Armstrong 600 era
 

Just to let people know I've put up a new webpage at

http://www.audiomisc.co.uk/Armstrong...iliconEra.html

This documents the 1973-4 period when they released the 600 range and it
got a lot of attention. Can be interesting to compare reviews to see when
they agree and when they conflict. :-)

FWIW I'm planning two more pages.

One to deal with the 1975-1985 period which covers the dissapearance of
Armstrong as a manufacturer. This is actually quite a complex set of events
so needs a lot of details. Also covers more reviews of the 600 and those of
the 700 amps, what happened with the tuner, etc. In some ways its also a
history of what went wrong in UK manufacturing and how equipment was
reviewed and sold by retailers, etc. Some skeletons will be dug up, and
oddities in 'reviews' examined. 8-]

The other page is to document more extensively the 'radio chassis era' from
1932 to about 1960. During this period Armstrong made a lot of different
models, some without their name or logo on the front! I'm still working
though old references, magazines, etc, to sort this out!

However I'm also doing some work to try and build a decent website for the
Museum of Communication, so it will take a while to do the above pages.

Cheers,

Jim

--
Please use the address on the audiomisc page 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

Armstrong 600 era
 

On 2015-11-08 12:21:20 +0000, Jim Lesurf said:

Just to let people know I've put up a new webpage at

http://www.audiomisc.co.uk/Armstrong...iliconEra.html

This documents the 1973-4 period when they released the 600 range and it
got a lot of attention. Can be interesting to compare reviews to see when
they agree and when they conflict. :-)

FWIW I'm planning two more pages.

One to deal with the 1975-1985 period which covers the dissapearance of
Armstrong as a manufacturer. This is actually quite a complex set of events
so needs a lot of details. Also covers more reviews of the 600 and those of
the 700 amps, what happened with the tuner, etc. In some ways its also a
history of what went wrong in UK manufacturing and how equipment was
reviewed and sold by retailers, etc. Some skeletons will be dug up, and
oddities in 'reviews' examined. 8-]

The other page is to document more extensively the 'radio chassis era' from
1932 to about 1960. During this period Armstrong made a lot of different
models, some without their name or logo on the front! I'm still working
though old references, magazines, etc, to sort this out!

However I'm also doing some work to try and build a decent website for the
Museum of Communication, so it will take a while to do the above pages.

Cheers,

Jim

Search and replace "arid" by "and" - a typical OCR error?

I like like idea of the secondary feedback loop to make the
capacitor-coupled output impedance less reactive at low frequencies.

Arthur

--
real email arthur at bellacat dot com

Armstrong 600 era
 

In article , Arthur Quinn
wrote:

Search and replace "arid" by "and" - a typical OCR error?

Sorry, I thought I'd corrected that! Yes, the text was done via OCR, which
did give errors like that. Spend some time reading and correcting. But must
have missed one (or more)...

I like like idea of the secondary feedback loop to make the
capacitor-coupled output impedance less reactive at low frequencies.

It wasn't a new idea entirely as IIRC some valve amps used the same trick
to reduce the effects of output transformer imperfections. The challenge is
to apply 'just the right amount'. Particularly in the days when batches of
'the same' transistor varied wildly in their properties.

Jim

--
Please use the address on the audiomisc page 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

Armstrong 600 era
 

On 08/11/2015 12:21, Jim Lesurf wrote:
Just to let people know I've put up a new webpage at

http://www.audiomisc.co.uk/Armstrong...iliconEra.html

This documents the 1973-4 period when they released the 600 range and it
got a lot of attention. Can be interesting to compare reviews to see when
they agree and when they conflict. :-)

FWIW I'm planning two more pages.

One to deal with the 1975-1985 period which covers the dissapearance of
Armstrong as a manufacturer. This is actually quite a complex set of events
so needs a lot of details. Also covers more reviews of the 600 and those of
the 700 amps, what happened with the tuner, etc. In some ways its also a
history of what went wrong in UK manufacturing and how equipment was
reviewed and sold by retailers, etc. Some skeletons will be dug up, and
oddities in 'reviews' examined. 8-]

The other page is to document more extensively the 'radio chassis era' from
1932 to about 1960. During this period Armstrong made a lot of different
models, some without their name or logo on the front! I'm still working
though old references, magazines, etc, to sort this out!

However I'm also doing some work to try and build a decent website for the
Museum of Communication, so it will take a while to do the above pages.



Below is a quote from your page at
http://www.audiomisc.co.uk/Armstrong...airandmod.html
'And listening to Radio 3 or 4 using the FM tuner demonstrates how much
nicer these can sound via FM than via DAB.'
I quite agree but would you say this is a result of the low bit rate the
bbc uses or is an indication of the inherent superiority of analogue vs
digital sound reproduction?

Armstrong 600 era
 

Jim Lesurf wrote:

Arthur Quinn
+

I like like idea of the secondary feedback loop to make the
capacitor-coupled output impedance less reactive at low frequencies.

It wasn't a new idea entirely as IIRC some valve amps used the same trick
to reduce the effects of output transformer imperfections. The challenge is
to apply 'just the right amount'.


** Taking some or even all NFB from the speaker side of the output capacitor was pretty common with amplifiers using one DC supply. Doing so however raises the issue of low frequency instability.

I recall seeing a Kenwood solid state receiver of late 60s vintage that when connected to a Philips 8 inch low resonance woofer ( AD8065) slowly went into oscillation at about 3Hz.

The trick was to use only a judicious amount OR have a capacitor or two internally rolling off the gain of the power stage at low frequencies - as is done with most valve amps.


.... Phil

Armstrong 600 era
 

In article . com,
Albert
Zweistein wrote:



Below is a quote from your page at
http://www.audiomisc.co.uk/Armstrong...airandmod.html 'And
listening to Radio 3 or 4 using the FM tuner demonstrates how much
nicer these can sound via FM than via DAB.' I quite agree but would you
say this is a result of the low bit rate the bbc uses or is an
indication of the inherent superiority of analogue vs digital sound
reproduction?

Alas I can't give a simple yes/no answer to that question because there are
a number of differences between FM and DAB in practice. Couple of examples:

FM tends to add some low order distortion, and also intermod, particularly
for stereo. Caused by the limited bandwidth, etc.

BBC FM has *level* compression applied in a different way to DAB. So the
dynamics are likely to be different. My impression is that this tends to
make the FM sound 'warmer' as it acts a bit like a 'sustain' pedel.

I assume the use of low bitrates contributes, but the result comes from
combining many differences. Overall, though I find listening to R3 FM from
the 626's tuner sounds more 'relaxed' or 'natural' than from a 'Pure' DAB
tuner though the 626 amp sections.

That said, in practice most of my serious R3/4 listening these days tends
to be via using get_iplayer to obtain the files and play them. The 626
produces nice sounds from these as well.

FWIW my other systems use Armstrong 700 amps and Quad ESLs.

Jim

--
Please use the address on the audiomisc page 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

Armstrong 600 era
 

On 2015-11-09 05:14:30 +0000, Phil Allison said:

Jim Lesurf wrote:

Arthur Quinn
+

I like like idea of the secondary feedback loop to make the
capacitor-coupled output impedance less reactive at low frequencies.

It wasn't a new idea entirely as IIRC some valve amps used the same trick
to reduce the effects of output transformer imperfections. The challenge is
to apply 'just the right amount'.


** Taking some or even all NFB from the speaker side of the output
capacitor was pretty common with amplifiers using one DC supply. Doing
so however raises the issue of low frequency instability.

I recall seeing a Kenwood solid state receiver of late 60s vintage that
when connected to a Philips 8 inch low resonance woofer ( AD8065)
slowly went into oscillation at about 3Hz.

The trick was to use only a judicious amount OR have a capacitor or two
internally rolling off the gain of the power stage at low frequencies
- as is done with most valve amps.


... Phil

Yes, the review says of the damping factor that "from about 2Hz to 50Hz
it tends towards slightly negative and infinity", implying that the
resistive component of the amplifier output impedance passes through
zero to negative within that frequency range. Oviously the negative
resistance will have been made much smaller than the expected
loudspeaker resistance to ensure stability.

Arthur

--
real email arthur at bellacat dot com

Armstrong 600 era
 

In article , Arthur Quinn
wrote:
Yes, the review says of the damping factor that "from about 2Hz to 50Hz
it tends towards slightly negative and infinity", implying that the
resistive component of the amplifier output impedance passes through
zero to negative within that frequency range. Oviously the negative
resistance will have been made much smaller than the expected
loudspeaker resistance to ensure stability.

May be worth adding that for the 600 amp the relevant capacitor values,
etc, were changed more than once during the period of manufacture. But in
all the cases I know of the results always gave negative output impedance
magnitudes well below an Ohm. So weren't a problem in general use.

There was sometimes a more devious problem, though. This was due to the use
(in early versions of the 600) of a resistor put into the dc rail feed to
limit the current inrush at switch-on.

After a few seconds this resistor was bypassed by a thermally operated
switch. However before that - or if that switch failed - the low output
impedance and flat LF response could cause the set's output to wag up and
down at LF. Wasn't good for the amp or speakers, and also could cause the
lamps to keep fading up and down! The effect was similar to the
'motorboating' others may know from amps driven by unsuitable power
supplies when the amp has an awkward load.

The problem wasn't common in use, but showed up particularly on speakers
with a very low near-d.c. impedance. It did cause some people to say the
600 wasn't 'stable' with electrostatics, but the problem was actually this
LF interaction with the power supply when the inrush resistor was in the
way. Not the classic HF bursting into song of an amp unstable into a
capacitive load.

FWIW in later sets I reduced the feedback at LF and also increased the
reservoir and output capacitors. So the results relied less on the feedback
from the speaker side of the output caps. I also removed the thermal switch
and just used a mains diode bridge that wasn't bothered by the switch on
inrush. Simpler all around. But to be fair, when the 600 amp was originally
designs, the components I used weren't available. So Ted did the best he
could with what was available at the time. I could simplify things because
I could find the components to do it!

Components improved a *lot* over th 1970s and into the 1980s. You only have
to compare a 1970 'ab' volume pot with a 1980 Alps 40mm one to see what
amazing changes were made.

Jim

--
Please use the address on the audiomisc page 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

Armstrong 600 era
 

In article . com,
Albert Zweistein wrote:
'And listening to Radio 3 or 4 using the FM tuner demonstrates how much
nicer these can sound via FM than via DAB.'
I quite agree but would you say this is a result of the low bit rate the
bbc uses or is an indication of the inherent superiority of analogue vs
digital sound reproduction?

Think you'll find that pretty well all of the chain from microphone to
transmitter is digital these days.

It's a very sad fact that it's all to easy to mess up a perfectly good
digital signal by simply reducing the data rate at the point of
transmission. They've done that with both radio and TV.

And don't even get me started on phones... ;-)

--
*Husband and cat lost -- reward for cat

Dave Plowman London SW
To e-mail, change noise into sound.

Armstrong 600 era
 

In article , Dave Plowman (News)
wrote:
In article . com,
Albert Zweistein wrote:
'And listening to Radio 3 or 4 using the FM tuner demonstrates how
much nicer these can sound via FM than via DAB.' I quite agree but
would you say this is a result of the low bit rate the bbc uses or is
an indication of the inherent superiority of analogue vs digital
sound reproduction?

Think you'll find that pretty well all of the chain from microphone to
transmitter is digital these days.

Indeed. And so far as I know, the BBC still use NICAM for the distribution
for FM. Hence it is digital with a 32k sample rate and less than 16 bits
per sample. So nominally 'worse than Audio CD'. Yet can sound fine. People
ceased being able to hear an all-analogue FM chain decades ago.

Jim

--
Please use the address on the audiomisc page 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

Armstrong 600 era
 

Arthur Quinn wrote:


** Taking some or even all NFB from the speaker side of the output
capacitor was pretty common with amplifiers using one DC supply. Doing
so however raises the issue of low frequency instability.

I recall seeing a Kenwood solid state receiver of late 60s vintage that
when connected to a Philips 8 inch low resonance woofer ( AD8065)
slowly went into oscillation at about 3Hz.

The trick was to use only a judicious amount OR have a capacitor or two
internally rolling off the gain of the power stage at low frequencies
- as is done with most valve amps.



Yes, the review says of the damping factor that "from about 2Hz to 50Hz
it tends towards slightly negative and infinity", implying that the
resistive component of the amplifier output impedance passes through
zero to negative within that frequency range.


** The get such test results implies the amplifier was being driven at its output with a varying frequency of known current while watching the voltage and phase at the terminals. It's a powerful technique that not many reviewers ever used.

BTW

The output stage of the 626 has very similar topology to the 40watt design published in the Philips "Audio Amplifier Systems" application book of 1970 - minus the regulated PSU.


..... Phil

Armstrong 600 era
 

On 09/11/2015 15:03, Dave Plowman (News) wrote:
In article . com,
Albert Zweistein wrote:
'And listening to Radio 3 or 4 using the FM tuner demonstrates how much
nicer these can sound via FM than via DAB.'
I quite agree but would you say this is a result of the low bit rate the
bbc uses or is an indication of the inherent superiority of analogue vs
digital sound reproduction?

Think you'll find that pretty well all of the chain from microphone to
transmitter is digital these days.

It's a very sad fact that it's all to easy to mess up a perfectly good
digital signal by simply reducing the data rate at the point of
transmission. They've done that with both radio and TV.


Yes reducing the transmission bitrate is easy to do and a lot of people
working in the industry who *should* know better either don't or don't
seem to care. Come the revolution I'll have them all shot. :(

Armstrong 600 era
 

On 09/11/2015 16:52, Jim Lesurf wrote:


Indeed. And so far as I know, the BBC still use NICAM for the distribution
for FM. Hence it is digital with a 32k sample rate and less than 16 bits
per sample. So nominally 'worse than Audio CD'. Yet can sound fine. People
ceased being able to hear an all-analogue FM chain decades ago.

Maybe fewer than 16 bits but it's almost a floating point encoding
so gives better resolution at low levels than you might think.

--
Eiron.

Armstrong 600 era
 

In article ,
Jim Lesurf wrote:
Indeed. And so far as I know, the BBC still use NICAM for the
distribution for FM. Hence it is digital with a 32k sample rate and less
than 16 bits per sample. So nominally 'worse than Audio CD'. Yet can
sound fine.

Dunno, Jim. The transmission side of the BBC was out sourced many years
ago. So may have changed things to commercial PCM equipment for
distribution too.

--
*Just give me chocolate and nobody gets hurt

Dave Plowman London SW
To e-mail, change noise into sound.

Armstrong 600 era
 

In article . com,
Albert Zweistein wrote:
It's a very sad fact that it's all to easy to mess up a perfectly good
digital signal by simply reducing the data rate at the point of
transmission. They've done that with both radio and TV.


Yes reducing the transmission bitrate is easy to do and a lot of people
working in the industry who *should* know better either don't or don't
seem to care. Come the revolution I'll have them all shot. :(

It's not really up to those working in the industry. More a government
thing on how bandwidth is allocated. The more channels, the higher the
taxes.

--
*I don't feel old. I don't feel anything until noon. Then it's time for my nap.

Dave Plowman London SW
To e-mail, change noise into sound.

Armstrong 600 era
 

In article , Dave Plowman (News)
wrote:
In article , Jim Lesurf
wrote:
Indeed. And so far as I know, the BBC still use NICAM for the
distribution for FM. Hence it is digital with a 32k sample rate and
less than 16 bits per sample. So nominally 'worse than Audio CD'. Yet
can sound fine.

Dunno, Jim. The transmission side of the BBC was out sourced many years
ago. So may have changed things to commercial PCM equipment for
distribution too.

That's possible, yes. I've asked in the past but never been able to find
out for sure. Although more than one BBC person has told me they think it
still is NICAM for FM distribution.

Jim

--
Please use the address on the audiomisc page 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

Armstrong 600 era
 

In article , Eiron
wrote:

Indeed. And so far as I know, the BBC still use NICAM for the
distribution for FM. Hence it is digital with a 32k sample rate and
less than 16 bits per sample. So nominally 'worse than Audio CD'. Yet
can sound fine. People ceased being able to hear an all-analogue FM
chain decades ago.

Maybe fewer than 16 bits but it's almost a floating point encoding so
gives better resolution at low levels than you might think.

Yes, this may help people who've not checked it out.

http://www.audiomisc.co.uk/BBC/PCMandNICAM/History.html

Jim

--
Please use the address on the audiomisc page 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

Armstrong 600 era
 

In article ,
Jim Lesurf wrote:
Dunno, Jim. The transmission side of the BBC was out sourced many years
ago. So may have changed things to commercial PCM equipment for
distribution too.

That's possible, yes. I've asked in the past but never been able to find
out for sure. Although more than one BBC person has told me they think it
still is NICAM for FM distribution.

The equipment would be getting on a bit by now. ;-) The department that
designed and had such things made was axed many years ago. But it could be
possible.

--
*Middle age is when work is a lot less fun - and fun a lot more work.

Dave Plowman London SW
To e-mail, change noise into sound.

Armstrong 600 era
 

In article , Dave Plowman (News)
wrote:
In article , Jim Lesurf
wrote:
Dunno, Jim. The transmission side of the BBC was out sourced many
years ago. So may have changed things to commercial PCM equipment
for distribution too.

That's possible, yes. I've asked in the past but never been able to
find out for sure. Although more than one BBC person has told me they
think it still is NICAM for FM distribution.

The equipment would be getting on a bit by now. ;-) The department that
designed and had such things made was axed many years ago. But it could
be possible.

The people who designed FM are probably also now all dead. :-)

Jim

--
Please use the address on the audiomisc page 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

Armstrong 600 era
 

In article . com,
Albert Zweistein scribeth thus
On 08/11/2015 12:21, Jim Lesurf wrote:
Just to let people know I've put up a new webpage at

http://www.audiomisc.co.uk/Armstrong...iliconEra.html

This documents the 1973-4 period when they released the 600 range and it
got a lot of attention. Can be interesting to compare reviews to see when
they agree and when they conflict. :-)

FWIW I'm planning two more pages.

One to deal with the 1975-1985 period which covers the dissapearance of
Armstrong as a manufacturer. This is actually quite a complex set of events
so needs a lot of details. Also covers more reviews of the 600 and those of
the 700 amps, what happened with the tuner, etc. In some ways its also a
history of what went wrong in UK manufacturing and how equipment was
reviewed and sold by retailers, etc. Some skeletons will be dug up, and
oddities in 'reviews' examined. 8-]

The other page is to document more extensively the 'radio chassis era' from
1932 to about 1960. During this period Armstrong made a lot of different
models, some without their name or logo on the front! I'm still working
though old references, magazines, etc, to sort this out!

However I'm also doing some work to try and build a decent website for the
Museum of Communication, so it will take a while to do the above pages.



Below is a quote from your page at
http://www.audiomisc.co.uk/Armstrong...airandmod.html
'And listening to Radio 3 or 4 using the FM tuner demonstrates how much
nicer these can sound via FM than via DAB.'
I quite agree but would you say this is a result of the low bit rate the
bbc uses or is an indication of the inherent superiority of analogue vs
digital sound reproduction?


Around the best these days is the high rate net feed.

FM is still processed apart from the limitations of the FM system and I
think at the moment BBC R3 DAB is at 160 K instead of the 192K it ought
to be at!.

--
Tony Sayer

Armstrong 600 era
 

On 17/11/2015 20:53, tony sayer wrote:
In article . com,
Albert Zweistein scribeth thus
On 08/11/2015 12:21, Jim Lesurf wrote:
Just to let people know I've put up a new webpage at

http://www.audiomisc.co.uk/Armstrong...iliconEra.html

This documents the 1973-4 period when they released the 600 range and it
got a lot of attention. Can be interesting to compare reviews to see when
they agree and when they conflict. :-)

FWIW I'm planning two more pages.

One to deal with the 1975-1985 period which covers the dissapearance of
Armstrong as a manufacturer. This is actually quite a complex set of events
so needs a lot of details. Also covers more reviews of the 600 and those of
the 700 amps, what happened with the tuner, etc. In some ways its also a
history of what went wrong in UK manufacturing and how equipment was
reviewed and sold by retailers, etc. Some skeletons will be dug up, and
oddities in 'reviews' examined. 8-]

The other page is to document more extensively the 'radio chassis era' from
1932 to about 1960. During this period Armstrong made a lot of different
models, some without their name or logo on the front! I'm still working
though old references, magazines, etc, to sort this out!

However I'm also doing some work to try and build a decent website for the
Museum of Communication, so it will take a while to do the above pages.



Below is a quote from your page at
http://www.audiomisc.co.uk/Armstrong...airandmod.html
'And listening to Radio 3 or 4 using the FM tuner demonstrates how much
nicer these can sound via FM than via DAB.'
I quite agree but would you say this is a result of the low bit rate the
bbc uses or is an indication of the inherent superiority of analogue vs
digital sound reproduction?


Around the best these days is the high rate net feed.

FM is still processed apart from the limitations of the FM system and I
think at the moment BBC R3 DAB is at 160 K instead of the 192K it ought
to be at!.

Penny pinching at the BBC so the bosses can pay themselves inflated
salaries...come the revolution etc.

Armstrong 600 era
 

On 09/11/2015 08:59, Jim Lesurf wrote:
In article . com,
Albert
Zweistein wrote:



Below is a quote from your page at
http://www.audiomisc.co.uk/Armstrong...airandmod.html 'And
listening to Radio 3 or 4 using the FM tuner demonstrates how much
nicer these can sound via FM than via DAB.' I quite agree but would you
say this is a result of the low bit rate the bbc uses or is an
indication of the inherent superiority of analogue vs digital sound
reproduction?

Alas I can't give a simple yes/no answer to that question because there are
a number of differences between FM and DAB in practice. Couple of examples:

FM tends to add some low order distortion, and also intermod, particularly
for stereo. Caused by the limited bandwidth, etc.

BBC FM has *level* compression applied in a different way to DAB. So the
dynamics are likely to be different. My impression is that this tends to
make the FM sound 'warmer' as it acts a bit like a 'sustain' pedel.


I wonder why human ears prefer the sound of a bit of 'sustain'? I
certainly do.

Armstrong 600 era
 

In article . com,
Albert Zweistein wrote:
On 09/11/2015 08:59, Jim Lesurf wrote:
In article . com,
Albert
Zweistein wrote:



Below is a quote from your page at
http://www.audiomisc.co.uk/Armstrong...airandmod.html
'And listening to Radio 3 or 4 using the FM tuner demonstrates how
much nicer these can sound via FM than via DAB.' I quite agree but
would you say this is a result of the low bit rate the bbc uses or is
an indication of the inherent superiority of analogue vs digital
sound reproduction?

Alas I can't give a simple yes/no answer to that question because
there are a number of differences between FM and DAB in practice.
Couple of examples:

FM tends to add some low order distortion, and also intermod,
particularly for stereo. Caused by the limited bandwidth, etc.

BBC FM has *level* compression applied in a different way to DAB. So
the dynamics are likely to be different. My impression is that this
tends to make the FM sound 'warmer' as it acts a bit like a 'sustain'
pedel.


I wonder why human ears prefer the sound of a bit of 'sustain'? I
certainly do.

Have a mate who constantly goes on about how much better FM is than
digital.

So set up a test for him. Three tuners all on R3 - one FM, one DAB, one
Freeview. Levels carefully balanced. A long silent pause when switching
between them - so the delay on digital didn't give the game away.

He failed miserably to distinguish which was which. ;-)

--
*The last thing I want to do is hurt you. But it's still on my list.

Dave Plowman London SW
To e-mail, change noise into sound.

Armstrong 600 era
 

In message , "Dave Plowman (News)"
writes

So set up a test for him. Three tuners all on R3 - one FM, one DAB, one
Freeview. Levels carefully balanced. A long silent pause when switching
between them - so the delay on digital didn't give the game away.

He failed miserably to distinguish which was which. ;-)

Without wishing to be deliberately provocative, I think that result
applies to many tests, such as LPs/CDs, valves/solid state etc. Whilst
accepting that there are those with finely tuned ears who will pass the
test, I'm quite sure I wouldn't.

Recent fun has been resurrecting my turntable (TD125/SME3009) and having
great fun playing LPs that I have not duplicated on CD, and have not
heard for too many years. However, were I to play the same album on
vinyl and CD, I doubt I could tell the difference.
--
Graeme

Armstrong 600 era
 

In article , News
wrote:

Recent fun has been resurrecting my turntable (TD125/SME3009) and having
great fun playing LPs that I have not duplicated on CD, and have not
heard for too many years. However, were I to play the same album on
vinyl and CD, I doubt I could tell the difference.

Depends on the LP/CD. e.g. Many rock/pop CDs of recent years have been
level-compressed heavily compared to their earlier LP versions. The
challenge would be to find CDs that haven't been mucked about like this
compared with the LP.

And alas, many early CDs may have been very badly made in other ways.

The problem with arguments about the 'inherent' audible differences is the
ways in which the music biz fouls up real world examples of both LPs and
CDs. Means the playing field isn't flat.

Jim

--
Please use the address on the audiomisc page 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

Armstrong 600 era
 

On 27/11/2015 13:13, News wrote:
In message , "Dave Plowman (News)"
writes

So set up a test for him. Three tuners all on R3 - one FM, one DAB, one
Freeview. Levels carefully balanced. A long silent pause when switching
between them - so the delay on digital didn't give the game away.

He failed miserably to distinguish which was which. ;-)

Without wishing to be deliberately provocative, I think that result
applies to many tests, such as LPs/CDs, valves/solid state etc. Whilst
accepting that there are those with finely tuned ears who will pass the
test, I'm quite sure I wouldn't.


No, I'd agree. Partly training, partly hearing, partly stress. And
doubtless a variety of other factors contribute to such tests and their
'truths'.

Recent fun has been resurrecting my turntable (TD125/SME3009) and having
great fun playing LPs that I have not duplicated on CD, and have not
heard for too many years. However, were I to play the same album on
vinyl and CD, I doubt I could tell the difference.

Ooh, not sure about that :-)

--
Cheers, Rob

Armstrong 600 era
 

On 27/11/2015 15:52, RJH wrote:
On 27/11/2015 13:13, News wrote:
In message , "Dave Plowman (News)"
writes

So set up a test for him. Three tuners all on R3 - one FM, one DAB, one
Freeview. Levels carefully balanced. A long silent pause when switching
between them - so the delay on digital didn't give the game away.

He failed miserably to distinguish which was which. ;-)

Without wishing to be deliberately provocative, I think that result
applies to many tests, such as LPs/CDs, valves/solid state etc. Whilst
accepting that there are those with finely tuned ears who will pass the
test, I'm quite sure I wouldn't.


No, I'd agree. Partly training, partly hearing, partly stress. And
doubtless a variety of other factors contribute to such tests and their
'truths'.

Recent fun has been resurrecting my turntable (TD125/SME3009) and having
great fun playing LPs that I have not duplicated on CD, and have not
heard for too many years. However, were I to play the same album on
vinyl and CD, I doubt I could tell the difference.

Ooh, not sure about that :-)

I'd have thought the snap crackle and pop would give one away. Not that
I've owned or listened to a vinyl player for about 35 years so maybe the
new ones have some anti-snaclepop built-in.

Armstrong 600 era
 

In article ,
News wrote:
Recent fun has been resurrecting my turntable (TD125/SME3009) and having
great fun playing LPs that I have not duplicated on CD, and have not
heard for too many years. However, were I to play the same album on
vinyl and CD, I doubt I could tell the difference.

It's usually easiest towards the end of an LP where the lower velocity
between disc and stylus shows up the inherent problems rather more.

--
*CAN VEGETARIANS EAT ANIMAL CRACKERS?

Dave Plowman London SW
To e-mail, change noise into sound.

Armstrong 600 era
 

On 28/11/2015 00:32, Dave Plowman (News) wrote:
In article ,
News wrote:
Recent fun has been resurrecting my turntable (TD125/SME3009) and having
great fun playing LPs that I have not duplicated on CD, and have not
heard for too many years. However, were I to play the same album on
vinyl and CD, I doubt I could tell the difference.

It's usually easiest towards the end of an LP where the lower velocity
between disc and stylus shows up the inherent problems rather more.


Don't follow that - I'd have thought the distance travelled would be
less, but the disc speed the same? Actually, having written that I start
to get it (disc/stylus-time/distance), but I thought the inner groove
thing was related to tracking anomalies caused by the geometry of the
various bits.

Anyhoo, and FWIW, I've found that 'inner groove' poor quality sound
could be all but solved by certain types of cartridge. Not sure why/how,
but in my case an AT 440, and AT OC5

--
Cheers, Rob

Armstrong 600 era
 

In article , RJH
wrote:
[snip inner groove distortion]

Don't follow that - I'd have thought the distance travelled would be
less, but the disc speed the same? Actually, having written that I start
to get it (disc/stylus-time/distance), but I thought the inner groove
thing was related to tracking anomalies caused by the geometry of the
various bits.

It occurs for both reasons. In principle, you can deal with the tracking
geometry with something like a parallel-tracking or articulated arm. But
the groove 'wavelength' for a given frequency still reduces as you get
nearer the center as the actual velocity (in m/s) falls. Thus the wall
curvature increases and 'pinches' the stylus.

Anyhoo, and FWIW, I've found that 'inner groove' poor quality sound
could be all but solved by certain types of cartridge. Not sure why/how,
but in my case an AT 440, and AT OC5

Stylus shape is critical here. And also being able to track at low playing
weight to avoid groove deformation for the best shapes in geometric terms.
These don't prevent a rise in end-of-side distortion, but can reduce how
severe it becomes.

Its a shame none of the current hifi mags ever print full explanations of
such 'technical' issues. I've been going though my early Hi Fi News issues
putting together a searchable index.[1] And they are full of careful and
detailed explanations of such matters. Alas the work by Kelly, Crabbe,
Walton, etc, seem to be long out-of-print. Maybe time for a new book or
some reprints.

Also, the old mags had lots of DIY/constructional features which - even if
you never built them - are a mine for info for anyone wanting to understand
such details. Again, such things are hen's teeth these days. :-/

Editor's seem to have decided that such things would frighten off
wooden-header readers. Personally, I suspect some would be put off, but new
readers would be attracted.

Jim

[1] If anyone wants a copy there is a zip of a csv version here
http://jcgl.orpheusweb.co.uk/temp/HiFiNewsIndex7.zip
As yet only up to volume 7 and I lack most of volume 1. But I am
slowly adding more volumes.

--
Please use the address on the audiomisc page 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

Armstrong 600 era
 

In article , Huge
wrote:

Editor's seem to have decided that such things would frighten off
wooden-header readers. Personally, I suspect some would be put off,
but new readers would be attracted.

I fear you are wrong. Building things at home is dying (which is why the
DIY sheds are closing stores). Young people these days don't even know
how to change a fuse.

That's always been true for a large section of people. However the RPi has
been a spectacular success and hackspaces have grown. So when you consider
the small size of the number of 'hi fi enthusiasts" I suspect a magazine
could attract people who'd prefer to DIY and learn how things work rather
than pay 1,000 quid for mains cables. You only need to sell to a small
percentage of the UK population to make a monthly mag a success. Question
of which particular audience you're going for.

The problem at present is, I suspect, reader 'surveys' that by their nature
only cover the preferences of *existing* readers.

My speakers are "A no-compromise loudspeaker for the home constructor"
from HFN&RR around 1980-ish (possibly). Sadly, I seem to have lost the
magazine.

I probably have the issue, but off-hand don't know the speakers.

Jim

--
Please use the address on the audiomisc page 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

Armstrong 600 era
 

In article , Jim Lesurf
wrote:
I suspect a magazine could attract people who'd prefer to DIY and learn
how things work rather than pay 1,000 quid for mains cables. You only
need to sell to a small percentage of the UK population to make a
monthly mag a success. Question of which particular audience you're
going for.

Occurs to me to add: I've noticed an increasing tendency for people to
write to magazines, etc, asking for help with computer-based audio. And
that the magazines tend to be a bit shy of this topic. "Ooo! Too
complicated, we're not a computer mag." Which again seems a weird fear of
DIY to me given that the same mags often praise the quality of high rez
files. Again the assumption seems to be that such files are dealt with via
expensive closed dedidcated consumer devices. Not by the user learning or
doing anything.

Stark contrast to earlier decades. And I can't help feeling that a magazine
that *did* deal with these matters with enthusiam might well gain readers.

Jim

--
Please use the address on the audiomisc page 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

Armstrong 600 era
 

On 28/11/2015 11:46, Huge wrote:
On 2015-11-28, Jim Lesurf wrote:
In article , Huge
wrote:

[19 lines snipped]

My speakers are "A no-compromise loudspeaker for the home constructor"

... built by yours truly ...

from HFN&RR around 1980-ish (possibly). Sadly, I seem to have lost the
magazine.

I probably have the issue, but off-hand don't know the speakers.

If you came across the issue (IIRC, it was on the front cover), I'd
cheerfully swap a photocopy for a bottle of something nice!

Although I'm still mulling over buying a pair of Quad ESLs. I'm about
to move into a house with a very big lounge, so I could probably fit
them in.


You can describe your speakers though. What drivers, crossover and
enclosure type?

ESLs are not for the faint-hearted. :-)

--
Eiron.

Armstrong 600 era
 

On 28/11/2015 12:02, Huge wrote:
On 2015-11-28, Eiron wrote:
On 28/11/2015 11:46, Huge wrote:
On 2015-11-28, Jim Lesurf wrote:
In article , Huge
wrote:

[19 lines snipped]

My speakers are "A no-compromise loudspeaker for the home constructor"

... built by yours truly ...

from HFN&RR around 1980-ish (possibly). Sadly, I seem to have lost the
magazine.

I probably have the issue, but off-hand don't know the speakers.

If you came across the issue (IIRC, it was on the front cover), I'd
cheerfully swap a photocopy for a bottle of something nice!

Although I'm still mulling over buying a pair of Quad ESLs. I'm about
to move into a house with a very big lounge, so I could probably fit
them in.


You can describe your speakers though. What drivers, crossover and
enclosure type?

That's why I want the article. I made them nearly 30 years ago, and
can't really remember what's in them, other than they're sealed box (aka
"infinite baffle") with two enclosures (one bass, one mid-range) in the
same box. The bass, midrange and treble drivers are KEF and I can't
recall the supertweeter manufacturer. (Nor indeed, hear it any more,
I suspect). The crossover is home-made from the design in the article
with components supplied by Wilmslow Audio.

They stand nearly 4ft tall and weigh a great deal, since they're lined
with concrete. It was amusing to watch the removal man trying to pick
one up, the last time we moved house.

Here's a transmission line from the mid seventies with the standard issue
Wilmslow Audio KEF drivers and supertweeter.
http://p10hifi.net/planet10/TLS/downloads/Pro9TL-1.pdf
The crossover and drivers might well be the same.

--
Eiron.

Armstrong 600 era
 

On 28/11/2015 11:09, Jim Lesurf wrote:
In article , Jim Lesurf
wrote:
I suspect a magazine could attract people who'd prefer to DIY and learn
how things work rather than pay 1,000 quid for mains cables. You only
need to sell to a small percentage of the UK population to make a
monthly mag a success. Question of which particular audience you're
going for.

Occurs to me to add: I've noticed an increasing tendency for people to
write to magazines, etc, asking for help with computer-based audio. And
that the magazines tend to be a bit shy of this topic. "Ooo! Too
complicated, we're not a computer mag." Which again seems a weird fear of
DIY to me given that the same mags often praise the quality of high rez
files. Again the assumption seems to be that such files are dealt with via
expensive closed dedidcated consumer devices. Not by the user learning or
doing anything.

Stark contrast to earlier decades. And I can't help feeling that a magazine
that *did* deal with these matters with enthusiam might well gain readers.


I've been quite intrigued by some of the Raspberry Pi projects. If I get
some spare time (not likely right now), I'll have a go at a media server
and connect it to my NAS. 3 things:

1. I'm not that sure about the hardware - the Pi itself, and the DAC -
in objective terms. Would they be as good as, say, the Cambridge NP30 I use?

2. The interface, box, knobs, remote. This is something I am interested
in - making it look good and easy to use.

3. The software. I use 3 'apps' to control the NP30 - each do slightly
different things I like - proper listing (ignoring 'The' prefix for
example), playlist creation, and an ability to not crash. I have a
feeling there'd be steep learning curve, but it's probably this more
than anything that'd motivate.

(1) I'm not that bothered about, and there's plenty of blog and wiki
type resources for support.

(2) and (3) I'm not so sure of.

--
Cheers, Rob

Armstrong 600 era
 

In article , RJH
wrote:

I've been quite intrigued by some of the Raspberry Pi projects. If I get
some spare time (not likely right now), I'll have a go at a media
server and connect it to my NAS. 3 things:

1. I'm not that sure about the hardware - the Pi itself, and the DAC -
in objective terms. Would they be as good as, say, the Cambridge NP30 I
use?

IIRC someone like Woolfson make an excellent decidcated RPi ADC/DAC. But
beyond that I couldn't say if the 'Pi's own DACs would match something
else. Never even had an RPi.

2. The interface, box, knobs, remote. This is something I am interested
in - making it look good and easy to use.

3. The software. I use 3 'apps' to control the NP30 - each do slightly
different things I like - proper listing (ignoring 'The' prefix for
example), playlist creation, and an ability to not crash. I have a
feeling there'd be steep learning curve, but it's probably this more
than anything that'd motivate.

(1) I'm not that bothered about, and there's plenty of blog and wiki
type resources for support.

(2) and (3) I'm not so sure of.

I'd also check if the system is using Pulse Audio. That can be the kiss of
death for good audio. The developers are obsessed with 'mixing' all streams
to a nailed-to-the-wall sample rate and bit depth. And it can be a real
PITA to control, despite the claims. Devil in various details.

In a recent Linux mag I read a smug comment that Pulse now has excellent
mixer software for good audio. Erm. My Oxymoron alert buzzed. Good audio
means *avoiding* any software resamplings you can avoid. Particularly ones
you can't check or control.

Jim

--
Please use the address on the audiomisc page 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

Armstrong 600 era
 

On 28/11/2015 11:46, Huge wrote:

Although I'm still mulling over buying a pair of Quad ESLs. I'm about
to move into a house with a very big lounge, so I could probably fit
them in.

By a strange coincidence I looked in my local bazaar today;
it had a 303 (£150) and a pair of 57s (£400).
I managed to resist temptation.

The proprietors have no idea of marketing as these were hidden away
in different corners of the shop and not connected up.
Or maybe they were defective so playing music through them would
deter the punters.

--
Eiron.

Armstrong 600 era
 

In article ,
Eiron wrote:
On 28/11/2015 11:46, Huge wrote:

Although I'm still mulling over buying a pair of Quad ESLs. I'm about
to move into a house with a very big lounge, so I could probably fit
them in.

By a strange coincidence I looked in my local bazaar today;
it had a 303 (£150) and a pair of 57s (£400).
I managed to resist temptation.

The proprietors have no idea of marketing as these were hidden away
in different corners of the shop and not connected up.
Or maybe they were defective so playing music through them would
deter the punters.

ESL 57 could well have faulty drivers etc if not recently serviced. Nice
though they are - assuming you don't need more than moderate levels.

--
*IF A PARSLEY FARMER IS SUED, CAN THEY GARNISH HIS WAGES?

Dave Plowman London SW
To e-mail, change noise into sound.

Armstrong 600 era
 

In article , Dave Plowman (News)
scribeth thus
In article . com,
Albert Zweistein wrote:
On 09/11/2015 08:59, Jim Lesurf wrote:
In article . com,
Albert
Zweistein wrote:



Below is a quote from your page at
http://www.audiomisc.co.uk/Armstrong...airandmod.html
'And listening to Radio 3 or 4 using the FM tuner demonstrates how
much nicer these can sound via FM than via DAB.' I quite agree but
would you say this is a result of the low bit rate the bbc uses or is
an indication of the inherent superiority of analogue vs digital
sound reproduction?

Alas I can't give a simple yes/no answer to that question because
there are a number of differences between FM and DAB in practice.
Couple of examples:

FM tends to add some low order distortion, and also intermod,
particularly for stereo. Caused by the limited bandwidth, etc.

BBC FM has *level* compression applied in a different way to DAB. So
the dynamics are likely to be different. My impression is that this
tends to make the FM sound 'warmer' as it acts a bit like a 'sustain'
pedel.


I wonder why human ears prefer the sound of a bit of 'sustain'? I
certainly do.

Have a mate who constantly goes on about how much better FM is than
digital.

So set up a test for him. Three tuners all on R3 - one FM, one DAB, one
Freeview. Levels carefully balanced. A long silent pause when switching
between them - so the delay on digital didn't give the game away.

He failed miserably to distinguish which was which. ;-)



He should get his hearing checked then!....

--
Tony Sayer

Armstrong 600 era
 

In message , "Dave Plowman (News)"
writes
In article ,
News wrote:

However, were I to play the same album on
vinyl and CD, I doubt I could tell the difference.

It's usually easiest towards the end of an LP where the lower velocity
between disc and stylus shows up the inherent problems rather more.

I must find an album I have on both vinyl and CD, and conduct a
listening test.

Back when I was young and single, I would arrange my speakers to match
my favourite sitting position but now, in a family environment, that
doesn't happen. Couple that with usually doing something else whilst
listening, aging ears and other noises within the house and I'm happy to
listen to mp3s played on a laptop and 'cast' to my amp. The next test
will be playing the same track on CD and mp3 and seeing whether I can
detect any difference.
--
Graeme