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PO89ZB , an inline DC filter for SMPS wall warts . Preamps, HPA, Korg NuTube, etc
PO89ZB , an inline DC filter for SMPS wall warts . Preamps, HPA, Korg NuTube, etc
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Old 25th February 2021, 04:46 PM   #481
Mark Johnson is offline Mark Johnson  United States
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PO89ZB , an inline DC filter for SMPS wall warts . Preamps, HPA, Korg NuTube, etc
Just follow the procedure, it is correct as written.

Ignore people who assert that 0.004 (four one-thousandths) equals 4 percent.
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Old 25th February 2021, 04:57 PM   #482
ClaudeG is offline ClaudeG
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Mark.. I didn't say that 0.004 equal 4%...

Assuming the total DC R of the filter is 0.1R, which it is likely to be without connections or so

i current through the filter, feeding whatever device you plug it into

Alice = Vin

Bob = Vin-Vout

Bob/Alice = (Vin-Vout)/Vin = 1- Vout/Vin = Ri / Vin = 0.1 x i / Vin = Carol



Carol < 0.004 => Small Carol, 2 filters will work
means

0.1 x i / Vin < 0.004


i <0.04 Vin


Hence i < 4% Vin
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Old 25th February 2021, 05:46 PM   #483
rtate is offline rtate  Canada
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We are measuring DC millivolts correct ?
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Old 25th February 2021, 05:57 PM   #484
hoxuanduc is offline hoxuanduc
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Quote:
Originally Posted by Signal lost View Post
Found it Post #221 Dec 11th

647-UHW1H471MPD Nichicon 470uF 50V LS=5 D=10 LEN=25 100K ESR 0.015
Yup, that's the cap I ordered, out of stock now @ Mouser
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Old 25th February 2021, 06:47 PM   #485
Mark Johnson is offline Mark Johnson  United States
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PO89ZB , an inline DC filter for SMPS wall warts . Preamps, HPA, Korg NuTube, etc
Welcome to the Big Boy world where these kinds of things happen a lot. Luckily you've got (a) the search engine at octopart.com ; (b) two other part numbers you can look up ; (c) the required capacitance, voltage, lead spacing, diameter, length, and ESR ... so you can evaluate whether substitutes you find online, are acceptable.
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Old 25th February 2021, 06:56 PM   #486
sonidos is offline sonidos  United States
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PO89ZB , an inline DC filter for SMPS wall warts . Preamps, HPA, Korg NuTube, etc
Quote:
Originally Posted by hoxuanduc View Post
Yup, that's the cap I ordered, out of stock now @ Mouser
There are still some of the United Chemicon version still in stock, but not many. I grabbed 8 pcs. 661-EKYA500E471MJ25S
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Old 27th February 2021, 09:44 AM   #487
dfreemansc is offline dfreemansc  United Kingdom
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Has anyone got any boards available at the moment.
I’d be looking for 2 ideally.
Dave
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Old 27th February 2021, 02:56 PM   #488
thomasnadeau is offline thomasnadeau  United States
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PO89ZB , an inline DC filter for SMPS wall warts . Preamps, HPA, Korg NuTube, etc
Quote:
Originally Posted by ClaudeG View Post
Mark went the trouble to define exactly his filter, with given components that are well chosen and proven. That doesn't mean others won't work, but the result might not be the same.

I experimented with a similar filters and bigger caps, hoping it would work even better (lower Fc, lower ESR etc), but not really. Worked, but the real Mc Coy is just that. By Mark.

Claude
I cleaned out parts express a few weeks ago to use them to supply the kits I'm putting together for the store. No one else seems to actually carry the Kemets right right now - a quick look at octopart will show you this. Sorry about that, but the good news is that in the meantime really look for Low ESR caps that fit the spec of the board - meaning lead spacing and length. After consulting with Mark the caps for the kit, he recommended the Kemets in the original BOM as they consistently measure out well as do the Panasonic FM/FR series (which apparently are the same thing under the sleeve so you can use either). The top pick is still the Nichicon 647-UHW1H471MPD. I have some of all 3 of these, and will be doing some tests when I get the run of boards I had fabbed, which should be in this week. I'll post my results shortly.

--Tom
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Old 27th February 2021, 02:57 PM   #489
thomasnadeau is offline thomasnadeau  United States
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PO89ZB , an inline DC filter for SMPS wall warts . Preamps, HPA, Korg NuTube, etc
Quote:
Originally Posted by ClaudeG View Post
Mark went the trouble to define exactly his filter, with given components that are well chosen and proven. That doesn't mean others won't work, but the result might not be the same.

I experimented with a similar filters and bigger caps, hoping it would work even better (lower Fc, lower ESR etc), but not really. Worked, but the real Mc Coy is just that. By Mark.

Claude
Quote:
Originally Posted by thomasnadeau View Post
I cleaned out parts express a few weeks ago to use them to supply the kits I'm putting together for the store. No one else seems to actually carry the Kemets right right now - a quick look at octopart will show you this. Sorry about that, but the good news is that in the meantime really look for Low ESR caps that fit the spec of the board - meaning lead spacing and length. After consulting with Mark the caps for the kit, he recommended the Kemets in the original BOM as they consistently measure out well as do the Panasonic FM/FR series (which apparently are the same thing under the sleeve so you can use either). The top pick is still the Nichicon 647-UHW1H471MPD. I have some of all 3 of these, and will be doing some tests when I get the run of boards I had fabbed, which should be in this week. I'll post my results shortly.

--Tom
Correction, that was digikey above not parts-express.

--Tom
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Old 27th February 2021, 04:13 PM   #490
ItsAllInMyHead is offline ItsAllInMyHead  United States
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PO89ZB , an inline DC filter for SMPS wall warts . Preamps, HPA, Korg NuTube, etc
Quote:
Originally Posted by thomasnadeau View Post
I cleaned out parts express a few weeks ago to use them to supply the kits I'm putting together for the store.

I have some of all 3 of these, and will be doing some tests when I get the run of boards I had fabbed, which should be in this week. I'll post my results shortly.

--Tom
Great news. Thank you for doing this!
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