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What are the advantages of having a pedal or amp that is point to point wired as opposed to one that is built on top of a printed circuit board? Are there any disadvantages of PTP?

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9 Answers 9

Without going into too much technical detail (since it is a bit over my head...) One very good thing about a PTP amp is that they are easy to maintain and repair compared to a PCB... The biggest disadvantage of building a PTP amp is cost, since it takes a lot of planning and wiring by hand compared to a PCB!

As for the differences I think a well planned and well built PCB will be as good as a well planned PTP (and a lot cheaper to make).

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I'm actually looking for technical details :), but these are good thoughts nonetheless! Not sure I agree with this yet though: "As for the differences I think a well planned and well built PCB will be as good as a well planned PTP (and a lot cheaper to make)" –  Jduv Apr 5 '11 at 14:01

I'll give you the answer from an electrical engineering perspective:

  1. PTP can be easier to service when the problem is with the interconnects between components. If you've got a bad lead from one component to another it's an straight forward matter to unsolder a wire and replace it with a new one. Bad leads on a PCB design aren't impossible to repair, but they aren't as easy either.

And that's it.

As for disadvantages:

  1. It's a harder thing to lay out a PTP amp because you don't get to lean on software to ensure that your signal routes are sane. With a PCB-based amp you can use software to ensure that parasitic capacitances in parallel traces aren't a problem, that traces are sized properly for the power they're expected to handle, that components are spaced adequately and so on. And it's an easy thing to change the layout, in software, and simulate new designs for problems without having to resort to a time-consuming prototype build.

And that's it.

It's pretty minor stuff really.

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Great info. About a year ago my Orange amp melted down. Why? Crappy components: the heaters had plastic interconnects and the melted down causing circuit failure. I had everything point to point wired by Will at Orange USA and in addition to a more resilient amplifier, it sounds stronger, cleaner, and with much more kick-in-the-pants. Not to start a holy war, but I think signal quality also is a little better on a PTP amp. –  Jduv Apr 5 '11 at 13:59
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Cheap components are not unique to PCB or PTP amps. And poor layouts are not unique to PCB or PTP amps. Both components to use and the manufacturing method are entirely a design decisions. Signal quality can be better or worse in either a PCB or PTP build method. They are a product of the designer and design decisions, not the build method. "I think the signal quality is a little better on a PTP amp" is not empirically true at all. –  Ian C. Apr 5 '11 at 14:04
    
Cool thanks for setting me straight! –  Jduv Apr 5 '11 at 14:07
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Heh, ask me about my buddy who "cleaned up" the wiring in his PTP amp by re-wiring parts of it with longer wires so he could "cable" them all together in a bundle. FAIL. –  Anonymous Apr 5 '11 at 16:06
    
@TMN: an excellent example of how the construction method doesn't guarantee a superior result. Neither method is superior, both have their own challenges, both can and have been used by amazing engineers to produce great sounding amplifiers. In all cases it was the engineer, not the construction method, that made it sound great. –  Ian C. Apr 5 '11 at 16:38

Advantages to the user of PTP: you can maintain it much more easily. You can simply see the signal path and often component spacing is less fiddle.

Potential advantages in PCB design is often easier to make robust circuits. Broad generalisation, but a well made circuit board can be very resistant to drop damage, whereas a larger layout PTP may suffer from more of a bending moment if dropped. Analysis tools for PCB design are also readily available.

I always prefer to PTP in prototype and finalize on PCB.

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Another advantage of PCB is that it's much more easily repeatable. Your comment "I always prefer to PTP in prototype and finalize on PCB" made me think of this. –  Jduv Apr 7 '11 at 13:21

Theoretically, there's not necessarily any difference.

Practically speaking, however, there's a fairly fundamental difference: air has a much lower dielectric constant than epoxy (which is what most PC boards are made out of). This means even a fairly small gap of air between PTP wires reduces the capacitative coupling to a very low level. Achieving exactly the same (or even less) capacitance between traces on a PC board is always possible, but often quite impractical.

As already noted, however, that all goes out the window if you bundle wires together -- the minute you have direct insulation-to-insulation contact between the wires, you're dealing with the dielectric constant of the insulation rather than of air (and it's typically in the same general range as epoxy -- much higher than air in any case). The higher dielectric constant of insulation is why some people actually use uninsulated PTP wiring -- as long as you assure against the wires touching, it (nearly) minimizes capacitative coupling (though, of course, there is that oh-so-minor detail that catastrophic problems change from "if" to "when").

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I'd say it's exactly the opposite. Theoretically, there's a small difference concerning the signal quality, coupling and so on. The amount and sign of the difference depends on the PCB and PTP designer, it's possible to deliver bad designs in both approaches. Practically however, there is no hearable difference in sound. –  groovingandi Sep 10 '12 at 11:14

You're going to pay more for PTP than PCB and that is the only difference. I challenge anyone to post an audio clip where you can discern the difference between PTP and PCB of the same design, because there will be no audible difference if the boards are laid out and made properly.

Additionally, even observing w/oscilloscope or running noise analysis on the board vs point-to-point should give you nearly exactly the same results.

PCBs were really expensive back when Fender was making the Deluxe, that's why it was all PTP. Now they're cheap, so there's no reason to go through the extensive labor.

Also there's talk about parasitic or inter-channel capacitances and other phenomenon like that. Analog stuff found in electronic warfare at extremely high frequencies like 6GHZ+ work great on PCB and they are astronomically more sensitive to noise than a guitar signal is - you'll never find that stuff wired PTP because I suspect you'll actually start to hit more unknowns in workmanship such as inconsistent contact being made. In fact, the one trick they use for RF analog designs is to use large ground plane "pours" on boards. If there's any improvement over a standard PCB it isn't to go PTP, it's to design a very well grounded board.

That said I've owned a 5E3, but that's just because they are awesome :) Get what you like, but don't be fooled by the pseudo-science

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"You're going to pay more for PTP than PCB and that is the only difference." -- have you seen the price of a Mesa Boogie Mark V? :) –  Ian C. Apr 6 '11 at 13:35
    
+1 for mentioning the oscilloscope point--I consider that the silver bullet and empiric proof that PTP and PCB should theoretically be exactly the same when built with similar quality components. If I could, I'd go another +1 for this: " If there's any improvement over a standard PCB it isn't to go PTP, it's to design a very well grounded board." –  Jduv Apr 7 '11 at 13:19
    
+1 for everything, but especially for using the word "pseudoscience" –  slim Jul 8 at 7:41

There's a nice article called "PCB vs. HANDWIRED" at The Pro Guitar Workshop's site.

Basically it says a good PCB can be as good as good PTP.

The way I look at it, super-high-end audio circuits like we'd find in expensive stereo amps and radios, recording equipment and synthesizers, among many other devices, which have a lot higher frequency and sound accuracy demands than guitar, use PCB. So, a printed circuit board has the capability to move audio around at least as well as point-to-point wiring. It comes down to the components and care taken when designing it all.

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+1 I completely agree on this one! and PCB can be as good as good PTP is something I am pretty sure of as well! –  mrbuxley Apr 12 '11 at 5:36

I find it much easier to modify a PTP circuit than a PCB, even for simple mods that only involve adjusting the value of a preamp cathode resistor or capacitor.

You might like to draw a distinction between a PTP "rats nest" circuit with a dozen resistors hanging off valve sockets and PTP circuits built around an eyelet board or turret board. Personally I prefer eyelet or turret boards for their tidiness, which to me is an advantage when servicing or repairing.

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I prefer eyelet's as well ;). Nothing makes me happier than to get a new pedal in the mail, open it up, and find a nice, tidy build with everything where it makes sense. Thanks for the answer. –  Jduv Jul 18 '11 at 12:42

If you don't plan to modify your amplifier much, get the PCB. I have played both types and can't tell the difference. If you are building one, it will be a lot easier to change and modify the circuit to get "that sound" YOU want to hear with PTP wiring. I would reccomend using a turrret board or tag board to build the next one, if you are planning to duplicate the amp for sales or a stereo guitar setup.

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A point to point wired amp will generally have a rectifier, a nice big transformer, simple but high quality components, and be connected to a decent speaker; anyone with a PTP amp probably has a decent sounding axe. This will sound better. Rectifiers have nice natural compression. Seems a lot of people haven't heard old amps much. There's a reason they're expensive. They sound better. I know transistors can be good, but I also know old hard wired amps can be great.

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