I've recently started designing PCBs in Kicad and would like to know of any people or companies who make circuit boards that you'd consider exceptional examples or even interesting examples of design styles. I'm spending plenty of time reading about design methodology and I'd like to supplement that by looking at a variety of implementations.
Luxman emphasize their circuit boards and their maybeslightlygimmicky curvy lines, Audio Research has a sort of stylistic signature, Audio Note UK certainly does, Lavardin does some pretty patterned ground planes, Aavik likes planar inductors, and there are many examples of creative component and case mounting.
Whose boards do you consider exemplary?
Luxman emphasize their circuit boards and their maybeslightlygimmicky curvy lines, Audio Research has a sort of stylistic signature, Audio Note UK certainly does, Lavardin does some pretty patterned ground planes, Aavik likes planar inductors, and there are many examples of creative component and case mounting.
Whose boards do you consider exemplary?
Why would a PCB need to have style or creativity? PCB layouts need to be functional to meet various engineering design criteria.
^^^^^ that.
PCBs in principle must provide connectivity and hold your parts; first ones will look clumsy, no big deal, we all started that way.
Practice makes perfect, so you will improve by doing.
Plus Kicad is an excellent tool, mainly meant for hobby use, so you won´t find TOO fancy features on it, just what´s needed for competent designs.
PCBs in principle must provide connectivity and hold your parts; first ones will look clumsy, no big deal, we all started that way.
Practice makes perfect, so you will improve by doing.
Plus Kicad is an excellent tool, mainly meant for hobby use, so you won´t find TOO fancy features on it, just what´s needed for competent designs.
Just because - we can😉
Even a pcb layout may or may not have its own aesthetic - it is part of the design as well.
There is no single correct way to meet design criteria. Finding solutions to complex problems requires creativity. Designers and engineers (creative people) tend to find preferred techniques for how they solve similar problems, which creates styles. This is why every PCB doesn't look identical. I find it useful to learn by looking at how different people have solved similar problems.
I am not looking for decorated boards. I wanted to know if anyone else could think of times they noticed particularly well-designed boards or board implementation within a component.
For some circuits pcb layout is unimportant.
However for others it is vital is is done right.
1/ Interference between two tracks. I ran 10KHz signal next to an audio track and the audio track picked it up nicely.
2/ Not allowing smoothing cap charging inpulses infect the ground line. Have power supplies flow through so the charging impulses dont get on the output ground.
3/ Long sensitive tracks. Keep sensitive tracks as short as possible and away from transformers HVAC etc. Valve circuits are high impedance and pick up noise easily.
However for others it is vital is is done right.
1/ Interference between two tracks. I ran 10KHz signal next to an audio track and the audio track picked it up nicely.
2/ Not allowing smoothing cap charging inpulses infect the ground line. Have power supplies flow through so the charging impulses dont get on the output ground.
3/ Long sensitive tracks. Keep sensitive tracks as short as possible and away from transformers HVAC etc. Valve circuits are high impedance and pick up noise easily.
I would look first for thoughtful parts/connectors layout, which is essential for a well functioning pcb.
Neurochrome designs are interesting because of the low distortion results. Not easy to produce a design that outperform nearly every amp on the planet.
Regarding PCB layout and amplifier distortion, I remember an article of professor Cherry about magnetic coupling from the currents through the output devices of a class-(A)B amplifier to its input and output. Those output device currents are basically half-wave rectified versions of the signal, so they have a huge THD (theoretically 100 % THD, all even order). You can also describe them as the sum and difference of half the desired output current and a full-wave rectified current, the full-wave rectified current flowing from the positive supply via the output devices to the negative supply and back.
Cherry ended up recommending figure-of-eight PCB patterns for the supply decoupling and output devices to minimize even-order distortion caused by magnetic coupling. I have the article in the attic somewhere. Another thing to keep in mind is that you first have to combine the currents from the positive and negative parts of the output stage, and then take the feedback.
For audio DACs, you normally have to apply RF layout techniques, particularly for sigma-delta DACs.
Cherry ended up recommending figure-of-eight PCB patterns for the supply decoupling and output devices to minimize even-order distortion caused by magnetic coupling. I have the article in the attic somewhere. Another thing to keep in mind is that you first have to combine the currents from the positive and negative parts of the output stage, and then take the feedback.
For audio DACs, you normally have to apply RF layout techniques, particularly for sigma-delta DACs.
Artfully tacked on like an unquestionable fact, a reliable technique. Tom at Neurochrome has certainly created a valuable resource that I've spent plenty of time reading, as have I spent plenty of time looking at the way he splits his planes on circuit boards. I wish his tube amp pages were still active.
100% agreed. You exactly describe one issue I had with my class-ab reference amp and after some exploration of significant H2 distortion I came to just the same conclusions. Summing up the two halfwaves is hypercritical if you are in for really low THD.
I choosed symm figure of 8 decoupling for my TPA3255 pcb layout with fine results.
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Currents are pretty much irrelevant in voltage feedback amplifiers.
The main currents flow through from smooting caps to output transistors, speaker and back in to smoothing caps. They don't affect the rest of the amplifier circuit.
Sounds like a bit of audiophoolery to me ?
Not at all. We are talking of measurable asymm distortions depending on output layout.
And yes, this is a matter of current flow, i.e. disappears with no load at all.
You are wrong. The feedback divider can null out THD to near zero exactly at the point where it measures. Your load is physically never exactly at the same point. Current flow of the two half waves creates tiny voltage drops across the conducting traces - and you always should keep in mind that your output signal must be composed of to halfwaves. Each one distorts in itself considerably. Every tiny asymmetry of summing both halfwaves results in asymmetric distortion, i.e. H2 etc.
This is no crude theory but I had to learn this the hard way: H2 was much bigger in reality than in sim. You will not experience this effect at THD in the range of 0.1% - which is pretty good. But if you want to squeeze THD to <0.001% these effects matter.
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I always run feedback from centre of output transistors so I shouldn't have that problem.
I suspect any difference is as little as makes an irrelevant difference.
As I said earlier its audiophoolery.
I cant hear 0.001% distortion so why worry about it ?
You are missing the point. We do not discuss what is audible, but what can be measured beyond audibility. If that is not interesting for you, that is fine. But if you do not understand the underlying physics there is no point calling this audiophoolery.
I understand exactly what your saying, my point is it is not worth bothering about if you cant hear the difference.
You won't believe it, but sometimes it makes sense to design amps that far exceed you hearing capabilities.