PCB for simple OP-preamp

[kmj]

to keep it short, will this do for a pcb-layout? I have never made a pcb before but i had some time over and parts that were of no use at the moment 🙂
the ground from the pot is at the same place as the inputground.

 

[tobias_svensk]

Hello kmj 🙂

Looks good I think, you could move your 0.1uF on the V+ rail I guess. Put it between the Output L/R resistors and move your Output ground hole a little bit.

 

[Roushon]

it might be a good idea to make and connect the input ground to the power ground by a thin track, otherwise distortion may get into the input signal.

 

[kmj]

Roushon
So just make the rail between the 0,1uF MKP cap and the inputground thinner then.

tobias_svensk
Just move the cap to the other side of the electrolyte then.
(those yellow things next to the out R and out L text are two VERY big capacitors )😀

I'll have to test your advice, i put it together this afternoon and it works. However, i get a loud background buzz, like a bad radioreception.

 

[Roushon]

make the whole vertical track on the left hand side of the pcb thin.

 

[kmj]

Will do.
The buzzing is still there and i stumbled on a strange problem.

It still works with the NE5532 op, buzz and all, but not with opa2604.
If i shut the pre down and change op the fuses melt. strange since the opa2604 only need about 5-6mA and the fuse is rated at 125mA-slow and the supply is a regulated 12V.

one shouldn't have any prblem with something as simple as this....

 

[veteran]

Several months ago I also designed pcb for single op-amp preamplifier 😉 I enclose several pictures. There is also dedicated symmetrical power supply based on LT317/337 regulators.

 

[veteran]

Power supply pcb...

 

[veteran]

Bottom side of preamplifier pcb.