Bottlehead Forum

Bottlehead Kits => BeePre => Topic started by: xcortes on February 06, 2013, 04:38:23 AM

Title: Ps chokes
Post by: xcortes on February 06, 2013, 04:38:23 AM
Assuming one finds a way to place them, is there a reason not to replace the 300 ohm ps resistors with chokes? The good old c7x looks good there. Or a pair of BAC 80s that are 300 ohm DCR (maybe in a separate chassis with an umbilical). I already have a pair of BAC100s that  at 250 ohm DCR should work too.
Title: Re: Ps chokes
Post by: Paul Birkeland on February 06, 2013, 07:50:07 AM
The BeePre high voltage current slightly exceeds the current rating of the C-7X. 

The Hammond 157M might be a good place to start, and there may be enough room on the outside edges of the chassis next to each power transformer.

-PB
Title: Re: Ps chokes
Post by: Grainger49 on February 06, 2013, 07:57:53 AM
Paul,

That answer shows real confidence in the transformer shielding.  I believe it is right.  Paully put some power supply chokes smack up against his Paramount transformers.  That is, directly behind them.  Neither of us ever heard any noise impressed on the power supply.
Title: Re: Ps chokes
Post by: caffeinator on February 14, 2013, 06:32:19 AM
What kind of specs does a candidate choke need to possess?  Looking at the Hammonds that have been suggested, looks like at least 100mA DC current capability, around 260-300 Ohm DCR, and voltage of what - at least 400V?
Title: Re: Ps chokes
Post by: Paul Birkeland on February 15, 2013, 04:17:38 AM
What kind of specs does a candidate choke need to possess?  Looking at the Hammonds that have been suggested, looks like at least 100mA DC current capability, around 260-300 Ohm DCR, and voltage of what - at least 400V?

Yeah, the voltage is much less important in the BeePre, 250V would be enough.  Keeping the DCR as close to 300 Ohms as possible will help avoid destruction and ensure proper operation of the C4S loads.