Bypassing caps? How about with wire?

[Guest]

Archived from groups: rec.audio.pro (More info?)

>I think you overstate the case. As far as I'm concerned cd playback hasn't
>improved at all.

Were you LISTENING to CD's in the early 80's on the CD players that a normal
guy could afford? Gaaack!!

-jeff

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

"so what" <sowhat@nospam.edu>
>
> > The opinions of audiophools are notoriously always WRONG.
>

> Have you really not noticed that your opinions are notoriously always
> irrelevant?



** Another closet audiophool has just identified itself.




.......... Phil

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

In article <cec7he$ln0$1@panix2.panix.com> kludge@panix.com writes:

> >But someone was making add-on auto air conditioners called Mark IV.
>
> Didn't they make a capacitive discharge ignition system too? I remember
> one of our neighbors installed one on his Maverick and said that the points
> lasted forever.

I had a Delta-something ignition system on my 240Z. I think it was the
same unit that Heathkit sold in kit form.



--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

"Arny Krueger"

> I'm looking at the schematic of the PL700 output stage, downloaded from
the
> PL web site http/hometown.aol.com/PhaseTek/ .
>

** That is the PL700B - the later PL700 mk2 is very different.


> From the schematic I see that the output stage emitter resistor is 0.31
> ohms, and the SOA protection transistors are 2N1304/1305 (germanium!).
>

** The emitter ballast resistors were 0.33 ohms + rail side and 0.27 ohms -
rail side.


> It takes about 0.2 volts to turn on a germanium transistor, and the whole
> SOA network Vout= 0 volts, at best could be estimated as a stright shot
from
> the drop across the emitter resistor to the base of the protection
> transistor. So, some place around 0.66 amps per output transistor, with a
> worst case reactive load worst stress on the output device, the protection
> circuit switches on.


** There is a 47 uF cap in the feed to the SOA transistors that
*dramatically* alters that estimation for AC signals.


> B+ and B- are 100 volts. So, were there any horizontal output transistors
in
> those days that had 100 volt SOA of 0.66 amps? No way!


** They were NOT horizontal output transistors - HOT devices have at
least 1000 volt collector ratings.


> I found the collector current spec for the DTS411 that the PL site
mentions.
> It's a 3.5 amp part.


** Phase Linears never used those devices - Delco supplied modified and
matched devices under the numbers XPL909 and XPL910.


> A modern part with a 3.5 amp current rating would at
> best have 100 volt SOA of about 0.4 amps. Legacy parts were no doubt
worse.


** The XPL909 or 910 output devices in a PL700B delivered 5 amps each into
a 4 ohms load on test with no problems - driving a 4 ohm load with 95 volt
supply rails and 5 devices in parallel requires this.

Samples I have kept here pass 6 amps on test using a bench DC supply with
no problems - so 3.5 amps is NOT the upper limit of the device. PL700Bs
were well able to drive reactive speaker loads without the spiking
distortion problem suffered by so many other amps - even today.

The really interesting part of the story was when Bob Carver left and
production changed to the PL700 Mk2 and its relatives - this involved a
complete redesign of the drive circuit plus a change to using the new
Motorola MJ15024s as output devices.

Astonishingly, the new PL700 Mk2 and PL400 Mk2 models proved to be unable
to drive reactive speaker loads producing severe spikes even with 8 ohm
impedances that were inductive ! This was something Phase Linear under Bob
Carver had prided themselves their amps were immune from !!

Worse than that, and despite the hair trigger SOA limiter, output stage
failure rates were actually higher in PA system usage than the old PL700B
model !! When contacted, the advice from Phase Linear was NOT to use 4 ohm
speaker loads and NOT to use the amps for PA systems - their warranty
was voided by such usage.




............ Phil

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

"Handywired"<

>
> Were you LISTENING to CD's in the early 80's on the CD players that a
normal
> guy could afford? Gaaack!!



** Another audiophool myth repeater just identified itself.



............ Phil

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

Scott Dorsey wrote:

> I do know that David Hafler does use it as an example of one of the
> bad early power amp designs.

I think "did" is more appropriate there ....

geoff

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

Paul Stamler wrote:

> I doubt that was the explanation; after all there was a Mark VI. My
> question is why they had Marks II, III, IV and VI but skipped V.

Maybe the V blew up ?!! Sooner than the others .

geoff

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

In article <2mgvqcFmb541U1@uni-berlin.de>,
"Phil Allison" <philallison@tpg.com.au> wrote:

> "Monte McGuire"
> > "Phil Allison" :
> > > "Paul Stamler"
> > > > >
> > > > > Be careful about loading, though; the TL07x has an insipid output
> > > > > stage, and it hates driving anything under 10k (don't forget to
> > > > > include the feedback network when you calculate total load). It's
> > > > > really happiest with a 50k load or higher.
> > >
> > >
> > > ** The TL072 in fact drives loads down to around 2 kohms with 0.001 %
> THD.
> >
> > If you think that's good enough, then have at it. Chips like the
> > OPA2132 can do a lot better and the end result sounds that way too.
>
>
> ** Got DBT results to prove that ??
>
> Thought not.

I've got an AP2322. I find that an FFT of a distortion analyzer
residual tells me a lot more about the hows and whys of a circuit than a
listening test, DBT or not, could ever tell me. Sure, listening is the
whole point, but I don't schedule DBT tests between every single
adjustment I'll make to a circuit. You'd never get anything done or
know what you'd need to do anyway!


> > Also check the THD at something other than 1KHz. It's not so pretty as
> > you go further up.
>
>
> ** 0.003% at 10 kHz with a 3.3k ohms load sure aint ugly.

Well, it's 20-30dB more than you need to take. You choose. BTW, I'm
quoting the level of spurs directly, not THD+N. You need an FFT of the
residual to do any meaningful tests of amps these days. The spurs
should be (and usually are) way better than .003% - most of that .003%
is probably noise.


Regards,

Monte McGuire
monte.mcguire@verizon.net

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

In article <Roudnb6Ze9TLH57cRVn-uw@comcast.com>,
"Arny Krueger" <arnyk@hotpop.com> wrote:

> "Monte McGuire" <monte.mcguire@verizon.net> wrote in message
> news:monte.mcguire-6A1C1D.01090525072004@news.verizon.net
>
>
> > IIRC, Walt Jung built a circuit that bootstrapped the op amp's
> > substrate (V-) with the common mode input voltage to nullify the
> > effects of the nonlinear drain to substrate capacitance (that causes
> > the common mode problems) and a bunch of distortion went away. The
> > other solution is to use a low source Z, in which case you don't need
> > a JFET input in the first place.
>
> This seems to be described in
>
> http/www.analog.com/UploadedFiles/Application_Notes/742022599AN232.pdf

Hey Arny,

Thanks for digging this up! My hardcopy version is still buried
upstairs somewhere. Nice to read it again...


Regards,

Monte McGuire
monte.mcguire@verizon.net

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

"Monte McGuire"
> "Phil Allison"
>
> > > > > > Be careful about loading, though; the TL07x has an insipid
output
> > > > > > stage, and it hates driving anything under 10k (don't forget to
> > > > > > include the feedback network when you calculate total load).
It's
> > > > > > really happiest with a 50k load or higher.
> > > >
> > > >
> > > > ** The TL072 in fact drives loads down to around 2 kohms with 0.001
%
> > THD.
> > >
> > > If you think that's good enough, then have at it. Chips like the
> > OPA2132 can do a lot better and the end result sounds that way too.
> >
> >
> > ** Got DBT results to prove that ??
> >
> > Thought not.
>
>
> I've got an AP2322. I find that an FFT of a distortion analyzer
> residual tells me a lot more about the hows and whys of a circuit than a
> listening test, DBT or not, could ever tell me.


** That was **NOT** what I asked nor even on the same point. YOU simply
made the claim about audibility without any grounds. It is just another
idiotic audiophool mantra that whatever can be measured can be heard.


>
> > > Also check the THD at something other than 1KHz. It's not so pretty
as
> > > you go further up.
> >
> >
> > ** 0.003% at 10 kHz with a 3.3k ohms load sure aint ugly.

>
> Well, it's 20-30dB more than you need to take. You choose.


** So you have no case - yet again.


> BTW, I'm quoting the level of spurs directly, not THD+N. You need an
FFT of the
> residual to do any meaningful tests of amps these days.


** But you have NEVER established that there is any meaning to the test.


> The spurs should be (and usually are) way better than .003% - most of
that .003%
> is probably noise.


** The full audio band noise from a TL072 with 5 times gain would be well
below that figure at about -117 dB ( rel 5 volts out) or 0.0003%.




............. Phil

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

In article <2ne75uFuuemvU1@uni-berlin.de>,
"Phil Allison" <philallison@tpg.com.au> wrote:

> "Monte McGuire"
> > "Phil Allison"
> >
> > > > > > > Be careful about loading, though; the TL07x has an insipid
> output
> > > > > > > stage, and it hates driving anything under 10k (don't forget to
> > > > > > > include the feedback network when you calculate total load).
> It's
> > > > > > > really happiest with a 50k load or higher.
> > > > >
> > > > >
> > > > > ** The TL072 in fact drives loads down to around 2 kohms with 0.001
> %
> > > THD.
> > > >
> > > > If you think that's good enough, then have at it. Chips like the
> > > OPA2132 can do a lot better and the end result sounds that way too.
> > >
> > >
> > > ** Got DBT results to prove that ??
> > >
> > > Thought not.
> >
> >
> > I've got an AP2322. I find that an FFT of a distortion analyzer
> > residual tells me a lot more about the hows and whys of a circuit than a
> > listening test, DBT or not, could ever tell me.
>
>
> ** That was **NOT** what I asked nor even on the same point. YOU simply
> made the claim about audibility without any grounds. It is just another
> idiotic audiophool mantra that whatever can be measured can be heard.

What grounds do I need? Of course such statements from me are going to
be my opinion. You're either a fool to believe them a priori, you're a
fool to deny them a priori, you hear things the way I do and came to the
same conclusion after listening, or you disagree and prefer things that
I dislike. I could care less which situation applies - take your choice.

What is irrefutable are the AP2322 results, and that's what I use to get
work done. Sure, it may not tell me which devices sound good that have
what I'd consider to be lots of distortion, but it surely does help to
identify devices that have distortions that I don't like the sound of
most of the time. It's useful to have such a box like an AP around.
No, it's not complete, but it's a hell of a lot more practical than
doing DBT all day.

And, back to the point, it shows me that op amps like the OPA2132 have
less HF distortion than a TL072. I claim that this sounds better, you
apparently do not - let's drop that point. You cannot claim that the
numbers are wrong though.



>
> >
> > > > Also check the THD at something other than 1KHz. It's not so pretty
> as
> > > > you go further up.
> > >
> > >
> > > ** 0.003% at 10 kHz with a 3.3k ohms load sure aint ugly.
>
> >
> > Well, it's 20-30dB more than you need to take. You choose.
>
>
> ** So you have no case - yet again.

What are you saying? That more distortion at HF is better? OK, some
people I know prefer that, but I personally don't (most of the time).
You're welcome to your opinions. Like I said before... have at it.


> > BTW, I'm quoting the level of spurs directly, not THD+N. You need an
> FFT of the
> > residual to do any meaningful tests of amps these days.
>
>
> ** But you have NEVER established that there is any meaning to the test.

I did with my own nonscientific listening tests, which everyone in their
right mind, and you too, should ignore. If you believe me, then you're
a fool. We either share opinions or not and the two alternatives are
equivalent to me.

I personally think that amplifiers that have a rising THD+N curve with
frequency sound bad when asked to handle complex material. So, when I
find one of them, I try to find a way to move the turnover frequency up
or reduce the slope by recompensating it, changing the circuit topology
or redesigning the amp. Given that the amp is an IC that can't be
redesigned in this way, the action item here is to choose another IC.
But, you don't have to. Ignore me, please.

> > The spurs should be (and usually are) way better than .003% - most of
> that .003%
> > is probably noise.
>
>
> ** The full audio band noise from a TL072 with 5 times gain would be well
> below that figure at about -117 dB ( rel 5 volts out) or 0.0003%.

I usually use a measurement bandwidth for THD+N that allows for
harmonics above 20KHz, since nonlinearities up there could also manifest
themselves as IMD, not just as harmonics that are inaudible. So, that's
why I suggested that your .003% number might be mostly noise.

But, if .003% is specified with a tight bandwidth, then maybe it really
is all distortion and the TL072 really does make hash out of signals
like I originally proposed. You choose... it's your number.


Regards,

Monte McGuire
monte.mcguire@verizon.net

 

[penguin]

Archived from groups: rec.audio.pro (More info?)

>
>
> ( snip references to published papers full of drivel )
>

What specifically about his references made them full of drivel? What
was wrong with the listening tests therein, and/or why didn't they
apply to his claim?

Ken

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

"Monte McGuire" <monte.mcguire@verizon.net> wrote in message
news:monte.mcguire-B5A0A2.00522006082004@news.verizon.net...
> But, if .003% is specified with a tight bandwidth, then maybe it really
> is all distortion and the TL072 really does make hash out of signals
> like I originally proposed. You choose... it's your number.

Now if I could just find some speakers with less "hash" than that, and ears
that could actually hear all that 0.003% "hash".

TonyP.

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

TonyP <TonyP@optus.net.com.au> wrote:
>"Monte McGuire" <monte.mcguire@verizon.net> wrote in message
>news:monte.mcguire-B5A0A2.00522006082004@news.verizon.net...
>> But, if .003% is specified with a tight bandwidth, then maybe it really
>> is all distortion and the TL072 really does make hash out of signals
>> like I originally proposed. You choose... it's your number.
>
>Now if I could just find some speakers with less "hash" than that, and ears
>that could actually hear all that 0.003% "hash".

My speakers probably have no more hash than that in the top octave.
They have a whole hell of a lot more of it in the bottom octave.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

"Monte McGuire"
Phil Allison
>>>>>
> > > > > If you think that's good enough, then have at it. Chips like the
> > > > OPA2132 can do a lot better and the end result sounds that way too.
> > > >
> > >
> > > > ** Got DBT results to prove that ??
> > > >
> > > > Thought not.
> > >
> > >
> > > I've got an AP2322. I find that an FFT of a distortion analyzer
> > > residual tells me a lot more about the hows and whys of a circuit than
a
> > > listening test, DBT or not, could ever tell me.
> >
> >
> > ** That was **NOT** what I asked nor even on the same point. YOU
simply
> > made the claim about audibility without any grounds. It is just another
> > idiotic audiophool mantra that whatever can be measured can be heard.
>
> What grounds do I need?

** Proof that it is audible - as you claimed above.



> Of course such statements from me are going to
> be my opinion. You're either a fool to believe them a priori, you're a
> fool to deny them a priori, you hear things the way I do and came to the
> same conclusion after listening, or you disagree and prefer things that
> I dislike. I could care less which situation applies - take your choice.
>

** What a pile of drivel - you clearly have no interest in basic facts
about audio or human hearing.


> And, back to the point, it shows me that op amps like the OPA2132 have
> less HF distortion than a TL072.

> I claim that this sounds better,


** But that is both utterly implausible and you have no proof.


> > > >
> > > > ** 0.003% at 10 kHz with a 3.3k ohms load sure aint ugly.
> >
> > >
> > > Well, it's 20-30dB more than you need to take. You choose.
> >
> >
> > ** So you have no case - yet again.

>
> What are you saying?

** So you cannot read ?

You have no proof to back up your claims - ie no case.


> That more distortion at HF is better?


** Has it never occurred to you that human hearing is not like modern test
gear ?

Do you simply ASSUME that if it can be measured it can be heard ???


> > ** But you have NEVER established that there is any meaning to the
test.
>
> I did with my own nonscientific listening tests, which everyone in their
> right mind, and you too, should ignore. If you believe me, then you're
> a fool. We either share opinions or not and the two alternatives are
> equivalent to me.


** Monty - you are just another audiophool, made even more dangerous by
using test gear.


> Ignore me, please.


** You bet I will - but I will also try to make sure that others do the
same.



> I usually use a measurement bandwidth for THD+N that allows for
> harmonics above 20KHz, since nonlinearities up there could also manifest
> themselves as IMD, not just as harmonics that are inaudible. So, that's
> why I suggested that your .003% number might be mostly noise.


** Do a test - see that it is not.


>
> But, if .003% is specified with a tight bandwidth, then maybe it really
> is all distortion and the TL072 really does make hash out of signals
> like I originally proposed.


** Where did you get the ridiculous idea that anyone can hear 0.003% THD
of any signal ????




.............. Phil

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

In article <2ngpeiFnhk0U1@uni-berlin.de> philallison@tpg.com.au writes:

> > Ignore me, please. [Monte]
>
>
> ** You bet I will - but I will also try to make sure that others do the
> same.

Phil, you're really silly and I continue to faithfully read your posts
for amusement, but you've really topped yourself this time. This is
the funniest thing you've written yet.

Keep it up. This newsgroup needs a jester.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

"Phil Allison" <philallison@tpg.com.au> wrote in message news:2ngpeiFnhk0U1@uni-berlin.de...

> ** What a pile of drivel - you clearly have no interest in basic facts
> about audio or human hearing.

> ** But that is both utterly implausible and you have no proof.

> ** So you have no case - yet again.

> ** So you cannot read ?

> ** Monty - you are just another audiophool, made even more dangerous by
> using test gear.

> ** Where did you get the ridiculous idea that anyone can hear 0.003% THD
> of any signal ????


Do you have any facts to offer up here, or is this rhetorical bullshit all we
are ever going to get from you?

--
David Morgan (MAMS)
http/www.m-a-m-s DOT com
Morgan Audio Media Service
Dallas, Texas (214) 662-9901
_______________________________________
http/www.artisan-recordingstudio.com

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

Hey Phil:

> Is snipping posts to shreds and posting mindless abuse all we are
> going to see from you?
>
> The answer to that is already clear.

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

"Mike Rivers"
Phil Allison
>>>>
> > > Ignore me, please. [Monte]
> >
> >
> > ** You bet I will - but I will also try to make sure that others do
the
> > same.
>
> Phil, you're really silly and I continue to faithfully read your posts
> for amusement, but you've really topped yourself this time. This is
> the funniest thing you've written yet.


** Why is it funny to you Mike ???

Does it amuse you to see me outing another of RAP's resident charlatans
??

You must explain what the joke is - we all need a good laugh.




.............. Phil

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

In article <2nhdk8FufdgU1@uni-berlin.de> philallison@tpg.com.au writes:

> "Mike Rivers"
> Phil Allison
> >>>>
> > > > Ignore me, please. [Monte]
> > >
> > >
> > > ** You bet I will - but I will also try to make sure that others do
> the
> > > same.
> >
> > Phil, you're really silly and I continue to faithfully read your posts
> > for amusement, but you've really topped yourself this time. This is
> > the funniest thing you've written yet.
>
>
> ** Why is it funny to you Mike ???
>
> Does it amuse you to see me outing another of RAP's resident charlatans
> ??
>
> You must explain what the joke is - we all need a good laugh.

You've become the joke of the newsgroup, Phil. People will continue to
listen to people like Monte for a long time because he has a good
track record of credibility, accuracy, and most important, patience
with those who don't fully see his point and ask intelligent
questions. It will be a long time before you have that level of
credibility by doing little other than challanging the statements of
others and declaring them patently false. It's funny that you think
you're doing a service to the readers of the newsgroup.

Don't laugh if you don't think it's funny.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo