus (e.g., A CD player or digital media player). Simply connect the I²S bus to the γ2 board and hook up a 5V DC power supply. See the instructions section for details.
On the γ2 board, the digital audio stream is upsampled to 24-bit 96KHz by an asynchronous sample rate converter (ASRC) and then converted to analog with Wolfson's top-of-the-line ΔΣ oversampling DAC chip. An onboard ultra-low jitter oscillator provides the master clock for the ASRC and DAC chips. A high-performance analog output stage serves as a balanced-unbalanced converter, low-pass filter and line-drive buffer.
For the cost-conscious builder, the ASRC chip and onboard oscillator may be omitted and bypassed with jumpers. They can be populated later (and jumpers removed) as funds allow. Without the ASRC, no upsampling will occur.
A front panel switch selects between linear phase brickwall, minimum phase slow-rolloff, and linear phase slow-rolloff digital filter modes, allowing the user to choose the performance characteristics on-the-fly. Another front panel switch enables an anti-clipping mode.
A rail-to-rail, low-noise, precision CMOS dual opamp implements balanced-to-unbalanced conversion, 100KHz analog low pass filtration and output buffering. The low output impedance and high output current capability allows a long interconnect cable to be used without degradation. It could even directly drive low-impedance headphones (AD8656).
With an off-the-shelf enclosure solution and wire-free board mounting of all components, γ2 is relatively easy and inexpensive to build. The only surface-mount parts are the integrated circuits, all other parts are through-hole. See the Tech highlights and Parts list sections for details.
γ2 is designed by AMB and MisterX with community input. See the History section for details. Basic feature set
Αποτελείτε από δύο βασικά μέρη το γ1 και το γ2.
Για το γ1:
[SIZE=-1]γ1 is a high-performance, full-featured DIY stereo digital-to-analog converter (DAC) for portable and home use. Designed to be housed in a very compact enclosure, its footprint is almost exactly the size of a credit card, and about 0.9" (23mm) thick. Despite the size, a full-configuration γ1 has S/PDIF coaxial and optical digital inputs as well as a USB interface. Ideal for computer audio, CD/DVD players and digital media players, γ1 offers an economical DIY alternative to costly commercial DACs. Its 1.5Vrms analog output provides line-level interface to a stereo preamp, headphone amplifier or other device. The low output impedance and high output current capability allows a long interconnect cable to be used without degradation.
γ1 is also designed to be modular, its two circuit boards can be used together or independently in different configurations, allowing it to suit different usage needs. See below for details.
In conjunction with an off-the-shelf enclosure solution and wire-free board mounting of all components, γ1 is easy and inexpensive to build. The only surface-mount parts are the integrated circuits, all other parts are through-hole. See the Tech highlights section for details.
γ1 is designed by AMB and MisterX with community input. See the History section for details. Basic feature set
- Designed for the Hammond 1455C80x case (same as Mini³ portable headphone amplifier).
- The γ1 "full++" configuration uses the Box Enclosures B2-080 series case.
- Supports USB, S/PDIF coax and optical inputs (switchable).
- 24-bit 192KHz high-performance Wolfson ΔΣ oversampling DAC chip.
- 192KHz S/PDIF receiver chip with low-jitter clock recovery.
- Modular: A separate DAC board and a USB interface board that could each be used standalone, or mated to each other for the full feature set.
- The S/PDIF inputs (coax and optical) support resolutions and sampling rates up to 24-bits 192KHz, but the DAC configuration is limited to 24-bit 96KHz for best digital filter response (see the circuit descriptions in the schematic diagram section for details).
- The maximum USB resolution and sampling rate is 16-bit 48KHz.
- When used standalone, the USB interface board can be configured as a bus-powered USB-to-S/PDIF or USB-to-I²S converter.
- When used standalone, the DAC board supports only S/PDIF (coax or optical) inputs and must be powered by external power.
- When mated to each other, the two boards can support all inputs and can be USB-powered or externally-powered.
- Auto-sensing of external-power.
- Onboard power supply voltage regulation (separate LDO voltage regulators for the USB board, DAC digital and analog sections).
- Analog line output (3.5mm stereo mini jack), with high output current and low output impedance.
- Illuminated mini-toggle input selector switch (USB/coax/optical) with power-on indication and operation status (green = normal, red = error or no audio).
- 1.3mm miniature barrel-type DC power jack, RCA phono S/PDIF coax jacks, standard Toslink-style S/PDIF optical jacks, 3.5mm stereo mini jack for audio line output, mini-USB connector.
- Through-hole resistors, capacitors, ferrites and other parts to reduce build difficulty. The only SMD parts are the various ICs and voltage regulators.
- In default configuration, all parts (including jacks) are PCB-mounted. No internal wiring necessary.
- USB host interface supports Linux, MacOS and Windows (no additional software driver necessary).
Due to γ1's modular nature, there are five main possible configurations:
- A: Full configuration (USB, S/PDIF coax and optical inputs, selectable with front panel switch).
- B: Lite configuration (USB input only, no selector switch).
- C: USB-to-S/PDIF converter (no DAC board).
- D: USB-to-I²S converter (no DAC board).
- E: S/PDIF DAC only (coax and optical inputs, selectable with front panel switch, no USB board).
- F: Full++ configuration (combination of A and C).
και για το γ2:
[SIZE=-1]γ2 (gamma2) is an extension and upgrade to the γ1 DIY stereo digital-to-analog converter (DAC). It builds on γ1's modular idea, and pushes the concept far into the high-end. Designed for the compact, attractive and sturdy Box Enclosures B2-080 series extruded aluminum casing, γ2's tightly integrated packaging makes it ideal for home and portable use, such as computer audio, CD/DVD players and digital media players.
The γ1 and γ2 boards plug into each other to form a two-board "sandwich". γ1 provides USB and S/PDIF receiver functionality and feeds the I²S digital audio datastream to the γ2. γ1 also supplies the raw 5V DC power to the γ2, which is then regulated locally on the γ2 board.
The γ1 Full++ (F) configuration is most easily upgraded to γ2, as it uses the same enclosure. The γ1 Full (A), Lite (B), USB-to-I²S (D) and S/PDIF-only (E) configurations may also be upgraded to γ2 by joining the two γ1 board sections back together and changing the enclosure. The only incompatible γ1 configuration is USB-to-S/PDIF (C), because it does not produce an I²S output. See the γ1 website about its various configurations and options.
γ2 could also used standalone as an upgrade DAC for any device that already has an I²S bus (e.g., A CD player or digital media player). Simply connect the I²S bus to the γ2 board and hook up a 5V DC power supply. See the instructions section for details.
On the γ2 board, the digital audio stream is upsampled to 24-bit 96KHz by an asynchronous sample rate converter (ASRC) and then converted to analog with Wolfson's top-of-the-line ΔΣ oversampling DAC chip. An onboard ultra-low jitter oscillator provides the master clock for the ASRC and DAC chips. A high-performance analog output stage serves as a balanced-unbalanced converter, low-pass filter and line-drive buffer.
For the cost-conscious builder, the ASRC chip and onboard oscillator may be omitted and bypassed with jumpers. They can be populated later (and jumpers removed) as funds allow. Without the ASRC, no upsampling will occur.
A front panel switch selects between linear phase brickwall, minimum phase slow-rolloff, and linear phase slow-rolloff digital filter modes, allowing the user to choose the performance characteristics on-the-fly. Another front panel switch enables an anti-clipping mode.
A rail-to-rail, low-noise, precision CMOS dual opamp implements balanced-to-unbalanced conversion, 100KHz analog low pass filtration and output buffering. The low output impedance and high output current capability allows a long interconnect cable to be used without degradation. It could even directly drive low-impedance headphones (AD8656).
With an off-the-shelf enclosure solution and wire-free board mounting of all components, γ2 is relatively easy and inexpensive to build. The only surface-mount parts are the integrated circuits, all other parts are through-hole. See the Tech highlights and Parts list sections for details.
γ2 is designed by AMB and MisterX with community input. See the History section for details. Basic feature set
- Designed for the Box Enclosures B2-080 series extruded aluminum case, available in various colors.
- 24-bit 192KHz top-of-the-line Wolfson WM8741, WM8742 or WM8740 DAC chips.
- Texas Instruments/Burr-Brown SRC4192 or Analog Devices AD1896 ASRC.
- Ultra-low jitter onboard CMOS oscillator for I²S master clock.
- The upsampling process eliminates jitter, and optimizes the DAC chip's digital filter performance.
- ASRC chip and oscillator may be omitted and bypassed with jumpers.
- Plugs into γ1 for USB and S/PDIF (coax and optical) inputs and power. γ1's onboard WM8501 DAC is retained for two DACs sharing one enclosure.
- Unbalanced-to-balanced converter, analog 100KHz low-pass filter, output buffer based on the Texas Instruments/Burr-Brown OPA2365 or Analog Devices AD8656 CMOS rail-to-rail dual opamp.
- Analog line outputs (RCA jacks and 3.5mm stereo mini jack), with high output current and low output impedance.
- Onboard power supply voltage regulation (separate LDO voltage regulators for the digital and analog sections), with extensive use of ferrite beads for noise rejection.
- Through-hole resistors, capacitors, ferrites and other parts to reduce build difficulty. The only SMD parts are the various ICs and voltage regulators.
- In default configuration, all parts (including jacks) are PCB-mounted. No internal wiring necessary.
- The printed circuit board has three copper layers, two of which contain largely contiguous, low-impedance ground planes which are tightly-coupled with a matrix of vias. This minimizes current loops. Traces are carefully routed to assure maximum signal integrity and minimum jitter.
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