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Develop ultra capacitor power supply and LiFePO4 battery power supply
Develop ultra capacitor power supply and LiFePO4 battery power supply
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Old 14th June 2019, 12:31 AM   #661
alazira is offline alazira  United States
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So I obtained the LiFePO4 specifically as a replacement for the NiMH battery pack I made for EUVL’s SEN IV. This circuit works best with a floating supply.
Zen -> Cen -> Sen, evolution of a minimalistic IV Converter

Upon first hookup the results were disappointing. There was a lot of hum/hiss audible from my 8’ listening distance, a rather violent on/off pop (even lightly tapping the encoder knob produced a zap through the speakers) and, something I haven’t experienced in a while, listening fatigue.

Floating supplies are very sensitive to emf pickup so I started wrapping the batteries with Al & Cu foil. Some improvement. Encouraged, I kept adding shielding (magnet shield on the top Magnetic Shielding Materials). I now had to go to 2’ to hear the noise. Finally, earth-grounding things just about slayed the noise (tiny bit detectable with ear to driver). It also stopped the pops from merely tapping the board but not the on/off one (still working on solution to that).

Okay, so why am I telling you this? The improvement in the music was much more than a mere lowering of the noise floor. There was more texture to the notes, better atmosphere, improved bass, less sibilance on "s", and no more listening fatigue. This has made me reconsider the importance of shielding and perhaps explain improvements like this reported my Markw4
IanCanada's Latest RPi GB Goodies Impressions... and your tweaks, mods and hints...

Last edited by alazira; 14th June 2019 at 12:37 AM.
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Old 14th June 2019, 12:44 AM   #662
iancanada is offline iancanada  Canada
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Develop ultra capacitor power supply and LiFePO4 battery power supply
@alazira

It's so great that you implemented the LifePO4 power supply to CES/SEN I/V stage. Congratulations!

I know that the LifePO4 power supply is ideal for floating power application. So that what I want to do the next. But I've never thought the noise issue. Thank you so much for sharing your experiences. Do you have pictures of your system?

Regards,
Ian
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Old 14th June 2019, 09:10 PM   #663
alazira is offline alazira  United States
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Quote:
Originally Posted by iancanada View Post
@alazira

It's so great that you implemented the LifePO4 power supply to CES/SEN I/V stage. Congratulations!

I know that the LifePO4 power supply is ideal for floating power application. So that what I want to do the next. But I've never thought the noise issue. Thank you so much for sharing your experiences. Do you have pictures of your system?

Regards,
Ian
Magnet shield on top, giron mat bottom. I will see if I can find a similar weight aluminum sheet to compare with the magnet shield from less emf. An aluminum foil I tried was not nearly as effective. In this picture the earth ground is not connected to the magnet shield. Using the thin clip wire to attach it to ground improved things but grounding directly much more so.
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Last edited by alazira; 14th June 2019 at 09:16 PM.
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Old 15th June 2019, 11:03 PM   #664
alazira is offline alazira  United States
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Quote:
Originally Posted by alazira View Post
Magnet shield on top, giron mat bottom. I will see if I can find a similar weight aluminum sheet to compare with the magnet shield from less emf. An aluminum foil I tried was not nearly as effective. In this picture the earth ground is not connected to the magnet shield. Using the thin clip wire to attach it to ground improved things but grounding directly much more so.
I tried a larger/heavier aluminum piece (from F5-X amp). It works as good as the magnet shield, but it is much more substantial so I don't know if Al is = to magnet shield or not, but shielding your LiFePO4 in an grounded aluminum case is probably a good idea.
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Old 20th June 2019, 10:45 PM   #665
alazira is offline alazira  United States
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I've been troubleshooting my 3rd LiFePO4 board which has a loud hum an order of magnitude more than what the other boards started with.

Things I've tried:
Checked output voltages - correct
Shielding - minimal effect
Swap batteries with the other boards - no difference
inspect for missing resistors/capacitors - all present

Is there anything else I could try?
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Old 21st June 2019, 01:34 PM   #666
iancanada is offline iancanada  Canada
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Develop ultra capacitor power supply and LiFePO4 battery power supply
Quote:
Originally Posted by alazira View Post
I've been troubleshooting my 3rd LiFePO4 board which has a loud hum an order of magnitude more than what the other boards started with.

Things I've tried:
Checked output voltages - correct
Shielding - minimal effect
Swap batteries with the other boards - no difference
inspect for missing resistors/capacitors - all present

Is there anything else I could try?
@ alazira

Please reference to the LifePO4 mkII user's manual from the gitHub link below my signature.

Regards,
Ian
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Old 22nd June 2019, 05:33 PM   #667
Supersurfer is offline Supersurfer  Netherlands
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Quote:
Originally Posted by alazira View Post
I've been troubleshooting my 3rd LiFePO4 board which has a loud hum an order of magnitude more than what the other boards started with.

Things I've tried:
Checked output voltages - correct
Shielding - minimal effect
Swap batteries with the other boards - no difference
inspect for missing resistors/capacitors - all present

Is there anything else I could try?
Is it possible that the noise is coming from an attached smps?
I had this issue a while ago with an asus smps, there was so much noise (probably also high freq. noise out of the audible band) that it blew up a sparkoslabs opamp.
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Old 23rd June 2019, 12:03 AM   #668
alazira is offline alazira  United States
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Quote:
Originally Posted by Supersurfer View Post
Is it possible that the noise is coming from an attached smps?
I had this issue a while ago with an asus smps, there was so much noise (probably also high freq. noise out of the audible band) that it blew up a sparkoslabs opamp.
Hi Supersurfer,
It is comming out of the speaker. I did have the smps issue, but after changing the smps to 15V (it was selectable) it is now quiet. It is just one board that is a problem. The other boards in the same setup are okay.

Ian, I've read the new manual. Is there something specific you were thinking? The only thing I can see to try is checking the R015 resistors.
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Old Yesterday, 07:36 PM   #669
alazira is offline alazira  United States
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All of the R015 check out. Anything else I can try? Might try to reflow some solder even though everything looks okay.
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