Transistors - Old Technology?
 

OK, I'll 'fess up. The bipolar transistor was invented in 1947, as is
well known, but almost all modern electronics uses MOSFETS, which were
patented in 1928 by the brilliant Julius Lilenfield, who also patented
the junction FET in the same year.

However, the advance in solid-state amplifier techniques since that
time has been massively greater than that of the thermionic amplifier.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Transistors - Old Technology?
 

On Thu, 18 Nov 2004 17:21:04 +0000 (UTC), Stewart Pinkerton
wrote:

OK, I'll 'fess up. The bipolar transistor was invented in 1947, as is
well known, but almost all modern electronics uses MOSFETS, which were
patented in 1928 by the brilliant Julius Lilenfield, who also patented
the junction FET in the same year.

However, the advance in solid-state amplifier techniques since that
time has been massively greater than that of the thermionic amplifier.

But of course he never actually managed to make one work. I think that
is a pretty important part of any claim of priority.

d
Pearce Consulting
http://www.pearce.uk.com

Transistors - Old Technology?
 

Stewart Pinkerton wrote:

almost all modern electronics uses MOSFETS

Uh ! Pardon ? The amplifiers I've been associated with in recent times
have actually stopped using Mosfets as output devices and we're using
bipolars again ( cost reasons - and limited sources of nice lateral
mosfets ).

Not a single mosfet in the signal path.

Care to elaborate ?


Graham

Transistors - Old Technology?
 

"Pooh Bear" wrote in message
...

Stewart Pinkerton wrote:

almost all modern electronics uses MOSFETS

Uh ! Pardon ? The amplifiers I've been associated with in recent times
have actually stopped using Mosfets as output devices and we're using
bipolars again ( cost reasons - and limited sources of nice lateral
mosfets ).

Not a single mosfet in the signal path.

Care to elaborate ?

**MOSFETs will come into their own when switching amplifiers hit the
mainstream in a big way. For the here and now, however, BJTs offer some
compelling advantages over MOSFETs. BJTs:

* Are more linear.
* Are far more linear, at modest bias currents.
* Offer higher peak current capacity, at lower cost (though this aspect is
changing).
* Do not suffer the problems associated with falling gm at elevated
temperatures.

And, before anyone jumps all over me, I am well aware of the very
significant advantages conferred by the use of MOSFETs. None of those
advantages translate to superior sound quality, however. Those advantages
include:

* Better HF response (pretty much academic, however, unless we're talking
switching amps).
* Slightly lower levels of complexity, due to ease of drive and lack of
current limiters.
* No secondary breakdown effects.


--
Trevor Wilson
www.rageaudio.com.au



--
Trevor Wilson
www.rageaudio.com.au

Transistors - Old Technology?
 

"Pooh Bear" wrote in message

Stewart Pinkerton wrote:

almost all modern electronics uses MOSFETS

Uh ! Pardon ? The amplifiers I've been associated with in recent times
have actually stopped using Mosfets as output devices and we're using
bipolars again ( cost reasons - and limited sources of nice lateral
mosfets ).

Not a single mosfet in the signal path.

Care to elaborate ?

Two words: digital audio.

Transistors - Old Technology?
 

"Fleetie" wrote in message
...
"Stewart Pinkerton" wrote
OK, I'll 'fess up. The bipolar transistor was invented in 1947, as is
well known, but almost all modern electronics uses MOSFETS, which were
patented in 1928 by the brilliant Julius Lilenfield, who also patented
the junction FET in the same year.

However, the advance in solid-state amplifier techniques since that
time has been massively greater than that of the thermionic amplifier.



Pinkypoof possibly protoposting or am I losing posts again???


Krell use bipolars, IIRC.


So do Technics in the o/p stage, MOSFETS in the signal stages.

Transistors - Old Technology?
 

Arny Krueger wrote:

"Pooh Bear" wrote in message

Stewart Pinkerton wrote:

almost all modern electronics uses MOSFETS

Uh ! Pardon ? The amplifiers I've been associated with in recent times
have actually stopped using Mosfets as output devices and we're using
bipolars again ( cost reasons - and limited sources of nice lateral
mosfets ).

Not a single mosfet in the signal path.

Care to elaborate ?

Two words: digital audio.

Stewart was talking in the present tense. All modern electronics ( at least
audio since this is an audio group ) use mosfets very sparingly.

Graham

Transistors - Old Technology?
 

"Keith G" wrote
Krell use bipolars, IIRC.


So do Technics in the o/p stage, MOSFETS in the signal stages.

My point was that Krell still represent the very tip top of current power
amp technology, e.g. their "Full Power Balanced" 600 WPC amp which I cited
on here recently. ISTR the review said there wasn't a single MOSFET in the
amp; it's all bipolar. So it can be done with bipolar transistors.

I have no particular axe to grind here. I'm happy with my valve amp but I'm
currently also looking for a big solid state (low op/p Z) power amp too.


Martin
--
M.A.Poyser Tel.: 07967 110890
Manchester, U.K. http://www.fleetie.demon.co.uk

Transistors - Old Technology?
 

"Pooh Bear" wrote in message

Arny Krueger wrote:

"Pooh Bear" wrote in message

Stewart Pinkerton wrote:

almost all modern electronics uses MOSFETS

Uh ! Pardon ? The amplifiers I've been associated with in recent
times have actually stopped using Mosfets as output devices and
we're using bipolars again ( cost reasons - and limited sources of
nice lateral mosfets ).

Not a single mosfet in the signal path.

Care to elaborate ?

Two words: digital audio.

Stewart was talking in the present tense. All modern electronics ( at
least audio since this is an audio group ) use mosfets very
sparingly.

Why isn't it appropriate to speak of digital audio in the present tense?

Transistors - Old Technology?
 

Arny Krueger wrote:

"Pooh Bear" wrote in message

Arny Krueger wrote:

"Pooh Bear" wrote in message

Stewart Pinkerton wrote:

almost all modern electronics uses MOSFETS

Uh ! Pardon ? The amplifiers I've been associated with in recent
times have actually stopped using Mosfets as output devices and
we're using bipolars again ( cost reasons - and limited sources of
nice lateral mosfets ).

Not a single mosfet in the signal path.

Care to elaborate ?

Two words: digital audio.

Stewart was talking in the present tense. All modern electronics ( at
least audio since this is an audio group ) use mosfets very
sparingly.

Why isn't it appropriate to speak of digital audio in the present tense?

I assumed you meant 'digital amps'. Not *that* mainstream yet.

I expect most digital source products use CMOS technology for digital signal
processing.

The analogue path rarely uses mosfets however.


Graham