74HC244:
      +-----U-----+
 1 -->|/1OE    Vcc|<-- 20
 2 -->|1A0    /2OE|<-- 19
 3 <--|2Y0     1Y0|--> 18
 4 -->|1A1     2A0|<-- 17
 5 <--|2Y1     1Y1|--> 16
 6 -->|1A2     2A1|<-- 15
 7 <--|2Y2     1Y2|--> 14
 8 -->|1A3     2A2|<-- 13
 9 <--|2Y3     1Y3|--> 12
10 -->|GND     2A3|<-- 11
      +-----------+


CIRCUITRY:

 D0 o----[BUF]----[2R]----o----[2R]----[GND]
                          |
                         [R]
                          |
 D1 o----[BUF]----[2R]----o
                          |
                         [R]
                          |
 D2 o----[BUF]----[2R]----o

  :        :       :      :

D14 o----[BUF]----[2R]----o
                          |
                         [R]
                          |     +
D15 o----[BUF]----[2R]----o------||--------o AUDIO OUT
                          |    6.3V 10uF
                         [2R]
                          |
                        [GND]

NOTE:

  Vcc = 3.3V

  /1OE = /2OE = GND

  R  = 150[Ohm]
  2R = 150+150[Ohm]

  BUF = xAy --> xYy  (x = 1,2  y = 0,1,2,3)

  Use 2 x 74HC244 or equivalent buffers