200W MOSFET CFA amp

[Krisfr]

Don't forget to make a space for bigger R9 22R resistor, it should be min 1W or better 2W.

Just like this.. ALL DONE

 

[gaborbela]

Is there any interest in a SMALL group buy for this board? I have a quote for about $100 for 5 boards. I can get quotes for larger numbers of boards.

Interested but wee need more people $20 per PC board plus shipping from US a bit pricy.
Greetings gabor

 

[Krisfr]

Interested but wee need more people $20 per PC board plus shipping from US a bit pricy.
Greetings gabor

That is why I posted this. I agree... Now where is my richer Uncle

 

[Krisfr]

By the way this is double sided 2 oz. and fully masked. Anyone know of a cheaper source of 240 X85 mm boards please tell me. Open to all input.

 

[Krisfr]

Question:

What is an acceptable distance for clearance of 120V difference on a PCB between High Voltage and Ground? This is on the same plane. right next to each other. Or surrounded as in a capacitor lead. The same for 100 volts.

 

[Krisfr]

Same company for 20 boards with shipping to me $165. Same as 8.25 a board... go figure. And add 2 bucks a board for gold. WOW.

 

[gaborbela]

That sound great, way better than 5PC. Hope more people will join.
Maybe if you start a tread at Group buy, of course at first ask for the designer blessing on that.
Greetings

 

[Krisfr]

That sound great, way better than 5PC. Hope more people will join.
Maybe if you start a tread at Group buy, of course at first ask for the designer blessing on that.
Greetings

Damir is all in before I posted this, and would be happy with anything reasonable. So would I. The cost of shipping outside of the USA will be the biggest hurdle IMHO.

I think shooting for 25 dollars a pair including ship in the USA is a doable deal.

Time and people will tell.

 

[jwilhelm]

By the way this is double sided 2 oz. and fully masked. Anyone know of a cheaper source of 240 X85 mm boards please tell me. Open to all input.

$93 at ITEAD Studio 2Layer PCB Larger than 20cm x 20cm for 5 boards + 2 free extras if you say it's open source.

 

[31697B]

OK I'm in for two channels. What do I do next?

THx-RNMarsh

 

[gannaji]

Thanks Damir, for your effort and response. I have got all the answers I needed from the thread you pointed to. I want to use this for +-24V, 2.40 Amps and +-35V, 3.20 Amps. Is there an updated schematic? Thanks again.

A PM for you!

 

[dadod]

Damir is all in before I posted this, and would be happy with anything reasonable. So would I. The cost of shipping outside of the USA will be the biggest hurdle IMHO.

I think shooting for 25 dollars a pair including ship in the USA is a doable deal.

Time and people will tell.

Chris, as this amp was not built yet, could be very useful to have a prototype built first.
I am quite confident that the amp will work as in simulation, but better to start with small quantity first. What do you think about? I would like to build it myself first, but to buy all necessary parts I can't afford in reasonably short time.
Damir

 

[thimios]

Chris, as this amp was not built yet, could be very useful to have a prototype built first.
I am quite confident that the amp will work as in simulation, but better to start with small quantity first. What do you think about? I would like to build it myself first, but to buy all necessary parts I can't afford in reasonably short time.
Damir

I agree this is the right way,a working prototype is absolutely necessary.

 

[Krisfr]

Well I guess I will fire up a breadboard prototype and put the PCB on hold.

 

[Krisfr]

pcbway is the cheapest so far for 2 oz etc. and such. But I will do the breadboard rather than take the risk of a not great topology.

 

[dadod]

I decided to build 120W CFA lateral MOSFET version. I will use the box and power supply from my JLH 80W MOSFET amp, and of course, lateral MOSFETs.
As this is 120W version of 200W amp, if everything vent OK, the 200W version PCB can be ordered with no fear of its function.
I ordered set of the PCB from local producer. I prefer do it here in Zagreb as I can control the process and it is not to expensive.
Damir

 

[kimschips]

What about the version with EF VAS from post 426, why don't you Use that, it gives very low distortion?
Do you also make a PCB for mosfet in "normal packages" i Think 120W@8 ohm version, 2 pair OPS with bipolar driver??

 

[dadod]

What about the version with EF VAS from post 426, why don't you Use that, it gives very low distortion?
Do you also make a PCB for mosfet in "normal packages" i Think 120W@8 ohm version, 2 pair OPS with bipolar driver??

You are right about EF VAS, THD20k is 7 to 10 dB lover, but harmonic distribution is not so good. Small improvement at 1kHz, and SR is going down, GM is lower.
I will try it after some real tests of simple VAS.
A lot of people here think that distortion is not so important if low enough, and I am going to try the simplest VAS first.
I you meant by normal package, a plastic package, yes I will make a layout for that too, but as I have lateral mosfets in TO3 package I did that first.

 

[kimschips]

What is pssr for this version post 616?
Don't you use cap multiplier any more?
Thanks Again

 

[dadod]

What is pssr for this version post 616?
Don't you use cap multiplier any more?
Thanks Again

As this amp is going to use JLH 80W mosfet amp stabilized PS regulator with separate regulation for the OPS and separate for IPS I don't need a cap multiplier here.
After I finish and test this amp I am going to make a layout for this amp but with TO 3P laterals and a cup multiplier will be included between OPS and IPS.