Dual supply for LM1875 split supply

[danielwritesbac]

If heatsink has voltage, must use wooden amplifier enclosure.
Even better to do a wooden enclosure and an insulated heatsink.

Its not a good idea to have both a voltage source (heatsink) and a voltage reference (metal enclosure) within the reach of fingers.

For metal enclosure, insulate the back of the chip--use a size TO220 Mica insulator, White thermal compound and shoulder washers.

Any amplifier enclosure needs air inlet at the bottom and air outlet at the top (or top of back panel).

The surface of MDF is flammable. MDF needs finished, like paint, Lacquer, polyurethane, etc. . . You can use brown spray primer, scribble that with a black sharpie (wood grain looking scribbles), and then paint with "Polyshades" of a dark color like Bombay red or Walnut brown, for a fairly pretty finish on MDF.

P.S.
Also observe a common 2-cell flashlight. This is similar to a split rail power supply. The centrepoint between the two batteries in the 2-cell flashlight is the 0v tap.