Are multiple amplifier stages better than one ???

[Bill Bowden]

On Sep 13, 4:33 am, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:

Bill Bowden wrote:
Why would a higher gain first stage improve noise performance? Seems
like identical op-amps would produce the same total noise regardless
of how the gain was distributed?

Let me simplifiy this for you.

Let's say the input noise of your amp stage is 1 uV ?

You set your fist stage gain to ONE. It theoretically produces 1uV of output noise. This then
adds to the second stage noise of 1uV making 1.4uV equivalent input noise (addition of random
sources).

So you just made a noisier amplifier. Now do the calculations for other gain distributions.

Graham

I don't follow the logic. The first stage is ideal since it adds no
noise. I assume the second stage is a also ideal and adds no noise.
Therefore two amplifiers with a gain of ONE will produce the same
output as the input.

What am I missing?

-Bill

 

On Sep 14, 7:51 am, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:

On Tue, 9 Sep 2008 08:08:30 -0700 (PDT), "jalb...@bsu.edu"

jalb...@bsu.edu> wrote:
I have a few questions about the design of the circuit in Figure 1
page 71 located athttps://ilocker.bsu.edu/users/jalbers/WORLD_SHARED/WireTracer.PDF

The gain of the first op amp stage is 10 and the gain fo the second op
amp stage is 33 for a total net gain of 330.  Why not just use one op
amp and set the gain to 330?

When designing a circuit like this, why use a low gain of 330, why not
a higher value?  How did the author arrive at 300?

Is it better to have multiple stages in an amplifier rather than just
using one op amp to get the job done?  If so, why?

Any help would be greatly appreciated.  Thanks

Interesting aside: if you want to make an amp out of some number of
simple RC-coupled tube stages, the plate resistor determines the gain,
where the gain-bandwidth is pretty much fixed. If you want the maximum
gain-bandwidth from a cascade of stages, the optimum gain per stage is
e, the base of the natural logs.

e keeps popping up all over the place.

John

as the op- amp generally practical one gives the less gain.


its better to use the cascading amplifiers.
ofcours it all depends on the application.
ok rinds.

 

[extremesoundandlight@yaho]

On Sep 10, 8:45 am, Bill <z...@z.z> wrote:

On Wed, 10 Sep 2008 06:19:32 -0700 (PDT),
"extremesoundandli...@yahoo.com" <extremesoundandli...@yahoo.com
wrote:

the more stages just amplafies your thermal distortion and passes it
to the next stage and thats not an effeicient way and you end up with
much more distortion over all

Man, you are a crack. I hope you are not trying to live off this.

Explain why you’re not passing distortion from your 4055 or any other
op amp and then amplifying that distortion in multiple stages.

I work for Yamaha Roland, fender and 5 other companies that make
amplifiers as a factory authorized repair tech I think I know
something about the first question that was purposed.
Be constructive and tell me why I am wrong maybe a explanation other
thanbtbant
Man, you are a crack. I hope you are not trying to live off this.