What is wrong with op-amps?

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#1,621
Since you are trying everything to avoid remaining technical:

Ronald Pethig would be a good start as far as his length of time in the field and the quality of review articles he's written. Vogelstein and Diaz at JHU would be good for starting into the diagnostics side of cell-free tumor markers. The latter wrote a great review paper a year ago that would be a helpful entry point.

But I would encourage you to first start with John Clerk Maxwell and his buddies to get the basics before getting into the biology side. It is pretty important to be able to visualize how electric fields are going to distribute before contemplating other intricacies. I've been working on this stuff for a number of years and I still

Zero commercially released audio gear. Which mean, yes, I don't know a thing about the business end of your world. I'd be terrible at it, given my message would run something like, "Hey, there's a bunch of well-designed, modest priced equipment from people bothered to be in this industry, go buy it and spend more on music." 😉

I don't pretend to be good at marketing. None of these guys I mentioned above have an idea who I am, so I can't even realistically name drop them.
 
#1,622
Ooookkay. Bio-electrical stuff? So I used to work for a musician who had wicked perfect pitch and uncanny skills at sight reading and music composition. Yet he liked to watch WWF wrestling!! Sooooo you hanging at an audio forum is similar? Maybe a little beneath you as far as hardcore physics? Is audio something you wish you could do, just not enough money in it maybe?
 
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#1,623
Yeah, bio-electrical thing-a-ma-gigies.

I enjoy building things and really like music. It's fun, and probably the reason I went EE for undergrad versus ME or ChemE. And diyA offers a lot of really good technical stuff and brings together a lot of smart folks.

I'm not "above" audio by any stretch, especially when it comes to the speakers/acoustics side; it's just a bit more than insulting to be told having an analytical and skeptical mind is "soul-less". It's also a brain that doesn't really stop, so even when I step away from my work, I'm still very data-driven and rigorous.

Which is why we end up in discussions like this. 🙂
 
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#1,624
DPH said:
But I would encourage you to first start with John Clerk Maxwell and his buddies to get the basics before getting into the biology side. It is pretty important to be able to visualize how electric fields are going to distribute before contemplating other intricacies. I've been working on this stuff for a number of years and I still
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...screw it up regularly. (Thank goodness for modeling tools to catch those errors before they get too far)
 
#1,625
morinix said:
I worked at Alesis all through the 90's. I was playing around with a little tube preamp circuit on my bench. I wired it up with normal parts at first. So after playing around with resister types I tried rewiring it with silver wire. I started with just the ground. Low and behold it was a little cleaner sounding. I took a 3 foot section and terminated my scope input with it. I check it against a 3 ft piece of normal wire. There was less hash on the silver wire. I get to talking with the VP of engineering. He flat out rejects that this could be true. I tell him to try it out. He says "no". "Why not?" I ask. "because the math doesn't point to this being true" he says.

That was the beginning of what I still deal with when I post here. Closed mindedness. It's kind of funny really.
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If you see "less hash" on the silver wire, it's because something is wrong in your test setup. A garden variety scope can't really see a damn thing, to be honest, so if you saw something it was some kind of gross problem. I've had copper wire with "no hash" hooked up to an Agilent VNA. Looks good to a few GHz to me.

Maybe you should ping James Randi and see if you can win that million dollars if it's still up for grabs.

Sounds like Alesis had a good VP of Engineering.
 
#1,626
DPH said:
Again, anecdote is not data.
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Of course it is data. It is probably the most important data
and the fact that we are all hear reading this supports this.

Now before we get are jocks in a wad and break out the
mail appendage measuring instruments consider this.

Ancient people who used to mine asbestos knew they were
getting ill from what they were mining, this word was passed down
anecdotally.

In the last century, people spread the word anecdotally that we
should not spend a lot of time in the x-ray machine that showed
people how their feet fit in the shoes.

Also anecdotally in the last century people noticed that bird populations
lowering and began a process to save them. The word was spread anecdotally
that the use of DDT was the culprit.

Anecdotal information is data and it can be acted upon for further study.
Like it or not, it is data.

Cheers,

Sync
 
#1,628
SyncTronX said:
Of course it is data. It is probably the most important data
and the fact that we are all hear reading this supports this.

Now before we get are jocks in a wad and break out the
mail appendage measuring instruments consider this.

Ancient people who used to mine asbestos knew they were
getting ill from what they were mining, this word was passed down
anecdotally.

In the last century, people spread the word anecdotally that we
should not spend a lot of time in the x-ray machine that showed
people how their feet fit in the shoes.

Also anecdotally in the last century people noticed that bird populations
lowering and began a process to save them. The word was spread anecdotally
that the use of DDT was the culprit.

Anecdotal information is data and it can be acted upon for further study.
Like it or not, it is data.

Cheers,

Sync
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Oddly enough, I think the DDT link to eggshell issues was mostly debunked...

http://www.nytimes.com/2007/06/05/s...odule=Search&mabReward=relbias:w,{"1":"RI:6"}

https://junkscience.com/1999/07/100-things-you-should-know-about-ddt/#ref11
 
#1,630
chris719 said:
If you see "less hash" on the silver wire, it's because something is wrong in your test setup. A garden variety scope can't really see a damn thing, to be honest, so if you saw something it was some kind of gross problem. I've had copper wire with "no hash" hooked up to an Agilent VNA. Looks good to a few GHz to me.

Maybe you should ping James Randi and see if you can win that million dollars if it's still up for grabs.

Sounds like Alesis had a good VP of Engineering.
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Good for you. I didn't use copper wire in my little test. Think for minute about how my little test could show some noise that your hot-shot Agilent didn't.
 
#1,632
billshurv said:
well this whole 'closer/further back' part is well known about and often due to a midrange dip in FR, usually referred to as the 'presence dip'. There may also be HF roll off at play. If you look here Records and Reality and scroll down a bit there is the standard graph of air absorption. A dB here or there could make it seem like you are further back in the hall. Now of course whether the listener perceives this as being further back , or the sound stage moving back depends on a number of things, not least how he has calibrated his perception. Most of us don't get to move seats during a concert after all to know what 3 rows further back sounds like!

You don't mention the cartridge he is using, but it's entirely plausible that one of the Phono stages he was using gave audible FR differences and he preferred one to the other. Which one we will never know!
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I'm reading your link. And that's right about the "we will never know"; I have to often figure out a customers problem as if I'm blindfolded.
 
#1,633
Kirchhoff said:
It is easier for humans to continously follow the changes in sound, and interpret and correlate them with their own movements and the characteristics of the "hidden" materials - as compared to following numbers on a screen.

If you think that visual indicators are better than the sound they try to describe, then I suggest you sell your speakers and just watch the VU-meters. :joker:
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Looks like you have no idea about electronic design...😕
You cannot reliably design electronic equipment without some measurement's, and for music replay it requires both measurements and listening...

On op-amps just done an instrumentation board with about 500 of the 8 legged beasties on it, how come they are good enough for sensitive instrumentation but not good enough for audio...
 
#1,634
morinix said:
Good for you. I didn't use copper wire in my little test. Think for minute about how my little test could show some noise that your hot-shot Agilent didn't.
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In an open environment you will be prone to pick up any hash in the environment, if you have ever done EMC testing or seen it done, even moving a cable a few mm can have an effect on the result, so without proper testing the differing results could be down to many factors.
 
#1,637
marce said:
In an open environment you will be prone to pick up any hash in the environment, if you have ever done EMC testing or seen it done, even moving a cable a few mm can have an effect on the result, so without proper testing the differing results could be down to many factors.
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I remember moving the wire around and the noise didn't change. But yes, it was up picking noise. And the silver had less ESR so less noise dropped across it. It wasn't huge, but it was there.
 
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