Saturday, July 21, 2007

Optocoupler volume control

Audio level control with resistive optocouplers

DIY Audio thread (very looooong).

Use low noise PSU (SLA battery) and add capacitor (good 100uF low-LSR; consider Murata 47uF ceramic) in parallel to LDR LEDs.
I recommend usage of Silonex NSL-32SR2S (sorted, matched).


On SLA PSUs...

"... you power it with unregulated +/-12V SLA batteries and use plenty of fast capacitance across the battery terminals and bypass caps at the IC pins ..."

Sunday, July 15, 2007

PSU implementations


this weekend I am working on the PSU reimplementation.
After lots of thinking I end up with.

HT PSU - simple (R)CRCRC using high quality electrolyte aluminium capacitors (220uF; low ERS, high ripple current - e.g. EPCOS), bypassing them with polypropene (4,7uF; WIMA MKP4). Since ElCo-s are slower than polypropene and do not hanle high requencies well, I will use decoupled electrolytic capacitor technique - patented by Audio Research. See AR-LS22 schematic for realy good design. I like it very much.

LV PSU - simple C(R)C with LM317 regualtor (initialy low ripple configuration, later with slow start-up). This power could also be used as digital power supply (receivers, USB, XO-DAC).


Reclocking (implementation)

(mail to Guido Tent)


I am considering buying an XO-DAC, but I have one technical question before purchasing.
I have use CS8414 and AD1865N (Audio Note config).

Using XO-DAC will get MCK (and DGND) from the CS8414 and will output clean clock. Since no filter is being used, connection is not so straight forward.
CS8414 has outputs:
- this is being replaced by XO-DAC
- SCK (=MCK/4)
- I can get this by dividing new MCK (2 flip-flops)

The question is what to do with these:


I guess simply aligning them (w/ D flip-flops) to the new MCK, is the best ting to do? Right.
Well, decoding SDATA and FSYNC to left/right data before D flip-flops is slightly better - to avoid gate's jitter.