The γ2 compact high performance DAC

Parts list

The table below is a complete parts list for the γ2. See the sections below for specific parts recommendations and options. For parts not offered by AMB audio shop, Mouser, Digi-Key, Newark, Farnell, RS Components or another vendor's stock numbers for the recommended parts are listed for your convenience. Part IDs shown in parentheses "()" are alternates. Additional alternative parts are listed in the Parts selection guide section below.

Part ID Description Mouser # Digi-Key # Farnell # RS # Notes
Circuit board
PCB γ2 PCB AMB audio shop -
Resistors
R1, R2 resistor network SIP-8 isolated 68Ωx4 AMB audio shop See note 1
R4, R8, R11, R15 miniature 1% thin film or metal film resistor 3.3KΩ 270-3.3K-RC S3.3KCACT-ND 9343040 - -
(R4, R8, R11, R15) miniature 1% thin film or metal film resistor 3.3KΩ 71-RN50C3321F CMF3.32KQFCT-ND - - -
R5, R7, R12, R14 miniature 1% thin film or metal film resistor 2KΩ 270-2K-RC S2KCACT-ND 9342788 - -
(R5, R7, R12, R14) miniature 1% thin film or metal film resistor 2KΩ 71-RN50C-F-2K CMF2.00KQFCT-ND - - -
R3, R6, R10, R13 miniature 1% thin film or metal film resistor 4.7KΩ 270-4.7K-RC S4.7KCACT-ND 9343253 - -
(R3, R6, R10, R13) miniature 1% thin film or metal film resistor 4.7KΩ 71-RN50C-F-4.75K CMF4.75KQFCT-ND - - -
R9, R16 miniature 1% thin film or metal film resistor 47KΩ 270-47K-RC S47KCACT-ND 9343261 - -
(R9, R16) miniature 1% thin film or metal film resistor 47KΩ 71-RN50C-F-47.5K CMF47.5KQFCT-ND - - -
Capacitors
C1, C4, C7, C8, C9, C10, C12, C14, C27 multilayer ceramic capacitor X7R 0.1uF 50V 80-C320C104K5R 399-4264-ND 1457655 or
1141775
538-1310 See note 1
C2, C5 multilayer ceramic capacitor X7R 10nF 50V 80-C315C103K5R 399-4148-ND 1457653 538-1196 -
C15, C17, C21, C23 polypropylene film capacitor 100pF 100V 505-FKP2100/100/2.5 or 505-FKP2100/100/5 - 1005979 - -
C16, C18, C22, C24 polypropylene film capacitor 220pF 100V 505-FKP2220/100/2.5 or 505-FKP2220/100/5 - 1005983 - -
C19, C25 metallized polyester capacitor MKT or MKS 1µF 63V AMB audio shop -
C3, C6 conductive polymer electrolytic low-ESR capacitor 47µF 10V 661-PSA10VB47M 565-3051-ND - - -
C11, C13 audio-grade electrolytic capacitor 22µF 6.3V+ 647-UKW1H220MDD or 647-UES1E220MEM 604-1051-ND 8766762 or 8766959 215-5691 or 521-1738 -
C20, C26 audio-grade electrolytic capacitor 22µF 6.3V+ 647-UKW1H220MDD or 647-UES1E220MEM 604-1051-ND 8766762 or 8766959 215-5691 or 521-1738 See note 9
(C20, C26) audio-grade electrolytic capacitor 470µF 6.3V+ 647-UKW1A471MED or 647-UFW1A471MED - - - See note 9
Ferrite beads
L1, L2, L3, L4, L5 Ferrite bead, axial lead AMB audio shop -
Integrated circuits
U1 4.75V LDO fixed voltage regulator Texas Instruments TPS793475DBVR (SOT23-5) 595-TPS793475DBVR 296-12160-1-ND 1755653 661-4494 -
(U1) 4.5V LDO fixed voltage regulator Texas Instruments LP2985AIM5-4.5 (SOT23-5) 926-LP2985AIM545NOPB LP2985AIM5-4.5/NOPBCT-ND 1685756 761-6488 -
U2 3.3V LDO fixed voltage regulator Texas Instruments TPS79333DBVR (SOT23-5) 595-TPS79333DBVR 296-12961-1-ND 1470478 661-4490 -
(U2) 3.3V LDO fixed voltage regulator Texas Instruments LP2985AIM5-3.3 (SOT23-5) 926-2985AIM53.3/NOPB LP2985AIM5-3.3/NOPBCT-ND 1469134 652-0033 -
U3 reset manager Microchip Technology MCP100 (TO-92) 579-MCP100-315DI/TO or 579-MCP100-300DI/TO MCP100-315DI/TO-ND or MCP100-300DI/TO-ND 1212673 667-4124 See note 1
(U3) reset manager Maxim/Dallas DS1818 (TO-92) - DS1818-10+CT-ND - - See note 1
U4 asynchronous sample rate converter Texas Instruments/Burr-Brown SRC4192IDB (SSOP28) 595-SRC4192IDB 296-15234-5-ND 8452741 665-8797 See note 1
(U4) asynchronous sample rate converter Analog Devices AD1896AYRS (SSOP28) - AD1896AYRSZ-ND 1321318 497-2410 See note 1
U5 24-bit 192KHz stereo DAC Wolfson WM8741GEDS/V (SSOP28) 238-WM8741GEDS/V WM8741GEDS/RVCT-ND 1776268 - -
(U5) 24-bit 192KHz stereo DAC Wolfson WM8742GEDS/V (SSOP28) 238-WM8742GEDS/V - - - -
(U5) 24-bit 192KHz stereo DAC Wolfson WM8740SEDS (SSOP28) 238-WM8740SEDS - 1354181 - See notes 4
U6 (not populated) - - - - -
U7 CMOS dual opamp Texas Instruments/Burr-Brown OPA2365AID (SOIC8) 595-OPA2365AID 296-20801-ND 1329587 661-0782 See note 2
(U7) CMOS dual opamp Analog Devices AD8656ARZ (SOIC8) - AD8656ARZ-ND 1117887 412-321 See note 2
Oscillator
X1 24.576MHz 3.3V CMOS oscillator Crystek C3391-24.576 549-C3391-24.576 - - - See notes 1 and 3
(X1) 24.576MHz 3.3V CMOS oscillator Abracon ACHL-24.576MHz-EK ACHL-24.576MHZ-EK - - - See notes 1 and 3
(X1) 24.576MHz 3.3V CMOS oscillator EuroQuartz 24.576MHz XO91050UITA - - 1640947 - See notes 1 and 3
(X1) 24.576MHz 3.3V CMOS oscillator Aker S73305-24.576-X-15 - - 1538882 - See notes 1 and 3
Switches
SW1 subminiature toggle PCB-mount SPDT on-off-on NKK 633-G13AV or 633-G13AV-RO 360-1770-ND 1524234 - See note 4
(SW1) subminiature toggle PCB-mount SPDT on-off-on Mountain Switch 108-2US3T1767-EV - - - See note 4
SW2 subminiature toggle PCB-mount SPDT on-none-on NKK 633-G12AV or 633-G12AV-RO 360-1759-ND 1524233 - See note 4
(SW2) subminiature toggle PCB-mount SPDT on-none-on Mountain Switch 108-2US1T1765-EV - - - See note 4
Connectors and jacks
J1 3P pin receptacle AMB audio shop -
J2 5P pin receptacle AMB audio shop -
J4, J5 9P long pin header AMB audio shop -
J3 2P pin receptacle 517-850-01-08 (break apart) S7035-ND 1593458 - See note 5 and 6
J6, J7 PCB-mount RCA jack AMB audio shop -
J8 PCB-mount 3.5mm stereo mini jack AMB audio shop -
JP1 2P jumper - - - - See note 7
JP2-[1-4] 2-row 4P short pin header 649-67997-108HLF S2022E-04-ND 9733582 - See notes 1 and 8
Enclosure and hardware
Box Enclosures B2-080BK or
B2-080BL or
B2-080GD or
B2-080GR or
B2-080RD or
B2-080SI
- - 1015173
1015174
1418582
1418583
1015176
1015172 or 1549967
2508349218
2508349224
2508349230
2508349246
2508349252
2508349202
Newark
26K9019
26K9020
26K9021
26K9022
26K9023
26K9024
(optional) Precision CNC-machined and engraved front/rear aluminum panel set AMB audio shop -
(optional) imperial #6-32 or metric M3.5 socket cap screws (for front and rear panel) - - - - McMaster-Carr or local hardware store

Notes

See the parts list table above, which refer to specific notes here.
  1. Install U4 if you want the upsampling feature. If U4 is not installed, then also omit U3, X1, R1, C7, C8, and install jumpers JP2-[1-4].
  2. AD8656 preferred for driving headphones directly.
  3. Crystek, EuroQuartz and Aker are SMD, with slightly better specs. Abracon is through hole.
  4. SW1 and SW2 should not be installed if U5 is a WM8740 -- Short the FSEL and ACLIP pads to GND (see PCB silkscreen at the SW1 and SW2 locations).
  5. If you use the "break apart" style of pin headers and receptacles, only one of each type is enough for all positions.
  6. J3 must be omitted if the matching γ1 is a Lite (B) configuration. For γ1 Full (A), USB-to-I²S (D), S/PDIF-only (E) or Full++ (F) configurations, also install a 1P long header pin into γ1's JP1D pin 2.
  7. Install this jumper if γ1 is a "Lite" configuration. You can simply use a resistor lead cutoff.
  8. These jumpers should only be installed if U4 is not populated.
  9. 470µF should be used if driving headphones directly. You may alternatively replace γ1's C24D and C25D with 470µF units and use that section to drive headphones.

Parts selection guide

Due to the tight spacing within the enclosure, and to ensure proper fit when the γ1 and γ2 boards are plugged into each other, please observe the following recommendations. Do not use oversized parts or mount parts in a manner that was not intended. Do not change part values unless you know what you're doing. All parts are carefully selected for optimum operation.

Resistors

All discrete resistors (except the resistor networks R1 and R2) are miniature through-hole axial-lead types with a body length no longer than about 4mm, and no wider than 1.9mm. Thin film or metal film 1% resistors are recommended for their thermal stability.
R1 and R2 are SIP-8 "isolated" resistor network, with four independent internal resistors. The lead pitch is 0.1" (2.5mm).

Capacitors

There are five types of capacitors used in the γ2: conductive polymer electrolytic, audio-grade electrolytic, metallized polyester, polypropylene film and multi-layer ceramic.

C3 and C6 are conductive polymer electrolytic type for their ultra low ESR characteristics. They are through-hole with radial leads, 2.5mm lead-pitch, a maximum diameter of 6.3mm and a maximum height of 12.5mm.
  • United Chemi-Con PSA
  • Nichicon PLF
  • other similar
C11, C13, C20 and C26 are "audio grade" electrolytic capacitors. They are through-hole with radial leads, 2mm or 2.5mm lead pitch, a maximum diameter of 6.3mm and a maximum height of 12.5mm. C11 and C13 are the WM874x DAC's mid-rail decoupling capacitors, and should have the specified capacitance. C20 and C26 are the DAC's analog output coupling capacitors, and are bypassed by C19 and C25, respectively. See the metallized polyester capacitor descriptions below for C20/C26 options. If you plan to drive headphones directly from the γ2, then you should use Nichicon KW or FW 470µF 6.3V or 10V capacitors to avoid low-frequency roll-off. Note that some of these "for audio" electrolytic capacitors are non-polarized.
  • Elna RFS (Silmic II)
  • Nichicon ES (Muse)
  • Nichicon KW
  • Nichicon FW
  • Rubycon Black Gate NX Hi-Q
  • Panasonic AK
  • Elna ARD(ROD) (Starget)
  • CapXon NK
  • other similar
C19 and C25 are through-hole, radial-lead 1µF "box"-style metallized polyester capacitors with a lead spacing of 5mm. You may use MKT or MKS types (or metallized polypropylene (MKP) in a lower capacitance, but be sure that the footprint is no larger than 7.5mm x 5.5mm and the maximum height is 12.5mm. C19 and C25 are "bypass" capacitors for the C20 and C26 audio-grade electrolytic output coupling capacitors. Depending on your preference, you may omit C19/C25 and run C20/C26 unbypassed, or you may omit C20/C26 and run C19/C25 alone (but increase their capacitance of C19/C25 to 3.3µF or higher to avoid low-frequency rolloff and phase shift within the audio band). If you choose the latter option, the Wima MKS 3.3µF 50V or 4.7µF 16V capacitors are the only known ones that would fit.
C15-C18 and C21-C24 are through-hole, radial-lead polypropylene film or metallized polypropylene capacitors for the analog low-pass filter. Their lead spacing is 5mm and the footprint should be no larger than 7.5mm x 4.5mm, with a maximum height of 6mm. 5% tolerance or better is recommended for accurate filter response.
  • Wima FKP2
  • Kemet (Evox Rifa) PFR
  • other similar
All remaining capacitors are multi-layer ceramic type, with through-hole, radial-leads and 2.5mm lead-spacing. Some capacitors have 2.5mm pitch leads but come pre-bent to 5mm, you must straighten them to fit the board. All multi-layer ceramic capacitors are X7R grade. Do not use Z5U, Y5V or other lower grades.

Ferrite beads

  • L1 - L5: Panasonic EXC-ELSA35 (available from AMB audio shop)

Integrated circuits

The integrated circuits in the parts list table above should be used, with alternatives as specified below. Some ICs come in several package styles, be sure to use the correct ones that the board is designed for.

You may use either the LP2985 series or the TPS793xx series LDO voltage regulators for U1 and U2, as shown in the parts list table above.

For U3, you may use MCP100 or DS1818 in TO-92 package. Each of these come in several "threshold voltage" variants. It is recommended that you use the 3.15V or 3.00V versions if available (see their datasheets for the meaning of the part number suffix).

U6 is not needed in all configurations. Leave it vacant.

You may use either the SRC4192 or the AD1896 asynchronous sample rate converter for U4 as shown in the parts list table above. SRC4192 has somewhat superior specifications.

The default U5 stereo DAC chip is Wolfson WM8741GEDS/V. The WM8742GEDS/V is equivalent, except the S/N performance is 2dB less. The WM8740SEDS costs the least, and is the previous-generation top DAC from Wolfson, and lacks the switchable digital filters and anti-clipping mode features. See the parts list table above.

U7 should be either a OPA2365AID or AD8656ARZ. These two were chosen for their stringent rail-to-rail swing characteristics, low-noise, low distortion and high CMRR performance. Do not substitute with other opamps. OPA2365 is recommended for line-level use while AD8656 is recommended if you plan to drive headphones directly.

Oscillator

X1 is a 24.576MHz 3.3V low-jitter CMOS oscillator. The γ2 board supports either a 5mm x 7mm SMD unit or a "DIP8" 4-pin metal can through-hole device.

Connectors

Chassis / case

  • Box Enclosures B2-080 anodized with aluminum end-panels
    Add the following suffix to specify the color:
    BK - black
    BL - blue
    GD - gold
    GR - green
    RD - red
    SI - silver
    Box enclosures are available from Newark, Farnell and RS Components.
A precision CNC-machined and engraved aluminum for the γ2 + γ1 Full++ (F) combination is available from AMB audio shop. Use these for ease-of-build, upgraded appearance, and to assure a perfect fit. The γ2s shown in the Overview section are equipped with these panels.


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