Two areas of possible improvement that I am looking at, are the stock SMPS (Switched Mode Power Supply) and the headphone out circuit.
The SMSP MAY be replaced with a linear supply of our own design. This will benefit the video and other aspects of the player, that are not fed from the linear audio power supply in the 105.
The headphone circuit is another area of potential improvement. It already uses a very good current-feedback amplifier, to match HP impedance. It is, however, driven by an op-amp circuit of VERY low gain. Not sure why, but according to the Oppo folks, there was a firmware conflict that required them to keep the gain low on the HP outs. I believe I have a way to replace the op-amps with tube signal and still retain the SS impedance matching HP amplifier, as THAT chip is exceptional and uses no negative feedback, only current feedback.
I am looking at both options, regardless, but if I had a show of hands, as to how many people will WANT these upgrades, it would be helpful!
Sincerely,
Dan W.