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/repurposed 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 from the USB 2.0 DIY power-only cable to the required 9V. At max I believe this converter is using under 1W (<167mA @ <5V). agdr Audio OPA1688 Parallel Super CMoy Specs Output Current (peak): 150 mA per channel Output Current (rms): 106.05 mA per channel Output Impedance: ~0 ohms Voltage Gain: 1x ("unity-gain amplifier") Voltage Cut-Off Level: 8.4 Vnominal Voltage Swing (peak): 7.4 Vp (aka Vdc) Voltage Swing (rms): 5.23 Vrms 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 Dual-Chip OPA1688s in Parallel "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) 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 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 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 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) 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) 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/ STANDOFFS I 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.