design layout

[blues man]

I was reading in Kendrick's book you should keep "in phase" parts of the circuit 3" apart. That is to say with 3 stages of gain, pre-amp 1 goes thru pre-amp 2, which is 180 degrees out of phase, then thru pre-amp 3 which puts the signal back "in phase" with pre-amp 1. With that being said that means keeping the wires coming off the plate 3" apart (if there "in phase"). What about the cathode res & cap. Does that apply as well? With that being said wouldn't it be a better design to have the tubes 3" apart instead of the 2.25" they normally are in a fender amp. Just a thought. I have one more question. What is the distance between the turret lugs on Doug's boards for mounting components. Ive been doing a 1/2" apart spacing. I read somewhere if the circuit wires are closer together (parallel) they cause less capacitance in the circuit than if they are farther apart which can cause more capacitance in the circuit. That leads me to think I am creating problems in my circuits by having my turret lug spacing at 1/2". Any thoughts?

[HotBluePlates]

Spacing, lead dress, layout, etc. is the end result of a mix of many competing factors.

I think the Weber is trying to avoid presenting the can o' worms in favor of giving a simple "rule" to follow, based on your post. I'd advise you not to take it as gospel.

Below is the preamp of my last amp build. I didn't bother with "heater phasing," didn't follow any particular spacing rule. I did consider a number of factors when deciding how to arrange the parts & wiring, including the potential for hum. This preamp (and the rest of the accompanying amp) is free of hum or noise up to max volume. Turret spacing is broadly-similar to Hoffman's spacing (3/16" to 1/4" or so, I don't really recall).

I read somewhere if the circuit wires are closer together (parallel) they cause less capacitance in the circuit than if they are farther apart which can cause more capacitance in the circuit.

Closer = More Capacitance

Types of capacitor Scroll down to "Theory of conventional construction"

If you make the 2 conductors so they have a larger surface area ("A" in the equation), capacitance increases. If you move the plates/conductors closer (by making "d," distance, in the equation smaller), capacitance increases. The other term in the equation is a value based on what material separates the 2 conductors.

[blues man]

closer= more capacitance
Yes you are right. I went back and re-read and had reversed it in my mind originally. That makes much more sense. I have an amp that I built that has always had an oddball after note distortion. I finally gutted it to rebuild it. None of my other builds have this problem. Just a bad layout I guess. It was my first attempt at my own layout. Thank for your input.