Lateral CFA 120W - BSA

[AKSA]

We are in agreement - I learned from those guys too! And compensation is pivotal and mathematically based and more people need to understand it fully, including me........

Hugh

 

[dadod]

Hello Damir,


what transformer do you recommend for a class A 40W mono block? 2x24V AC with xxxVA?


BR
Günni

Hi Gunni,
This amp will take about 3A per rail with no signal, and you need double at full power.
I would say good choice will be 2x25V 6A, and to be on save side 10A, so 300VA to 500VA transformer for mono or 600VA to 800VA for stereo.
BR Damir

 

[dadod]

We are in agreement - I learned from those guys too! And compensation is pivotal and mathematically based and more people need to understand it fully, including me........

Hugh

We are lucky now with free spice software, no need to calculate, but still understanding is essential.

 

[anti]

spice makes you see better

 

[Mark Tillotson]

Bloodshot eyes are more likely the result of a long LTspice session though!

 

[thimios]

A very early progress

 

[thimios]

Is it ok i continue posting here or does i need to start a new thread?

 

[dadod]

Is it ok i continue posting here or does i need to start a new thread?

It is OK. I am interested about your build.

 

[thimios]

It is OK. I am interested about your build.

Ok thanks damir!
Drilled, not perfectly but acceptable.. 😉
Last picture, once again in the UV exposure for completely photoresist removal.

 

[thimios]

Starting to assembling.
Unfortunately i must start to desolder.
They are wrong polarity placed electrolytis at the offset controller power supply c22, c23.

 

[Flikoman]

Starting to assembling.
Unfortunately i must start to desolder.
They are wrong polarity placed electrolytis at the offset controller power supply c22, c23.

Wrong polarity on the schematic/pcb or?

Regards

 

[thimios]

Wrong polarity on the schematic/pcb or?

Regards

Wrong on schematic,pcb is ok but was looking on schematic.

 

[dadod]

Wrong on schematic,pcb is ok but was looking on schematic.

Thanks Thimios, I missed that.

 

[rsavas]

That's cool Thimos, using UV led's in your exposure frame.
Use BP (UES) ecaps and do not worry about polarity.

 

[thimios]

Small progress but i have many missing parts...
I have 0,22R & 0.33R non inductance.
I have 0,27R wire resistors.
I think that 0. 22R is ok.
I haven't boutique caps for compensation,so i will use multilayer for test.

 

[dadod]

Small progress but i have many missing parts...
I have 0,22R & 0.33R non inductance.
I have 0,27R wire resistors.
I think that 0. 22R is ok.

Yes you ca use 0.22R, I use 0.27 as I have those.

 

[thimios]

Yes you ca use 0.22R, I use 0.27 as I have those.

Thanks damir! 🙂
Another question, i see that Vbe multiplier isn't thermaly contact with the heatshink.
Is this really?
Is it because of latfets usage?

 

[dadod]

Thanks damir! 🙂
Another question, i see that Vbe multiplier isn't thermaly contact with the heatshink.
Is this really?
Is it because of latfets usage?

Yes, for lateral mosfet no need to be thermally connected to the heatsink.

 

[rsavas]

The beauty of the lateral mosfet is the bias stability. I did up Bob Cordell's DH-220C design, it is rock steady, no bjt design can do this.

 

[johnego]

no bjt design can do this.

The Vbe transistors in my BJT CFP amps have also no contact with drivers/output/heatsink. Rock stable too 🙂