It could be one opamp is broken. I had a similar problem. Change the opamps from position, if the measure also changes position you’ve found the error.
I finally got some ultracaps added to my player. I have a Mk1 battery board and added them as per Ian's original instruction across the cells after pre-charging...very carefully! There is potential for nasty unintended consequences here. I used some RC battery pack connectors to enable straightforward disconnection and insertion of a pre-charging resistor if need be. I cable tied the caps to a perspex sheet and stacked them underneath to neaten things up.
As I had three pairs I ultracapped the DAC AVCC, FiFoPi and separated clock supply rails. Early days as nothing has broken in yet, but initial impressions are yet another small veil of artifice has dropped away. I didn't want to stop listening. I don't think I can be bothered to A/B and isolate the effect on each of the three rails... but you never know I might get that bored/curious.
The only downside here is the ultracap pair balancing resistors slowly bleed away the charge so, if like me, you don't listen every day you need to remember to charge them before they get too hungry for the charge circuit!
As I had three pairs I ultracapped the DAC AVCC, FiFoPi and separated clock supply rails. Early days as nothing has broken in yet, but initial impressions are yet another small veil of artifice has dropped away. I didn't want to stop listening. I don't think I can be bothered to A/B and isolate the effect on each of the three rails... but you never know I might get that bored/curious.
The only downside here is the ultracap pair balancing resistors slowly bleed away the charge so, if like me, you don't listen every day you need to remember to charge them before they get too hungry for the charge circuit!
Attachments
@misterdog the problem with these great rambling threads...
Separate clock power is tricky. If you haven't got a decent magnifier get one! I subsequently ditched the OsCon and went with a 1uF Wima MKP2 on Greg Stewarts advice. There is a 100pF NPO as close to each NDK as I could manange as per the datasheet. I also wound up making two little RF cans for the oscillators too, they are definitely very emmissive. Another subtle improvement but definitely worth trying. Stray RF is the enemy!
IanCanada's Latest RPi GB Goodies Impressions... and your tweaks, mods and hints...
Additional 3v3 rail:
Develop ultra capacitor power supply and LiFePO4 battery power supply
Separate clock power is tricky. If you haven't got a decent magnifier get one! I subsequently ditched the OsCon and went with a 1uF Wima MKP2 on Greg Stewarts advice. There is a 100pF NPO as close to each NDK as I could manange as per the datasheet. I also wound up making two little RF cans for the oscillators too, they are definitely very emmissive. Another subtle improvement but definitely worth trying. Stray RF is the enemy!
IanCanada's Latest RPi GB Goodies Impressions... and your tweaks, mods and hints...
Additional 3v3 rail:
Develop ultra capacitor power supply and LiFePO4 battery power supply
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Of course if you are running clocks with the adaptors it's a lot easier. You can just remove the power pin from each little pcb and attach a wire straight on. I just like making things difficult for myself
Though in these challenging times, having a good challenge can alleviate the monotony..
Thank you for your reply.
Hi, did you get the DAC running at 768kHz ?
How the Accusilicon Clock are sounding ?
Did anybody running the dac @ 768kHz ? Which clocks in place ?
I have order the 90/98 as I want to run the DAC @ 768kHz.
Actual the NDKs are installed, I hope the Accusilicon playing on the same level as NDK.
Best
Marcus
Great Thanks. I will take a look.
I almost forgot that the other thread "well tempered clock" will have something new coming up soon. I will check it out and wait.
I put the Fifopi in along with AD1865 R2R Dac Hat for RPI.
It is just wonderful. The harshness is virtually gone; bass is more solid.
Everything is so sweet and wonderful.