"François Yves Le Gal" wrote:

On Mon, 06 Sep 2004 11:35:47 GMT, justin wrote:

Does anyone know how it compares to the 5532 (which I'm more familiar
with) when it comes to noise?

If I rember correctly, it's slightly lower.

Check the datasheets:
http://www.njr.co.jp/pdf/ae/ae04022.pdf
http://www.fairchildsemi.com/ds/NE/NE5532.pdf

Trouble is - the 2068 datasheet quotes *A weighted* noise - so you can't do
a meaningful comparison.

I've only seen the 2068 once. I would stick with the 5532 since it's
multi-sourced.

If you're looking for better noise, the 5534 single op-amp is 3dB quieter
than its dual 5532 cousin.


Graham

justin wrote:

In article , Pooh Bear
wrote:

"Fran?ois Yves Le Gal" wrote:

On Mon, 06 Sep 2004 11:35:47 GMT, justin wrote:

Does anyone know how it compares to the 5532 (which I'm more familiar
with) when it comes to noise?

If I rember correctly, it's slightly lower.

How did you do that? Just cuorious as Graham pointed out (see below)
that figures aren't directly comparable.


Check the datasheets:
http://www.njr.co.jp/pdf/ae/ae04022.pdf
http://www.fairchildsemi.com/ds/NE/NE5532.pdf

Trouble is - the 2068 datasheet quotes *A weighted* noise - so you can't do
a meaningful comparison.

Exactly - and weighted figures always look better.


I've only seen the 2068 once. I would stick with the 5532 since it's
multi-sourced.

Currently 2068 seems to be chip du jour in semi-pro equipment. To me it
sounds noisier than 5532. It is a subjective judgment and that's why
I'm asking.

Now, how does one compare noise figures in µV to nVsqrt(Hz) for the
identical source impedance?

You're talking noise analysis.

If you're taking the source R into account you need to calculate the thermal
noise of its contribution to the total.

En = sqrt ( 4*k*T*R*BW)

k = Boltmann's constant = 1.37*10^-23
T = absolute temperature in Kelvins ( degrees C +273 )
R = the source resitance
BW = bandwiidth ( eg 20*10^3 )

Separate noise sources sum as the root of the sum of the squares

e.g En(tot) = srqt ( En1^2 + En2^2 )

For higher source impedances you need to consider input noise *current* too.



To convert nV/sqrtHz to uV ( for 20kHz audio bandwidth ) just multiply by 141.


Graham

justin wrote:

Currently 2068 seems to be chip du jour in semi-pro equipment. To me it
sounds noisier than 5532. It is a subjective judgment and that's why
I'm asking.

Doing some quick figures suggests that the 2068's A weighted figures aren't much
different to the 5532 unweighted, so I suspect your hearing or measuring gear is
right !


Graham

"justin" wrote in message


Currently 2068 seems to be chip du jour in semi-pro equipment. To me
it sounds noisier than 5532. It is a subjective judgment and that's
why I'm asking.

Methinks money has something to do with the popularity of the 2068.

"justin" wrote in message

In article , Arny Krueger
wrote:

"justin" wrote in message


Currently 2068 seems to be chip du jour in semi-pro equipment. To me
it sounds noisier than 5532. It is a subjective judgment and that's
why I'm asking.

Methinks money has something to do with the popularity of the 2068.

Or chip manufacturer fluffing up the specs?

I don't see any problems with the 2068 spec sheet.

Mackie, Event, Behringer, they all went ga-ga over it!

Methinks money has something to do with the popularity of the 2068.

Just checked the pricing, you're right, 2068: $0.25, 5532A: $1.20.
(Mouser online)

Last time I rummaged around, the 5532 can be found for more $.50, but that's
still twice $0.25.

Okay, here is what I'm thinking: if any of the above offered an audio
mixer priced, say $1000 and a "low noise" version of the same for $100
more, what the hell they think customers would go for?

It's often a matter of requirements. I've seen many cases where plugging a
5532 into a socket did nothing to improve the over all performance of the
piece of equipment.

Arny Krueger wrote:

It's often a matter of requirements. I've seen many cases where
plugging a 5532 into a socket did nothing to improve the over
all performance of the piece of equipment.

Hmm ... O;-)


Kind regards

Peter Larsen


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