Bottlehead Forum

Bottlehead Kits => Legacy Kit Products => Foreplay III => Topic started by: Laudanum on September 23, 2011, 06:17:15 AM

Title: PS cap FPIII
Post by: Laudanum on September 23, 2011, 06:17:15 AM

I was interested in knowing why the FPIII uses the BH "standard" 220uf 250V caps for the first two caps in the supply but then follows those with a 47uF 450 volt cap?    Why not another 220uf 250V cap like in Crack and Seduction.   Just curious in learning a little something here.

Thanks

Title: Re: PS cap FPIII
Post by: Grainger49 on September 23, 2011, 06:29:39 AM

The first two caps are in series, so they are in effect a 110uF@500V cap.  (the resistors in parallel with each 220uF@250V cap keeps the voltage across the caps properly divided and they bleed the caps when power is not applied) 

Bottlehead already stocks those for other kits and it makes it simpler for them to stock fewer parts.  They get a discount making larger orders of the same parts. 

Title: Re: PS cap FPIII
Post by: Laudanum on September 23, 2011, 06:34:40 AM

Nevermind, I think I answered my own question.   The 220uf 250 volt caps are in series so actually the voltage rating is double to 500 volt ... I think.   Yes?

Title: Re: PS cap FPIII
Post by: Laudanum on September 23, 2011, 06:35:38 AM

Thanks Doc, I actually figured it out while you were posting.

Title: Re: PS cap FPIII
Post by: Paul Joppa on September 23, 2011, 10:03:11 AM

More specifically, the power supply is what's called a "voltage doubler". The winding is 160 volts rms; one diode and cap makes +200 volts, the other diode and cap are reversed to make -200v, for a total of 400v. The 400 volts is used in stock Foreplay and in the SEX amp.

The same winding is used with a fullwave bridge rectifier to make 200 volts, for Crack, Smack, and eXtended Foreplay. This way we do not need different transformers, and can buy them in larger quantities at a better price.

Title: Re: PS cap FPIII
Post by: Grainger49 on September 23, 2011, 10:45:09 AM

Quote from: Laudanum on September 23, 2011, 06:35:38 AM

Thanks Doc, I actually figured it out while you were posting.

Doc didn't post.  But I appreciate being confused with Doc, I'm flattered.

Title: Re: PS cap FPIII
Post by: Laudanum on September 23, 2011, 01:26:05 PM

Thanks Paul and you're welcome Grainger.