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June 27, 2022, 11:58:03 AM

Author Topic: Choke specs for the Crack  (Read 22434 times)

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Offline larcenasb

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Re: Choke specs for the Crack
« Reply #90 on: May 31, 2017, 08:03:51 PM »
I'd use the 470uF->choke->470uF in parallel with whatever film caps you have, then use 47uF or 68uF caps on the outputs.  The extra R-C power supply node shouldn't be necessary with the rest of the changes.
I'm sorry, please forgive my ignorance, but what do you mean "The extra R-C power supply node shouldn't be necessary with the rest of the changes."? What's an R-C power supply node? Is it the final PS cap?

« Last Edit: May 31, 2017, 08:18:15 PM by larcenasb »

Offline Paul Birkeland

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Re: Choke specs for the Crack
« Reply #91 on: June 01, 2017, 10:19:56 AM »
I'm sorry, please forgive my ignorance, but what do you mean "The extra R-C power supply node shouldn't be necessary with the rest of the changes."? What's an R-C power supply node? Is it the final PS cap?
The extra RC power supply node is the 270 Ohm resistor and whatever cap follows it.  With the choke and the increased capacitance, the extra filtering shouldn't be necessary.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline larcenasb

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Re: Choke specs for the Crack
« Reply #92 on: June 01, 2017, 12:02:12 PM »
The extra RC power supply node is the 270 Ohm resistor and whatever cap follows it.  With the choke and the increased capacitance, the extra filtering shouldn't be necessary.
Thank you, Paul for helping me understand. :) But what about the relationship between the last PS cap and the outputs for the "effective capacitance"?

If I don't use a last PS cap, just the two 470uF caps and the choke, how will that affect my effective capacitance? Will the 68uF outputs indeed effectively be 68uF or much less than that? Thanks!

Offline Paul Birkeland

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Re: Choke specs for the Crack
« Reply #93 on: June 01, 2017, 12:34:22 PM »
As PJ mentioned, they are effectively in series.  The larger the last PS cap is, the closer your coupling cap will be to giving its corner frequency as though it was the only cap that mattered.  With 470uF as the last cap in your power supply, your 68uF cap will perform better in this regard than if the last cap in the power supply was 220uF.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man