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Posts posted by justin

  1. 16 hours ago, themystical said:

    Seems to be working really well!! 
    Any comments/initial reaction on SQ with and without base boost?

    How warm is the heat sink getting?  Could it be much smaller?

    keep in mind the thermal transfer for this package is not great, with a good insulator the IC will be 3C/W hotter than the heatsink. so you do need to keep the heatsink cool. temperature in this case with the RAAL is dependent on music and how loud you're listening. My guess is in most uses the heatsink will not exceed 40C. with no audio it will be room temp.

    so if the heatsink reaches 40C w/ an average of 15W per IC then the IC temp will be around 85C

    There is also the TO-3 package @ $150 ea. and Apex has parts of a similar price

  2. I received a suggestion that the grounds for the L/R output, which in this case is the 4-pin XLR but would also be the negative posts on the speaker terminals, be wired back to each L/R channel board rather to the star ground at the switching PSUs

    open for debate on that

  3. 7 hours ago, n_maher said:

    Sweet!  You up for giving it a shot driving speakers instead of ear speakers?

    can try but it will be limited by voltage swing. 25W/8-ohm and 50W/4-ohm

    as of right now here is where the difficult work actually starts, and the time consuming work. I'd be interested if anyone wanted to finish it up before putting in the $$/cost on their own unit. 

    for future board revisions:

    - make the jumper over the bass boost 3x 0.1" pins so a push-on jumper can be used + have a place to store it and/or add small signal DPDT 24v relay to switch it (add a 2nd value with moar boost?)

    - don't block the heatsinked part mounting screws with the electrolytic caps

    - holes for wires too small to accommodate 16awg, used 20awg instead

    - caddock resistors need to be bent in an L, move them closer to edge of pcb if possible

    - 2nd output hole for wiring another output

    • Like 2
  4. Mouser #: 595-OPA541AP
    Mfr. #: OPA541AP
    Desc.: Operational Amplifiers - Op Amps Operational Amplifiers - Op Amps Hi-Power Monolithic Op Amp
      4 $21.40 $85.60
    4 Shipped 06-Aug-20 57782631
    Mouser #: 80-T354G106K035AT
    Mfr. #: T354G106K035AT
    Desc.: Tantalum Capacitors - Solid Leaded Tantalum Capacitors - Solid Leaded 10.0uF 35.0V10%
      10 $1.28 $12.80
    10 Shipped 06-Aug-20 57782631
    Mouser #: 710-860160575031
    Mfr. #: 860160575031
    Desc.: Aluminum Electrolytic Capacitors - Radial Leaded Aluminum Electrolytic Capacitors - Radial Leaded WCAP-ATLL 35V 1000uF 20% Radial
      4 $1.29 $5.16
    4 Shipped 06-Aug-20 57782631
    Mouser #: 581-SR212A200JAR
    Mfr. #: SR212A200JAR
    Desc.: Multilayer Ceramic Capacitors MLCC - Leaded Multilayer Ceramic Capacitors MLCC - Leaded 200V 20pF 5% C0G
      4 $0.45 $1.80
    4 Shipped 06-Aug-20 57782631
    Mouser #: 505-MKP20.022/100/5
    Mfr. #: MKP2D022201B00JSSD
    Desc.: Film Capacitors Film Capacitors 100V .022uF 5%
      2 $0.48 $0.96
    2 Shipped 06-Aug-20 57782631
    Mouser #: 71-RN55C6501B
    Mfr. #: RN55C6501BB14
    Desc.: Metal Film Resistors - Through Hole Metal Film Resistors - Through Hole 1/10watt 6.5Kohms .1% 50ppm
      2 $0.61 $1.22
    2 Shipped 06-Aug-20 57782631
    Mouser #: 71-RN55C-B-10K
    Mfr. #: RN55C1002BB14
    Desc.: Metal Film Resistors - Through Hole Metal Film Resistors - Through Hole 1/10watt 10Kohms .1% 50ppm
      10 $0.999 $9.99
    10 Shipped 06-Aug-20 57782631
    Mouser #: 709-UHP-350-24
    Mfr. #: UHP-350-24
    Desc.: Switching Power Supplies Switching Power Supplies 350.4W 24V 14.6A W/ PFC
      2 $67.31 $134.62
    2 Shipped 06-Aug-20 57782631
    Mouser #: 684-MP930-0.1
    Mfr. #: MP930-0.10-1%
    Desc.: Thick Film Resistors - Through Hole Thick Film Resistors - Through Hole 0.1 ohm 30W 1% TO-220 PKG PWR FILM


    Qty 4

  5. 3 hours ago, kevin gilmore said:

    I would think that a minimum of 50 watts of heat per channel seems reasonable. 

    a dissipante 3U seems like it would work. probably 1 size down would also work if there is enough room for the switchers.

    I like how a heatsinked 3U chassis is now the modest build answer

    • Like 3
    • Haha 3
  6. Since i'm getting behind the times, i finally installed Roon last night. Worked instantly on my 2015 Android TV, Mytek Manhattan II, Denon receiver (though that is a bit redundant with the TV, not sure which is better). Only negative so far is you can't stream the same music to multiple devices simultaneously if they do not use the same protocol.

    For Mytek it's a no brainer, it's infinitely better than the mcontrol software

  7. 12 hours ago, puretaka said:

    Didn't you read the JH marketing quote above?  The sound is:

    • warm
    • neutral
    • analog

    All at the same time! 🥴

    so many IEMs for sale now are straight copies of JH designs..its not even possible to keep up anymore. Just about everything is all marketing these days so to go after JH marketing is a bit ironic

    • Like 5
  8. Jerry Harvey Audio is releasing a universal fit version of their JIMI custom IEM, limited to 200pcs, and offering it exclusively to dealers (HeadAmp is one). We have some on the way, and some black shelled demo pairs as well. The shells are are also smaller than JH's previous generation of universal fit earphones.


    From Jerry Harvey Audio: 


    We are excited to introduce the Jimi Aion Series! The initial launch of our universal fit Jimi's will be a dealer exclusive, limited edition run of only 200 sets. The Jimi Aion features our Sonic Tube Chassis, Acoustic Sound Chamber, 7-pin Connector, and limited edition Purple Haze shell. Jimi uses a 7-driver BA configuration offering a warm, neutral, analog sound signature. Using our Sonic Tube Chassis, we were able to considerably reduce the size, making it the smallest in the Aion series. Listen for hours, comfortably. These won't last long, so contact your local dealer soon to pre-order!



    • Like 1
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