In article ,
Trevor Wilson wrote:
BTW: There are far less costly ways of reducing inductance than using
Nordost. I've said so in the past and I'll say so again. Use RG213/U if
you want low inductance, low resistance and low cost.

RG213/U isn't near capable of carrying satisfactorily the 50 amp peaks you
spoke of earlier.

--
*I got a sweater for Christmas. I really wanted a screamer or a moaner*

Dave Plowman London SW
To e-mail, change noise into sound.

Laurence Payne wrote:

On Tue, 9 Jan 2007 06:33:46 +1100, "Trevor Wilson"
wrote:

Have a look at their site. Quite amusing.

I liked:-

" Blazingly fast, Blue Heaven transmits signals at over 93% the speed of
light."

Wow!!!

Trevor Wilson wrote:

"Eeyore" wrote
Trevor Wilson wrote:
"Eeyore" wrote
Trevor Wilson wrote:
"Eeyore" wrote
Trevor Wilson wrote:
"Eeyore" wrote
Trevor Wilson wrote:

* Use an amplifier which can deal with 2 Ohm (or better) load
impedances,
without Voltage drop or current limiting (no MOSFETs or valves,
of course).

MY mosfet amps will drive 2 ohms no trouble !

**That's what you think.

Do you know anything about them ?

**About the ones you use? Nothing.


Tell me about your objection to mosfets in this regard.

**I've never heard ANY MOSFET amp drive Quads adequately. Yours
may well be different.

Is your objection to them based on any specific scientific principle is
what I was trying to get at.

**Indeed. Several. MOSFETs:

* Exhibit much higher levels of distortion, at low bias currents, than
(modern) BJTs.

Ok, I don't use them at low bias currents.

**Smart move. Of course, using BJTs eliminates that little inconvenience.
BJTs are MUCH better at low bias currents and slightly better at high bias
currents. Win - win.

BJTs also have far worse cross-over characteristics.


* Exhibit a negative tempco of gm. BJTs do not.

Is that a real problem ?

**Sure. If you're using the MOSFETs within a feedback loop. Or outside one.

Why ?


BJTs allow for external VI limiting, which, in turn, allows for ensuring the
limiting can be kept outside any feedback loops.

I fail to see the distinction here between the two. In any case mosfets require
far less VI limiting, being more durable, which is a 'good thing'.


* Exhibit somewhat higher levels of distortion, at high bias currents,
than (modern) BJTs.

Gm related. Indeed. I use multiple devices in parallel with an attentant
increase in output stage gm.

**Good stuff. Of course, BJTs are still better. And cheaper.

Since when was cheaper about good sound ?

Graham

KeithR wrote:

Laurence Payne wrote:

"Trevor Wilson" wrote:

Have a look at their site. Quite amusing.

I liked:-

" Blazingly fast, Blue Heaven transmits signals at over 93% the speed of
light."

Wow!!!

Yes, the sound gets there faster ! ;~)

Graham

"Eeyore" wrote in message
...


Trevor Wilson wrote:

"Eeyore" wrote
Trevor Wilson wrote:
"Eeyore" wrote
Trevor Wilson wrote:
"Eeyore" wrote
Trevor Wilson wrote:
"Eeyore" wrote
Trevor Wilson wrote:

* Use an amplifier which can deal with 2 Ohm (or better) load
impedances,
without Voltage drop or current limiting (no MOSFETs or
valves,
of course).

MY mosfet amps will drive 2 ohms no trouble !

**That's what you think.

Do you know anything about them ?

**About the ones you use? Nothing.


Tell me about your objection to mosfets in this regard.

**I've never heard ANY MOSFET amp drive Quads adequately. Yours

may well be different.

Is your objection to them based on any specific scientific principle
is
what I was trying to get at.

**Indeed. Several. MOSFETs:

* Exhibit much higher levels of distortion, at low bias currents, than
(modern) BJTs.

Ok, I don't use them at low bias currents.

**Smart move. Of course, using BJTs eliminates that little inconvenience.
BJTs are MUCH better at low bias currents and slightly better at high
bias
currents. Win - win.

BJTs also have far worse cross-over characteristics.

**Nope. That would be a myth. Decently matched devices, coupled with modest
bias currents will eliminate all cross over distortion.



* Exhibit a negative tempco of gm. BJTs do not.

Is that a real problem ?

**Sure. If you're using the MOSFETs within a feedback loop. Or outside
one.

Why ?

**Think about it.



BJTs allow for external VI limiting, which, in turn, allows for ensuring
the
limiting can be kept outside any feedback loops.

I fail to see the distinction here between the two. In any case mosfets
require
far less VI limiting, being more durable, which is a 'good thing'.

**Not really. As a designer, you have no control over the point where
current limiting operates, nor what happens when it does. However, MOSFETs
do certainly have clear and unequivocal advantages. They are certainly more
durable and lack storage effects, thus providing an excellent HF response (I
built a MOSFET amp and measured a flat response out to 800kHz at 500 Watts!
Very impressive). None of which allows them to equal decent BJTs though.
BJTs are STILL lower in distortion. Particularly at low bias currents.



* Exhibit somewhat higher levels of distortion, at high bias currents,
than (modern) BJTs.

Gm related. Indeed. I use multiple devices in parallel with an
attentant
increase in output stage gm.

**Good stuff. Of course, BJTs are still better. And cheaper.

Since when was cheaper about good sound ?

**I did say they were better. Cheaper is just a bonus.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

Dave Plowman (News) wrote:

In article ,
Trevor Wilson wrote:

BTW: There are far less costly ways of reducing inductance than using
Nordost. I've said so in the past and I'll say so again. Use RG213/U if
you want low inductance, low resistance and low cost.


RG213/U isn't near capable of carrying satisfactorily the 50 amp peaks you
spoke of earlier.

The core is about 3mm^2, so reasonable for short runs. Don't know about
the screen.

Has anyone come up with an explanation of How Nordost cables
have low inductance and low capacitance? It seems to break the laws
of physics.

--
Eiron.

On Wed, 10 Jan 2007 09:46:15 +0000, Eiron wrote:

Dave Plowman (News) wrote:

In article ,
Trevor Wilson wrote:

BTW: There are far less costly ways of reducing inductance than using
Nordost. I've said so in the past and I'll say so again. Use RG213/U if
you want low inductance, low resistance and low cost.


RG213/U isn't near capable of carrying satisfactorily the 50 amp peaks you
spoke of earlier.

The core is about 3mm^2, so reasonable for short runs. Don't know about
the screen.

Has anyone come up with an explanation of How Nordost cables
have low inductance and low capacitance? It seems to break the laws
of physics.

Virtually everything they claim in their technical notes breaks the
laws of physics.

d

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

In article ,
Eiron wrote:
Dave Plowman (News) wrote:

In article ,
Trevor Wilson wrote:

BTW: There are far less costly ways of reducing inductance than using
Nordost. I've said so in the past and I'll say so again. Use RG213/U if
you want low inductance, low resistance and low cost.


RG213/U isn't near capable of carrying satisfactorily the 50 amp peaks
you spoke of earlier.

The core is about 3mm^2, so reasonable for short runs. Don't know about
the screen.

Indeed; but then so is pretty well any design of cable. That's the problem
with this discussion - throw in *very* long runs and you might hear or
measure a difference. But then no one with any sense has very long low
impedance speaker cable runs.

Has anyone come up with an explanation of How Nordost cables
have low inductance and low capacitance? It seems to break the laws
of physics.

As do all these 'snake oil' products. They are sold to the gullible on
price alone. If they were cheap or even value for money they'd loose their
cache.

--
*In some places, C:\ is the root of all directories *

Dave Plowman London SW
To e-mail, change noise into sound.

On Wed, 10 Jan 2007 10:15:31 +0000 (GMT), "Dave Plowman (News)"
wrote:

Indeed; but then so is pretty well any design of cable. That's the problem
with this discussion - throw in *very* long runs and you might hear or
measure a difference. But then no one with any sense has very long low
impedance speaker cable runs.

Certainly preferable to long runs of high impedance cable. If we
ignore coax and stick to standard twin, a low impedance speaker cable
will tend to have a lot of copper in it to achieve the high
capacitance and low inductance necessary for a low impedance. That
makes it better suited to long runs.

Also, being much closer to the impedance of a speaker it will have a
much flatter frequency response than a high impedance cable, which
will tend to wander away from flat at the top end.

d

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

--
Posted via a free Usenet account from http://www.teranews.com

Don Pearce wrote:

On Wed, 10 Jan 2007 10:15:31 +0000 (GMT), "Dave Plowman (News)"
wrote:

Indeed; but then so is pretty well any design of cable. That's the problem
with this discussion - throw in *very* long runs and you might hear or
measure a difference. But then no one with any sense has very long low
impedance speaker cable runs.

Certainly preferable to long runs of high impedance cable. If we
ignore coax and stick to standard twin, a low impedance speaker cable
will tend to have a lot of copper in it to achieve the high
capacitance and low inductance necessary for a low impedance. That
makes it better suited to long runs.

The inductance is almost totally unaffected by the quantity of copper involved (
assuming an intelligent design ).

Graham