EDITED WITH ADDITIONAL BUILD UPGRADE INFORMATION & PICS
My USB-Powered "Steampunk" DAC headAMP build in three (3) parts...
BUILD; PART 1 (Case)
The case was constructed out of two (2) reclaimed/re-purposed wooden cigar boxes; a small sheet of Hardboard - High-Density Fiberboard (HDF); and copious amounts of wood glue. The case was then decorated with vintage postage stamps with decoupage glue... with well over fifty (50) thin layers of finely sanded decoupage varnish.
BUILD; PART 2 (USB-Powered HeadAMP)
I used agdr audio's OPA1688 Parallel (Dual Chip) "Super CMoy" head amp board and it is performing wonderfully! Many thanks to @adydula for assisting me in more ways than one with this build... very much appreciated good sir! The board has been upgraded from 2 X 9V battery operation to a USB-feed DC-DC Converter power supply.
The power module consists of a RECOM RW-0509D DC-DC Converter which converts the 5V (500mA; ~2.5W) from the USB 2.0 DIY power-only cable to the required 9V. USB 2 easily covers the converter's current requirement of ~167mA per rail (~334mA total) and when at max loading this converter is using less than 1.9W!
agdr Audio OPA1688 Parallel Super CMoy Specs
Output Impedance (ohms): ~0 Ω
Voltage Gain: 1x ("unity-gain amplifier")
Peak Voltage Swing: 7.4 V (aka Vp or Vdc)
Peak Output Current: 150 mA per channel
RMS Output Voltage: 5.23 Vrms
RMS Output Current: 106.05 mA rms per channel
Maximum Power (rms): 181 mW @ 16Ω (1.7 V)
Maximum Power (rms): 360 mW @ 32Ω (3.4 V)
Maximum Power (rms): 427 mW @ 64Ω (5.23 V)
Maximum Power (rms): 228 mW @ 120Ω (5.23 V)
Maximum Power (rms): 182 mW @ 150Ω (5.23 V)
Maximum Power (rms): 91 mW @ 300Ω (5.23 V)
Maximum Power (rms): 46 mW @ 600Ω (5.23 V)
Without further ado, my creation (please kindly excuse the 'shotty' soldering and gluing... I battle severe hand tremors):
THE GUTS (INSIDE)
The copper tomb... no EMI/RFI getting in this here amp!
Ground wire point is at top right
Larger diameter cord grip/cable gland had to be used to allow for USB connector to pass through, as well as for future extra cables and upgrade capability.
A Silica Gel Pack Has Been Taped On The Under-Side Of The Lid To Battle The Siamese Humidity. As you can see the copper under the lid is already quickly tarnishing.
Chicago Sex Screws (Female Bottoms) for the leather straps are seen on the underside of the lid.
agdr Audio Super CMoy headAMP module
"OPA1688 Parallel Super CMoy dual-chip headphone amplifier with a real ground and a headphone relay for zero turn-on or turn-off thump and essentially zero (250uV) DC output offset voltage. Uses two (2) of the brand new Texas Instruments OPA1688 ( http://www.ti.com/product/OPA1688 ) headphone driver chips in parallel for 150mA output per channel (6x the output of most op-amps). Ultra low distortion with extremely low idle current for long battery life. Uses 2 9V batteries with a real ground and "solid state relay" technology - no virtual grounds or rail splitters to distort the sound." - agdr audio
The black colored hot glue messes you see are only to protect the power leads solder joints from my inept hands
FACE (FRONT SIDE)[/B]
Brass Volume Knob (6mm Shaft Diameter X 19mm Knob Diameter); UPDATE: see most recent post in this thread; the knob has been replaced with a 1930s vintage tube radio knob.
Switchcraft 35RA 3.5mm Headphone Jack (Stereo TRS 3-Position Switched)
1840 Penny Black
1841 Two Pence Blue
1841 Penny Red
1853 Four Pence Cape of Good Hope
1901-1934 Federated Malay States (FMS) Tigers
1898 US Battleship Revenues (U.S.S. Maine); aka "Battles"
BACK SIDE
Left: Hammond Cordgrip / Cable Gland 1427CG7 (2.54mm-6.6mm)
Right: WZOG Ouguan Electric Cordgrip / Cable Gland PG-11 (5mm-10mm)
US Internal Revenue RS114d John Henry Medicine
More "Battles" and "Tigers"...
LEFT SIDE[/B]
Chicago Sex Screws (Male 6mm Tops; Female 6mm & 8mm Bottoms) with Raw Brown Leather Straps
1898 US Battleship Proprietary Revenue Set RB20-RB31 with a few First Tax Day Issue dates
RIGHT SIDE[/B]
1898 US Battleship Documentary Revenue Set R161-R172 with a few First Tax Day Issue dates and late/post tax usage dates 2 May 1902
TOPSIDE[/B]
Bronze Cigar Box Protective Corners
Chicago Sex Screws (Male 6mm Tops; Female 6mm & 8mm Bottoms) with Raw Brown Leather Straps
1936 Germany Zeppelin Airship LZ 129 Hindenburg First Mail Flight Cover
1934 Germany Death Of President Hindenburg; Complete Set (Black Mourning Border)
1936/1938 Germany Zeppelin & Lufthansa Air Post Stamps
1899 Russia Zemstvo Postal; Imperial Post (Moscow)
UNDERSIDE (BOTTOM)
Bronze Cigar Box Protective Corners
Adhesive Rubber Silicon Feet
1914 US Cover Mailed Onboard SS (RMS) LUSITANIA 1914 (RMS Lusitania was a British ocean liner and briefly the world's largest passenger ship; she was sunk on 7 May 1915 by Imperial German Navy U-boat SM U-20)
Various Great War Propaganda Stamps
More "Battles"
RECOM RW-0509D DC-DC CONVERTER POWER SUPPLY MODULE (PIC 1 & 2)
CTS Black Aluminum Heat Sink 40mm x 40mm x 9.5mm
RECOM RW-0509D DC-DC CONVERTER POWER SUPPLY MODULE (PIC 3)
Heat Sink Insulation & Grounding Pad
BUILD; PART 3 (DAC)[/B]
For the DAC I used the new Khadas "Tone Board" by WesionTEK after reading the reviews and testing measurements on Audio Science Review (thanks @amirm !). Very detailed measurements are provided by Amir.
WesionTEK Khadas Hi-Res Audio Board (Generic Edition) Specs
XMOS: XU208-128-QF48 (8x Cores up to 500MIPS)
DAC: ESS Sabre ES9038Q2M (32-Bit Stereo Audio)
Output Impedance (ohms): ~100Ω
RMS Output Voltage: ~2Vrms
THD+N: ≤ 0.000337% @1KHz
SNR: ≥ 120dB @ 10Hz~20KHz
DNR: ≥ 120dB @ 10Hz~20KHz
Crosstalk: ≥ 127dB @ 10Hz~20KHz
Frequency Response: ±0.08 dB @ 10Hz~20KHz
Sampling Frequency: PCM: Up to 768KHz @ 32bit; DSD: Up to DSD256 @ 1bit
Clock Jitter: Reference Clock Jitter < 3ps; Data Clock Jitter < 30 ps
Audio Formats: APE2/FLAC/OGG/WAV/ACC/ALAC/MP3/WMA…
Line Out: 1x Red RCA for Right, 1x White RCA for Left
S/PDIF IN: Up to 192KHz (S/PDIF OUT: Not Supported)
USB-C Port: Power Supply (DC: 5V/500mA) & USB 2.0 Data
Compatibility: Windows PC; Linux PC; Mac OS X; Raspberry Pi
Dimensions: 82.0 x 74.5 x 17.0 mm
GENERIC EDITION TONE BOARD
PCB - PERFBOARD MOUNTING w/ STANDOFFSI super glued two (2) perfboards together and mounted the Tone Board to them.
BOTTOM OF BOARD
Heat Sink Insulation & Grounding Pads before removing the adhesive backing strips to affix to bottom of case
INTERCONNECT
ghentaudio B02 3.5 (⅛") TRS ♂to RCA (♂+♂) Canare L-2B2AT Cable
Length: 10 cm; customized order.
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