Since we're speaking about Princeton Reverbs

[simonallaway]

I apologise in advance for the slight change of topic....

Seeing this gut-shot reinforces the colour coding of wires that you'd mentioned to me in the past. I makes total sense now that I see it applied.

I also like the use of the red sleeves off the B+ "rail" where wires cross over.

Your heater wires...are they deliberately "up in the air" as opposed to being next to the chassis? When wiring my P1 I couldn't help but think that using 3-dimensional space ought to offer advantages over thinking of the chassis as a 2D space. Am I over thinking this? 

[HotBluePlates]

Your heater wires...are they deliberately "up in the air" as opposed to being next to the chassis? When wiring my P1 I couldn't help but think that using 3-dimensional space ought to offer advantages over thinking of the chassis as a 2D space. Am I over thinking this?

No, you're not over-thinking. And his heaters are up in the air as an accurate copy of how Fender wired 60's amps.

If you can find pictures of Fender original tweed and blackface amps, compare gut-shots.

The 60's era amps had a chassis change which placed the circuit board and tube sockets on the same plane. In that situation, Fender apparently felt it best to have the heater wiring up in the air. It keeps those wires furthest from all other circuit elements. If you contrast tweed-era amps, the sockets and circuit board are not on the same plane, but at a 90-degree angle. Fender kept the heater wiring tucked down against the chassis, and tight into the lip in the chassis. If you use the circuit board as your reference plane in both cases, the heater wiring is in the same orientation relative to the circuit board.

My guess is that they felt it was the furthest you could readily place those wires away from the circuit board, where heater hum might cause the most problems. In the case of the tweed chassis though, it also makes for the neatest wiring, with the heaters completely out of the way (and almost invisible unless you know where to look for them). In the cramped tweed chassis, that's an important feature.

[Fresh_Start]

Your heater wires...are they deliberately "up in the air" as opposed to being next to the chassis? When wiring my P1 I couldn't help but think that using 3-dimensional space ought to offer advantages over thinking of the chassis as a 2D space. Am I over thinking this?

IMHO you're not "over-thinking" at all.  For me, it's important to think in terms of 3 dimensions for your layout and lead dress.

HBP has it exactly right in terms of me copying the BF Fender approach to layout for the heater wires.  IIRC Marshall lays the heater wires flat on the chassis and tucked up against the back corner, similar to a Tweed Fender.  However, that puts 'em closer to any controls and/or jacks on the back side of the amp.  If it weren't for the reverb jacks, I'd probably do it Marshall-style.  Since the reverb send & return are very sensitive parts of the circuit, the heaters are as high "up in the air" as I could get them.

While we're hi-jacking this thread, the color-coded wiring emphasizes a couple of other "principles" I follow for lead dress.  The blue plate wires go straight down to the chassis, lay flat on the chassis, and are kept away from other things (high voltage & high current).  Orange grid leads (where not shielded) are in the air and perpendicular to anything else because they're the most sensitive to interference (low voltage/low current).  Yellow cathodes aren't as critical, but I try to keep some separation.

Another example of 3-D separation is the blue leads from the tremolo Intensity pot to the board in This Shot.  They go almost straight up off the board and are kept away from everything else, especially the tone controls & related leads (white, between pots).  I'd had problems with hearing tremolo noise interference and this physical separation seemed to help.

Sorry for going off topic.

Chip

[bnwitt]

Nice work Chip.  I especially like the insulated wire on the B+ rail and the shrink tubing on component leads crossing it.  I like the color coding but I also like push back wire and I can't find orange push back anywhere that is worth a crud.

[Fresh_Start]

Thanks bnwitt!  Doug has brown push-back cloth insulated wire and that's an alternative for orange on grid leads.

My shortened version of "standard" color coding:
plates - blue
cathodes - yellow
grids - orange (or brown)
ground - green or black
B+ is red
B- (bias) violet (or blue)
control leads - white (sometimes alternating w/ another color to avoid confusion)
Heaters - green or red/black

FWIW the red covering on the plate resistor leads (usually) is shrink tubing, but the B+ bus is 22 AWG Teflon insulated wire.  Sometimes I use insulation stripped from red wire on the component leads instead of shrink tubing.  The purpose is 2-fold.  First, B+ is high voltage so red means "danger".  Second, shorting B+ to ground is "BAD".

Cheers,

Chip

P.S.  would a separate "Layout basics, tips, tricks, whatever..." thread be worthwhile?  I don't like going totally off topic here.

[Imntgrumpy]

I had a feeling it was that wire.  And like I said, the ohm meter is your friend.

So how do you like the sound of the tremolo?

Very nice.  Now I know what all my buddies are talking about.  Now I have to make a footswitch to control it.

Thanks

[mojo]

IMNTGRUMPY, glad to see you got it right. Great job.

Chip, I'd love to see a layout basics thread. If you had any tips on learning to read schematics, I'd appreciate that too.

Thanks to EL34 and all the moderators, and all the other "Superstars" at Hoffman Amps.com.

Regards,
Al