PCB Layout Process and Guidelines?

[AndrewT]

split power attachments as on Alex' is not the way to layout.

[alex mm]

jkuetemann ,
What can I say , your board it's fine , I have learned a lot, myself from this thread . The skill comme by every layout , so we can practice all time we have , dedicated to prepare PCB's. I like PCB's compact , all in one ,so my PCB look like this attached below.
Regards Alex.

[jkuetemann]

Originally Posted by AndrewT

split power attachments as on Alex' is not the way to layout.

You disagree with power being delivered via the other side of the TO-3 flange? I wouldn't have thought it to have made much difference and eases the placement of MF decoupling, rail catching diodes and facilitates board testing prior to fitting the output transistors. I rather liked the approach. What is the issue? There are no long traces involved and essentially the power is still being delivered directly to the outputs.

Or did I miss something else in Alex's layout? It is fundamentally very similar to mine, but with his own signature flair.

[AndrewT]

No, I disagree with the high loop area power connections. See the spacing of V+ & V- and PG.
Note also how these three wires span over the low level stages.

[jkuetemann]

I understand what you are suggesting now, not so much an issue on the PCB but rather the power delivery to the PCB. Fair enough. Like I said before this is an exercise in skill development.

So, here's a few changes. MF rail decoupling, diodes across the audio ground isolation resistor, some rerouting of traces and a few components moved. Still haven't decided where the place catching diodes just yet.

Thanks for the active discussion so far folks, it might not be pretty but I think I'm beginning to see the light.

[jkuetemann]

The 'Generic PSU' to compliment the 'Generic Amp'. Planning on the project being modular, Soft Start, PSU, Speaker Protect, et al as separate 'modules'.

[AndrewT]

The input fuses can't do much to improve safety.
]The high charge rates into the discharged capacitors require high value T rated fues.
These fuses then tolerate enormous overload currents.

Far better to close rate the transformer primary circuit fuse.
eg 200VA with 110/120Vac mains requires <=2A fuse to run the following 100W to 150W of maximum output power amplifier all day long at party volume levels.
I would experiment with T1.6A and T2A, to see just how low in fuse rating I could go, without incurring nuisance blowing.

[rsavas]

Hi Jason,

I am basically doing a similar task as you are. I have designed a power amp using the LME49830 + LatFet, similar as was done by OPC (Owen). I managed to get a used transformer from a scraped Pioneer SX-1250 via eBay. I am merging two designs, the power supply section of the SX-1250 & the National Audio Power Amp Power Supply application note. I have done the Power Amp Recifier assembly & the PowerAmp assembly, so far and working on the attached PCB/schematic of the AC input assy. Still need to figure out the regulator for the LME49830, probably will just use a simple LM317/337, for that. Disregard the thin traces, as I just did a quick route last night, they will be beefed up with thick traces & copper pours. This gives me a chance to have people review what I am doing and get feedback as well. Hope that this is of some help to you. If you have any question, please ask.

Regards
Rick

[Walkalone]

What good result for tracks distance/spacing for voltage levels. I'm remember the UL-60950-1 standard say the tracks distance/spacing is 1mm for < 100V.
Correct me if i wrong!