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Old 18th December 2012, 02:24 AM   #8841
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Gonna try a version of Joachims' prefilter with common mode choke after the transformer. This will fed Mur860 then KG 4.7mF, 1R Fukushima, then SSLV with another 4.7mF KG on board. What do you think. Should i throw a nother choke in and drop the R. How do i size the choke? Got boards done. May not get to mounting parts unitl after Christmas with the In-Laws
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Old 18th December 2012, 03:05 AM   #8842
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Nah, its enough filtering already.
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Old 18th December 2012, 10:33 AM   #8843
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Hi Buzz

Those CM f-cored inductors, could choke the sonics...
...The 1R Fukushima sounds cool !
What is it ?

Cheers.

Si.
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Old 18th December 2012, 10:36 AM   #8844
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Quote:
Originally Posted by The Space Egg Corp View Post
Hi Buzz

Those CM f-cored inductors, could choke the sonics...
...The 1R Fukushima sounds cool !
What is it ?

Cheers.

Si.
From what I understand, just for Hf filtering of mains. Easily added or taken away. The Fukshima MPC 74 are high power resistors from famous nuclear island and have a bit of a following in the japanese audio world( you tihnk we got it bad)
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Old 18th December 2012, 10:38 AM   #8845
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Its good to break some EMI from the rectification. So drop 1 or 2 volts with an R before board's main C if with outboard bridge or by a small hack. Better still is choke input with some leftover speaker air coil.
Took the time to REALLY read you r post. SO you just suggesting a choke after transformer and before onboard cap. If so, Ill bump teh cap up to 10mF KG cap I have on hand and the only option will be the CM choke before rectifiers.

Just simmed a Hammond feeding the 10mF cap and it looks good and comes up pretty slow for electronic world.
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Last edited by buzzforb; 18th December 2012 at 11:08 AM.
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Old 18th December 2012, 11:11 AM   #8846
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What value AC secondary TX you got in Volt and VA?
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Old 18th December 2012, 11:27 AM   #8847
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Screwed up the sim. Need big inductor with low dc or I drop too much voltage......like you said! Looking at 50VA Hammond 36V sec. Duals wold be better, but just want to get it up and running.
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Old 18th December 2012, 11:32 AM   #8848
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Use this config. 2mH air coil plus 20 Ohm in series with it (included with its DCR in the sim).
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Old 18th December 2012, 11:35 AM   #8849
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sort of what I am playing with now. Quick question. What makes loading transformer directly with choke so difficult?
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Old 18th December 2012, 11:45 AM   #8850
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Loses too much voltage by having no capacitive storage at input. Choke input PSUs in tube audio use a high secondary Tx typically if you look in rectifier valves documents. They usually give choke input and max Cin curves.
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