"John Phillips" wrote in message
...
On 2008-10-13, Eeyore wrote:


wrote:

Jim Lesurf wrote:

It would depend on various factors: What kind of music you like.
How large
your listening room is. What speakers you will be using. etc.

Classical music - not excessively loudly but of course orchestral
climaxes can be loud.
Digital sources - not vinyl.
Room 11' x 13' x 8' high (rather small probably for the speakers
Focal
JMLab Chorus 714V Power handling 130W max (90W nom) Sensitivity
91dB)

An orchestra even in the auditorium can peak at over 120dB.

Do you have a reference for this? I have been looking for credible
sources for peak orchestral SPLs in the auditorium for a long while.

I have quite a few health & safety measurements of very good
credibility
inside the orchestra and a few at the conductor's rostrum. However I
have only semi-credible figures for places in the auditorium and they
only go up to 109 dB SPL.

--
John Phillips



Funny that - and I'm not psychic. Before I finished reading the first
paragraph of your reply the number 109 was in my mind. Then I read the
second paragraph.... we must have read the same comic at some time (I
have one of those memories for numbers.)


--
Woody

harrogate three at ntlworld dot com

In article , Eeyore rabbitsfriendsandrel
scribeth thus


tony sayer wrote:

Eeyore scribeth thus
tony sayer wrote:
Eeyore scribeth thus
tony sayer wrote:

I reckon you'd be well pushed to improve of the Audiolab excellent
amplifier even at 20 years old)..

You must be living in a very weird world then. Its design is utterly
'agricultural' by today's standards. It's barely any better than a decent
semiconductor manufacturer's application note of that era. Frankly it's a
joke. Plus any one you can find will need total re-capping of the
electrolytics.

Graham (pro-audio designer with 37 yrs experience)

Bet you'd be hard pressed to tell one apart in a listening test!..

No perhaps not.. their prolly too neutral for your linking;!...

If you want neutral you need one of my ultra-performance mosfet designs. The
actual'amp block' has a THD+N of 0.0008% @ 1 kHz (SINAD -103dB) measured on
an AP
with a residual THD+N of 0.0007% ! That 'back calculates' to a true THD of
0.0004%
(SINAD -108dB). The response is VERY flat too. About -0.2dB @ 10 Hz and 20kHz
IIRC.

Oh and I designed it about 19 years ago.

Sadly, the figure is degraded by the op-amp front end (5532s) ! But I could
replace these with LME49720s instead.

Humm...

I Wonder how may pro recording bits of gear are around with 5532's..

Just about most of it in current use.

Did you check the spec of the LME49720 ?
http://www.national.com/pf/LM/LME49720.html

They had to devise a special method to measure the THD without the noise
dominating.
They're not even that shockingly expensive.

Shockingly enough in small quantities;!...

Graham

Wonder what Doc Martin would have to say;?...
--
Tony Sayer

In article , Eeyore rabbitsfriendsandrela
scribeth thus


Jim Lesurf wrote:

Eeyore wrote:
Jim Lesurf wrote:

For some reason I have come to be wary of claims thrown around on the
basis of being a "well known fact".

http://www.musicalfidelity.com/produ..._response.html

" We know for a fact that concert hall peak sound pressure level (SPL)
for a medium sized symphony orchestra is 109-110dB. For a big symphony
orchestra or rock concert the levels are much higher."

Interesting that he seems able to narrow down all orchestras to a 1dB range
like that. Reminiscent of the way undergrads sometimes write down a lab
experiment result to as many significant figures as their hand calculator
displays - regardless of having input figures only roughly accurate. :-)

I also still have my natty copy of the 'sliderule' he had sent out with one
issue of HFN. This seems to imply I should change to a more powerful amp. I
confess seeing this was one of the things that prompted my curiosity and
lead to the HFN article I mentioned. Like yourself, I suspect, I've spent
far more hours than any sane person should watching a scope display, etc,
of power amp output whilst playing music to see what demands the music
waveforms place on the amp and speakers.

My personal conclusion was that his sliderule rather over-egged how much
amplifier power I'd need for my domestic use. However my listening room is
somewhat smaller than the Royal Festival Hall... ;-

As I wrote, it seems common for people to make assertions on the basis of
"we know that", or "everyone knows that". But alas making such a claim does
not automatically make an assertion true. Of course, that doesn't make it
false, either.

And the nearer you sit !

...although of course since you mentioned nearfield versus farfield in
another posting you will doubtless be aware that this does not always
follow the 1/r^2 law you might expect from school physics books. :-)

Like John Phillips I've seen assertions about this on many occasions.
However also like him, I can't recall seeing reliable peak measurement
values. Although I do recall reading recently the old article by JC I can't
currently remember which back-issue this was, or what values her got.

The peaks may well reach 120dB [1], that seems quite possible to me. But
plausible assumptions or assertions aren't actually measured results. As I
explained, I've seen all kinds of claims made by people on the "everyone
knows" basis, and have become wary of simply believing everything I'm told.
Up to you what you believe, but I'd prefer evidence when possible.

Slainte,

Jim

[1] You might apply your own "reference what?" question here, BTW. :-)

Seems to be tricky to find anything actually.

This mic has a max input SPL of 134dB which receives the comment "Hi-SPL
handling is perfect for suspension over choirs and orchestras"

http://www.dv247.com/invt/11582/

Graham



Can't say any prom or other concert I've been to this year was "that"
loud and most we're quite quiet..
--
Tony Sayer

In article
s.com, scribeth thus


Jim Lesurf wrote:
However if your audiolab seems to you not to clip or overheat I doubt you
will have a problem with most other = 50Wpc amps in terms of power unless
your speakers drop to low impedance. The 8000 series tends to have pokey
small heatsinks[1], but can IIRC deliver reasonably high peak currents.

Above said, I haven't yet seen you say anything that makes me feel you
would benefit from a new amp. Except perhaps in the way of feeling pleased
to own and use a newer and - allegedly - 'better' one.

Well the phono sockets needed replacing 18 months ago - I'd like an
amp with sockets which don't self destruct.

Phileas

Wonder if that was a poor batch none of mine are duff at all!...
--
Tony Sayer

In article , Eeyore wrote:


Rob wrote:

Eeyore wrote:
Once only wrote:
wrote in message

If all (properly designed) amps sound the same, how do I decide which
amp to buy?

Is it just a case of choosing one with sufficient power output and how
do I determine this?

No, thats not true - the myth of long wire with gain.
Amplifiers can have very similar specs but have different
sonic characters and abilities.
Bandwidth and an amps ability to pump out the amperes
when fronted with an awkward load etc etc etc.
If I were you the first thing is to not pay too much attention
to the big girls blouses of this group.
Do yourself a favour, don't heed mag reviewers advice either.
Try the pre-owned market, plenty of stereo bargains to be had.
This is just one example, the Pioneer A400 was a huge success
because of it ultra wide stable bandwidth (5 - 100) and it's
impressive ability to drive any loudspeaker and remain stable -
thats the ability to churn out amperes!
It sold by the truck load and often crops up in the for sale ads,
and it is proven to be a rugged longstander, can be picked up
for less than £100. But then there are others, Nad, and even Sony
from the late 80's and early 90's.
First port of call believe it or not would be Cash Converters,
then the specialist pre-owned dealers, then the small ads.
Once you've found a model, look it up!
Don't bother with Naim or Arcam, over-priced and nothing
special.

But don't buy antiques. No matter how well they were supposed to sound. All
the electrolytic caps will need replacing and standards weren't as high
then.
Modern amplifiers are much better on the whole.

cross-posted intentionally to rec.audio tech

I have a 20 year old (at least) NAD 3020 - works perfectly but sounds
distinctly soft/mellow compared to a newish SS amp, and indeed an even
older Pioneer receiver. Is this a symptom of old caps, and/or poor design?

I know the 3020 moderately well. It was very well regarded (and designed - I
fact I
met the designer) and should still sound at least decent today. At that age,
recapping the electrolytic caps specifically is likely to be a good move.
Especially if you're competent with a soldering iron yourself or have a friend
who
is. The parts won't cost much.

I have gone over many amps, and its really rare that I would need to replace
the main caps. Many times the smaller caps will go bad. If I were really
going over an amp in every detail, if I had plenty of time, then I might
check the main caps, or even buffer them. Its likely an amp will sound
just fine if not driven hard with lossy main caps. If it can obtain max
power with resonable distortion then I would not touch the main caps.

greg



You don't have the 'soft clip' engaged do you ? That would make it mellower.
Also
clean ALL the input and output sockets. Damn RCA / phono / Cinch crap !

Funnily enough, around the time of the 3020 I nearly worked as a designer for
NAD.
The deal breaker was that I wanted to do it on contract and they wanted me full
time. I can still remember the excellent lunch they took me out for btw ! Super
Italian.

Graham

On Tue, 14 Oct 2008 21:06:34 +0100, tony sayer
wrote:

In article , Eeyore rabbitsfriendsandrel
scribeth thus


tony sayer wrote:

Eeyore scribeth thus
tony sayer wrote:
Eeyore scribeth thus
tony sayer wrote:

I reckon you'd be well pushed to improve of the Audiolab excellent
amplifier even at 20 years old)..

You must be living in a very weird world then. Its design is utterly
'agricultural' by today's standards. It's barely any better than a decent
semiconductor manufacturer's application note of that era. Frankly it's a
joke. Plus any one you can find will need total re-capping of the
electrolytics.

Graham (pro-audio designer with 37 yrs experience)

Bet you'd be hard pressed to tell one apart in a listening test!..

No perhaps not.. their prolly too neutral for your linking;!...

If you want neutral you need one of my ultra-performance mosfet designs. The
actual'amp block' has a THD+N of 0.0008% @ 1 kHz (SINAD -103dB) measured on
an AP
with a residual THD+N of 0.0007% ! That 'back calculates' to a true THD of
0.0004%
(SINAD -108dB). The response is VERY flat too. About -0.2dB @ 10 Hz and 20kHz
IIRC.

Oh and I designed it about 19 years ago.

Sadly, the figure is degraded by the op-amp front end (5532s) ! But I could
replace these with LME49720s instead.

Humm...

I Wonder how may pro recording bits of gear are around with 5532's..

Just about most of it in current use.


Are they at all similar to 5534's? Sure I used them in a phono
pre-amp in the 80's, copied out of a R. A. Penfold book.


Marky P.

On Tue, 14 Oct 2008 19:23:19 +0200, (Martin
Schöön) wrote:

Eeyore writes:

Rob wrote:

I have a 20 year old (at least) NAD 3020 - works perfectly but sounds
distinctly soft/mellow compared to a newish SS amp, and indeed an even
older Pioneer receiver. Is this a symptom of old caps, and/or poor design?

I know the 3020 moderately well. It was very well regarded (and designed - I fact I
met the designer) and should still sound at least decent today. At that age,
recapping the electrolytic caps specifically is likely to be a good move.
Especially if you're competent with a soldering iron yourself or have a friend who
is. The parts won't cost much.

So true.

Some ten years ago I did this to a ten plus but not quite twenty years
old amp (not NAD) and the improvement was a jaw dropper.

I replaced all the caps in my 1960 Wurlitzer amp. Made a world of
difference.

Marky P.

In article , Marky P
scribeth thus
On Tue, 14 Oct 2008 21:06:34 +0100, tony sayer
wrote:

In article , Eeyore rabbitsfriendsandrel
scribeth thus


tony sayer wrote:

Eeyore scribeth thus
tony sayer wrote:
Eeyore scribeth thus
tony sayer wrote:

I reckon you'd be well pushed to improve of the Audiolab excellent
amplifier even at 20 years old)..

You must be living in a very weird world then. Its design is utterly
'agricultural' by today's standards. It's barely any better than a
decent
semiconductor manufacturer's application note of that era. Frankly it's
a
joke. Plus any one you can find will need total re-capping of the
electrolytics.

Graham (pro-audio designer with 37 yrs experience)

Bet you'd be hard pressed to tell one apart in a listening test!..

No perhaps not.. their prolly too neutral for your linking;!...

If you want neutral you need one of my ultra-performance mosfet designs.
The
actual'amp block' has a THD+N of 0.0008% @ 1 kHz (SINAD -103dB) measured on
an AP
with a residual THD+N of 0.0007% ! That 'back calculates' to a true THD of
0.0004%
(SINAD -108dB). The response is VERY flat too. About -0.2dB @ 10 Hz and
20kHz
IIRC.

Oh and I designed it about 19 years ago.

Sadly, the figure is degraded by the op-amp front end (5532s) ! But I could
replace these with LME49720s instead.

Humm...

I Wonder how may pro recording bits of gear are around with 5532's..

Just about most of it in current use.


Are they at all similar to 5534's? Sure I used them in a phono
pre-amp in the 80's, copied out of a R. A. Penfold book.


Marky P.

Ones a single and ones a dual i.e. two Op amps in the one package and
apart form some silly buggers usage their excellent chips for most all
applications...
--
Tony Sayer

tony sayer wrote:
In article
s.com, scribeth thus

Jim Lesurf wrote:
However if your audiolab seems to you not to clip or overheat I doubt you
will have a problem with most other = 50Wpc amps in terms of power unless
your speakers drop to low impedance. The 8000 series tends to have pokey
small heatsinks[1], but can IIRC deliver reasonably high peak currents.

Above said, I haven't yet seen you say anything that makes me feel you
would benefit from a new amp. Except perhaps in the way of feeling pleased
to own and use a newer and - allegedly - 'better' one.

Well the phono sockets needed replacing 18 months ago - I'd like an
amp with sockets which don't self destruct.

Phileas

Wonder if that was a poor batch none of mine are duff at all!...

I believe it's a common problem with 8000As.

John Phillips wrote:

Eeyore wrote:
John Phillips wrote:
Eeyore wrote:
wrote:
Jim Lesurf wrote:

It would depend on various factors: What kind of music you like. How large
your listening room is. What speakers you will be using. etc.

Classical music - not excessively loudly but of course orchestral
climaxes can be loud.
Digital sources - not vinyl.
Room 11' x 13' x 8' high (rather small probably for the speakers Focal
JMLab Chorus 714V Power handling 130W max (90W nom) Sensitivity 91dB)

An orchestra even in the auditorium can peak at over 120dB.

Do you have a reference for this? I have been looking for credible
sources for peak orchestral SPLs in the auditorium for a long while.

It's a 'well known fact' amongst audio professionals. Google it.

I have indeed Googled it rather extensively. What I mostly see is
unsupported assertion that seems to have been copied without question
from unsupported sources. I have seen no good, well-documented evidence.
This is why I am interested in asking.

I have quite a few health & safety measurements of very good credibility
inside the orchestra and a few at the conductor's rostrum.

In other words completely useless because they haven't the tiniest clue what
they're measuring. Thankfully or even orchestras would have to be banned from
playing for HSE reasons.

You have it quite wrong. The H&S reports (typically for North American
orchestras) are not always perfect but they usually are good enough
at specifying the instrument and what it was set to measure.

If they're anything like our HSE, they only ever measure dBA, which is absurdly wrong
at high volume levels.

I assume you know why ?


On the credibility scale they rate generally well. I am happy to accept peak
levels inside the orchestra well on the eye-watering side of 130 dB SPL.

Very likely.


However while these are good enough measurements for checking musicians'
exposure to sound, they don't give the positional data for source and
measurement to allow projection to levels in the auditorium.

It's complex for 101 reasons.


However I have only semi-credible figures for places in the auditorium and they
only go up to 109 dB SPL.

Undoubtedly averaged not peak.


A or C weighted on fast or slow response ? The average dB meter is about as useful
as a wet blanket when measuring either impulses or frankly most music. There is no
correlation between industrial hearing damage levels as measured by a typical dB
meter and music because the waveforms and wavefronts are WILDLY different.

Good questions - these are exactly why I am not happy with the
"semi-credible" source in question. BTW this particular source was the
one Musical Fidelity used in the advertising that's been brought up later
in this thread. And used by HFN in its fairly recent "how much power do
you need" articles.

So, at the risk of giving offence I am afraid I am still not prepared to
assign any credibility to unsupported assertions of "well known fact".
For exactly the reasons you state. That's why I am still interested in
seeking credible, well supported data.

I only wish I could quote you a Studio Sound article of about 30 years ago.

As I said audio-pros understand it.

Graham