Any info to back this up... Because my experience is different.
RF in a CD player!!!!
FR4 many types, perfect for everything up to a few GHz, class 3 designs use it (Mil, aerospace, medical) should be good enough for audio..... Its good enough for low level sensitive analogue designs, high speed digital, a lot of RF stuff.
As mentioned before, the text document is a list of the documents the IPC C1000 series, this is the basic documentation set relating to PCB design, materials assembly manufacture etc...
I also have another 5G of documents, presentations and more in depth PCB related material on layout for analogue, high speed, RF, SELV etc. including many white papers that go into some depth on such things as DA etc.
Like the Bybees we go round in a circle and FR3 is mentioned...
that's really up to date... Of course over the last 15 years you may have noticed the change from tin/lead solders to lead free, this along with the increasing rise times and clock frequencies (DDR memory, gigabit Ethernet, RF on everything for wireless communications) has meant that PCB laminate materials specifically FR4 has developed over the years...Here is a nice presentation showing the different glass weaves available.....
http://www.ieca-inc.com/images/Tutorial_-_Understanding_The_PCB_Laminate_and_Prepreg_Process.pdf
Last edited:
Yes, of course, and far away in the landscape (0.001pF). As i was lazy to suppress-it, i divided its original value par > 100 ;-)
I always set my compensations that way: Miller for a flat response curve of the closed loop, cap on the feedback for no overshoot on high level square waves if needed, low pass input filter for no overshoot on square waves of little signal square waves. This last one to be increased, if necessary, for the best listening results in a particular system.
Thanks for the correction of my typo: "1122 Ohms", of course.
Thanks, bcarso, interesting (as usual with you ;-), i will dig this a little more.
Not such a matter of importance, just about feeling good all the workings of the clock.
Last edited:
The phenolic paper materials are very rarely used these days apart from cheap products.
Though as previously mentioned even this usage is shrinking as the use of SMD components really requires a Tg of at least 160 and preferably higher to handle the lead free reflow temperatures.
Paper and CEM based laminated make up about 5% of total world PCB production, high performance laminates (Teflon! is one sort that gets so many audiophiles excited!) is about 3%..... Most of the rest is flame retardant epoxy with woven glass reinforcement based laminates.
FR-2 - Wikipedia, the free encyclopedia
Basic Board Materials
http://www.dfrsolutions.com/wp-content/uploads/2013/09/Characterization-of-CEM-1-Boards.pdf
Though as previously mentioned even this usage is shrinking as the use of SMD components really requires a Tg of at least 160 and preferably higher to handle the lead free reflow temperatures.
Paper and CEM based laminated make up about 5% of total world PCB production, high performance laminates (Teflon! is one sort that gets so many audiophiles excited!) is about 3%..... Most of the rest is flame retardant epoxy with woven glass reinforcement based laminates.
FR-2 - Wikipedia, the free encyclopedia
Basic Board Materials
http://www.dfrsolutions.com/wp-content/uploads/2013/09/Characterization-of-CEM-1-Boards.pdf
Back to around 1970, I remember my first boss trying to make-us (the R&D department) change our boards (we made the prototypes in epoxy) for some of those cheap cart boards ones.
There were 4 boards. Input section, preamp, volume and bass treble switches, power amp.
- Input ? "Impossible, Sir, the input connectors are mechanically fixed on it. There is a risk they break."
- Volume and correctors board ? "Same answer, Sir."
- Preamp ? "Impossible, Sir, the circuit is large and will warp with time. And the push buttons are soldered directly above."
- Power amp ? At least no mechanical components on it ?"Not a good idea, Sir, there are hot parts on it, and epoxy do not burn so easily."
Saved by (dielectric) dialectic ;-)
The 'levels of engineering involved' gather once a week in the fight club to sort out the weight distribution by bare knuckle.
(some individuals find it hard to grasp that engineers have had basic education at all levels)
Almost true, and certain UK company does flight refuelling kit for a certain USA company, during the check process a fight nearly broke out over the spelling of certain words on drawings...colour is one that comes to mind....
The best comment I have seen recently though was...
"most audio gear sounds bad because its designed by engineers not audiophiles"
The best comment I have seen recently though was...
"most audio gear sounds bad because its designed by engineers not audiophiles"
In essence I'm emphasising that my approach is very different from most in the game - the usual desire is to make the "best" amplifier, or the "best" speaker, etc - my desire is to have the "best" listening experience, and everything is just a set of jigsaw pieces for achieving that - I work back from a known end result, and keep altering and experimenting until that goal is achieved.
My latest hobby experimenting - delving into laptop audio - is confirming, yet again, that optimising of everyday equipment yields remarkably competent sound - the same pattern repeats over and over again ... the equivalent is that an extremely basic, ultralight, DIY aircraft can gets the basics of flying a person safely from one place to another resoundingly correct, if all the relevant details are taken properly into account ...
A more 'correct' statement is, "most audio gear sounds bad because its designed by engineers, who don't know how to measure good sound" ..."most audio gear sounds bad because its designed by engineers not audiophiles"
.I agree, I don't know how they ever got jobs designing audio gear... Same with the guys I've worked on doing communication systems and hearing protection, all the technology and measuring equipment they have and even acoustic engineers running round the place, all they need is a good pair of ears connected to a true audiophile.....
Its the equivalent of letting pilots design the plane.........
Its the equivalent of letting pilots design the plane.........
Yes (not just creep, but overall lousy mechanical properties) and yes. If you load up the PTFE with enough glass to make it more rigid, the dielectric characteristics deteriorate and you have something much closer to epoxy fiberglass. But those dielectric characteristics are indeed irrelevant for the impedances found in audio- except for microphones and electrets and the very rare high impedance nodes in other circuits. The standoffs are absolutely the best way to deal with those issues, and that's what competent engineers in critical fields tend to use.
Voodoo is designing in known problems in order to solve nonexistent problems.
A more 'correct' statement is, "most audio gear sounds bad because its designed by engineers, who don't know how to measure good sound" ...
So...? how do you measure 'good sound' and what is different from measuring 'bad sound' (maybe like Bach against ABBA (or the other way around, what ever your poison is)).
Well, I meant that seriously - we still don't know how to competently measure the acoustic output of a complete system such that it correlates with the subjective perception.
I've got around the problem by defining 'good sound' as that which doesn't have any audible 'badness'. Ignoring taste considerations, ABBA is equally 'good' to Bach - a system that gets ABBA right will also get Bach spot on, and vice versa ...
I've got around the problem by defining 'good sound' as that which doesn't have any audible 'badness'. Ignoring taste considerations, ABBA is equally 'good' to Bach - a system that gets ABBA right will also get Bach spot on, and vice versa ...
I let-you file this yourself. Because it is just YOUR point of view. (Expressed delicately as usual).
Sorry you did not understood the analogy. We listen music for our pleasure. There is a part of taste, and a part of "credibility" in this make believe game.
3D to 2D as a start.
I wonder if you use an oscilloscope instead of speakers when you listen to music ?
I understood it just fine. It's just a completely inapt analogy, though commonly trotted out (in various forms) by the voodoo crowd.
When she is not in the kitchen telling me that she immediately heard the improvement when I put a magic rock on my power cord, my wife is a professional artist (and former professional musician) who also works in photography. Despite not being an engineer, she does understand that evaluation of a photograph is a different activity than designing a lens.
Yes, this is part of a more useful "calibration" process - I used a simple DVD setup disk for the TV, and getting everything "spot on" by its method resulted in the colours still being fairly inaccurate - there was a "fakeness" to the presentation, in many situations. By a process of trial and error, and subtle adjustments over time, the last vestiges of that "incorrectness" were lost - I'm never struck by the sense that "the colour could be better" ...
I never heard a perfect system, convincing on all the instruments. Given-me the perfect illusion i was in an other room, listening to a real live performance.
I always know and feel it is a so calling HIFY system playing, and i have efforts to make believe myself Michael Jackson is in my room.
And i don't thing i would love an ideal system, as my system give-me, sometimes, more pleasure than a real performance (thanks to sound engineers and producers).
Starting from this, i don't believe a perfect system for everybody will never exist. If it was so simple, it would be enough to buy the best measuring gears. Some tried, with non convincing results ;-)
We all are looking for different balance between various aspects, like spacialization, dynamic, details, separation between instruments, sound stage, listening fatigue etc.
Is-it so stupid to rely on his ears, when it is about listening music ? Only deaf people could believe that.
Saying this, i don't exempt myself of trying the most correct engineering process i can, using measuring instruments to improve the things, or find the cause of an issue i don't like. But sorry, when i cannot hear any hiss or hum, i consider the signal noise ratio good enough, what ever says the measurements.
I always know and feel it is a so calling HIFY system playing, and i have efforts to make believe myself Michael Jackson is in my room.
And i don't thing i would love an ideal system, as my system give-me, sometimes, more pleasure than a real performance (thanks to sound engineers and producers).
Starting from this, i don't believe a perfect system for everybody will never exist. If it was so simple, it would be enough to buy the best measuring gears. Some tried, with non convincing results ;-)
We all are looking for different balance between various aspects, like spacialization, dynamic, details, separation between instruments, sound stage, listening fatigue etc.
Is-it so stupid to rely on his ears, when it is about listening music ? Only deaf people could believe that.
Saying this, i don't exempt myself of trying the most correct engineering process i can, using measuring instruments to improve the things, or find the cause of an issue i don't like. But sorry, when i cannot hear any hiss or hum, i consider the signal noise ratio good enough, what ever says the measurements.
Last edited:
- Status
- Not open for further replies.