ESP P3A

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AndrewT

R.I.P.
Joined 2004
C2 is ~20mm away from the FET power pin.
That is at least 15mm too far.
Next you must bring the two decoupling caps very close to each other so that the total trace length from +FET (T2) to C1 to PGND to C2 to -FET (T1) is a short as possible.
This can only be done if the FETs are moved to near each other.
 
N

Neutrality

Member
Joined 2004
AndrewT said:
C2 is ~20mm away from the FET power pin.
That is at least 15mm too far.
Next you must bring the two decoupling caps very close to each other so that the total trace length from +FET (T2) to C1 to PGND to C2 to -FET (T1) is a short as possible.
This can only be done if the FETs are moved to near each other.
Click to expand...

In an ideal world that might be how it should be, but after looking at the original P3A layout it doesnt seem to matter much. Or Rod's original design is crap, which I sincerely doubt. :)

Took the previous version, rearranged a few components, added a 4.7uF cap again and switched from single to dual output pairs, for extreme situations when driving 4 Ohm loads and with enough power to drive atleast a resistive load down to 2 Ohm without trouble.

The amp PCB's have been ordered, now the waiting game begins.
 
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A

AndrewT

R.I.P.
Joined 2004
Neutrality said:
now with the recommended MJL4281A/MJL4302A output transistors.
Click to expand...
AndrewT said:
C2 is ~20mm away from the FET power pin...........
..............This can only be done if the FETs are moved to near each other.
Click to expand...

richie00boy said:
Where have the FETs come from Andrew? Are you getting confused :D
Click to expand...
looks like I have gone way beyond "getting" confused.

I'll have a look in the garden for my brain, I'm fairly sure that's where I last remember it being.
 
N

Neutrality

Member
Joined 2004
carlmart said:
Not my intention to sound negative, but why didn't you just use a single-sided pcb for this project?

As far as I see there's only one trace you would need a bypass-wire for.



Carlos
Click to expand...

Well, firstly, some component placements was made easier and made for an overall cleaner layout. Secondly, the new version with dual output pairs needed a dual sided pcb anyway.

Besides, I'm getting them profesionally made so single or dual sided? Doesnt really matter.

Where I'm getting them made the price is the same, whether single or dual sided.
 
effebi

effebi

Member
Joined 2010
Neutrality said:
PCB's are on their way from China. Should be here sometime end of the week/early next week. I hope so anyway.
Click to expand...
I would be really interested to know HOW you doubled the outputs. With CFPsit should not be as trivial as with EFs. Did you double the drivers as well? Did you add emitter resistors on the power devices? Did you put base stoppers? Just some question that arise...
Bye
effebi
 
N

Neutrality

Member
Joined 2004
I have already received my first PCB's, however Im already considering other options, like a P3A with 2 x pairs of TO-3 transistors.

Like the attached picture.

Ill most likely use my current PCB's but one can always consider future versions. :)
 

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N

Neutrality

Member
Joined 2004
effebi said:
I would be really interested to know HOW you doubled the outputs. With CFPsit should not be as trivial as with EFs. Did you double the drivers as well? Did you add emitter resistors on the power devices? Did you put base stoppers? Just some question that arise...
Bye
effebi
Click to expand...

Emitter resistors, yes, they have been added.

It is done as recommended by the designer, Rod Elliott.
 
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