Point to Point wiring +/-?

gyrene

gyrene

No Marconi:Gomer MacGyver
Sometimes when I surf I find pics of point to point wiring done on homemade amps and I find it almost beautiful in a sort of raw way.Like "Manhattan" style.
What can you guys tell me about the plus and minus of wiring anything up point to point?Seems like much of the old stuff was done point to point.
If I had a bill of materials and a schematic I could wire any unit up right?
Seems like all the leads would have to be protected and other than the "messy" look what is the down side?
 
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PCBs are often the most important part of any gear they are in. They are in essence the entire circuit. Anything that damages them, etc. is a bad thing, as they are often not easily replaceable. Age, heat, poor soldering, and other things can contribute to the deterioration of a PCB. They often make it difficult or impossible to mod a circuit, if that's what your intention is. They can complicate reverse-engineering of a circuit, tho as you've likely noticed it's not cake walk with P2P either.

PCBs do allow faster and easier builds. A lot better chance of "getting it right the first time".

I've taken the cheap way out and built a few circuits P2P that otherwise come on a PCB. It requires a lot of forethought to get it neat, but you don't have to pay for a PCB, and you can lay it out any way you want.

I got my start in DIY audio building gear out of PCBs. It's a great way to get your feet wet. Later when I gained skill (and attitude ;) ) I decided that P2P was the way for my later builds to go. I could still see using a PCB for small and complicated circuits, like phase splitters, CCS units, and the like.
 
Printed circuits didn't get popular until the late 1950s. Point to point has its advantages, such as ease of modification, less stray capacitance, ease of repair, etc. The main advantage of PC is to lower assembly cost, and of course more uniformity in performance, one unit to the next. It also provides the opportunity to identify parts for schematic diagram reference.

They carried it too far when they made multilayer boards and surface mount components; it's almost impossible to make repairs these days, even if troubleshooting were possible. Many circuit points are simply not accessible now. Integrated circuits are bad that way as well.
 
Point-to-point wiring was the standard for vacuum-tube circuits when low component count and large robust components were common. As solid state reduced component size and increased circuit complexity, point-to-point wiring became impractical. It also became quite uneconomical, since printed circuit boards facilitate automated assembly and wave soldering, where point-to-point requires extensive manual work.

For DIY projects, the production advantages of PCBs may be negated by the difficulty or expense of short-run or one-off circuit board production. I have etched plated circuit boards for past projects but that was smelly, messy and labor intensive, especially since I made double-sided boards with a ground plane and set feed-through eyelets since I had no way to plate through the holes.
 
Bob91343 said:
Printed circuits didn't get popular until the late 1950s. Point to point has its advantages, such as ease of modification, less stray capacitance, ease of repair, etc. The main advantage of PC is to lower assembly cost, and of course more uniformity in performance, one unit to the next. It also provides the opportunity to identify parts for schematic diagram reference.
Click to expand...
I've never had any trouble following schematics or identifying components on point-to-point wired units...
They carried it too far when they made multilayer boards and surface mount components; it's almost impossible to make repairs these days, even if troubleshooting were possible. Many circuit points are simply not accessible now. Integrated circuits are bad that way as well.
Click to expand...
... I haven't had trouble troubleshooting or repairing multi-layer boards or SMD assemblies, either; they just require more attention to detail than older style PCBs.
 
Thank you for your thoughts guys.
I'm going to go ahead and build "something"...I don't know what just yet.
Maybe a 40w amp and do it point to point for the challenge and experience.
I like the way the Manhattan style looks.
I emailed a friend of mine that has been working at Big Blue for 35 years and asked him a few questions about capacitors and resistsors and his reply included something like this "...no one works at the component level anymore...hell most of the guys here wouldn't recognize a resistor if it introduced itself".
They just throw out a bad unit or board.No attempt to troubleshoot or repair.
Could be cool to work on.I think I'll do that this summer.
Anyone else do point to point work?
Got any pics or hints or comments I could use.
Thanks
 
I've done some small things on pref board with what essentially amounts to P2P wiring, but nothing terribly complex. Don't really have any specific tips or tricks to suggest though.
 
If you're laying out a tube project, I could suggest the following:

Lay it out first in respect to the signal path. Keep it as short as possible.

Next, figure out where all of your heater will run. Keep them as far away from everything else as possible.

Finally, lay out the power supply around the rest of it with an eye towards neatness.

When you actually wire it up, do the heaters first. Make sure they are twisted nicely, and are routed away from everything else. You can check your work at that point with no other circuitry involved: If you plug it in, and all the tubes light up, you'ge got one thing working!

Good luck on the project, keep us posted either here or in the Tube forum.
 
FWIW, Radio Shack sells a general-purpose project PCB that works well for solid-state circuits here. This type of board works best for ICs and small-package transistors; with some attention and thought, you can use components and short jumper wires to link segments of the board into a relatively sophisticated circuit.

They also still sell double-clad copper boards here, if you want to try etch-your-own PCBs...
 
Squidward said:
...Next, figure out where all of your heater will run. Keep them as far away from everything else as possible...
Click to expand...
You can also reduce filament-circuit induced noise by keeping the filament wires at right angles to your signal paths. I've also known some designers who rectify the filament voltage and heat their tubes with DC to keep 60 Hz wiring as far from audio signals as possible.
 
DC heat is it's own can of worms. I find I often don't need it if I'm careful with heater placement, etc. Some circuits are so sensitive (phono preamps, etc.), DC heat is the way to go. Good comment about the right angle wiring.
 
Re-manufactured (i.e. repaired) PCB's are quite common in the field service industry.
Any PCB's that are pulled from customer equipment, get sent back to a companies tech center.
They rework the defective PCB, then put it back into stock.
So when the next field tech needs a replacement PCB........................................

I personally think point-to-point wiring is the way to go with DIY, especially if the parts count is reasonably low.
Makes troubleshooting pretty easy too.

Steve
 
O.K. very cool guy.Thanks.
Now I just have to choose an amp design and get some parts.
 
Just FYI: If you want power with "reasonable" high voltage (300-400VDC) look at push-pull amps. If you want more power with a single-ended design, you need pretty high voltage, and a tube that can take it.

If I wanted a 40wpc tube amp, I'd be looking at a push-pull design with EL34/6L6/KT-whatever outputs. Maybe something along the lines of a ST-70.

Good luck with the project!
 
gyrene said:
Thank you for your thoughts guys.
I'm going to go ahead and build "something"...I don't know what just yet.
Maybe a 40w amp and do it point to point for the challenge and experience.
I like the way the Manhattan style looks.
I emailed a friend of mine that has been working at Big Blue for 35 years and asked him a few questions about capacitors and resistsors and his reply included something like this "...no one works at the component level anymore...hell most of the guys here wouldn't recognize a resistor if it introduced itself".
They just throw out a bad unit or board.No attempt to troubleshoot or repair.
Could be cool to work on.I think I'll do that this summer.
Anyone else do point to point work?
Got any pics or hints or comments I could use.
Thanks
Click to expand...


If you would have any interest in a tube amp kit I highly recommend this one http://picasaweb.google.com/arnoldm...DesignedByBobLatinoAssembledByArnoldMatthews#. I built one a couple of years ago and was very happy with the kit and results. It uses mostly point to point wiring with a circuit board for the driver board. It is a little pricey but was well worth it :yes:
 
CallMeJoe said:
I've never had any trouble following schematics or identifying components on point-to-point wired units...
Click to expand...
What I think Bob meant was you can silkscreen the component # onto the PCB to ID. Hard to silkscreen in air on a p2p.

For tube circuits or one off SS with leaded components, p2p is easier and quicker. I've built many tube amp prototypes with clipleads in a fraction of the time it would have taken to design a PCB.
 
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