Still another opinion - or maybe even some enlightenment? Decide by yourself!
By principle it's possible, to design an awesome PCB with enough space between the components and with very low amounts of crosstalk between the traces, the layers and the components at all - as well as it's possible, to desing a poor and strange behaving PTP layout! This all depends on the knowledge & experience of the designer - by principle!
Another aspect is, that certainly some ~companies~ would like to build their amps on PCB, to save cost and labor time, to enhance their profit or to may offer their amps cheaper, to enhance the possible numbers of sale. But to those sometimes it appears, that it's not economical, to make a PCB design for their 5-10 amps, they're selling in a year. Or they've tried it in the past, but after the 5-th or 6-th not properly working PCB they've decided, to not longer waste time and nerves with the try on still more experiments - knowing, that on a PTP board you can swap parts easily, if you have an oscillation issue, damping or cancelling out effects, aso. Even with a just average knowledge you can experiment as long, until it 'works', though haven't recognized, 'why' it's working now - but a PCB is as it is, any experiments on it are extremely restricted.
Not seldom (or even almost always) cost & economical aspects come into play, when a company has to decide, whether this amp should be build PTP or PCB! The often heard argument of the higher or better consistency of a PCB amp by any means is fact, if you have only 'trained on the job' people, but otherwise not with that huge knowledge about tube amps, to assemble and complete the amps. But when a skilled person is building a PTP amp with all his knowledge about the stray fields occuring in amps and the knowledge & experience about, which cable's stray field is influencing the signal voltage in another cable, component, aso. in a bad way, then he's even able, to build this amp with a still higher consistency, than a PCB amp usually is built!
Keep in mind, that the electrons don't flow only in the cables and in the components! There are sometimes huge electro-magnetic fields around every conductor! Some areas inside a tube amp and sometimes only 'this' or 'that' single cable are highly sensitive for catching any stray field surrounding there - they're acting like antennas of a receiver. Other areas or certain cables, who contend eddy current and/or high voltages in contrast are acting like transmitters, who sometimes are straying out unbelievable far. Then you have to take in account the phase of any single cable, part, the phase shift produced by passing the signal through a cap and many more, what's impossible to describe here, if I don't intend to write a book.
And all these stray fields are influencing each other, from where sometimes some bad and unwanted results might occur, which i.e. are oscillating (audible & not audible), ringing (ice pick highs), intermodulations, dampening, cancelling out of some frequencies and many more. And because an amp, where nothing would influence another cable, component or area would be about 7 feet wide, 3 feet deep and 1 foot high (only the chassis), the designer must have huge knowledge about these fields and a lot of experience with tube amps at all, to be able to build a 'flawlessly working tube amp' inside a smaller space.
He must know concretely, what cable might be routed along the other, or across which component, in which space to each other - and which ones have to be avoided to only come close to this area, not to mention close to this cable or component. He further must know, which component might be placed next to the other, in which space... and which one never may be placed there at all on the PCB or on the turret/eyelet board. And this skills IMO are more important, than (the from reading other schems) acquired knowledge of determining the values of this cathode resistor, that coupling cap, the tube's supply voltages, aso.
You now can see, that tube amps are highly sensitive animals inside! And I'm sure, that if it would be possible, to make all those fields, phasings, phase shifts
outside of the cables & components inside a tube amp's chassis visible, then among not less of the tube amp builders would occur an 'ah-ha effect' - and some of them would quit their business forever, they'd capitulate after this
And now keep in mind, that not all and everything in a PCB amp is 'fixed' on the PCB! There are lots of cables from the PCB to the tube sockets, to the pots, to the jacks & switches. Moreover there are cables from the OT & PT - and all these cables, the entire lead dress might be routed today in this manner - and tomorrow different. Or 'Rick' does it always 'this way', whereas 'Nancy' always does it different... The final test result is: "amp is working" - so simply put it in the cardboard - ready for shipping
Still another aspect, why i.e. I never will design and offer a PCB based amp is, that in my PTP eyelet-board based amps I'm able to fine-tweak and optimize the amp's sound even w/o swapping tube brands or component's values just by moving the cables back & forth. I'm using very stiff cables (not solid core), which stay in place even when the amp inside is heated up much after a 4h gig. The location of the cables anyway is optimal choosen, but by moving it a bit closer there, or a bit closer to (the shielding effect of) the chassis - or rather more away from the chassis and maybe closer to another cable, to get an expected influence from another field still more present... is similar to getting still the last 20...30 more horsepower out of a Formula 1 engine
But on a PCB I can't move any trace
The short version or lets say the resume of this above I've already written here in another topic 1.5 years ago. Here:
viewtopic.php?f=3&t=27434&p=332530
For those, who are interested in reading it once again, here pasted in:
novosibir":3qdzd059 said:
chunktone":3qdzd059 said:
jack butler":3qdzd059 said:
Larry's amps are PTP not PC board, look at the photo's---like a high end sports car.......typical German quality at it's finest!
So your saying since it's PTP instead of a PC, that justifys the cost. Diezel's use the highest grade components available, and from the look inside the Herbert, I'm not sure PTP would even be possible.
Check this link on PTP vs. PCB.
http://www.bogneramplification.com/cust ... index.html
Yes, a great explanation!
But almost every preacher with a good elocution could explain (and maybe convince) you, why his religion is better than all the others and why his church is the best at all
Believe me, there's a reason, why I spend 80 hours of work in hand building a British Purist and even 100 hours of work in hand building a DINO - and this reason can't be replaced just with a PCB, maybe already completely assembled and delivered by another company! And I'd do it different, if I'd get the same results with a PCB, what I'm getting with my procedure
Larry
I very much hope, that you all could understand my German's English
Larry
