Voltage on f1 power supply ?

bigfishe · 30th November 2010, 06:38 PM

Well after a long long build time I have my f1 up and crawling.
(crawling) I say because I'm only getting 9 volts on my bias . I get 21 volts on my rectifier and 21 volts on the power supply output
The only thing diff from the norm is I put 10000uf caps instead of 15000uf caps
Any takers ?

Nelson Pass · 30th November 2010, 08:20 PM

The bias should be such that you get about 13 volts on
the Drains of the power transistors. If you increase the
value of R15, then it should bias to a higher voltage.

bigfishe · 30th November 2010, 08:30 PM

How much to start?

Zen Mod · 30th November 2010, 08:40 PM

some fun with schematic and maybe any editing program will tell us exactly what you mean

so - I'm repeating my self - there are myriad different schematics of same things , so it's really helpful when someone posts adequate one

bigfishe · 30th November 2010, 08:45 PM

Hey ZM mr pass said I need to increase the value of r15 being a 475ohm resistor
I would like to know of a starting point
I'm going of the first watt manual

bigfishe · 2nd December 2010, 09:05 PM

Can I Add to much and blow the amp?

Tea-Bag · 2nd December 2010, 09:18 PM

change R15 to 1k or 680r, whatever is around. Bias is partially controlled by 5k pot.

bigfishe · 3rd December 2010, 01:22 AM

Great TeaBag,I was going to place one ohm at a time!

30th November 2010, 06:38 PM	#1
bigfishe diyAudio Member Join Date: Jan 2007 Location: Nashville	Voltage on f1 power supply ? Well after a long long build time I have my f1 up and crawling. (crawling) I say because I'm only getting 9 volts on my bias . I get 21 volts on my rectifier and 21 volts on the power supply output The only thing diff from the norm is I put 10000uf caps instead of 15000uf caps Any takers ?

30th November 2010, 08:40 PM	#4
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	some fun with schematic and maybe any editing program will tell us exactly what you mean so - I'm repeating my self - there are myriad different schematics of same things , so it's really helpful when someone posts adequate one __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; BAF Forum & Gallery;I'm dumb

2nd December 2010, 09:18 PM	#7
Tea-Bag not politcally affiliated diyAudio Member Join Date: Feb 2006 Location: Kennebunk Blog Entries: 5	change R15 to 1k or 680r, whatever is around. Bias is partially controlled by 5k pot. __________________ DCB1/BiB Sign up Sheet Round #2 2012 CLICK HERE\|SSHV2 Shipping\| F5TConvertible Circuit Board Sign Up Sheet (Shipping)CLICK HERE\|Semisouth R100A/R085 available PM

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30th November 2010, 08:20 PM	#2
Nelson Pass The one and only Join Date: Mar 2001	The bias should be such that you get about 13 volts on the Drains of the power transistors. If you increase the value of R15, then it should bias to a higher voltage.

30th November 2010, 08:30 PM	#3
bigfishe diyAudio Member Join Date: Jan 2007 Location: Nashville	How much to start?

30th November 2010, 08:45 PM	#5
bigfishe diyAudio Member Join Date: Jan 2007 Location: Nashville	Hey ZM mr pass said I need to increase the value of r15 being a 475ohm resistor I would like to know of a starting point I'm going of the first watt manual

2nd December 2010, 09:05 PM	#6
bigfishe diyAudio Member Join Date: Jan 2007 Location: Nashville	Can I Add to much and blow the amp?

3rd December 2010, 01:22 AM	#8
bigfishe diyAudio Member Join Date: Jan 2007 Location: Nashville	Great TeaBag,I was going to place one ohm at a time!

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