You are right @Potentiallyincorrect, but implementing those changes in a layout will be pretty easy. But I do understand, that the schematic is far from finished.
I'm thinking 65x90mm layout to mount flat on the radiator. Should fit in a 2U chassis.
I'm thinking 65x90mm layout to mount flat on the radiator. Should fit in a 2U chassis.
I assume PGND is the point to connect the negative terminal of the speaker output to? If that's the case you will want the GND terminal of R4 directly connected to this point and not via the PCB plane. Any currents induced there will negatively impact the NFB taken from this point. And yes, not only the speaker output gives negative feedback via R5 but also R4 does so.
Then your GND terminal of R4 should also go directly to PSU ground. Reason as stated before. Any ever so small currents between PSU ground and the GND terminal of R4 will negatively impact NFB and thus THD performance. If you're aiming for THD < -120dB this WILL have an impact. I know this from building an actual amplifier with this kind of performance, not only from sims 
EDIT: you're probably better off connecting PSU GND to your pcb and put the speaker output terminal on it. And then branch off directly from the negative speaker output terminal to R4.
EDIT2: an example can be seen here: https://gitlab.com/t-5/amp-dr
The negative feedback for the inverting input of the diff amp is taken directly from the Speakon output connector via a net tie.
EDIT: you're probably better off connecting PSU GND to your pcb and put the speaker output terminal on it. And then branch off directly from the negative speaker output terminal to R4.
EDIT2: an example can be seen here: https://gitlab.com/t-5/amp-dr
The negative feedback for the inverting input of the diff amp is taken directly from the Speakon output connector via a net tie.
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Have checked your schematic with lineup's - all seems fine.
One comment - you have shown the J113 fet as "U$1" on your schematic and the silk screen for the pcb, probably should be called J3.
Also, I would allow more holes for capacitor C1 to allow for different lead spacings for the input cap. Members like to use exotic caps here as well as more run of the mill film caps. You have done this on many other designs you have shown.
Apart from those comments and my one above in post #29 about ground connections, the pcb is a good size with good spacing for the output laterals.
Keep up the good work prasi.
One comment - you have shown the J113 fet as "U$1" on your schematic and the silk screen for the pcb, probably should be called J3.
Also, I would allow more holes for capacitor C1 to allow for different lead spacings for the input cap. Members like to use exotic caps here as well as more run of the mill film caps. You have done this on many other designs you have shown.
Apart from those comments and my one above in post #29 about ground connections, the pcb is a good size with good spacing for the output laterals.
Keep up the good work prasi.
Same here Gary, parts already in the bins. Probably can use the same chassis the “4Watter” was built in. 😉
Anything under 100x100 is good because it qualifies for the $5 for 10 PCB rate at the usual fab houses
I don't know any other supplier than Profusion electronic.Anything under 100x100 is good because it qualifies for the $5 for 10 PCB rate at the usual fab houses
https://www.profusionplc.com/parts/ecx10n20