Parasound JC3 Phono

[dimitri]

yes, they do

http://www.intersil.com/data/fn/fn2902.pdf 11nV/sqrtHz

 

[scott wurcer]

Darlington inputs, if you made this circuit have non-darlington inputs and 1nV the current noise would go through the roof especially on their original process.

 

[john curl]

Why don't we start with jfets, instead? Or, modern bipolar transistors?

 

[scott wurcer]

Just for the record R. C. Hughes (US 3473134) of the US Navy invented the folded cascode and assigned it to Uncle Sam in 1966 (granted 1969).

 

[john curl]

As the folded cascode was published in other articles in 1969 or so, I doubt that the patent is actionable, at least. However, the use of a folded cascode single differential gain stage appears to be first in this specific op amp in 1971. Any earlier cites?

 

[Joachim Gerhard]

I made good experiences with this one :
http://cds.linear.com/docs/Datasheet/1468fb.pdf

 

[john curl]

Too noisy, but a good basic design, Joachim. How can we get one quieter?

 

[Joachim Gerhard]

This one :http://www.analog.com/static/imported-files/data_sheets/ADA4898-1_4898-2.pdf

 

[Joachim Gerhard]

I have not found the book yet about surround sound from two channels but this guys claim to be able to do it with ONE channel only.
OK, Scott, with processing.
http://www.swissaudec.com/pdf/FAQ_Home.pdf

 

[scott wurcer]

I have not found the book yet about surround sound from two channels but this guys claim to be able to do it with ONE channel only.
OK, Scott, with processing.
http://www.swissaudec.com/pdf/FAQ_Home.pdf

Gotta have that "professional" recording studio in your IPHONE. As I said before Bob Adams showed me a circuit with a cheap dual op-amp and a pot that moved the image around your head and back again.

EDIT- Read more, a real Swiss Army Knife product, even improves doppler ultrasound. No "world wide" patents found yet.

 

[Joachim Gerhard]

Do you remember Q-Sound ?

 

[john curl]

Joachim, what is the schematic? Of course, we can find quiet enough op amps. However, they have other tradeoffs, at least tradeoffs from MY perspective.

 

[Joachim Gerhard]

QSound - Wikipedia, the free encyclopedia

 

[tvi]

"The MAX9632 is a low-noise, precision, wide-band operational amplifier that can operate in a very wide +4.5V to +36V supply voltage range. The IC operates in dual (±18V) or single-supply mode (36V)."

No simplified Schematic in the data sheet

Rgds
James

 

[scott wurcer]

QSound - Wikipedia, the free encyclopedia

No, as I mentioned this stuff doesn't do much for me.

found it http://www.faqs.org/patents/app/20110075850

EDIT - Tech question, is there an escape sequence so real text does not turn into a smilie?

 

[john curl]

Noise is only ONE PARAMETER. What are the others?

 

[godfrey]

I have not found the book yet about surround sound from two channels but this guys claim to be able to do it with ONE channel only.
OK, Scott, with processing.
http://www.swissaudec.com/pdf/FAQ_Home.pdf

Their explanation of how it works seems to boil down to:
a) Stereo can be reconstructed from sum and difference signals (duh!)
b) Every year electronic devices get smaller
c) Most FM broadcasts are still mono
d) Sometimes bad weather adversely affects TV reception
e) Something about a patent

Don't think I'll invest just yet

 

[tvi]

CMRR @DC (dB) 135
PSRR @DC (dB) 140
Input IBIAS (nA) 180
Unity Gain BW (MHz) 55
Slew Rate (V/µs) 30
in (pA/√Hz) 3.75

MAX9632.pdf

 

[john curl]

I see those parameters, but I don't know enough yet, except that it is a workable op amp for many applications. How about output Xover distortion? Open loop bandwidth, can we get more? etc.

 

[Joachim Gerhard]

OPAmps can be paralleled too to reduce voltage noise. I tried it out. I works but gets rather expensive.