FS#12354 - WM8985 DAC voltage tweak for Cowon D2
Opened by Stanislav Chizhik (anotherche) - Thursday, 27 October 2011, 07:40 GMT
Last edited by MichaelGiacomelli (saratoga) - Tuesday, 15 November 2011, 23:39 GMT
Some tech details. Audio codec Wolfson WM8985 uses 4 power supplies: DCVDD - for digital core logic, DBVDD - for digital I/O buffer, AVDD1 and AVDD2 - for analogue output. Allowed range for them is 1.7 to 3.6 V (1.8 to 3.3V recommended for DCVDD and DBVDD, while 2.5 to 3.3V is for AVDD1/2). Rockbox configures these voltages as following DCVDD=1.8V, DBVDD=AVDD1/2=3.3V, which is optimal for quality and power consumption according to wm8985 documentation.
There is an opinion that rising the DCVDD voltage can give some additional improvement of audio quality for the cost of power consumption (up to ~10% higher consumption). The idea is first implement by CowonWorld.ru user stridervvv and discussed at http://cowonworld.ru/forum/viewtopic.php?f=52&t=1342&start=165 (Russian).
The patch develops the idea by allowing Cowon D2(+) users to regulate the DCVDD voltage in the menu (sound settings menu). Voltage range: 1.8 - 3.3 V. Changes are applied immediately. The patch is for r29795.
Tuesday, 15 November 2011, 23:39 GMT
Reason for closing: Rejected
Additional comments about closing: We don't want user customization of voltages, and it seems very likely that these changes are not beneficial. If some of the D2(+) voltages should be adjusted, feel free to start a new task.