Suncalc wrote:
Tom, this looks awesome! This looks like there is no preferred side for components (other than the tube socket) with the possible exception of the 7812. I also like that one could simply replace R1 with an off board inductor and get even better filtering and lower noise. C5 and C6 are obviously optional depending on the desired cathode bypass state. This is really excellent.
I would suggest one very small change. I would add two resistors from terminals 1 and 8 to ground. This would allow the board to be used with an output potentiometer (by leaving the resistors off the board) or a fixed output resistance as a stand alone gain stage (with the resistors on the board). Just a suggestion.
Excellent work!
Matt,
Thanks a lot! The 7812 can be mounted upside down. The pins stay in the same direction.
Yes, R1 can be replaced with the choke leads, that's what i will do. I have some more time at the beginning of the next week.
I hope i'll have a proto ready after christmasmas for some first and final testings. The first prints were very promising, except
some solder pad sizes. Some were to small for soldering the wires directly and i want to change them for at least 20AWG
with enough copper surface on the pads. The Resistor pads will be added

.
Mark,
the layout is for (and from) Your and Matt's project and for the Forum members and guests.
I've spent some hours with it to get some serious and well thought stuff. The layout is 100% hand made (No Autorouting or fixed DRC),
just plain component placement, adjusting the sizes, track adjustement and taking care of minimal parallel tracks (capacitive induction) except the heater DC -
and thinking about the versatile usage of the boards...
I believe it could make the simple preamp even more simple and this might help a lot other people out there.
Basically it is more simple to print a positive, etch the board and hook up the wires. The count of errors is minimized
and you don't have to think about point 2 point component wirings. The chance to get problems with noise or HF through
the wiring also is minimized.
I'd rather like to enjoy some posts and pics from happy builders than having trouble with a buisiness..
Maybe later..