Driver to drive?

[Rich Grise]

On Wed, 22 Oct 2008 11:03:15 -0700, mpm wrote:

On Oct 22, 1:42 pm, Richard The Dreaded Libertarian <n...@example.net

I wonder how the bureaucrats came to believe that they know more about
plumbing than the plumbers do?

That's too easy: "Shit flows downhill."

The only other thing you got to know is hot's on left, cold's on
right.
Viola! You're a plumber.

It might be not quite that simple - one time, the company had to call in
a plumber because the toilet drain needed to be snaked out. He found
the access plug, and while he was opening it, I got volunteered to hold
the shop-vac to suck up the liquid that would escape, but it wasn't
liquid - it was shit. I almost threw up. This plumber points at this
shit that's oozing out of the access plug and says, "That's my bread
and butter!". I threw up.

So ya gotta have a strong stomach, apparently.

Thanks,
Rich

 

[John Fields]

On Wed, 22 Oct 2008 20:41:16 GMT, "Kevin Aylward"
<kaExtractThis@kevinaylward.co.uk> wrote:

John Larkin wrote:

"Pro" audio design seems like an infinite chain of stolen circuits.

Lets not kid ourselves, "all" circuits are stolen, whatever the field.

---
Not true.

In the dim recesses of time, an idea flashed into being which was unique
and was fleshed out electromechanically into our being here, now, so
_that_ circuit wasn't stolen.

On a more mundane level, some of us work through the problems of design
without resorting to directly infringing the work of others, whether
that prior work exists or not.

For example, a circuit I designed years ago doubled an input signal's
frequency while preserving its duty cycle over something like an 8 or 10
octave range if I recall correctly.

Was using a right shift stealing?

You tell me.
---

Its
that simple. Show me *any* design, and I will show you a bit of is in a
prior design.

---
WRT my frequency doubler, I'd love to see what you can come up with.
---

Like diff pairs, current mirrors, cascodes, are all the same
building blocks we all use. However, designing say a cmos opamp, even with a
standard topology, can take considerable time in getting just the right
combination of W, L and M to satisfy a particular specification.

The only way to make production designs reliable, is to use what is already
known to work, and only add the minimal of new additions.That's what being
an engineer is. Maximising profit with the minimum of RISK. There are no
brownie points for a novel circuit that achieves no net advantage. All new
design is based on modifications of existing design. That's just the way it
is. Like, how do you proposes a new car engine is "designed"..Like some new
law of thermodynamics is discovered? I don't think so mate...

Anyone that says that they don't use say, 95% of existing work is either a
liar, or seriously deluding themselves.

---
So anyone who uses, say, an opamp in an invention, even though the opamp
is only characterized as a gain block which isn't unique to the idea
behind the functioning of the invention, owes 95% of his invention to
the author of the opamp?

JF

 

[Martin Brown]

On Oct 22, 6:06 pm, Richard The Dreaded Libertarian <n...@example.net>
wrote:

On Wed, 22 Oct 2008 01:42:55 -0700, Martin Brown wrote:
On Oct 21, 7:22 pm, Richard The Dreaded Libertarian <n...@example.net
On Tue, 21 Oct 2008 10:05:16 -0700, mpm wrote:

The point is, like everything else Republican the last 8 years, the
FCC also deregulated.

DE-regulated? Are you insane? What's "You must pay your hard-earned money
for this box to see TV any more" other than EXCESSIVE regulation?

It is pure market forces. You want to watch the TV in future you have
to buy the box.
A bit monopolistic I grant you. But if you want to receive the signal
then you have to buy a receiver and decoder.

So, should we all start wearing swastika armbands, marching the goose-step,
and saying "Seig Heil" whenever we see a bureaucrat?

The only person goosestepping here is you.
You are not *compelled* to watch TV at all. Switch it off instead.

Regards,
Martin Brown

 

[Eeyore]

Kevin Aylward wrote:

Eeyore 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.

I don't disagree with you overall Kevin. I keep a little trick up my
sleeve with power amps that changes the game somewhat and eliminates
any such 'expenses'. However it's absurdly obvious (when you think
about it) and consequently couldn't be patented I'm sure and the
moment the 'secret' gets out everyone will be doing it. It's insanely
simple too. You just have to have the wits to think of it.

Note, as in the mosfet 1000, basically a stolen idea from Hitachi. The
second stage is a diff pair. This diff pair has less distortion inherently.
Don't know why D.Self don't use it in his Blameless amp. Keep everything
differential is one of my mottos.

Ditto. It's crazy to throw away that advantage.

The current mirror load gives the prior
post mentioned push/pull drive to the output buffer. The current source
loads (CMFB) on the 1st stage, rather than resisters, makes the total LF
loop gain, truly huge, making LF distortion, vanishing small.

Indeed so. Mind you, I actually *limited* my LF gain because it was so huge
already ! It didn't need any more. THD didn't start to climb on the 1200B
design until about 2-3 kHz. Knowing what I do now, I'm sure I could do better
than that. This was 20 years ago you know.

The Matti Otala idea of 3 voltage gain stages attracts me. Ever hear of the
Electro-Companiet amplifier ?
http://www.google.com/search?hl=en&rls=en&hs=3lm&q=Companiet+amplifier&btnG=Search

They were hopelessly built (I ended up fixing an early one) but the technical
idea was sound.

Graham

 

[Eeyore]

Kevin Aylward wrote:

You miss the point, as usual. The whole concept is crap, and
people who bought them have been returning them as soon as they
realize what a crappy concept it is. You can't have a station down,
even overnight to do an emergency exchange on unrepairable
equipment. If you think the concept is ancient, it doesn't matter,
because its still shit. So much for you being so great at audio
design. There is no reason to use a digital abortion like that,
when analog is simpler, sufficient, and can be field serviced. Any
broadcast engineer worth his pay would run from crap like that.

AMS-Neve don't seem to have that problem. Read the client list.


I am *really* loving my new tascam digital multitrack. Its a joy to record
and randomly seek to any point in the song. The digital saving and operation
of tuneable tone controls are magic. Now I want a digital desk, with
infinite rotate pots with position lights on each channel. Like, there is no
going back once one has the digital controllability.

Horses for courses. The control surface and GUI of a digital desk can make or
break it.

For live situations where many engineers may use the desk, analogue is still
unbeatable for its simplicity and anyone experienced can master one in 5 minutes
even if they never saw that model before (and they're not short on performance
these days either) but even in live, digital is making increasing inroads.

Check out Cadac's S-Digital for example. Just out and I think they hit the sweet
spot.

Graham

 

[Eeyore]

Kevin Aylward wrote:

Jamie wrote:
Eeyore wrote:
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

Cough, Cough.................................

Jesus Christ...

Who the hell would want your reverb code.

Do you honestly believe people out there can not do their
own DSP coding?

Choosing the right co-efficient could take a month of Sundays though, so not
surprising one don't want to tell anyone what they are.

Like, the basics of a nuclear bomp are pretty trivial, but its the final
details that matter.

I have tried quite a lot of digital delays, and it is somewhat surprising
that many, many of them, still sound like shit. Not one usable setting.
Trust me.

Oh so true. Read the reviews.

Like, do you know the one about the Coke A Cola formula....that's not rocket
science either.

I don't have the time to read most of this thread, Graham, but...

'Designing' those reverbs was a fascinating task, not least because they had to
sound as near identical as possible to some on a withdrawn OEM module we'd used.
I managed a replica as good as anyone could tell. Why ? Because people *loved*
those reverbs and wanted us to keep them.

I read no less than 3 long papers on the subject in the process. And I threw out
some 'holy cows' about how to make them sound right that have always been
assumed - because they actually sound shit.

Just as I do with EQ, I only sign off for production when it *sounds* right as
well as measures right.

Graham

 

[Eeyore]

Kevin Aylward wrote:

Eeyore wrote:
"Michael A. Terrell" wrote:

Any ass can throw together a design for audio equipment and sell
it,

Simply untrue, the market is VERY competitive.

Indeed. Its just about impossible to make a profit in "pro audio" now adays.
Too much stuff on the market.

Thankfully there are still a few areas with profit left in them.

Graham

 

[Eeyore]

Kevin Aylward wrote:

John Larkin wrote:

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;

No its doesn't. Its a push/pull class AB current drive to the mosfets, and
secondly, you don't need much. 20ma class drive is way more than enough for
at least 500w at 200Khz power BW.

I thought he was wrong about that. I confess I didn't look it up again at the
time but my 1200B does exactly the same as your approach Kevin.

Graham

 

[Eeyore]

Kevin Aylward wrote:

Eeyore wrote:

Is testing done at the die level ?

Yes. Wafer probe.

That must be some fine machinery !

Grham

 

[Eeyore]

John Larkin wrote:

"Pro" audio design seems like an infinite chain of stolen circuits.

Only in China.

To reseach the issue fully would take you months full time.

Graham

 

[Eeyore]

Kevin Aylward wrote:

Eeyore wrote:
Kevin Aylward wrote:
John Fields wrote:
Eeyore wrote:
John Fields wrote:
Eeyore wrote:

You're a babe in arms in this discipline.
---
You wish.

I cut my teeth on audio and was designing and building bridge
amplifiers in the early '60's, even before RCA came out with them,
as I recall.

The world has moved on John.

---
As have I, while you guys keep struggling to lower THD to limits
which are so far beyond the threshold of audibility that the point
of the exercise becomes ludicrous.

My take on this is more of what is the limits one can achieve in
terms of accuracy and speed, irrespective of anything audio.
Extremely high performance, obviously has no intrinsic value when
applied to audio, but I can think of a few things where the
techniques might be applied elsewhere.

So, in terms of THD, s/n ratio and response flatness where would you
draw the line where it becomes overkill ?

0.01% IMD @ 20Khz/19Khz at all power levels. 1db flatness to 50Khz power BW.

I don't claim that this is necessary, but my take is that it is sufficient.
I won't buy a PA amp if it is say, 0.1% at 20khz.

As far as what I am interested in as a personal achievement goal, its
probably 0.001% IMD at 20khz, 1db flatness to 1Mhz power BW.

How about flatness in the audio band ?

Graham

 

[Eeyore]

Kevin Aylward wrote:

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

I don't disagree with you overall Kevin. I keep a little trick up my
sleeve with power amps that changes the game somewhat and eliminates
any such 'expenses'. However it's absurdly obvious (when you think
about it) and consequently couldn't be patented I'm sure and the
moment the 'secret' gets out everyone will be doing it. It's
insanely simple too. You just have to have the wits to think of it.

Graham

Note, as in the mosfet 1000, basically a stolen idea from Hitachi.
The second stage is a diff pair. This diff pair has less distortion
inherently. Don't know why D.Self don't use it in his Blameless amp.
Keep everything differential is one of my mottos. The current mirror
load gives the prior post mentioned push/pull drive to the output
buffer. The current source loads (CMFB) on the 1st stage, rather
than resisters, makes the total LF loop gain, truly huge, making LF
distortion, vanishing small.

Kevin Aylward

"Pro" audio design seems like an infinite chain of stolen circuits.

Lets not kid ourselves, "all" circuits are stolen, whatever the field. Its
that simple. Show me *any* design, and I will show you a bit of is in a
prior design. Like diff pairs, current mirrors, cascodes, are all the same
building blocks we all use.

But these are simply 'prior art', not actually 'stolen'.

Coming up with a genuinely new configuration these days is increasingly
difficult, although the USPTO will probably still give you a patent on it !

Graham

 

[Eeyore]

JosephKK wrote:

Eeyore wrote:
JosephKK wrote:
Eeyore wrote:
JosephKK wrote:

Nor have i disagreed when those points were expressed. They are quite
true. In the long run i think i might use a valve preamplifier to get
the sound and a highly derated very linear post amp.

Several people have done this in the past. The name Phoenix comes to mind which was funded
by (I think by then) ex-members of the band Argent. That's the first I know of.

I suspect Marshall is doing something like this now too but I'm not up to date on their
stuff, it's not actual 'pro' audio, it's what we call MI (musical instrument) technology.

And for the masses we now have what's called prosumer. Near real pro kit performance at a
bargain >price and usually in small sizes but more of a 'consumable' than real pro kit.
Somecan be quite good >actually. I've designed a fair few of that ilk myself.


My first piece of semi-pro gear is an Ampex AX-300 open reel tape
deck, i still have it. Hey, i can afford to put new heads on it now.
Probably only $2400 now, if i can find them. Damn, i will need a
calibration tape too, if i can find it.

You'll have trouble finding anyone stocking 1/4" tape now too !

I actually have an 8 track 1" tape machine kicking around here !


Especially blank good stuff like Scotch (tm) Blackwatch (tm) 207.

I used 206 and 207 personally a lot. Beware of oxide and binder shed on some tapes of that era.
The popular polyurethane binder absorbs moisture and becomes a mess. It can be fixed by 'cooking'
gently lierally in an oven, then make a secondary master. See rec.audio.pro for details.

Calibration tapes will be really challenging, even used. Goggled for
a while, couldn't find either. I could get Maxell UD 35-90 blank tape
though, which is pretty good.

MRL used to be the guys. Magnetic Reference Labs. Cost a fortune though.

Graham

 

[Eeyore]

Kevin Aylward wrote:

For me, analogue tape is like dos, dead.

Throw it away and get a cheap digital one

Lots of mixing engineers still like to 'pre-process' drums through tape
first for the natural compression.

And I know (and have worked in) the Studio that hired in a Studer 4 track
J37 to do last year's ? re-production of Sgt Pepper's Lonely Hearts Club
band.

Graham

 

[Jamie]

Eeyore wrote:

Jamie wrote:


Eeyore wrote:

Jamie wrote:

Eeyore wrote:

Jamie wrote:


Oh btw, I also wrote some 8 Bit FFT code in a uc controller

Really ?

Mine was 32 bit code. Work out how to do that eh ?

Graham


Shit....
Any one that can't do higher precision in Uc's other than
what is supplied natively, does not belong coding in uc's

you're hitting bottom!..

and for you info, that was a 8 bit Uc but the FFT was 16 bit,.
more than enough.


FFTs have nothing to do with it.

Graham


What a pig shitting BS'er you are..

Go away!...

You're treaded on thin ice you old crony!


You're the fool. You are nothing more than a disgusting piece of pig
excrement.

You're just jealous because you can't do it. Bloody typical of idiots.


LOL!!!

Right... now go back to your room before the hall police see you
wondering around..
--
http://webpages.charter.net/jamie_5"

 

[Joop]

On Tue, 21 Oct 2008 21:32:36 +0200, Anton Erasmus
<nobody@spam.prevent.net> wrote:

On Tue, 21 Oct 2008 01:20:32 +0200, Joop <jojo@xs4all.nl> wrote:

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.

Yes, It works fine in V2.3.1. Not sure when it was added.

Regards
Anton Erasmus
Thanks. I'll download an update.

Joop

 

[John Fields]

On Thu, 23 Oct 2008 00:24:55 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

Kevin Aylward wrote:

Eeyore wrote:
Kevin Aylward wrote:
John Fields wrote:
Eeyore wrote:
John Fields wrote:
Eeyore wrote:

You're a babe in arms in this discipline.
---
You wish.

I cut my teeth on audio and was designing and building bridge
amplifiers in the early '60's, even before RCA came out with them,
as I recall.

The world has moved on John.

---
As have I, while you guys keep struggling to lower THD to limits
which are so far beyond the threshold of audibility that the point
of the exercise becomes ludicrous.

My take on this is more of what is the limits one can achieve in
terms of accuracy and speed, irrespective of anything audio.
Extremely high performance, obviously has no intrinsic value when
applied to audio, but I can think of a few things where the
techniques might be applied elsewhere.

So, in terms of THD, s/n ratio and response flatness where would you
draw the line where it becomes overkill ?

0.01% IMD @ 20Khz/19Khz at all power levels. 1db flatness to 50Khz power BW.

I don't claim that this is necessary, but my take is that it is sufficient.
I won't buy a PA amp if it is say, 0.1% at 20khz.

As far as what I am interested in as a personal achievement goal, its
probably 0.001% IMD at 20khz, 1db flatness to 1Mhz power BW.

How about flatness in the audio band ?

JF

 

[krw]

In article <pan.2008.10.22.21.46.47.291962@example.net>,
null@example.net says...

On Wed, 22 Oct 2008 09:50:27 -0700, mpm wrote:
On Oct 22, 12:38pm, Jim Thompson <To-Email-Use-The-Envelope-I...@My-

Even if they have to create fictional voters to do it :-(

Who better to recognize fiction than the Republicans?

Libertarians are better at _recognizing_ it - both of the socialist
parties (democrat and neocom) are wallowing in it.

The DemonicRats *ARE* the neocoms.

--
Keith

 

[Eeyore]

Jamie wrote:

Right... now go back to your room before the hall police see you
wondering around..

WTF are you babbling on about ?

You contribute nothing here except bad / erroneous / stupid and retarded
info.

GET LOST ! And stay lost !

Graham

 

[John Fields]

On Wed, 22 Oct 2008 20:00:55 -0400, Jamie
<jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:

Eeyore wrote:

Jamie wrote:


Eeyore wrote:

Jamie wrote:

Eeyore wrote:

Jamie wrote:


Oh btw, I also wrote some 8 Bit FFT code in a uc controller

Really ?

Mine was 32 bit code. Work out how to do that eh ?

Graham


Shit....
Any one that can't do higher precision in Uc's other than
what is supplied natively, does not belong coding in uc's

you're hitting bottom!..

and for you info, that was a 8 bit Uc but the FFT was 16 bit,.
more than enough.


FFTs have nothing to do with it.

Graham


What a pig shitting BS'er you are..

Go away!...

You're treaded on thin ice you old crony!


You're the fool. You are nothing more than a disgusting piece of pig
excrement.

You're just jealous because you can't do it. Bloody typical of idiots.


LOL!!!

Right... now go back to your room before the hall police see you
wondering around..

---
The hall police are responsible for bringing you to task for your
wandering around.

The mind police are responsible for bringing you to task for your
wondering around.

JF