My main area of focus for electronics (and life, for that matter) is audio; valve-based guitar amps, to be more precise. In the arena of guitar amps, one thing that you will always hear is that everyone wants a "Hand-wired point-to-point" tube amp, instead of one with a PCB. I hear this all the time, but I have not found a really rock solid answer as to exactly what point-to-point actually even means, much less why it is better than a PCB. I have Fender Blues Jr. tube amp, and I took it apart the other day for the first time. It has a PCB in it. I have watched a lot of people hand wire or repair old hand wired vintage amps on YouTube, and they always have some kind of "board" too. I mean, you can't just wire components together by twisting their leads together and making a big birds' nest of components. There is always a chassis and some kind of board screwed down to it. I believe the boards in a "point-to-point" am is called a turret board. But what does it matter if you drill out an make your own one-off "turret board" that you solder everything to, or you use an acid bath to create a printed circuit board, and then solder everything to that?

I def. get the idea of liking that a human being soldered your amp circuit together rather than a mass production robot soldering 300 identical PCBs an hour. But that is certainly just a mental placebo thing, right? There can't actually be an audible difference between hand-wiring a PCB and hand-wiring a turret board... can there?

 

In the arena of guitar amps, one thing that you will always hear is that everyone wants a "Hand-wired point-to-point" tube amp, instead of one with a PCB.

That's why such people are referred to as "audiophools"; their technical judgements are based on pure superstition.

I hear this all the time, but I have not found a really rock solid answer as to exactly what point-to-point actually even means, much less why it is better than a PCB.

"Point-to-point" probably refers to older methods of construction used prior to the advent of printed circuit boards: tube sockets mounted on punched chassis, resistors and capacitors soldered to terminal strips (and to the tube sockets), and everything connected with insulated wires instead of via tracks on a PCB. Very old-school.

 

In the arena of guitar amps, one thing that you will always hear is that everyone wants a "Hand-wired point-to-point" tube amp, instead of one with a PCB.

"Point-to-point" probably refers to older methods of construction used prior to the advent of printed circuit boards: tube sockets mounted on punched chassis, resistors and capacitors soldered to terminal strips (and to the tube sockets), and everything connected with insulated wires instead of via tracks on a PCB. Very old-school.

Not a professional myself, when I started as a radio amateur, in the need of components, I was given (50 years ago) equipment already OLD, obviously all hand wired. From sockets to turrets/terminal strips, everything was neat and you could actually follow what the schematic described. One name comes to mind, Ericsson. Some kind of strange terminal strips looked like what today could be a crude PCB on a turret. They looked nice.

I recall disassembling the console from a coastal radio station where the operator could actually "dial" the frequency he needed for a certain xmtr. I can imagine the training the people building that, had.

 

Tube gear was wired using these https://tubedepot.com/products/5-lug-terminal-strip "terminal strips" . Later amplifers added turret boards. Later yet, in TV's and audio, you might find A PCB for part of the amp. Tube sockets were riveted to the chassis.

This is an amp I did own at one time until I drilled the rivet out and destroyed a transformer. No internet back then and I only had one.
This only has one terminal strip and a turret board.

In some new PCB applications for tube gear, I've seem PCB's of 1/8" used. Tubes generate a lot of heat, so thin boards are not a good idea.

I own a version of the TV 7 and it's the most intense point to point wiring I've ever seen. Some sockets in mine need to be replaced. One interesting comment on calibration. Ohms/V matters when calibrating.

 

My main area of focus for electronics (and life, for that matter) is audio; valve-based guitar amps, to be more precise. In the arena of guitar amps, one thing that you will always hear is that everyone wants a "Hand-wired point-to-point" tube amp, instead of one with a PCB. I hear this all the time, but I have not found a really rock solid answer as to exactly what point-to-point actually even means, much less why it is better than a PCB. I have Fender Blues Jr. tube amp, and I took it apart the other day for the first time. It has a PCB in it. I have watched a lot of people hand wire or repair old hand wired vintage amps on YouTube, and they always have some kind of "board" too. I mean, you can't just wire components together by twisting their leads together and making a big birds' nest of components. There is always a chassis and some kind of board screwed down to it. I believe the boards in a "point-to-point" am is called a turret board. But what does it matter if you drill out an make your own one-off "turret board" that you solder everything to, or you use an acid bath to create a printed circuit board, and then solder everything to that?

I def. get the idea of liking that a human being soldered your amp circuit together rather than a mass production robot soldering 300 identical PCBs an hour. But that is certainly just a mental placebo thing, right? There can't actually be an audible difference between hand-wiring a PCB and hand-wiring a turret board... can there?

In the long term - the PCB heat discolours around the valve holders. the old paxolin stuff did surprisingly well - the only carbonised tracking I've seen was around high voltage pulse stuff in TVs. laminated glass fibre boards are MUCH better, but you still get some discolouration in the fullness of time.

You have to know your star-point theory with power amplifiers, but it usually looks simpler on valve stuff. the point mainly being its easier to produce a new layout drawing for point to point wiring than scrap a batch of boards that don't give quite the expected results.

 

My main area of focus for electronics (and life, for that matter) is audio; valve-based guitar amps, to be more precise. In the arena of guitar amps, one thing that you will always hear is that everyone wants a "Hand-wired point-to-point" tube amp, instead of one with a PCB. I hear this all the time, but I have not found a really rock solid answer as to exactly what point-to-point actually even means, much less why it is better than a PCB.

I def. get the idea of liking that a human being soldered your amp circuit together rather than a mass production robot soldering 300 identical PCBs an hour. But that is certainly just a mental placebo thing, right? There can't actually be an audible difference between hand-wiring a PCB and hand-wiring a turret board... can there?

In the 80s I sold actual audiophile gear. Along with real concerns were a variety of silly and mythical things that cost a lot and did little or even nothing. It only got worse over time.

Not knowing this particular fetish, I can only speculate they believe that PCB traces are inferior to stranded wire for audio. This is not true, but it's a "reason". So long as the PCB layout is well done, and the electrical properties of the traces are appropriate to the signals they carry, you could only be better off than discrete wires which are much harder to manage from a quality control perspective, and from a repeatability perspective.

With any alternating current signal you need to reproduce with high fidelity, the conductors that carry it must be appropriately specified. They must have low impedance relative to the frequency and sufficient current carrying capacity. For audio signals, this is not very hard.

It's more about the quality of the design, the components, and the construction, not PCBs or wires.

 

I have studio audio gear that has point to point wiring like the UA LA2A. There may be some differences due to signal induction and isolation due to this method. There’s also the high cost of manufacturing that make that component cost thousands. If boards are designed well you can get the same or better performance as point to point wiring. All the Ampex, Trident and Neve stuff is on boards and they sound amazing. It’s a an old method.

Slightly off topic it’s similar to carburetor vs injection. My Harley is injected but I really love the sound of carbureted Harley’s. The actual intake being controlled by the vacuum of the engine gives it an organic sound. I would never trade the performance and reliability at any altitude but makes me want to pick up an older bike. But it’s a lot of maintenance and isn’t as efficient.

 

I have built a whole lot of equipment and repaired even more of it. What I have seen over the past 60 years is that in the hand wired non-circuit board equipment mostly the connections were made solid and then soldered. The result was that mostly vibration did not break the solder connections and cause failures. What I observed in poor quality circuit board assemblies is that leads poked through holes and soldered would often suffer metal fatigue breakage of solder joints. Some models were very stable while other brands and models were junk.. The junk equipment gave all of the circuit board equipment a poor reputation. I have repaired quite a few pieces of audio equipment simply by going through and resoldering every board connection. With the right iron that takes only a very few minutes and is faster than most diagnostic efforts. So the general prejudice against circuit boards had a valid basis, but it was not understood by many folks.
Of course, for equipment that needed to be identical in every package a well designed and well built circuit board allows the production of thousands of units all the same. But the extra design and assembly work required does cost a bit more, even today, when the boards are all machine stuffed and wave soldered. Even with totally automated production, adequate quality costs more than junk quality.

 

Point-to-point wiring: (scroll through the pictures)

https://images.search.yahoo.com/search/images?p=vintage+audio+point-to-point&fr=yfp-t-s&imgurl=https://cdn.mos.cms.futurecdn.net/6037e894b3a53eea66866b16c563c77e-1200-80.jpg#id=2&iurl=https://cdn.mos.cms.futurecdn.net/6037e894b3a53eea66866b16c563c77e-1200-80.jpg&action=click

 

The comment about the sound of a carbureted H.D. engine versus a fuel injected one is rather puzzling, since both have a throttle plate, at least all of them that I am familiar with. I was involved with the development of fuel metering systems at one point in my career and certainly with no air cleaner they were all quite loud. So with the FI Harley it is probably that the air cleaner is quite more effective at muffling the sound. At least that would be my guess. Try removing all of the air cleaner assembly up to the throttle body and see what it sounds like. Of course, the intake valve timing will also have an effect. Just listen to the intake noise of an engine with a camshaft having a "super track" grind. Of course that 1800RPM rough idle also has an effect, I suppose.

As for the sound of tube audio equipment with circuit boards versus the wired versions, probably there was no difference until some solder joints to the circuit boards failed. And bad soldering certainly did lead to failed solder connections in many instances.

 

Haha Bill I failed to mention. It’s not the volume of the Harley engine but that organic lope you get at idle with a carb. It sounds beautiful. The SPFI really evens out the engine and sounds too smooth. You’re right a hot cam would improve it.

 

Point to point alias hanging hedgehog style is brilliant for high frequency, where dielectric factor must be as small as possible and all wire lengths even less. It is ideal for the ultra-low current amplifiers like 3 fA where practically all materials create the serious leak curents. BUT it looks just ugly and is absolutely non-technologic.
In the early 80-ies russians tried to use robots thus created the sharp-ended four-edge hedge-wire around what the robot was fast winding some 10-20 turns of palladized thin wires. However next ten years demonstrated that bad contacts in such systems was happening everywhere more badly like bed-bugs in druncard house, thus never this technology was applied in nowadays.
Yet hot trouser-iron method is so fast and all around killing precize, - if from pcb sketch in computer to etchable piece of pcb is just 2 or 3 minutes plus those 15 for etching, then why to try force the already widely opened doors? Only case when this method is too week, is the 0,2 mm ptches for SMD - as here some 0,5mm ought be near limit. Then exists a "Positivus +" technology - bit more longish, bit more expensivish, but so much exact as much the printer is able for - own dedicated accuracy is hardly under 1 micrometer, whilst printer is able if best about 10 microns.

 

It’s not the volume of the Harley engine but that organic lope you get at idle with a carb. It sounds beautiful.

As an old time Harley guy the "lope' has little to do with the carb. It is the ignition making the lope. If you could get a FI to work using the wasted spark type ignition that was used with a carb it would have that sound. Electronic ignition used with the FI and even some of the after market ignitions used are done in 'single' fire mode instead of waste spark mode. It is the small amount of unburned gas being ignited in the exhaust pipe on the exhaust stroke that makes the 'lope' of a old Harley.

 

If you could get a FI to work using the wasted spark type ignition that was used with a carb it would have that sound.

The stock cam has very little overlap. So increasing durations and overlap might have a similar effect.

Back to topic. There's a lot of marketing involved with audio circuits. There are differences between $20,000 studio equipment vs $200 ones besides the features and specs. Those cool machined knobs and plated brass parts add to cost as well.