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"Steampunk" DAC HeadAMP (agdr Audio Super CMoy + WesionTEK Khadas Tone Board)

Discussion in 'Headphone Amps (full-size)' started by WoodyLuvr, Oct 21, 2018.
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  1. WoodyLuvr


    :robot::skull::scream: EDITED WITH ADDITIONAL BUILD UPGRADE INFORMATION & PICS :atom::radioactive::biohazard:

    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 USB-feed DC-DC Converter power.

    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 it is using under 1W (<180mA @ <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 V nominal
    Voltage Swing (peak): 7.4 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.[​IMG]

    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.
    [​IMG]

    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 :wink:
    [​IMG]

    FACE (FRONT SIDE)

    Brass Volume Knob (6mm Shaft Diameter X 19mm Knob Diameter)
    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"
    [​IMG]

    [​IMG]
    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"...
    [​IMG]

    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
    [​IMG]

    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
    [​IMG]

    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
    [​IMG]
    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)
    [​IMG]

    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"
    [​IMG]

    RECOM RW-0509D DC-DC CONVERTER POWER SUPPLY MODULE (PIC 1 & 2)

    CTS Black Aluminum Heat Sink 40mm x 40mm x 9.5mm

    [​IMG]
    [​IMG]

    RECOM RW-0509D DC-DC CONVERTER POWER SUPPLY MODULE (PIC 3)

    Heat Sink Insulation & Grounding Pad
    [​IMG]


    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
    [​IMG]

    PCB - PERFBOARD MOUNTING w/ STANDOFFS
    I super glued two (2) perfboards together and mounted the Tone Board to them.
    [​IMG]
    [​IMG]

    BOTTOM OF BOARD

    Heat Sink Insulation & Grounding Pads before removing the adhesive backing strips to affix to bottom of case[​IMG]

    INTERCONNECT

    ghentaudio B02 3.5 (⅛") TRS to RCA ( + ) Canare L-2B2AT Cable
    Length: 10 cm; customized order.
    [​IMG]
     
    Last edited: Jun 10, 2019
  2. adydula
    Ha!!

    Congratulations!!

    Great looking amp!

    Well....how does it sound to you?

    Smiling here!

    Alex
     
    WoodyLuvr likes this.
  3. DavidA
    Cool looking amp and like Alex noted above, HOW DOES IT SOUND :ksc75smile:
     
    WoodyLuvr likes this.
  4. WoodyLuvr
    Thus far, it is dead silent even with the volume pot at max volume.

    Here are some details and specs:

    "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 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

    150 mA output per channel
    zero output impedance (yes, 0 Ohms)
    unity gain

     
    Last edited: Dec 2, 2018
  5. WoodyLuvr
    This RECOM RW-0509D DC-DC CONVERTER POWER SUPPLY MODULE has been running now for more than 36 hours and running very cool coupled to a 40 x 40 x 9 mm aluminum heat sink. Easily handled with bare fingertips. I am pleased to say the least!
     
  6. adydula
    The OPA 1688 is a very nice op amp.....and its nice to see TI making a chip designed especially for this area of our hobby.

    AGDR did a great job designing this amp in its form factor and I was elated to wire it up and it worked wonderfully for me.

    I actually built three of them in AGDR's development phases....I still have a prototype and a single 1688 version. Sonically they are identical.

    I dont know if AGDR is still selling the pc boards..but you can PM him over at diyaudio.com

    Some of the soldering is indeed challenging!!

    Enjoy!
    Alex
     
    Last edited: Oct 22, 2018
    WoodyLuvr likes this.
  7. WoodyLuvr
    Volume knobs finally arrived from China and I decided on this bronze metal one.

    [​IMG]
     
    DavidA likes this.
  8. WoodyLuvr
    Now in it's place sitting beside "UV Siamese 2" Silent Fanless SFF PC

    [​IMG]
     
    DavidA likes this.
  9. WoodyLuvr

    Oh my this little amp sure is powerful!

    I have had to set foobar2k music player down to -16dB so it won't blow up my 32Ω Nhoord Reds or 300Ω Blurs! It pushes both drivers way too hard especially on a few prominent sub-bass tracks that I have (e.g. Gustav Holst: The Planets, Op.32/H.125: vii. Neptune, the Mystic; Andante Original Ending - Mark Elder; Hallé Orchestra & Choir or Jóhann Jóhannsson's Sicario: ii. The Beast).

    System volume (Win10) is still set at 100% though.

    Full Specs for agdr Audio OPA1688 Parallel Super CMoy
    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 V nominal
    Voltage Swing (peak): 7.4 Vdc
    Voltage Swing (rms): 5.23 Vrms


    So this 'little dual-chip head amp that could' should be able to handle not only the power hungry HE6 driving them up to 105 dB SPL but the mighty AKG K1000 as well... albeit only driving it to 97 dB SPL which is still doable for all but the most dynamic/heavy sub-bass pieces.

    HiFiMAN HE6
    [​IMG]

    AKG K-1000
    [​IMG]
     
    Last edited: Dec 2, 2018
    DavidA likes this.
  10. DavidA
    I'm so glad that you show sound technical info since lately there are so many that say you need an amp with 1.21 GW of power for even average headphones on some threads but I've found that its more of a synergy effect that tends to make one amp pair better with some headphones over other amps. My Teac UD301 headphone output only has 100mW but even it is enough for my HE560 and LCD-2f but there are still those that are recommending amps of >4W for them.

    FWIW I wish I had the time and knowledge to build an amp like you or another Head-Fi member who let me try a powerDAC (a bit like a Mojo) that he built for driving a HE400i but it has enough juice to drive even my HE560 which needs a bit more grunt to get to my listening levels.
     
    WoodyLuvr likes this.
  11. WoodyLuvr
    Concur, I don't get most of those "more power required" recommendations you speak of nor do the audiophiles that I know here in Thailand whom are very high level electrical engineers! Now there are a few (very few) headphones out there that are indeed power hungry and do require a higher voltage swing to perform well but not the amounts that are being readily recommended. So what it comes down to with insensitive headphones like the HE6 and K-1000 is not so much about the need for extreme wattage but rather the quality amp and it's power supply (synergy being part of that of course).

    Look at the recommended specs for your HiFiMAN HE-560:

    Nom. power rating: 2W (estimated)
    Max. voltage: 10V
    Max. current: 210mA
    Max. S.P.L.: 119dB
    Impedance: 45 Ω
    Efficiency: 86 dB/1mW (99dB/1V)

    So your HE560s only need 251mW, 75 mA, and 3.4V to reach 110 dB SPL. Your TEAC UD301 is driving your HE-560s perfectly fine providing 106 dB SPL and there is enough dynamic headroom there to handle sub-bass demands. As per the bottom portion of the table a 4W amp hooked up to your HE-560s would be very unwise... feeding your cans over 13.5V @ 300mA which is way beyond the recommended specs for your cans.

    [​IMG]


    The only headphones I can think of that truly would require a ~4W amp to reach ~110 dB SPL would be the almighty AKG K-1000... they require ~182 mA @ ~21.8Vrms! However again, with only 40mW @ 18mA and 2.2V the K-1000 can be easily driven to a very listenable 90dB SPL with all but the most dynamic and sub-bass heavy tracks.

    So where does one draw that line of diminishing returns in regards to a higher wattage amp and better yet wouldn't one rather focus on better build quality and power supply than seeking higher wattage?
     
    Last edited: Nov 5, 2018
  12. WoodyLuvr
    A sneak peek of what is coming in the mail... part two of the build will commence soon!

    [​IMG]
     
  13. DavidA
    :thumbsup:USB-C and I can't figure out why there are 3 RCA jacks? L & R output + digital coax input is my guess. A DAC board?
     
    WoodyLuvr likes this.
  14. WoodyLuvr
    Yep, a Khadas ES9038Q2M Tone Board with 2 x RCA Outputs and 1 x SPDIF/OPTICAL Input (offers output as well on the VIMs model).
     
  15. DavidA
    not bad for a wild guess, LOL
     
    WoodyLuvr likes this.
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