My own take on a layout for Rod Elliots P3A amplifier.
60-80W Power Amplifier
With heatsinks for the drivers transistors, 470uF supply caps on each rail, close to the output transistors. Used MJ15003/MJ15004 NPN/PNP TO-3 transistors for output.
Board is made somewhat long at 160 mm but only 80 mm wide. The extra length is for more spacing between output transistors which should lead to better utilization of the heatsink.
Board is singlesided for easy prototyping and because I can.
60-80W Power Amplifier
With heatsinks for the drivers transistors, 470uF supply caps on each rail, close to the output transistors. Used MJ15003/MJ15004 NPN/PNP TO-3 transistors for output.
Board is made somewhat long at 160 mm but only 80 mm wide. The extra length is for more spacing between output transistors which should lead to better utilization of the heatsink.
Board is singlesided for easy prototyping and because I can.
Attachments
Is pin26240 supposed to be the speaker ground? if so, it seems to be floating...
Speaker ground will be at the star ground.
I have +V pin, -V pin, input pin, 2 x input gnd pin of which one should go to the star gnd point, output pin, Zobel gnd pin.
But I might be seperating +V and -V gnd from signal gnd so I get separate supply gnd.
Last edited:
Why? That seems to go against what everyone else here usually advocates.
Last edited:
Dont mind that at all, and a good observation.
Funny, I know they should be apart but somehow didnt think about it when doing the layout.
Thats something Ill look at later today, as well as the separation of input gnd from the other grounds.
With the star ground off the board, there are a lot of wires to run. Although this would probably be fine, it is not optimal and not practical IMO. Better to create a power ground on the board, with one lead going back to main star ground (power supply smoothing caps).
It is also a good idea to move the + and - from opposite sides of the board. Getting them closer together and close to the power ground lets you neatly twist them, without leads running across the board.
It is also a good idea to move the + and - from opposite sides of the board. Getting them closer together and close to the power ground lets you neatly twist them, without leads running across the board.
Thought about it and there doesnt seem to be any consensus on what the 100% correct way of grounding is.
One person says one thing, a second something else, a third something completely different etc.
Confusing and annoying, especially since many different ways of doing it sounds like they all would work almost equally well.
e not
EDIT : Well, a single power ground would reduce gnd connections from the PCB from 5 to 2, power gnd and signal gnd. Separating power gnd and signal gnd is a must. Maybe I should do it or maybe not, gotta think about that some more.
Last edited:
if the RCA (or other input socket) has any exposed conductive part then the RCAs must be connected somewhere to chassis.
Leach and many others show this.
Ground Is Ground....
Anything else causes signal earth or power earth modulation which leads to distortions.....also understand loop areas and configure all stages to have non crossing circuit paths.....simple as that for max performance.
When that is done you can experimentally introduce current path crossing and earth current path modulation to cause 'voicing'.
Eric.
All roads lead to Rome......all loads must have their own unmodulated ground connection paths.
Anything else causes signal earth or power earth modulation which leads to distortions.....also understand loop areas and configure all stages to have non crossing circuit paths.....simple as that for max performance.
When that is done you can experimentally introduce current path crossing and earth current path modulation to cause 'voicing'.
Eric.
Which is why I went for separate GND for +V supply GND, -V Supply GND, Signal GND and Zobel GND.
A few extra wires imo isnt a big deal. 5 or 2 GND wires? Not really an issue.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.