Re: [R-390] 600 to 8 ohm phone mod

[DJED1 at aol.com]

I don't know if this made it into the "pearls of wisdom" but there is an easy 
fix for the headphone impedance problem.   The reason the low-Z phones don't 
work well is that there is a 6800 ohm series resistor between the audio line 
and the headphone jack. Thus 600 ohm phones divide the voltage a little, 8 ohm 
phones drop the voltage a lot.   However, you can parallel the resistor by 
connecting another lower value resistor from terminal 6 to terminal 8 of the 
audio terminal strip on the back.   I used 470 ohms, but it can be adjusted to 
suit your phones.   Works good with my 8 ohm phones.
Ed