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In Reply to: RE: Nobody here ever said tubes don't need break in. (nt) posted by morricab on August 24, 2015 at 04:25:28
It seems to me after reading this that a bunch of brilliant chemistry and physics Phd's took on an electronic design project thinking, "hey, we are Phd's, not lowly engineers. Surely we can build this rig ourselves".
Did you have a competent EE on your team? It doesn't look that way to me. These are very basic problems that should have been caught early in the blueprint phase.
" This was because of high capacitance in the dectors and having to pass through the high voltage section, which required blocking caps as well."
So you had to decouple the high voltage DC in that area? OK, the person that design that circuit didn't know that while it was in the blueprint stage?
"Because of the high frequencies we had ringing from the signal bouncing up and down the coax cable due to impedance mismatch. This required months of optimization and measuring return loss with a $100K HP network analyzer. We eventually redesigned the circuit to deliver more than 40db return loss (originally was only 6db)."
This is basic transmission line theory. As an RF engineer myself I find it hard to believe an experienced engineer wouldn't know to properly terminate coax cables in an RF application within the design stage.
"Nothing of the actual circuit elements were changed though, only the geometry of the parts layout (funny stuff RF)."
Yeah, what can I say. RF is tricky yet many engineers have mastered this so called black art.
Follow Ups:
"So you had to decouple the high voltage DC in that area? OK, the person that design that circuit didn't know that while it was in the blueprint stage? "
Please don't try to reverse engineer what you don't understand, ok? Obviously it was known but what wasn't known was the degree to which we would be having problems with signal reflections. Do you not understand how a Ph.D. is done? We don't have teams of EEs hanging around to sort out every problem (as if professional EEs forsee every potential design issue...LOL!). Let't not think about cost overruns and other issues big companies face or do you have the illusion it is all "first time right"??
"Yeah, what can I say. RF is tricky yet many engineers have mastered this so called black art"
Once again, did I say I was employed as an engineer for Siemens or HP? We sought the help of professional RF engineers...how do you think we got access to an HP network analyzer...it was not as trivial you would like everyone here to believe.
However, I understand a bit more why you are dismissive about audio engineering...nothing more or less than professional arrogance because you think your kind of EE is superior.
I am not dismissive about audio engineering at all. Quite the contrary.But reinforcing claims that 100hr solder connections sound different than fresh solder connections is hardly audio engineering. It falls under "audiophile voodoo".
Ditto that for most of the burn-in theories.
If you are so confident that exist, then prove it. Because the professional audio community as a majority does not subscribe to these claims. That is a fact.
You are just as arrogant to come into a field to which you have no professional experience and try and tell us our 100year old proven theories and concepts are based on shoddy information. Again prove it! Because otherwise nobody in a position of authority in the AV business is listening to you.
Edits: 08/24/15 08/24/15
"You are just as arrogant to come into a field to which you have no professional experience and try and tell us our 100year old proven theories and concepts are based on shoddy information."
THe funny thing is that you think it is me saying...I am getting this information from your own engineering community! I merely read and synthesize the information. I am not doing experiments in my basement laboratory on most of this stuff...just making a DD turntable with optical encoder feedback control at the moment is about it.
I know orthodox views on this stuff...it is the bulk of what's out there. But they were largely wrong about amp design and sound, to my ears, in the last 50 years so I can imagine they are largely wrong about break-in and parts audibility...I can also think of mechanisms for how those things might change...I too do not believe in voodoo but I am more respectful of human hearing than you seem to be...
So now you are saying (to your ears) that audio amplifier desing for the past 50 years is flawed?How?
Explain what lacking improvements are needed?
Now I am not going to be foolish to state amplifiers are perfect. But for PRACTICAL audio reproduction purposes, they are damn near straight wire with today's electronic components.
Also what is so special about an analog audio amplifer that is not relevant in other precision analog applications. Are you saying audio represents the most critical electrical noise and distortion floor?
Edits: 08/24/15
Gusser is right.
Infamous sockpuppet
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