100W Ultimate Fidelity Amplifier

[apexaudio]

Mr.Miles,
Here is an idea for Fx8 layout. Very compact, but I am not entirely satisfied with number of jumpers. Can you suggest improvements? I have added fuses and bypass caps.🙂. minimum 20mils spacing , dont know if its good enough for iron transfer, but enough for phtoresist.
reg
Prasi

FX8 pcb (based on AX11 pcb)

 

[sevenup2278]

Hi sir willjj78 pls share ax20 5pair output pcb layout copper side files

I have started to redraw this layout some time ago, with the intention to build a pair. Not completely finished yet...

 

[apexaudio]

FX8 nice pcb design...

 

[apexaudio]

Zeners and diodes add to pcb...

 

[thiagomogi]

very good

 

[still4given]

Zeners and diodes add to pcb...

Hi Mile,

How do we adjust bias?

Thanks, Terry

 

[still4given]

Hi Mile,

I went out on a limb and figured to add a resistor in series with the 1N4007 for bias adjust. I figured to just use a trimmer there and then replace with a resistor. Please look over my layout and see if things are OK for testing.

Thanks, Terry

 

[apexaudio]

Hi Mile,

I went out on a limb and figured to add a resistor in series with the 1N4007 for bias adjust. I figured to just use a trimmer there and then replace with a resistor. Please look over my layout and see if things are OK for testing.

Thanks, Terry

Nice pcb... use 1k trimmer instead 1N4007 for bias adjust.
Regards

 

[sonal kunal]

Pdf files for AX-20. If any one wants sprint file I can post them.

Hi Mile, do you have layout for other version of FX8 => FX8SCF?

Regards
Sonal Kunal

 

[apexaudio]

Pdf files for AX-20. If any one wants sprint file I can post them.

Hi Mile, do you have layout for other version of FX8 => FX8SCF?

Regards
Sonal Kunal

FX8SCF is idea for simple CFA amp with laterals it is not tested and no pcb.
Regards

 

[prasi]

FX8 nice pcb design...

Mr. Miles,
is there any advantage in keeping BC639/640 pair near heatsink and also the thermal bonding of i/p BC546 pair?
reg
Prasi

 

[panggih]

ax20 3pair

Pdf files for AX-20. If any one wants sprint file I can post them.

Hi Mile, do you have layout for other version of FX8 => FX8SCF?

Regards
Sonal Kunal

is this layout tested??
how about bias & DCO??

 

[apexaudio]

Mr. Miles,
is there any advantage in keeping BC639/640 pair near heatsink and also the thermal bonding of i/p BC546 pair?
reg
Prasi

VAS transistors need heatsinks, use BD139/140 instead BC639/640
Regards

 

[apexaudio]

Last pcb edit size 56x46mm

 

[wiljj78]

Last pcb edit size 56x46mm

Nice and very cute little amp.. is it tested?

 

[apexaudio]

Nice and very cute little amp.. is it tested?

FX8 is AX11 with lateral mosfet OS, not tested.
Regards

 

[still4given]

FX8 is AX11 with lateral mosfet OS, not tested.
Regards

What bias do you recommend? Has to be measured at the rail.

 

[prasi]

VAS transistors need heatsinks, use BD139/140 instead BC639/640
Regards

Mr. Mile,
Here is what I have come up with based on the blue PCB design. changes done
1. added zeners and 1N4148 diodes
2. Zobel
3. rail decoupling caps
4. Trimmer for bias instead of 1n4007

what trimmer value should i use?🙂

reg
Prasi

 

[still4given]

Mr. Mile,
Here is what I have come up with based on the blue PCB design. changes done
1. added zeners and 1N4148 diodes
2. Zobel
3. rail decoupling caps
4. Trimmer for bias instead of 1n4007

what trimmer value should i use?🙂

reg
Prasi

Have you measured the elco caps? Mine only have 2.5mm pitch.

I think he said 1k for the trimmer.

 

[sonal kunal]

Hi prasi, layout can be done without jumper, attached picture will help.

Remove R3 place it where R5 is and move R4 - R5 lower.

Regards,
Sonal Kunal