"tony sayer" wrote in message


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

Tons and tons.

But 5532s used right are really very good pieces, even by modern standards.
And for the price...!

The scarier part is how may pro recording bits of gear are around with
TL074s, or even NJM4558s in the signal path.

On Oct 15, 8:52*am, Jim Lesurf wrote:
I'm not sure that phono-socket lifetime is a spec you will find quoted for
most amps. :-) *Why did they need replacing?


The plastic body just fell apart. It wasn't as if I kept plugging
things in and out.
I do leave the amp on continuously - could this have an effect?

Phileas

tony sayer wrote:
In article , Anton Gÿsen
scribeth thus
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.

Well I've got Four of them and their all fine;!...

This site:

http://www.theaudiocellar.co.uk/

specialises in, amongst other things, RCA socket replacements for
Audiolab 8000As.

I can't comment on 8000As because I have a new model 8000S.

Funnily enough we've got four Band 1 transmitters , yes those
frequencies are still used, and the cores in one have all disintegrated
away whereas in the other their fine all about the same age!..

What is it that fails, the plastic moulding?..

I think so but I'm not sure. I've seen a couple on eBay which have been
damaged in transit, so be careful if you ever move yours.

wrote:
On Oct 15, 8:52 am, Jim Lesurf wrote:
I'm not sure that phono-socket lifetime is a spec you will find quoted for
most amps. :-) Why did they need replacing?


The plastic body just fell apart. It wasn't as if I kept plugging
things in and out.
I do leave the amp on continuously - could this have an effect?

I doubt it, if anything, heating up and then cooling down again would be
more likely to damage it.

Like I said, it's a common problem, if that make you feel any better.

tony sayer wrote:

Eeyore scribeth thus
tony sayer wrote:
Eeyore scribeth thus

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;!...

From the likes of Farnell maybe £4 seems a lot but compare that to a $400 wooden
volume control knob !
http://uk.farnell.com/1367613/semico...roduct.us0?sku
=national-semiconductor-lme49720ma-nopb&_requestid=131459

That's only £2 per divine op-amp !

What were those $150 ones for then?..

Evaluation boards I think ?


Wonder what Doc Martin would have to say;?...

You lost me

Him of Neve descent, didn't you work together once?..

DOC ? Martin ? I knew a Martin forget his surname who was in R&D.

Not Martin (M.H) (Hartley) Jones PhD you mean ? He'd left by the time I arrived. I
later did some work for him at Kelvin Hughes radar. Lovely chap. I still talk to him
very occasionally. In fact I was just on the point of asking if he'd be happy to be a
reference on my CV !
http://www.ibd-uk.com/members/jones-martin.htm

Graham

tony sayer wrote:

Eeyore scribeth thus
Robert Orban wrote:
says...

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/

Try this:

Dynamic-Range Requirement for Subjectively Noise-Free Reproduction of Music
JAES Volume 30 Issue 7/8 pp. 504-511; August 1982

A dynamic range of up to 118 dB is determined necessary for subjectively
noise-free reproeuction of music in an audio recorder with a white-noise
floor. Maximum peak sound-pressure levels in music are compared to the minimum
discernible level of white noise in a quiet listening situation. Microphone
noise limitations, monitoring loudspeaker capabilities, and performance
environment noise levels are also considered.

Author: Fielder, Louis D.
Affiliation: Ampex Corporation, Redwood City, CA

Well, I never imagined I'd have Bob Orban backing me up on a technical issue !

Thanks Bob !

Graham

Him being the one who will be criticised on other groups for making DAB
and FM ever more distorted;!...
--
Tony Sayer

You can't win 'em all !

Graham

Jim Lesurf wrote:

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

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.

Some time ago John Crabbe reported published work in which listeners'
perception of the same absolute loudness was rather different when
they were listening in a large concert hall compared to a domestic
listening room. This would suggest you do indeed need less in SPL
terms at home than you get in the auditorium.

Because the nearfield and farfield are closer at home.

You may be confusing cause and effect with a situation where the same
mechanism is causing two effects. :-)

How large is your living room ?

I can assure you it'll be an issue for many Americans. ;~)

Graham

In article
,
wrote:
On Oct 15, 8:52 am, Jim Lesurf wrote:
I'm not sure that phono-socket lifetime is a spec you will find quoted
for most amps. :-) Why did they need replacing?


The plastic body just fell apart. It wasn't as if I kept plugging things
in and out.

Interesting. Some polymers do deteriorate or change size shape with time. I
recently had problems with an ancient cartridge where the plastic body had
altered so the contact pins were loose.

I do leave the amp on continuously - could this have an effect?

Not sure. When I get a chance I'll try seeing if the ones of the 8000 I
have have a similar problem, but they seemed OK when I last checked.

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Jim Lesurf wrote:

Eeyore wrote:
Marky P wrote:
tony sayer wrote:

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.

Yes, they're the dual version and about 3dB noisier although not quite
sure why.

Not knowing why, my immediate suspicion was substrate noise caused by
having two lots of bias currents. But that is just a spur of the moment
guess. :-)

FWIW I came to prefer the HA12017 as a general purpose audio op-amp. But I
appreciate this is quite a weird choice.

Weird isn't the word for it. ;~)

Ever come across NJM 4560s, 4580s or 2068s ? From JRC/NJR (New Japan Radio
Company). Not at all bad and the 4560 doesn't burn as much current but is a bit
noiser than 5532s but still around TL07x levels.

Btw - don't EVER confuse the NJM4562 with the LM4562. Someone dropped a minor
clanger there and I think it was National, why is why the same device
(apparently) turns up as the LME49720 as well.

Graham

Jim Lesurf wrote:

Robert Orban wrote:

..and there's also this, which explicitly references peak level
measurements:

Pre- and Postemphasis Techniques as Applied to Audio Recording Systems
JAES Volume 33 Issue 9 pp. 649-658; September 1985

Thanks for the above. I've now had a chance to have a quick read-though of
it. I've probably missed things, and would need to check some of its
references, but my initial reactions were...

Firstly, that the levels reported are somewhat larger than asserted by
others elsewhere - e.g. already in this thread is values from MF. This
tends to support my suspicion that people assert numbers which may be
misleading if they don't actually know where they came from at origin.
Hence my preference for measured results. :-)

I wonder how that may relate to the following.

Secondly, that the paper doesn't give any real details of the peak meter
used. For example, not the bandwidth when 'flat', nor the response times of
the peak function. e.g. no value for underread of something like a
bandwidth-limited impulse. This might well affect results, but hard to say
more without any details.

Fast track and hold would be the only viable method.

Graham