F3 and F4 Clone PCB Reissue group buy, also F5 PCBs

[AlanElsdon]

Peter - there is a sketch by The Two Ronnies in which one of them answers the next question - rather like this exchange!!

So what was the purpose of the 8 (or 4) resistors on the capacitor board?

Alan

 

[Peter Daniel]

I always like to build my amps slightly different than commonly accepted methods, there were also reasons why the pcb was designed in that particular way.

It is one channel only, the caps in a back were afterthought as I originally planned to have them separately, together with transformer and bridges.

The resistors on PS board are part of passive filtering, I will have them here too, but they will be p2p wired.

 

[AlanElsdon]

Peter,

Understood - I may just build my first amps with the three boards.

Oh well dinner and music call me!

Alan

 

[woodturner-fran]

Peter, I saw a while back that you used a lower wattage output resistor - the caddocks IIRC. What rating are they, and did you parallel a couple or just use 1 x 50R?


Also.... is it worth it!?


Fran

 

[Peter Daniel]

I'm not sure if it's worth it: Caddocks MK132 seem to be marginally better than Mills, sort of smoother, but nothing major really. I used 2 x 150R in parallel per side, each one is 0.75W and they run cool. I used them, beacause I had them already on hand and I needed a bit more gain.

 

[woodturner-fran]

Thanks Peter, I'll stick with what I have so.


Fran

 

[José Humberto]

My pcbs arrived this week.
Thank you very much Peter.

 

[luis.martins]

Hi Peter,

Are still any F3 boards left?

Regards,
Luis

 

[tristania79]

for F4 what would be the minimum voltage for C1,C2,C3 and C4 capacitor ?
would 50 V capacitor would be enough ?

I am thinking of buying these nichicon capacitor, does anybody have an opinion about these capacitor ?

 

[Peter Daniel]

F3 amp and PS boards are all sold out. If there is more interest, I can always order them again

for F4 what would be the minimum voltage for C1,C2,C3 and C4 capacitor ?
would 50 V capacitor would be enough ?

It should be at least 25V.

 

[tristania79]

thank you peter !

 

[Peter Daniel]

Getting ready to close the amp.

 

[rigma]

Peter,

Do you like the binding post is the above photo better than the other Cardas?

rigma

 

[rickmcinnis]

Reason for the spacer between outputs

and the main heat sink?

Was this done for ease of packaging or do you think it assists in transferring heat?

I know you placed lengths of aluminum on top of some of the chip amps but I have not noticed you having done this before?

Would you explain?

Are you using mica for insulation?

Thanks, yet, again,

Rick McInnis

 

[Tea-Bag]

Peter,

Do you like the binding post is the above photo better than the other Cardas?

rigma

Let me say this, those Cardas safety outputs are nice, but the Pure Copper ones are a bugger to solder to and only like spades.

Myah to 2C

 

[Peter Daniel]

Re: Reason for the spacer between outputs

Do you like the binding post is the above photo better than the other Cardas?

Those are the best binding posts I've been using, easy to solder too.

and the main heat sink?

Are you using mica for insulation?

That is a main heatsink. The size is approx 11x5 and it's one heatsink per output device. I'm using beryllium oxide pads, those are discontinued now but Mouser should have similar product with aluminum oxide: http://www.diyaudio.com/forums/showthread.php?s=&postid=1494970&highlight=#post1494970

 

[José Humberto]

Luis
I don´t need my F3 psb now, realy I purchase for perhaps some day I´ll wont make one. I realy prefer now F5.
Write me if you are interesting. JHRAMOSS@telefonica.net
Jose

 

[woodturner-fran]

Peter,

I know many must have said it before now, but your workmanship on these amps and your other stuff is an inspiration.

Well done.


Fran

 

[luis.martins]

F3 amp and PS boards are all sold out. If there is more interest, I can always order them again

Hi Peter,

Thanks for your quick reply. It seems that another member in the forum has some F3 boards but no PS board.

Does anyone it the forum would spare a PS board for the F3?

Thanks,
Luis

 

[Peter Daniel]

Thanks Fran.

F4 PS board will also work with F3; you just need to reverse wires from bridges and install caps accordingly.