And many old amps had *terrible* wiring and grounding, using iron chassis as ground conductor was common practice, including grounding one end of all filaments so only filament return was through chassis.
Hum/buzz was common, not the exception.
Here's an example:
see grounds taken where available, meaning straight soldering to chassis without much concern, shielded wire also soldered at random.
In fact I remember (born in 1952) that often rather than store bought screened cable, you bought empty naked rolls of "screen" and built your own as needed, including multiple wires if needed.
Popular notg only in Audio but also in RF and TV stuff.
Or screened wire had no outer sleeve, since it was meant to be used inside a chassis anyway and screen was soldered to it where needed:
Really, if somebody thinks old "real" PTP wiring was "better" ... should reconsider his thoughts.
I built my first amps in the 60's, using terminal strips, and
quickly invested my weekly allowances to buy a bench mounted eyeletting machine , so I was able to make "Fender style eyeletted boards".
In fact I still have it

, working like the first day, and still in use eyeletting speaker cones and terminals
FWIW in my book Fender style eyeletted boards do not count as PTP by any means, I consider them "no etch PCBs" if you get what I mean.
They:
a) guarantee repeatability, even if built by basic trained workers.
b) can be built independent from available chassis, iron, cabinets, etc. so in slow times you can fruitfully build extra boards and keep them in stock for later orders .
And as a logical step forward, as soon as they could some major Factories, such as Ampeg and Marshall switched to PCBs (we are talking **many** years ago).
Don't think they were fools
