pcb materials

In 25 years servicing all types of audio gear, I have seen quite a few different pcb materials.
For example, most consumer audio uses brown phenolic paper pcb, Pioneer uses a white substrate (polyester ?), Yamaha uses a non fiberglass pcb that looks a bit like fiberglass, and of course fiberglass substrate.
I understand the economics reasons for hole punching versus hole drilling.
The question is has anybody built identical power amp modules using different substrate materials and found a sonic difference or preference ?
Same question for DAC stages ?

Thanks, Eric.
I must confess that I must answer NO to your question on having built identical stuff on different substrates.

However, if you are going to stray from the regular materials, move to Teflon straight away since Teflon is dielectrically the best solid material known to man.

If you have special needs (RF), you might want to go for a high K teflon composite to "electrically lengthen" your traces.

Is it worth it?

Having built electronic systems for many years, using all sorts of PCB materials, I wonder if the price for Teflon boards really justifies the effort, except for RF and strip line work where it is well worth the effort.

Teflon boards are a lot more difficult to work with, and except for Teflon composites not mechanically very good i my opinion.

I know some very high priced brands use these PCBs, but is using Teflon PCB really worth the price and effort, in sonic terms, or is it just PPM chasing, or even worse, plain hogwash ??

Any solid evidence, or plausible reports ??