The Catch-22 of Negative Feedback aka NFB
 

"Bret Ludwig" wrote in message
oups.com...

Ruud Broens wrote:

snip


The opamp is *designed* to use large amounts of linearising
: feedback, something that simply isn't an option with the inherently
: much lower open-loop gain of tubes.


Philbrick and Julie were building perfectly proper op amps with tubes
as early as 1943, but thanks for playing.


Part of my theory training was the K2-W :-)

Mike

The Catch-22 of Negative Feedback aka NFB
 

"Mike Gilmour" wrote in
message
"Bret Ludwig" wrote in message
oups.com...

Ruud Broens wrote:

snip


The opamp is *designed* to use large amounts of
linearising
feedback, something that simply isn't an option with
the inherently much lower open-loop gain of tubes.


Philbrick and Julie were building perfectly proper op
amps with tubes as early as 1943, but thanks for playing.

Part of my theory training was the K2-W :-)

I started out on a EAI TR-48 as an undergraduate:

http://archive.computerhistory.org/r....102646218.pdf

and moved on to the 680 in my senior year and in graduate school:

http://archive.computerhistory.org/r....102646244.pdf

The digital side of the system was an IBM 1130. We did not use the EAI
interface box, but instead used a third party interface that included a 200
KHz true 16 bit ADC/DAC box with 16-way multiplexors, in and out.

The Catch-22 of Negative Feedback aka NFB
 

"Arny Krueger" wrote in message
. ..
"Mike Gilmour" wrote in
message
"Bret Ludwig" wrote in message
oups.com...

Ruud Broens wrote:

snip


The opamp is *designed* to use large amounts of
linearising
feedback, something that simply isn't an option with
the inherently much lower open-loop gain of tubes.


Philbrick and Julie were building perfectly proper op
amps with tubes as early as 1943, but thanks for playing.

Part of my theory training was the K2-W :-)

I started out on a EAI TR-48 as an undergraduate:

http://archive.computerhistory.org/r....102646218.pdf

and moved on to the 680 in my senior year and in graduate school:

http://archive.computerhistory.org/r....102646244.pdf

The digital side of the system was an IBM 1130. We did not use the EAI
interface box, but instead used a third party interface that included a
200 KHz true 16 bit ADC/DAC box with 16-way multiplexors, in and out.


Looks very good for training. In the early days our Uni's and colleges
didn't invest to much in traing equipment, (except if your were at Aberdeen
Uni in the early 60's where their Univac used up most of the remaining valve
stocks ;-). Thats all SS so I assume you started your training later on,
as it mentions VTOL aircraft & nuclear.
My studies at Southampton were before all that, i.e. exclusively valve
based, hence the K2-W 2 valve opamp. I returned later to study SS over a two
year period then at regular intervals courtesy of Shell oil to study the
likes of microprocessors, instrumentation & control, dynamic positioning
etc. & gain my advanced Marine Electronics Cert. at Bristol. Shell then
relabelled me Senior Electronics Officer, stuck more stripes on my uniform
and put in charge of everthing electronic on supertankers and the building
thereof. (Great job). Then came years of more study time as ships
progressed to unmanned enginerooms with all that entailed. My very first
ship still had a reserve spark transmitter installed but of course it could
not be operated then! My last one had twin satcom, anticollision radars,
doppler logs etc. Quite an evolution process.... and I still love valves :-)