In article , Dave
xxxx wrote:
Derrick Fawsitt wrote:
I have just acquired Quad 989's Electrostatic Speakers

[snip]

They are designed for the Quad II-forties and QC 24 pre amplifier

I am not sure that was the case. Although the combination might sound fine
I'd note a few points:

1) The II-40 has a nominal power of 40wpc. This nominally translates into
17.8 Vrms and 25 Vpk for an assumed 8 Ohm tap. This is well below the
maximum which the 989 can accept. This means the combination will be
'safe', but not be able to reach the same peak sound levels as a more
powerful amp.

2) The II-40 has an output impedance of 0.4 Ohms. Given that the 989 has an
impedance that drops to just below 4 Ohms at some frequencies this may
cause a change in the response of the order of 1dB in the region around
10kHz and below 30Hz.

3) I don't have a value for the peak currents the II-40 can provide.
However unless it is significantly higher than implied by (1) the actual
levels may be further restricted when the signals have components in the
regions where the impedance of the 989 dips down well below 8 Ohms.

Hence although the combination may sound fine, the above factors can be
expected to have some impact on the results. If you only ever play music at
low levels, the above may not matter.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

On Fri, 06 Jan 2006 09:39:54 +0000 (GMT), Jim Lesurf
wrote:

In article , Dave
xxxx wrote:
Derrick Fawsitt wrote:
I have just acquired Quad 989's Electrostatic Speakers

[snip]

They are designed for the Quad II-forties and QC 24 pre amplifier

Absolute garbage! That combination is nowhere near capable of
extracting everything that the 989 is capable of delivering -
especially as it's valved.......................

I am not sure that was the case. Although the combination might sound fine
I'd note a few points:

1) The II-40 has a nominal power of 40wpc. This nominally translates into
17.8 Vrms and 25 Vpk for an assumed 8 Ohm tap. This is well below the
maximum which the 989 can accept. This means the combination will be
'safe', but not be able to reach the same peak sound levels as a more
powerful amp.

Quite so - and one of the basic tenets of the 989 is that it has
significantly more dynamic range than the '63.

2) The II-40 has an output impedance of 0.4 Ohms. Given that the 989 has an
impedance that drops to just below 4 Ohms at some frequencies this may
cause a change in the response of the order of 1dB in the region around
10kHz and below 30Hz.

Indeed so - although to be fair, I doubt that this will be of audible
significance for most listeners in most rooms. Still, it *is* a flaw
in a supposedly high-fidelity system, from one of the premium
engineering-led brands.

3) I don't have a value for the peak currents the II-40 can provide.
However unless it is significantly higher than implied by (1) the actual
levels may be further restricted when the signals have components in the
regions where the impedance of the 989 dips down well below 8 Ohms.

Indeed, current delivery is the Achilles heel of almost all valve
amps.

Hence although the combination may sound fine, the above factors can be
expected to have some impact on the results. If you only ever play music at
low levels, the above may not matter.

But you'll still get better results from any half-decent 60-watt SS
amplifier, of which there are dozens of excellent examples around, for
a fraction of the cost of the nostalgia-driven II-40.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Stewart Pinkerton wrote:
Absolute garbage! That combination is nowhere near capable of
extracting everything that the 989 is capable of delivering -
especially as it's valved.......................

That From the guy with **** for brains

The guy who built the Quad amps the design team of the speakers the
service department all say they work ok, and I think there point of
view is going to hold more sway. than your rantings

now I have used 57 63 988 speakers

with Quad 405 405-2 606 606 mark2 909 Quad II-forties

Various low powered Croft valve amplifiers pre and power

now you can sit there and do all the sums you want but when it gets
down to the proper testing

which for the stupid is using mark one ears

the 988 with Quad II-forties sound very nice

On Fri, 06 Jan 2006 21:47:24 GMT, " Dave xxxx"
wrote:

Stewart Pinkerton wrote:
Absolute garbage! That combination is nowhere near capable of
extracting everything that the 989 is capable of delivering -
especially as it's valved.......................

That From the guy with **** for brains

The guy who built the Quad amps the design team of the speakers the
service department all say they work ok, and I think there point of
view is going to hold more sway. than your rantings

Working 'OK' is not the same as driving to their full potential, you
twit. You think Quad people are going to say that their most expensive
amplfier does *not* work 'OK' with their most expensive speaker?

now I have used 57 63 988 speakers
with Quad 405 405-2 606 606 mark2 909 Quad II-forties
Various low powered Croft valve amplifiers pre and power
now you can sit there and do all the sums you want but when it gets
down to the proper testing

which for the stupid is using mark one ears

the 988 with Quad II-forties sound very nice

I'm sure they do - which has nothing to do with getting the *best* out
of the 989. For that, you need a good SS amp, such as the 909.

989 - 909, hmm, you think they might be designed to work together?

Anyone in possession of a functioning brain is well aware that the
II-40 is simply a cynical cashing in on the famous Quad II name, which
would never have been sanctioned by Peter Walker. He was a *real*
engineer, and always moved forward with his designs, never backward.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Stewart Pinkerton wrote:
Anyone in possession of a functioning brain

got me there got lesions on my brain


is well aware that the

II-40 is simply a cynical cashing in on the famous Quad II name,
which
would never have been sanctioned by Peter Walker.

He was still alive and very happy with the match as he had heard them
together, he was not in a postion to sanction it as company belongs to
IAG.
It was made by Andy Grove and is really just a big Quad II in fact so
close a copy early ones built in Bradford before production was moved
to China had the same problems early original Quad II had with
resistors.


He was a *real*
engineer, and always moved forward with his designs, never backward.

yes he was a real engineer and did always move forward with
designs............. but not long before he died I asked someone who
had just been to dinner with him

"What system he was using" ? I was shocked by the answer it was not
valve and not made by Quad it was a Sony type midi system lol

if you look at a Quad II-forty looks just like a Quad II (inside)
picture of inside
http://www.davewhitter.pwp.blueyonder.co.uk/quadc.jpg




--
Dave
www.davewhitter.myby.co.uk

Music is Art - Audio is Engineering
Steam is Fun

Dave xxxx wrote:

It was made by Andy Grove and is really just a big Quad II in fact so
close a copy early ones built in Bradford before production was moved
to China had the same problems early original Quad II had with
resistors.

That is dedication! Why didn't they copy a later model Quad II?
What were the problems?

People here have criticised Chinese transformers.
They (maybe not the same ones) have said that original Quad OPTs were
amongst the best.
So can we get Chinese transformers from the same factory that Quad does?

--
Eiron

I have no spirit to play with you; your dearth of judgment renders you
tedious - Ben Jonson.

In message , Eiron
writes
Dave xxxx wrote:

It was made by Andy Grove and is really just a big Quad II in fact so
close a copy early ones built in Bradford before production was moved
to China had the same problems early original Quad II had with resistors.

That is dedication! Why didn't they copy a later model Quad II?
What were the problems?

People here have criticised Chinese transformers.
They (maybe not the same ones) have said that original Quad OPTs were
amongst the best.
So can we get Chinese transformers from the same factory that Quad does?


Ahem!! I am still here, sorry to interrupt this fascinating thread but
unfortunately as a non "techie" I am lost by the abbreviations (OPT's
etc., etc.), but can understand the "gist" of the arguments. However, as
the originator of this thread, I would like to interject here to ask a
supplementary question while all you so knowledgeable people are
assembled, simply assuming you choose the best possible option to drive
the Quad 989's, what do you think of them in relation to the vast
legions of "moving coil" speakers out there. Yes I know it eventually
boils down to personal choice but as someone who is about to fork out
£5000 (sterling) for a pair I would appreciate some vindication of my
choice before I sign the dotted line. I have a pair on demo and frankly
I am stunned by the sound of the speakers, am I imagining this or have I
got possibly the best speakers around, especially for classical music.
--
Derrick Fawsitt

Eiron wrote:

That is dedication! Why didn't they copy a later model Quad II?
What were the problems?


The problems was the resisitors where not flame proof and on short
legs, if you look at the picture on my web site you can see the two
flame proof resistors on long legs. (big white ones)

www.davewhitter.pwp.blueyonder.co.uk/quadc.jpg

On Sat, 07 Jan 2006 13:40:58 +0000, Eiron wrote:

Dave xxxx wrote:

It was made by Andy Grove and is really just a big Quad II in fact so
close a copy early ones built in Bradford before production was moved
to China had the same problems early original Quad II had with
resistors.

That is dedication! Why didn't they copy a later model Quad II?
What were the problems?

People here have criticised Chinese transformers.
They (maybe not the same ones) have said that original Quad OPTs were
amongst the best.
So can we get Chinese transformers from the same factory that Quad does?

That would involve a major assumption - that the modern OPTs are of
the same quality as those used in the original Quad amps.

--

Stewart Pinkerton | Music is Art - Audio is Engineering

" Dave xxxx" wrote in message
. uk...
Stewart Pinkerton wrote:
Anyone in possession of a functioning brain

got me there got lesions on my brain


is well aware that the

II-40 is simply a cynical cashing in on the famous Quad II name,
which
would never have been sanctioned by Peter Walker.

He was still alive and very happy with the match as he had heard them
together, he was not in a postion to sanction it as company belongs to
IAG.
It was made by Andy Grove and is really just a big Quad II in fact so
close a copy early ones built in Bradford before production was moved
to China had the same problems early original Quad II had with
resistors.


He was a *real*
engineer, and always moved forward with his designs, never backward.

yes he was a real engineer and did always move forward with
designs............. but not long before he died I asked someone who
had just been to dinner with him

"What system he was using" ? I was shocked by the answer it was not
valve and not made by Quad it was a Sony type midi system lol

if you look at a Quad II-forty looks just like a Quad II (inside)
picture of inside
http://www.davewhitter.pwp.blueyonder.co.uk/quadc.jpg

Well I beg to differ. The Quad II innards look nothing like the II-40 unless
of course you've butchered your Quad II's to make them look the same as the
II-40. For a start the wiring loom (a.k.a. dogs breakfast) would not pass
muster compared to the original.
I guess if you were Tony Blair's spin doctor you could say they were to all
intents & purposes the same as they both have wire, a circuit board and some
components.........