Perhaps I am just over thinking this but considering that the majority of computers are made with 100% FR4 circuit boards and the fact that requires much high speeds and frequencies than any audio application I can't see any advantage besides advertising the use of Teflon of Polyimide/Glass for any of our non digital applications? Scott or J.Neutron can speak to this I suppose but I think this has been address more than once.
Richard, i'm facing exactly the same problems, in my new Portuguese exile. But i feel more home here than in my own country. Portuguese people are so nice, so friendly, so helpful, i can't believe-it. It was like that in France, when I was young, what happened ?
About Teflon or Polyimide/Glass, i have so many things i can improve first... ;-)
About Teflon or Polyimide/Glass, i have so many things i can improve first... ;-)
John,
If you could show any measured improvements with only changing the board material while using the exact same mounted components on an identical board layout I think people would then sit up and take notice. But to just say because you say so that this makes your products sound better is just more of that hot air that makes audiophile design a joke with so many EE engineers. Show where the FR4 material is limiting or interfering with analog audio signal by any designer in this industry? I would like to read some real science on this. I am not saying that components meant to work with a digital signal processing device such as a computer are preferred components in audio, that is not the same as saying the board materials are comparable to using a ceramic cap in an incorrect way.
If you could show any measured improvements with only changing the board material while using the exact same mounted components on an identical board layout I think people would then sit up and take notice. But to just say because you say so that this makes your products sound better is just more of that hot air that makes audiophile design a joke with so many EE engineers. Show where the FR4 material is limiting or interfering with analog audio signal by any designer in this industry? I would like to read some real science on this. I am not saying that components meant to work with a digital signal processing device such as a computer are preferred components in audio, that is not the same as saying the board materials are comparable to using a ceramic cap in an incorrect way.
If you are interested in circuit board materials look at Rogers and Isola Bob Cordell pointed me in the direction of Panasonic also. FR406 or equivalent is nice for power supplies as it has higher temperature and does 4 ounce copper nicely. Rogers 4350 ceramic composite with Gold is my current standard for low level.
For audio nothing to do with speed per se, with FR4 the parasitic capacitances will have lots of DA. It's up to the designer to determine if they matter, in general I would think you are far beyond diminishing returns for most audio applications.
OTOH Rogers and other materials ARE necessary for making striplines at >10GHz. Take an un-etched piece of FR4 sometime and put it on a capacitance bridge and see the loss angle
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Rogers Corp site provides an advanced Impedance calculator (a simple registration is required), the results of which support Scott’s position
Rogers Impedance Calculator
George
Rogers Impedance Calculator
George
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You also have to consider mechanicals- Teflon is far worse than (e.g.) FR4 in both flex and trace adhesion. If you put actual numbers to it, the electrical benefits are nearly non-existent, perhaps a reason why circuit and ears-only listening data aren't given.
We've been through this before. It's for marketing purposes, as the wildly misleading "dC/df" stuff indicates.
Thank you Scott.
Now I can consider that it is another parasitic capacitance with the FR4 material but not really a problem at audio frequencies. I guess a guru could put that parasitic capacitance to work in some way if it was included in a design. I'll leave the real high speed design problems to you Scott and those who truly need to deal with those problems.
Now I can consider that it is another parasitic capacitance with the FR4 material but not really a problem at audio frequencies. I guess a guru could put that parasitic capacitance to work in some way if it was included in a design. I'll leave the real high speed design problems to you Scott and those who truly need to deal with those problems.
To continue in that vein - it is important to address EVERY actual, audible, quality degrading problem to get the very best results.
How do you know there is an audible problem? When the sound is not 'right' to your ears, in any listening situation ... if you're not sure whether it is right or wrong, then it's definitely wrong - the key word is,
, "convincing" ...
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