Tube bass preamplifier power supply (Need Help)

[ruffrecords]

Should I worry about having channels too narrow? My grid is 50mils, so the closest points are about 30mils apart. Is that a problem?

Yes, they are far too close.

The only place you really need fat tracks is from the ac input to the diodes and from the diodes to the first filter cap. This is where the peak charge currents go and they can be 5 to 10 times the nominal load current. The rest of the circuit only needs to handle the load current. An earth plane is not necessary and only makes soldering more difficult. You really need to aim for 3mm minimum separation between the HT and 0V tracks.

Cheers

Ian

 

[fingerboy21]

I suppose I should spread out my parts a bit more then? 3mm is about 120 mils so I would need to move parts to get the pads far enough apart.

 

[fingerboy21]

Progress:

An externally hosted image should be here but it was not working when we last tested it.

That was the best I could do for track sizing. The larger tracks you see are 150 mils, and the smallest ones are 75 mils.

 

[ruffrecords]

That looks OK to me. I normally do my diodes the other way with the ac fed to the middle and the outputs above and below but that's largely a matter of taste. I alos make space for 1N5000 series diodes even if I fit 1N4000 series just to give a little extra clearance in that region. Looks like you have room to do that it you want.

Just one question, why do you have two caps in parallel just after the rectifier??

Cheers

Ian

 

[fingerboy21]

The largest caps that I could find that would fit my chassis and budget were 220uF, so I put them in parallel for a total of 440uF. I like your idea on having the AC fed to the center. I will try that. Thank you sir for your time and expertise.

 

[fingerboy21]

It's getting a bit frustrating trying to get my layout just the way I want it. I know that's not going to happen on a single layer board with no jumpers, but I have also read that legally mains voltage tracks needs to have around a 300mil separation. How the heck would I be able to do that?

For my diodes, simple turn each of them 180 degrees?

 

[mashaffer]

Sorry if I missed it, but for such a simple circuit why all the headache and bother of a PCB? Why not just knock it up point to point?

 

[fingerboy21]

It needs to look professional since it's a college senior project. I'm going to leave the PCB as it is and I will test it with precaution. Live and learn. If it's not optimal, so what? It's my first shot at it.

I want to thank you all for your incredible help.

 

[fingerboy21]

Final:

An externally hosted image should be here but it was not working when we last tested it.

 

[mastodon]

I know that's not going to happen on a single layer board with no jumpers

In case it helps (I dunno if it's good practice, but anyway): you could always 'stretch' a resistor and thereby implement a jumper of sorts. I.e., you could artificially make the resistor longer in your pcb design and effectively make use of the leads it comes with. Maybe it's superfluous and you've already tackled it; in that case, nevermind

But take the R3-C4 node at R3's end; it seems that B+ is a bit close to ground at that point. You could move C4 a bit more to the edge of the board (i.e. to the right), and place the node I mention between C3 and C4, thereby moving it away from the ground trace. Which looks a bit thin, btw, but this 'workaround' allows you to make that trace thicker as well.

Just trying to think along; I have no particular competence in PCB layout.