On Sun, 28 Sep 2003 10:20:46 GMT
"Trevor Wilson" wrote:


**Not enough. BJTs are more linear at those kinds of currents. In
fact, BJTs are more linear than those devices at *any* current.

Forgive a silly question, but isnt the linearity of a device in an amp
irrelevant once you employ feedback?

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with
ketchup.

"Ian Molton" wrote in message
...
On Sun, 28 Sep 2003 10:20:46 GMT
"Trevor Wilson" wrote:


**Not enough. BJTs are more linear at those kinds of currents. In
fact, BJTs are more linear than those devices at *any* current.

Forgive a silly question, but isnt the linearity of a device in an amp
irrelevant once you employ feedback?

**Nope. Points:

1) Some amps employ no Global NFB.
2) Massive non-linearity (such as what is present with low bias MOSFETs) may
not be able to completely corrected by NFB.

May as well use BJTs. You get better distortion figures, lower PDiss and
lower cost per peak Amp delivered to the load.


--
Trevor Wilson
www.rageaudio.com.au

"Ian Molton" wrote in message
...
On Sun, 28 Sep 2003 10:20:46 GMT
"Trevor Wilson" wrote:


**Not enough. BJTs are more linear at those kinds of currents. In
fact, BJTs are more linear than those devices at *any* current.

Forgive a silly question, but isnt the linearity of a device in an amp
irrelevant once you employ feedback?

**Nope. Points:

1) Some amps employ no Global NFB.
2) Massive non-linearity (such as what is present with low bias MOSFETs) may
not be able to completely corrected by NFB.

May as well use BJTs. You get better distortion figures, lower PDiss and
lower cost per peak Amp delivered to the load.


--
Trevor Wilson
www.rageaudio.com.au

On Wed, 01 Oct 2003 08:47:29 GMT
"Trevor Wilson" wrote:

Forgive a silly question, but isnt the linearity of a device in an
amp irrelevant once you employ feedback?

**Nope. Points:

1) Some amps employ no Global NFB.

I did say *once you employ feedback* which kinda rules out designs not
using feedback...

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with
ketchup.

On Wed, 01 Oct 2003 08:47:29 GMT
"Trevor Wilson" wrote:

Forgive a silly question, but isnt the linearity of a device in an
amp irrelevant once you employ feedback?

**Nope. Points:

1) Some amps employ no Global NFB.

I did say *once you employ feedback* which kinda rules out designs not
using feedback...

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with
ketchup.

"Keith G" wrote in message ...
(...)

It's just the same with bikes - a certain 500cc BMW did over180 mph way back
in the 30's with a mere 'handful' of horsepower compared with today's
claimed output figures for bikes of even greater capacity! (Serious Googling
will, I'm sure, provide the figures if anyone gives a sh*t...)

Well, not really. The bike (supercharged; it's rumoured that BMW are
considering a kompressor modern bike!) had a claimed 110hp and had a
fully enclosed 'bullet' fairing. Today, 110hp is more or less what's
claimed for a 600cc sportsbike and you'll get up to 160mph with a run
of the mill fairing. A Hayabusa has something like a claimed 160hp,
c.150 at the rear wheel, and a top speed of something like 185mph.


(...)

Swim's MR2 is utter ****e over 100 - front end goes light and it slides
about all over the place in the wet. They ain't real sports cars - no
'modern car' is, in my book!

Lotus Elise?
Grinnall Scorpion?

Steve.

"Keith G" wrote in message ...
(...)

It's just the same with bikes - a certain 500cc BMW did over180 mph way back
in the 30's with a mere 'handful' of horsepower compared with today's
claimed output figures for bikes of even greater capacity! (Serious Googling
will, I'm sure, provide the figures if anyone gives a sh*t...)

Well, not really. The bike (supercharged; it's rumoured that BMW are
considering a kompressor modern bike!) had a claimed 110hp and had a
fully enclosed 'bullet' fairing. Today, 110hp is more or less what's
claimed for a 600cc sportsbike and you'll get up to 160mph with a run
of the mill fairing. A Hayabusa has something like a claimed 160hp,
c.150 at the rear wheel, and a top speed of something like 185mph.


(...)

Swim's MR2 is utter ****e over 100 - front end goes light and it slides
about all over the place in the wet. They ain't real sports cars - no
'modern car' is, in my book!

Lotus Elise?
Grinnall Scorpion?

Steve.

"Steve G" wrote in message
om...
"Keith G" wrote in message
...
(...)

It's just the same with bikes - a certain 500cc BMW did over180 mph way
back
in the 30's with a mere 'handful' of horsepower compared with today's
claimed output figures for bikes of even greater capacity! (Serious
Googling
will, I'm sure, provide the figures if anyone gives a sh*t...)

Well, not really. The bike (supercharged; it's rumoured that BMW are
considering a kompressor modern bike!) had a claimed 110hp and had a
fully enclosed 'bullet' fairing. Today, 110hp is more or less what's
claimed for a 600cc sportsbike and you'll get up to 160mph with a run
of the mill fairing. A Hayabusa has something like a claimed 160hp,
c.150 at the rear wheel, and a top speed of something like 185mph.


OK, if your figures are right there's still a discrepancy well in favour of
the 30's BMW in comparison to today's Suzuki which have very similar top
speeds on vastly different power figures. Fairings are as fairings do - you
can damn soon start trading tyres, wheels, brakes, suspension figures to
come to some sort of balance between the two different bikes.

(I thought the Hyabusa was a genuine 200+ bike??? - It was, last time I
looked!)



(...)

Swim's MR2 is utter ****e over 100 - front end goes light and it slides
about all over the place in the wet. They ain't real sports cars - no
'modern car' is, in my book!

Lotus Elise?


My point entirely.......


Grinnall Scorpion?


Stoppit.....

"Steve G" wrote in message
om...
"Keith G" wrote in message
...
(...)

It's just the same with bikes - a certain 500cc BMW did over180 mph way
back
in the 30's with a mere 'handful' of horsepower compared with today's
claimed output figures for bikes of even greater capacity! (Serious
Googling
will, I'm sure, provide the figures if anyone gives a sh*t...)

Well, not really. The bike (supercharged; it's rumoured that BMW are
considering a kompressor modern bike!) had a claimed 110hp and had a
fully enclosed 'bullet' fairing. Today, 110hp is more or less what's
claimed for a 600cc sportsbike and you'll get up to 160mph with a run
of the mill fairing. A Hayabusa has something like a claimed 160hp,
c.150 at the rear wheel, and a top speed of something like 185mph.


OK, if your figures are right there's still a discrepancy well in favour of
the 30's BMW in comparison to today's Suzuki which have very similar top
speeds on vastly different power figures. Fairings are as fairings do - you
can damn soon start trading tyres, wheels, brakes, suspension figures to
come to some sort of balance between the two different bikes.

(I thought the Hyabusa was a genuine 200+ bike??? - It was, last time I
looked!)



(...)

Swim's MR2 is utter ****e over 100 - front end goes light and it slides
about all over the place in the wet. They ain't real sports cars - no
'modern car' is, in my book!

Lotus Elise?


My point entirely.......


Grinnall Scorpion?


Stoppit.....

"Ian Molton" wrote in message
...
On Wed, 01 Oct 2003 08:47:29 GMT
"Trevor Wilson" wrote:

Forgive a silly question, but isnt the linearity of a device in an
amp irrelevant once you employ feedback?

**Nope. Points:

1) Some amps employ no Global NFB.

I did say *once you employ feedback* which kinda rules out designs not
using feedback...

**You sure did. However, ruling amps which employ zero Global NFB is ruling
out a class of amplifiers which may offer audible advantages over the rest.


--
Trevor Wilson
www.rageaudio.com.au