F5 power amplifier

[estman]

and of course the PCB for comments

Please, take a close look to the D and S legs of Q3.

 

[Nordic]

Why? what are they doing?

 

[estman]

>Why?
To chek the connections to these legs.

>what are they doing?
They are imitating role of Source follower.

 

[Nordic]

Good catch, I see it now... I made an error on the schematic which translated to the PCB...

 

[jackinnj]

You will probably want to be able to trim the values of the source resistors as NP has recommended. I used snippable DIP connectors to parallel the resistors.

 

[Nordic]

If it is in the thread I will find it (on page 16 now), sadly I don't have a copy of the magazine article...

 

[Zen Mod]

If it is in the thread I will find it (on page 16 now), sadly I don't have a copy of the magazine article...

well- you certainly didn't read what's on FW site ;

Papa sez :

"In addition to the normal owner's manual information, I have appended the original DIY F5 article which appeared in AX" .

 

[Audiofanatic]

F5 Pcb

Hi Guy's


This is my first trial of the F5 PCB from the one and only Nelson Pass.

I don't know if you guy's can open it. It's a jpg. (print screen copy) It's made with Ultiboard 5.71

All comments are welcome.


Thanks,


Audiofanatic

 

[Zen Mod]

..................

juma - is this good enough ?

here shown without upper and lower gnd plane




my first pb , made with PC - ever !

Kicad proggie

 

[lgabco]

for audiofanatic

it seems to me that distance from MOSFET to heatsink could be more than the length of the pins. Depends on the positions of PCB and heatsinks. Consider to move MOSFETS closer to the edge of the PCB.
Ladislav

 

[Nordic]

If I may I ask... I don't see any decoupling caps in either the schematic or the photos of the amp...

Are they recommended for this topology... if so, is it a matter of bigger is better, or does there come a point where bigger just = smearing.

 

[Zen Mod]

juma - is this good enough ?

here shown without upper and lower gnd plane




my first pb , made with PC - ever !

Kicad proggie

seems that I forgot attachment

 

[juma]

juma - is this good enough ?
here shown without upper and lower gnd plane

my first pb , made with PC - ever !
Kicad proggie

seems that I forgot attachment

Looks nice to me !
What is it ?

 

[Zen Mod]

Looks nice to me !
What is it ?

borbely/juma F5 intended gain stage

 

[EUVL]

> borbely/juma F5 intended gain stage

Wrong thread !

http://www.diyaudio.com/forums/attachment.php?s=&postid=1555551&stamp=1215343219




Patrick

 

[Zen Mod]

>.......
Wrong thread !
.......

http://www.diyaudio.com/forums/showthread.php?postid=1565315#post1565315

 

[Audiofanatic]

Take Two!

Hi guy's,

I hope this one is better.


Best regards,


Audiofanatic

 

[udailey]

I dont think your pcb makes the requirement of the two 10r meeting at ground. Maybe it does and I am missing it.
Your left 10r and 100k meet but not at ground as in the schematic. I think you might need a ground trace running on bottom layer from 10r to 10r.
If I am wrong please burn me at the stake.
Uriah

 

[Tea-Bag]

f5 pcb

I dont think your pcb makes the requirement of the two 10r meeting at ground. Maybe it does and I am missing it.
Your left 10r and 100k meet but not at ground as in the schematic. I think you might need a ground trace running on bottom layer from 10r to 10r.
If I am wrong please burn me at the stake.
Uriah

Maybe the top SP connections are supposed to be the Speaker -, not sure, looks like a star or cross here. Doesnt ground at 10ohm ends like the AX schematic however as UDaily sayz.

Looks like the green traces are bottom side. I do like the layout.

 

[Audiofanatic]

Better ?

Hi,


This is a close ground where the 10R's are grounded.

Thanks for the feedback.


Audiofanatic

P.S. The PCB is 6.6 cm X 3.6 cm. Red is bottom and green is top! (edit)