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F5 pcb group buy...

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#261
F5 Pcb kit.

Hello Peter, Sorry if i missed some vital info for not reading all postings,
Is there still available pcb's for this great amp ?
If yes please give me a price for all boards that i need for this project and
where can i find a component list ? i downloaded the manual but didn't find
anything there exept for a schematic ,
Best Regards from Sweden
Kjell.
 
#263
bridge rectifier and monoblock transformer ?

Hi Peter
See the attached image -Will this do ?
I am planning to build F5 as monoblock.
Will 2 EI transformers of 0 18 Vac output at 10 amp per transformer sufficed ?
Thanks

kp93300
 

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#269
Position of th1 and th2

Hi All,
If i lay out as in the picture attached. The Q3 and Q4 is fixed to the side of heatsink and the board is on the bottom of the chasis. The link is by extension wires.
If I lay out as described,do i need to shift the position of Th1 and Th2 onto the heatsink also?
Thanks again
kp93300
 

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#270
Hi Peter,

I was checking out your F5 board ground scheme and was wondering if it's ok to send the power supply ground to earth ground. I see that the F5 speaker output ground is tapped off the power supply ground. Should they not be connected at the same earth ground point? Does it matter?

Thanks,

Vince
 
#271
Power supply ground should be connected with Chassis/Earth ground through thermistor as per F4 PS schematic (page 15): http://www.firstwatt.com/downloads/f4_om.pdf

Power supply ground is your main output ground reference and that's why it's tapped off the PS.

On the amp board you will only see input signal ground with two pads: one to connect ground from RCA socket, the other for a wire to PS ground (reference).
 

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#273
Hi Peter,

Been thinking about building another F5 (using your boards), but this time with only 1 power supply and transformer, ultra-fast diode bridge and no circuit protection. Probably will use Caddock or Vishay. Never used these before and wonder about their sound qualities.

Have you tried the F5 without the protection circuit, if so, is it worth the risk of shorting the amp? Would you keep the 4.7k thermistor out of the circuit?

Aside from a binding post to chassis short and speaker + - wires shorting, anything else I should be worried about? ...I guess that's bad enough! 😀
Any and all connection wire changes should be made with the amp off?

Thanks,

Vince
 
#274
Actually, I removed protection circuitry right on a first day I've built the amp and there was a noticable difference (to me it seemed for a better).

I've built another amp also without protection. This picture shows the board without protection parts

I don't think there is much risk in shorting binding posts, you can always spread them 2" or so to be shure 😉

It's always a good idea to turn the amp off when doing connections.
 

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#279
^^Please ignore the above. It is painfully obvious that I have to post something like this an hour before the postman drops it off. Thanks for the PCBs 🙂

Edit: And double thanks for the rectifier boards, a nice bonus even though I am using the KBPC-style monolithic rectifier. I'm sure I'll find a use for these at some point, so thanks again 🙂
 
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