Hi guys
I just finished designing a LA2A pcb and would like to have some advice, if the design is well made, some tips I should care, etc. I made the HT 50mils, on the bottom layer, from the psu to the anode of each tubes, and I ground filled the layer. The top layer is the audio traces, 30mils. I tried to not running the ht in parallele with the audio traces. For now, I don't draw the heaters at all. I don't know if I could put it on the bottom layer with the ht or i'm better of to connect it with twisted wires.
Also, I made 4 ground fill path. One for the inout, one for the output, one for the audio and one for the psu. I was warned to do it that way with tubes design.
I just finished designing a LA2A pcb and would like to have some advice, if the design is well made, some tips I should care, etc. I made the HT 50mils, on the bottom layer, from the psu to the anode of each tubes, and I ground filled the layer. The top layer is the audio traces, 30mils. I tried to not running the ht in parallele with the audio traces. For now, I don't draw the heaters at all. I don't know if I could put it on the bottom layer with the ht or i'm better of to connect it with twisted wires.
Also, I made 4 ground fill path. One for the inout, one for the output, one for the audio and one for the psu. I was warned to do it that way with tubes design.
All of the grounds must be connected together for proper operation. The way this is done is critical.
The large capacitors are rather far from the circuit. I would rethink the layout.
Make sure that there is enough creepage between the HV pads and the ground plane.
http://www.smps.us/pcbtracespacing.html
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ok just saw the link. concerning the creepage, is it a value we can set in the pcb designing software, or a specification we set when ordering pcb? For what I see, within my voltages, I'm more than ok with the traces width I set. Should I place my ground fill on the top layer with all the audio traces or on the bottom with the ht (and maybe the heaters) traces?
Yes, there should be a setting for the ground pour creepage. Even if all the traces are on one side and the ground plane is on the other side,
you will still have the same creepage problem with the tube pin pads, since they're also on the bottom layer.
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Why are R16 and R17 so far apart, also R19 and C3?
C4 seems to be shorted out with a trace through R22.
Move R14 so its connection is shorter to the valve.
C2 can be swung round making its connections shorter.
R12 seems to be shorted to ground via C1.
C1 could be nearer the pin, some sort of decoupling?
R34 and R35 could swap places.
R31, C8-1 and C8-2 could be rotated and the routes made neater.
Move C9 and connect direct to pin1 of valve (direct route to C12)... This will allow routes to above to be tidied up.
R26 is only connected at one end.
R27 connects to GND and then has a long route to pin 5 of a valve.
C7D no connection to GND.
There is not enough clearance round the HT leads.
Just a quick revue, without a schematic I can only guess at some things connection wise.
C4 seems to be shorted out with a trace through R22.
Move R14 so its connection is shorter to the valve.
C2 can be swung round making its connections shorter.
R12 seems to be shorted to ground via C1.
C1 could be nearer the pin, some sort of decoupling?
R34 and R35 could swap places.
R31, C8-1 and C8-2 could be rotated and the routes made neater.
Move C9 and connect direct to pin1 of valve (direct route to C12)... This will allow routes to above to be tidied up.
R26 is only connected at one end.
R27 connects to GND and then has a long route to pin 5 of a valve.
C7D no connection to GND.
There is not enough clearance round the HT leads.
Just a quick revue, without a schematic I can only guess at some things connection wise.
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Thanks for the advice guys. @ marce, i revised several trouble while looking back at the schematic. You were right about them all haha. I Will revised a couple of run, too. Yes the holes Will be plate through. For the size, it depend upon the part i connect. Dont remember the general diameter, thought.
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