Driver to drive?

[Eeyore]

John Larkin wrote:

"Kevin Aylward" wrote:

The point I am making is that this type of loop within a loop, does not
allow the overall speed of the complete amplifier to be made faster, if the
amplifier would otherwise already be optimumally designed for speed, despite
the allegation that it increases the net response of the output devices. It
doesn't, as a simple calculation will show. What it does buy is better LF
*accuracy* at the expense of speed.

Well, neither. I was suggesting a fast opamp

They would have to be fast for sure with decent DC and AC precision.

*per fet*, with feedback
from the source, to make each fet look like an ideal transconductance
device, perfectly linear, no offset or threshold, all exactly matched,
with very low input capacitance.

But how does improving and parallelizing gate drives cost speed? It
makes my amps faster and a lot more stable. Your amp (the one you
never built) has a couple of wimpy current sources driving 10 fets in
parallel;

Does it ? Hadn't looked closely enough.

I'm suggesting a beefy voltage source per fet gate,

That's what I do too

with local feedback.

Only overall in my case to linearise the output section. All previous gain stages
have local feedback within the overall loop though.

Graham

 

[john jardine]

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
newseQKk.5818$Ws1.5360@nlpi064.nbdc.sbc.com...

Jan Panteltje wrote:
The free spaces between US digital TV stations can now be used for
wireless services.
In spite of failed tests ;-)

In German:

http://www.heise.de/newsticker/US-Regulierer-will-den-Weissen-Raum-oeffnen--

/meldung/117556

That has been around since a long time. Our church uses wireless mikes
as a secondary UHF user. Of course we made sure that this doesn't bother
anyone. Love thy neighbor

DTV is a whole 'nother ballgame. It falls apart every other night around
here. And when it goes then most of the channels turn into a blocky
Picasso, not just one.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

Even though I can see the Emley Moor TV transmitter from my window and have
a steerable Yagi and have just replaced my set top box with a new one and
know I've an excellent signal cos the spectrum analyser says so, I still see
a crap picture.
A year ago it used to be 'nearly acceptable' now it's not even nearly.
Constant freezing, blocking out, loss of sound, paint-it-by-numbers colours
and Max Headroom staccatos.
An inbuilt tendency to conspiracy theory has deduced I'm losing bit
bandwidth to that HD thing the broadcasters seem to be pushing. They switch
off analogue in a couple of months, the telly's (and STBs) look like they'll
be heading down the council recycling centre at the same time.

 

[Eeyore]

John Larkin wrote:

"Kevin Aylward" wrote:
John Fields wrote:
Eeyore wrote:
John Larkin wrote:

Not if the "additional" pole is at a much higher frequency than the
previous pole inherent to the capacitances of a heap of fets driven
by some wimpy resistive source. Increasing the bandwidth of the
output stage - the serious speed problem - by, say, 20:1 has got to
help the overall loop.

Just buffering Ciss helps a ton.

There's no free lunch here: we're adding GBW, and paying for it. But
not much, since opamps are cheap.

I confess I do that kind of thing. Just not put op-amps round the
actual output devices myself so far but it sounds interesting.
They'd have to be damn fast though.

---
Hey, Mr. Expert, here's a circuit I designed about 30 years ago, but
in bipolar, that does what Larkin's talking about.

No it doesn't, not unless Larkin's taking about something completely
different other than what I am talking about.

What you have here is a simple amplifier driving mosfets. This is totally
standard, and not at issue in this discussion. It is not one amplifier
driving another amplifier, where the 2nd amp encloses the output devices and
forces a closed loop UG buffer, for example, like *my* circuit here.

http://www.kevinaylward.co.uk/ee/circuits/VeryLowDistortionAmp2.jpg

Note, the zener diode fed, (single transistor) buffer-in-the-loop around the
output mosfets.

The point I am making is that this type of loop within a loop, does not
allow the overall speed of the complete amplifier to be made faster, if the
amplifier would otherwise already be optimumally designed for speed, despite
the allegation that it increases the net response of the output devices. It
doesn't, as a simple calculation will show. What it does buy is better LF
*accuracy* at the expense of speed.


Well, neither. I was suggesting a fast opamp *per fet*, with feedback
from the source, to make each fet look like an ideal transconductance
device, perfectly linear, no offset or threshold, all exactly matched,
with very low input capacitance.

But how does improving and parallelizing gate drives cost speed? It
makes my amps faster and a lot more stable. Your amp (the one you
never built) has a couple of wimpy current sources driving 10 fets in
parallel; I'm suggesting a beefy voltage source per fet gate, with
local feedback.

Well, despite the occasional frayed temper and bruised ego, we've certainly got
one humdinger of a design discussion going here !

Graham

 

[Richard The Dreaded Liber]

On Fri, 17 Oct 2008 18:34:07 -0700, Richard Henry wrote:

On Oct 17, 3:22 pm, Richard The Dreaded Libertarian <n...@example.net
On Fri, 17 Oct 2008 11:33:19 -0700, Paul Hovnanian P.E. wrote:
But Obama is half white. So which race is it that I'll be discriminating
against?

The way I heard it, he's closer to 15/16 Polynesian[1] and 1/16 African.

I wonder if he's ever even met his Kenyan buck spermdonor?

He admits he's the son of a "single mom", which is a euphemism for "unwed
mother", which is a euphemism for "that slut that didn't have sense enough
to NOT get knocked up", which makes him .... wait for it....

A Bastard!

[1] which could include some white, from early colonizers, like the
Bounty crew and so on.

You could have just said "I know nothing" and save yourself a lot of
typing.

So, which of my statements proves inaccurate?

He himself said that he's the son of an unwed mother, and he calls himself
an "African" American - who in hell wants some half-assed American, who
puts Africa first, running the country? Where does his allegiance lie?

Thanks,
Rich

 

[Richard The Dreaded Liber]

On Fri, 17 Oct 2008 23:58:26 -0700, Robert Monsen wrote:

I wonder how much racism will affect the final vote? Looks like anger
at the black part of Obama seems to be fairly close to the surface in
this crowd. I hope it isn't representative of the general population.

I really, seriously, couldn't give a shit less what color his skin is,
but he identifies HIMSELF as a half-assed American, the son of an unwed
mother.

And he's so damned unctuous - he's the quintessential snake oil salesmen.

And that's woithout even bothering to mention that he's a raving socialist.

Thanks,
Rich

 

[JeffM]

JeffM wrote:
This ignores M$'s new "Ribbon" default interface
which will have to be adapted to by old users "upgrading".

Joel Koltner wrote:
The ribbon isn't difficult to use -- and long term may even be a win --,

As I have no intent to ever again contribute to the M$ coffers,

I'll have to take your word for it.

although it certainly causes some amount of lost time initially
as each user ploddingly figures out where their feature menu items
have been moved to.

Yup. You have underscored the point I tried to make.

I was surprised that even in the tiny land of southern Oregon
here, the community college has already switched over to MSO 2007
(and Vista too).

Many (smart, IMO) companies have decided to avoid both.
The new Apple ads (Don't use the "V" word) made me laugh.

It was recently noted here that journals are rejecting
items submitted with M$O2007 formatting (not just the file format
--more significantly, the way it does *text* formatting--
again, M$ not even compatible with itself). 8-(

 

[Eeyore]

Jamie wrote:

Eeyore wrote:

You clearly haven't the tiniest clue about the economics of high-volume manufacturing.
Or the importance of pcb layout. Not to mention the cost savings of offshore
manufacturing too.

One product of mine (in its various channel sizes) sold over 100,000 units.

If you really had that much involvement in projects as you speak of,
I'll wager the majority of them are off of some one else's back.!

You're as much of a cnut as I always thought.

Here's an example of the above btw.
http://cgi.ebay.co.uk/Studiomaster-Club-2000-18-channel-mixing-desk-excellent_W0QQitemZ220296706076QQihZ012QQcategoryZ23785QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

It was available with various numbers of channels (the above is the largest) and a DSP
reverb option.

Totally my own design thank you, although obviously I had guys working on stuff like pcb
layout and metalwork for me as part of a 3 man team.

Graham

 

[Jamie]

Eeyore wrote:

Jamie wrote:


Eeyore wrote:

Jamie wrote:

Eeyore wrote:

John Fields wrote:

Eeyore wrote:

John Fields wrote:


You make those claims and then, conveniently, fail to back them up
because of the restrictions you claim are placed upon you by copyright
and contractual limitations.

Fine. Pay me and I'll do something similar for you and you'll own the
copyright.

---
Pay you???

Thanks, that's the best laugh I've had all day!

Well, let's face it, you don't have the necessary skills.


Make sure you have a shovel, you'll need it for that hole
your about to dig for your self.


I'm quite sure that JF is far too out of touch with the technology currently
used in the best audio amplification.

Also, it has to be economic to manufacture. That's easily half of it.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
that being the case, then it must be shit you're making!
I think any beginner can accomplish that.


As ever you're quite clueless.

What do you a PCB / chassis mount professional audio XLR 3 pin gold-plated
connector should cost for example ?

Or an NE5532 ?


Graham

Something beyond you..

Cat whisker diodes.

http://webpages.charter.net/jamie_5"

 

[Eeyore]

Jamie wrote:

Eeyore wrote:

As ever you're quite clueless.

What do you [think] a PCB / chassis mount professional audio XLR 3 pin
gold-plated
connector should cost for example ?

Or an NE5532 ?

Something beyond you..

Cat whisker diodes.

I see you can't even begin to answer the question.

Graham

 

[Eeyore]

Jamie wrote:

Being it's audio, there shouldn't be any legality issues since that
field has no secrets, you twit!

Clueless arse.

Graham

 

[Jamie]

Eeyore wrote:

"Michael A. Terrell" wrote:


Eeyore wrote:

John Fields wrote:

Eeyore wrote:

John Fields wrote:

Eeyore wrote:

John Fields wrote:

You make those claims and then, conveniently, fail to back them up
because of the restrictions you claim are placed upon you by copyright
and contractual limitations.

Exactly. I'm behaving professionally. Nor do I want to let all the Chinese see
how to do it right.


Fine. Pay me and I'll do something similar for you and you'll own the
copyright.

---
Pay you???

Thanks, that's the best laugh I've had all day!

Well, let's face it, you don't have the necessary skills.

---
Trying to start a pissing contest?

You haven't the skills and experience in this field.


Ain't gonna work.

I'm sure you're very good at other things.

This is what I meant. If you can't stand the heat, quit shoveling on
the burning coal.


I am a true audio expert Michael, John Fields is not. Each to their own.

Graham

Please direct me to a product that you designed your

self!................................
Being it's audio, there shouldn't be any legality issues since that
field has no secrets, you twit!


http://webpages.charter.net/jamie_5"

 

[Joop]

On Mon, 20 Oct 2008 15:32:08 +0200, David Brown
<david@westcontrol.removethisbit.com> wrote:
<...>

I'm curious - what is it that Excel can do that Calc cannot?

I use OO at home but it is kinda old (1.1.4)
Does Calc nowadays support engineering format for numbers? So xxxE-6,
yyE-9 etc instead of x.xxE-4, y.yE-8?
That is something I missed from Excel.

Cheers,
Joop

 

[Eeyore]

Jamie wrote:

Being it's audio, there shouldn't be any legality issues since that
field has no secrets, you twit!

My DSP reverb code is definitely secret. Just to take one tiny example.

Graham

 

[Richard The Dreaded Liber]

On Fri, 17 Oct 2008 23:51:42 -0700, Robert Monsen wrote:

On Fri, 17 Oct 2008 07:30:59 -0700 (PDT), Richard Henry

I think he was set up by the Obama campaign to make McCain look
stupid.

It worked!

The republicans knew they would lose this one, and figured they could
spare McCain. They even protected their cannon fodder for next time by
forcing McCain into chosing a loser like Palin for vp. Didn't want to
him to take down somebody who might actually win in 2012.

By 2012, America herself will be unrecognizable as a Sovereign State.

Hell, even the NEOCONS have gone socialist.

Thanks,
Rich

 

[Richard The Dreaded Liber]

On Sat, 18 Oct 2008 08:53:03 -0700, mpm wrote:

On Oct 18, 11:30 am, UltimatePatriot

  Compared to retarded fucks like you, he is an Einstein.

Give it up "Ultimate Patriot"...
Even the LA Times is endorsing Barack Obama - the first time it has
endorsed any candidate since 1972 and the first ever endorsment by
them for a Democrat. Regarding the alternative, they go on to say...

This is not surprising - LA is sort of a gathering place for California
Socialists.

Thanks,
Rich

 

[Anthony Fremont]

Jon Slaughter wrote:

What I'd actually like to have is a sort of "cap" or "button" that I
could fit over the whole in the wood that I'll be mounting the led's
in that is scratch resistant. This will cover the led and should mix
the colors along with increase the viewing angle.

Frosted glass works pretty decently. Here are some 6mm beads:
http://www.themysticalgardenpath.com/servlet/the-1806/100-Crystal-Matte-Ghost/Detail
This place has white beads that would work as long as they aren't totally
opaque:
http://www.beadland.com/glassfrosted.htm
Two part epoxy is a good material to fill with, but it might mess up the
frosting effect of the glass beads by making them look clear.

 

[UltimatePatriot]

On Mon, 20 Oct 2008 08:24:36 -0500, "Anthony Fremont"
<nobody@noplace.net> wrote:

UltimatePatriot wrote:
mpm wrote:

Please make your check out to the Democratic National Convention, or
Planned Parenthood.
Or even "Joe the Plumber". Maybe it'll help him with his back-taxes.
Thank you.


Back taxes? You're an idiot. You believe all that bullshit the DP
started? You are one gullible dipshit then.

The guy owes back taxes, makes 40K/year, and isn't even licensed as a
plumber. These aren't some trumped up rumors, they are matters of public
record.

I still don't see the citations that back that claim up.

$40k a year... a man with a wife and kids.. Likely owes less than $3k
taxes a year. That should be set aside if one is a contract worker. If
he let that grow to several years, then that is his fault.


>

 

[Richard The Dreaded Liber]

On Fri, 17 Oct 2008 23:06:30 +0000, Guy Macon wrote:

... Whatever
happened to our inalienable rights?

The income tax, which essentially signed the death warrant for Liberty.

Socialist Obama will drive the last nail into the coffin.
Or McCheney^H^H^H^H^H^HCain's perpetual war.

One way or another, the country's going down the toilet, unless we can
get 200,000,000 people to vote for Bob Barr. He might not be much, but
he's the last hope for rescuing Constitutional Government in America.

Thanks,
Rich

 

[Don Klipstein]

In article <48FCC4ED.B207D5E@hovnanian.com>, Paul Hovnanian P.E. wrote:

ehsjr wrote:

[snip]

A simple approach may be best for you. An LED needs to have
the current limited to a (relatively wide) range, and needs
to be protected against reverse voltage. Placing a diode in
antiparallel with the LED accomplishes the latter.

Or another LED wired the other way around for 2X the light.

What I like to do is use a bridge rectifier to have both halves of the
AC cycle bcoming DC for the LED. A bridge rectifier will protect the LED
from reverse voltage while also never giving the LED reverse voltage.

Put the resistor upstream from the bridge rectifier, so that the
resistor limits current if the bridge rectifier shorts. And 400 volt
bridge rectifiers are cheap.

Have a resistor of sufficiently high power rating that no more than
50-60% of the power rating is actually dissipated into the resistor - and
consider worst case input voltage. Measure what the transformer's
or wallwart's output voltage is when loaded by nothing but either a
voltmeter, or a voltmeter in parallel with a resistor drawing a few mA.
That can be well above the nominal output voltage.

I have seen what the failure rate of resistors is when power dissipation
gets to about 60-70% of the rating. It is low, but I consider it
significant. A few times I have already fixed things where the problem
was a resistor failing while dissipating about 60-70% of rated power. In
one case, the resistance decreased greatly.

In critical applications, there are "flameproof" resistors. Some are
even UL recognized components.

One more thing - you can reduce heat production here: There are now
plenty of LEDs that get plenty bright at just a few milliamps.

- Don Klipstein (don@misty.com)

 

[Rich Grise]

On Sun, 19 Oct 2008 03:41:57 -0500, Jon Slaughter wrote:

Is there a cheap source for fiber optic that is't used for communication but
lighting? I need it in small lengths(< 1 in but of course I can cut it) and
don't mind imperfections. In fact I imagine even scrap would work. 1mm to
2mm in diameter too.

Although need it without the sheath or some easy way to remove it. Would be
nice if it had a coating on it so I could handle it but a very thin one that
was bonded to the fiber)

Go to the trinket & novelty shop, and get one of those fiber optic "mood
light" thingies.

Have Fun!
Rich