F5 Turbo Builders Thread - Page 54

Rush · 17th November 2012, 01:54 PM

Quote:

Originally Posted by anilva

Continuing on my post where the left channel is showing very low gain compared to right channel. There is proper reproduction from the right channel and the left channel, while the sound is clean is barely audible at full preamp output.

What else to look for?

Thanks

Have you checked the values of the feedback resistors on both channels?

buzzforb · 17th November 2012, 01:59 PM

Seems you have it under control then.

a.wayne · 18th November 2012, 12:15 AM

Buzz...

Finished yet...............

buzzforb · 18th November 2012, 01:10 AM

Nope, but thanks for the bump. I am doing battle with a cold. Did get thr other sink cut and the other heat spreader mounted. Just got to pull apart. Spread the heat goo and begin mounting components and boards. Also putting finishing touches on article spev'd psu. Trudging along.

anilva · 18th November 2012, 01:26 AM

Quote:

Originally Posted by buzzforb

Seems you have it under control then.

Buzzb, if this is addressed to me, then I am far away from having any control on the situation. Just one change of jFETS has altered the entire voltage rating across the PCB. I have removed the PCB and checked the P1 and P2. They are set to zero ohms. I do not see any dry solder. I resoldered all of them. Checked component values - no errors. I need to check tracks of the PCB, if there is any flakiness associated with the board. I will report back.

Last option is to discard the PCB and build another board.

Regards

buzzforb · 18th November 2012, 01:41 AM

Pics of the boards. Home brew or bought. Use mm to check traces, between traces, for copper hairs. Having one good channel, you have ultimaye guide. Start at input and work to output. Sounds like something is robbing current from one side of bias scheme.

anilva · 18th November 2012, 02:13 AM

Quote:

Originally Posted by buzzforb

Pics of the boards. Home brew or bought. Use mm to check traces, between traces, for copper hairs. Having one good channel, you have ultimaye guide. Start at input and work to output. Sounds like something is robbing current from one side of bias scheme.

Thanks. Will compare every line. The PCB is from a India forum group buy. It has been designed by fellow member Om Mishra. While the PCBs look well made, I am probably the first guy to use these boards. There could be manufacturing issues or may be not. With time at premium, this debugging hogs quite a bit of that.

Nelson Pass · 18th November 2012, 02:25 AM

Some people do crossword puzzles, others debug circuits.

Consider it time well spent.

anilva · 18th November 2012, 03:25 AM

Quote:

Originally Posted by Nelson Pass

Some people do crossword puzzles, others debug circuits.

Consider it time well spent.

Papa, pardon me for using the wrong word 'debugging'. Who am I to debug a perfect design. I am just trying to find out assembly errors committed by mortals like me. While I prefer playing around with circuits than crossword, the anxiety to listen to a F5T in a hurry is driving me nuts.

Thanks.

AudioSan · 18th November 2012, 05:34 AM

have you checked the output fets? you have about half the rail voltage as DC offsett with no voltage over any source resistors?

17th November 2012, 01:59 PM	#532
buzzforb diyAudio Member Join Date: Oct 2010 Location: Burlington, NC	Seems you have it under control then. __________________ \|F6 Kit/Trasnformer GB Sign up sheet Closed,\|Primrose GB Sign Up sheetClick Here ...Shape the sound , Man!

18th November 2012, 01:10 AM	#534
buzzforb diyAudio Member Join Date: Oct 2010 Location: Burlington, NC	Nope, but thanks for the bump. I am doing battle with a cold. Did get thr other sink cut and the other heat spreader mounted. Just got to pull apart. Spread the heat goo and begin mounting components and boards. Also putting finishing touches on article spev'd psu. Trudging along. __________________ \|F6 Kit/Trasnformer GB Sign up sheet Closed,\|Primrose GB Sign Up sheetClick Here ...Shape the sound , Man!

18th November 2012, 01:41 AM	#536
buzzforb diyAudio Member Join Date: Oct 2010 Location: Burlington, NC	Pics of the boards. Home brew or bought. Use mm to check traces, between traces, for copper hairs. Having one good channel, you have ultimaye guide. Start at input and work to output. Sounds like something is robbing current from one side of bias scheme. __________________ \|F6 Kit/Trasnformer GB Sign up sheet Closed,\|Primrose GB Sign Up sheetClick Here ...Shape the sound , Man!

18th November 2012, 05:34 AM	#540
AudioSan diyAudio Member Join Date: Feb 2009 Location: Trondheim	have you checked the output fets? you have about half the rail voltage as DC offsett with no voltage over any source resistors? __________________ aleph P1.7 pre. F5 power amp. CDpro2(need DAC). Vivaldi8 speakers

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18th November 2012, 12:15 AM	#533
a.wayne diyAudio Member Join Date: May 2008 Location: Front Row Center	Buzz... Finished yet...............

18th November 2012, 02:25 AM	#538
Nelson Pass The one and only Join Date: Mar 2001	Some people do crossword puzzles, others debug circuits. Consider it time well spent.

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