The Results:
1) The LPS is a NO GO in the 103. It runs too hot and the sonic benefits were simply not what I expected. The enclosure is sealed, so there is no good way to reject heat. Mr. Lee has designed a LPS that may be used in the unit. I have tested and installed a 'Lee' LPS and it is a good design. However, if you add Lee's LPS to a unit that we have modified, it WILL void our warranty. I simply feel that the LPS generates too much heat for the 103.
2) The LPS in the 105 I have looked at extensively and decided the following:
A) It ONLY provides 5V supply to the processor board and +15V to the drive.
B) Despite the fact that the unit is passively ventilated, it already runs warm and I am concerned about heat.
C) The LPS would put two transformers right below the MCH audio board and I would be concerned about EMI and other noise contributions.
D) Ultimately, due to my findings with the 103, I have decided that the LPS for the 105 is simply not going to provide a worthwhile benefit and I am not willing to add the risk of future reliability issues, due to excess heat.
3) I listened to the 103 with LPS and SMPS and found VERY little difference. I also measured the digital out signal and found no measurable difference.
4) The 103 stock is NOT as good as the 105 stock! The 105 is MUCH BETTER!
5) The modified 103 (without LPS), but with upgrades to shielding, damping, parts upgrades in analog stage and power supply is much better and closer to the performance of the stock 105, but I would have to give the edge to the stock 105.
I have decided that we will offer a $500 mod for the 103 that will include the following (2CH only):
Power Supply upgrades to stock SMPS.
Chassis damping and shielding.
Upgrades to analog stage (eliminate all coupling caps).
Upgrade IEC to Furutech Cryo-treated IEC.
I am still tweaking a couple of things, but I first had to make a decision about the LPS. I have not compared the two units strictly as transports, but would expect very similar results. In both units, the digital out circuit, on the processor board, is powered by the SMPS. This includes audio coax and optical out, as well as HDMI for video. Both 105 and 103 use the same processor board and video chipset, powered by the same SMPS (Power Supply) design.
Our mods for the 103 are intended to improve its use as a player primarily. The damping, shielding and power supply upgrades will provide some improvement to its use as a transport and for video.
Thanks guys, it has been a bit of a journey here and the results of the LPS surprised me, but I refuse to offer an upgrade that I do not feel is worthwhile and also that I am not confident of its ultimate reliability.
Sincerely,
Dan W.