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F5 pcb group buy...

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#81
F5 boards

Hello Peter,

time for another buy! Are you still on stock with the F5 boards?

Please send me 3x F5 boards (6 channels).

I've just made the PayPal transfer for the boards, if there are any problems, please let me know.

Thanks for your effort,

Michael
 
#84
samoloko said:
at first I had connected both yellow wires to the gnd of last filter cap
http://www.diyaudio.com/forums/showthread.php?postid=1807410#post1807410
but after Andrew T recommendation - one post ubove I did extension with gray wire
one last thing - I don't have safety network - I only experiment at that point
Click to expand...

That grey wire extention is not a good idea. Both ground wires should be connected directly to the caps.

Are you using a single supply to power both amp channels?
 
#85
Hi Peter

at the moment I am trying to find the reason why I get buzz so I use only one F5 amp pcb which Is connected like on the picture
0V from the PSU filter caps - gnd of F5 amp pcb - yellow wire
0V from the PSU filter caps - speaker return - yellow wire
the Input of F5 amp Is open circuit
 
#86
The input shouldn't be left open if you are checking for buzz.; you shoulkd have a properly operating source connected.

There is not much that can go wrong here, I've built many amps wired this way and all worked fine.

See pics of my latest one: http://www.diyaudio.com/forums/showthread.php?postid=1740824#post1740824

Just make sure that both ground wires are connected DIRECTLY to the commonn point on caps, without the extender. Ground from RCA connect directly to SG point on amp board and nowhere else. RCA should be isolated form a chassis.
 
#97
When it comes to standard resistors, I recommend Dale CMFxxxKQFCT available from DigiKey. If you want something better (which may not make much difference anyway) you can go with Caddocks MK132 or Vishay S102.

As to power resistors, blue 3W Panasonics fit the board, but I'd reather go with Mills 5W (available from percyaudio or partsconnexion)
 
#98
MK132 on the heatsink

On the amp most recently presented (post 2800) there is an MK132 mounted next to the output device.

As you know, and expect, I cannot figure out which resistor this is and why it is there.

Would you mind telling me?

AS ALWAYS, thanks very much,
 
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