[Andre Jute[_2_]]

Time to return to tech-talk.

In a modest-sized room (by horn standards anyway) I want to rig up a
singleton of my modded semi-Fidelio bicor horns for Lowther PM6A. I
thought I'd do the monoing in a specially made 1 metre cable between
the CD player and the power amp.

The QUAD CD expects to see at least 10K impedance on its outputs.
Output of the CD player is 2Vrms and about 0.5Vrms of that is required
to drive the amp to enough power to handle the horns, so high value
resistors can be used in the monomaker if there is any advantage to be
gained.

However, the sound is NOT intended to be reprocessed as stereo
downstream (home installation, not studio); if I want stereo again,
i'll just plug in a stereo cable.

The pot on the integrated amp is probably (the board won't be here
until Tuesday and i can't read the spec on the piccie) 50K Alps but I
can replace it with a DACT of which I have a good selection of values.

So what value resistors would you use for monoing?

How many? Only two, or three?

With your choice of values, what can I expect to lose from the monoing
in bandwidth as distinct from gain?

Andre Jute
Visit Jute on Amps at
http://www.audio-talk.co.uk/fiultra/
"wonderfully well written and reasoned information for the tube audio
constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site containing vital gems of
wisdom"
Stuart Perry Hi-Fi News & Record Review

[Eiron]

On 05/09/2010 21:43, Andre Jute wrote:
Time to return to tech-talk.

In a modest-sized room (by horn standards anyway) I want to rig up a
singleton of my modded semi-Fidelio bicor horns for Lowther PM6A. I
thought I'd do the monoing in a specially made 1 metre cable between
the CD player and the power amp.

The QUAD CD expects to see at least 10K impedance on its outputs.
Output of the CD player is 2Vrms and about 0.5Vrms of that is required
to drive the amp to enough power to handle the horns, so high value
resistors can be used in the monomaker if there is any advantage to be
gained.

However, the sound is NOT intended to be reprocessed as stereo
downstream (home installation, not studio); if I want stereo again,
i'll just plug in a stereo cable.

The pot on the integrated amp is probably (the board won't be here
until Tuesday and i can't read the spec on the piccie) 50K Alps but I
can replace it with a DACT of which I have a good selection of values.

So what value resistors would you use for monoing?

How many? Only two, or three?

Is this a trick question? Surely the real McCoy would know the answer.
Whatever resistors are to hand in the junk box, or a couple of 12k and a
2k2 resistor.
But I would throw in an extra resistor and a capacitor to give some bass
boost.
The values would depend on the in-room LF response of the speakers.

--
Eiron.

[Eeyore[_4_]]

Andre Jute wrote:

The QUAD CD expects to see at least 10K impedance on its outputs.

I suspect you are misreading the spec. I expect that is the 'nominal'
load but I'd be VERY surprised if it can't drive a lower impedance.
Without schematics to hand I couldn't give a precise figure.

Graham

[Eeyore[_4_]]

Eiron wrote:

Is this a trick question? Surely the real McCoy would know the answer.

That thought crossed my mind too ! :-)

Graham

[Andre Jute[_2_]]

On Sep 6, 5:08*am, Eeyore
m wrote:
Andre Jute wrote:

The QUAD CD expects to see at least 10K impedance on its outputs.

I suspect you are misreading the spec. I expect that is the 'nominal'
load but I'd be VERY surprised if it can't drive a lower impedance.
Without schematics to hand I couldn't give a precise figure.

Graham

I'm sure the designer left himself some leeway, but the 10K is such a
well-known number, I didn't even bother looking it up. -- Andre Jute

[Andre Jute[_2_]]

On Sep 6, 5:10*am, Eeyore
m wrote:
Eiron wrote:

Is this a trick question? Surely the real McCoy would know the answer.

That thought crossed my mind too ! *:-)

Graham

I come back after years away, and it is still the same unpleasant
mutual masturbation society with the same inadequates stroking each
other. Dunno why I bother. -- AJ

[Eiron]

On 06/09/2010 05:16, Andre Jute wrote:
On Sep 6, 5:10 am, Eeyore
m wrote:
Eiron wrote:

Is this a trick question? Surely the real McCoy would know the answer.

That thought crossed my mind too ! :-)

Graham

I come back after years away, and it is still the same unpleasant
mutual masturbation society with the same inadequates stroking each
other. Dunno why I bother. -- AJ

You got an answer so I don't know what you're complaining about.
Why didn't you pose the dumb question as one of your puppets
as you used to do so you could join the thread later and pretend
you knew the answer all along?

I had a similar problem connecting a DVD player to a stereo amp,
trying to mix the centre channel into L and R as it doesn't have
an option to output plain stereo from a 5.1 source.
Two 10k and a couple of 20k resistors did the job.

--
Eiron.

[David Looser]

"Eiron" wrote

I had a similar problem connecting a DVD player to a stereo amp,
trying to mix the centre channel into L and R as it doesn't have
an option to output plain stereo from a 5.1 source.
Two 10k and a couple of 20k resistors did the job.


That's odd. I've never met a DVD player that would not provide a 2-channel
mix-down from a 5.1 source if set up to do so. Indeed many low-cost DVD
players only have 2 audio output sockets, so 2-channel mixed-down audio is
the only option unless you connect the digital output to an external DD/DTS
decoder.

Or was it that you wanted discrete surround channels and it was only the
centre speaker that you didn't have?

David.

[John Byrns]

In article
,
Andre Jute wrote:

Time to return to tech-talk.

In a modest-sized room (by horn standards anyway) I want to rig up a
singleton of my modded semi-Fidelio bicor horns for Lowther PM6A. I
thought I'd do the monoing in a specially made 1 metre cable between
the CD player and the power amp.

The QUAD CD expects to see at least 10K impedance on its outputs.
Output of the CD player is 2Vrms and about 0.5Vrms of that is required
to drive the amp to enough power to handle the horns, so high value
resistors can be used in the monomaker if there is any advantage to be
gained.

However, the sound is NOT intended to be reprocessed as stereo
downstream (home installation, not studio); if I want stereo again,
i'll just plug in a stereo cable.

The pot on the integrated amp is probably (the board won't be here
until Tuesday and i can't read the spec on the piccie) 50K Alps but I
can replace it with a DACT of which I have a good selection of values.

So what value resistors would you use for monoing?

How many? Only two, or three?

With your choice of values, what can I expect to lose from the monoing
in bandwidth as distinct from gain?

Hi Andre,

I would use two 12k resistors, connecting one to each of the two outputs
of the CD player, with the other ends of the two resistors tied together
to feed mono amp. I would place the resistors at the output end of the
cable to minimize phase shifts at the higher frequencies due to the
effects of cable capacitance, that is use a stereo cable right up to the
input of the mono amp where the mixing network is. The loss with this
arrangement will be minimal, with a mono signal of 2Vrms from each
channel of the CD player, you will see 1.79Vrms across a 50k amplifier
input resistance.

--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/

[Arny Krueger]

"Eeyore" m
wrote in message

Andre Jute wrote:

The QUAD CD expects to see at least 10K impedance on its
outputs.

I suspect you are misreading the spec. I expect that is
the 'nominal' load but I'd be VERY surprised if it can't
drive a lower impedance. Without schematics to hand I
couldn't give a precise figure.

For openers, the title "QUAD CD" does not describe a single piece of
equipment, or even a single family of related products. There are at two
families of Quad CD players, the 67 family and the 99 family. The Quad 99
series players further compound the situation by having two different sets
of outputs with very difference performance specs.

I suspect that Jute is basing his alleged specification on the standard IHFM
line level load which includes a 10K resistive component. If that's the case
then he's still in error because the proper way to address that load is with
a device that expects to see 10K or *less*.

[Ian Bell[_2_]]

Andre Jute wrote:
Time to return to tech-talk.

In a modest-sized room (by horn standards anyway) I want to rig up a
singleton of my modded semi-Fidelio bicor horns for Lowther PM6A. I
thought I'd do the monoing in a specially made 1 metre cable between
the CD player and the power amp.

The QUAD CD expects to see at least 10K impedance on its outputs.
Output of the CD player is 2Vrms and about 0.5Vrms of that is required
to drive the amp to enough power to handle the horns, so high value
resistors can be used in the monomaker if there is any advantage to be
gained.

However, the sound is NOT intended to be reprocessed as stereo
downstream (home installation, not studio); if I want stereo again,
i'll just plug in a stereo cable.

The pot on the integrated amp is probably (the board won't be here
until Tuesday and i can't read the spec on the piccie) 50K Alps but I
can replace it with a DACT of which I have a good selection of values.

So what value resistors would you use for monoing?

How many? Only two, or three?

With your choice of values, what can I expect to lose from the monoing
in bandwidth as distinct from gain?

Andre Jute
Visit Jute on Amps at
http://www.audio-talk.co.uk/fiultra/
"wonderfully well written and reasoned information for the tube audio
constructor"
John Broskie TubeCAD& GlassWare
"an unbelievably comprehensive web site containing vital gems of
wisdom"
Stuart Perry Hi-Fi News& Record Review
#

I would use 3 resistors, all 10K. I think you can guess how to wire them. The important thing is to
place them at the amp end.

Cheers

Ian

[Eiron]

On 06/09/2010 20:48, Ian Bell wrote:
Andre Jute wrote:
Time to return to tech-talk.

In a modest-sized room (by horn standards anyway) I want to rig up a
singleton of my modded semi-Fidelio bicor horns for Lowther PM6A. I
thought I'd do the monoing in a specially made 1 metre cable between
the CD player and the power amp.

The QUAD CD expects to see at least 10K impedance on its outputs.
Output of the CD player is 2Vrms and about 0.5Vrms of that is required
to drive the amp to enough power to handle the horns, so high value
resistors can be used in the monomaker if there is any advantage to be
gained.

However, the sound is NOT intended to be reprocessed as stereo
downstream (home installation, not studio); if I want stereo again,
i'll just plug in a stereo cable.

The pot on the integrated amp is probably (the board won't be here
until Tuesday and i can't read the spec on the piccie) 50K Alps but I
can replace it with a DACT of which I have a good selection of values.

So what value resistors would you use for monoing?

How many? Only two, or three?

With your choice of values, what can I expect to lose from the monoing
in bandwidth as distinct from gain?

Andre Jute
Visit Jute on Amps at
http://www.audio-talk.co.uk/fiultra/
"wonderfully well written and reasoned information for the tube audio
constructor"
John Broskie TubeCAD& GlassWare
"an unbelievably comprehensive web site containing vital gems of
wisdom"
Stuart Perry Hi-Fi News& Record Review
#

I would use 3 resistors, all 10K. I think you can guess how to wire
them. The important thing is to place them at the amp end.

Can't guess how to wire them to give the desired attenuation.

--
Eiron.

[Andre Jute[_2_]]

On Sep 6, 3:26*pm, "Arny Krueger" wrote:
"Eeyore" m
wrote in . com

Andre Jute wrote:
The QUAD CD expects to see at least 10K impedance on its
outputs.
I suspect you are misreading the spec. I expect that is
the 'nominal' load but I'd be VERY surprised if it can't
drive a lower impedance. Without schematics to hand I
couldn't give a precise figure.

For openers, the title "QUAD CD" *does not describe a single piece of
equipment, or even a single family of related products. There are at two
families of Quad CD players, *the 67 family and the 99 family. * The Quad 99
series players further compound the situation by having two different sets
of outputs with very difference performance specs.

I suspect that Jute is basing his alleged specification on the standard IHFM
line level load which includes a 10K resistive component. If that's the case
then he's still in error because the proper way to address that load is with
a device that expects to see 10K or *less*.

You're a blustering idiot, Krueger. This is from the QUAD official
literature of the CD66 and it states "10K minimum*: " Audio Output:
2Vrms maximum. 300mV on normal progamme material. Minimum load
impedance 10kR."

What part of "minimum load impedance 10KR" do you fail to understand,
Krueger?

We have three idiots pontificating about a simple number, which all
three have got it wrong -- but not one of them has bothered to look it
up! But meaningwhile these three morons are smacking their chops in
glee that someone else got it "wrong." How childish. No wonder these
newsgroups remain in intensive care.

Andre Jute
"The brain of an engineer is a delicate instrument which must be
protected against the unevenness of the ground." -- Wifredo-Pelayo
Ricart Medina

[Andre Jute[_2_]]

On Sep 6, 3:10*pm, John Byrns wrote:
In article
,
*Andre Jute wrote:





Time to return to tech-talk.

In a modest-sized room (by horn standards anyway) I want to rig up a
singleton of my modded semi-Fidelio bicor horns for Lowther PM6A. I
thought I'd do the monoing in a specially made 1 metre cable between
the CD player and the power amp.

The QUAD CD expects to see at least 10K impedance on its outputs.
Output of the CD player is 2Vrms and about 0.5Vrms of that is required
to drive the amp to enough power to handle the horns, so high value
resistors can be used in the monomaker if there is any advantage to be
gained.

However, the sound is NOT intended to be reprocessed as stereo
downstream (home installation, not studio); if I want stereo again,
i'll just plug in a stereo cable.

The pot on the integrated amp is probably (the board won't be here
until Tuesday and i can't read the spec on the piccie) 50K Alps but I
can replace it with a DACT of which I have a good selection of values.

So what value resistors would you use for monoing?

How many? Only two, or three?

With your choice of values, what can I expect to lose from the monoing
in bandwidth as distinct from gain?

Hi Andre,

I would use two 12k resistors, connecting one to each of the two outputs
of the CD player, with the other ends of the two resistors tied together
to feed mono amp. *I would place the resistors at the output end of the
cable to minimize phase shifts at the higher frequencies due to the
effects of cable capacitance, that is use a stereo cable right up to the
input of the mono amp where the mixing network is. *The loss with this
arrangement will be minimal, with a mono signal of 2Vrms from each
channel of the CD player, you will see 1.79Vrms across a 50k amplifier
input resistance.

--
Regards,

John Byrns

Surf my web pages at, *http://fmamradios.com/

Thanks, John. I have a couple of 15K resistors in my junkbox, so I
think I'll use them, at the power amp end of the cable -- good tip
that. I don't see that it matters if the output impedance is 7K5 as
there is no cable-length to drive. More on the amp when the
installation is finished.

Thanks to all who contributed.

Andre Jute
Visit Jute on Amps at
http://www.audio-talk.co.uk/fiultra/
"wonderfully well written and reasoned information for the tube audio
constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site containing vital gems of
wisdom"
Stuart Perry Hi-Fi News & Record Review

[Watt? Me worry?]

On Sep 5, 3:43*pm, Andre Jute wrote:
Time to return to tech-talk.

So what value resistors would you use for monoing?


Hi RATs!

I just listen to one channel at a time. You do have to listen twice.
Adequate stereo separation.

Happy Ears!

Al Marcy

[Arny Krueger]

"Andre Jute" wrote in message

On Sep 6, 3:26 pm, "Arny Krueger"
wrote:
"Eeyore"
m
wrote in
. com

Andre Jute wrote:
The QUAD CD expects to see at least 10K impedance on
its outputs.
I suspect you are misreading the spec. I expect that is
the 'nominal' load but I'd be VERY surprised if it can't
drive a lower impedance. Without schematics to hand I
couldn't give a precise figure.

For openers, the title "QUAD CD" does not describe a
single piece of equipment, or even a single family of
related products. There are at two families of Quad CD
players, the 67 family and the 99 family. The Quad 99
series players further compound the situation by having
two different sets of outputs with very difference
performance specs.

I suspect that Jute is basing his alleged specification
on the standard IHFM line level load which includes a
10K resistive component. If that's the case then he's
still in error because the proper way to address that
load is with a device that expects to see 10K or *less*.

You're a blustering idiot, Krueger.

Jute, it is true that getting sucked into responding to one of your posts
takes a certain amount of either optimism (that you would have finally grown
a brain) or idiocy (expecting you to change your behavior).

This is from the QUAD
official literature of the CD66 and it states "10K
minimum*: " Audio Output: 2Vrms maximum. 300mV on normal
progamme material. Minimum load impedance 10kR."

Jute, I see that you've already assigned fault to me for not being able to
read your mind and somehow know which Quad CD player you were whining about.

Far be it from you to take responsibility for making a unnecessarily vague
post.

[John Byrns]

In article ,
Ian Bell wrote:

Andre Jute wrote:
Time to return to tech-talk.

In a modest-sized room (by horn standards anyway) I want to rig up a
singleton of my modded semi-Fidelio bicor horns for Lowther PM6A. I
thought I'd do the monoing in a specially made 1 metre cable between
the CD player and the power amp.

The QUAD CD expects to see at least 10K impedance on its outputs.
Output of the CD player is 2Vrms and about 0.5Vrms of that is required
to drive the amp to enough power to handle the horns, so high value
resistors can be used in the monomaker if there is any advantage to be
gained.

However, the sound is NOT intended to be reprocessed as stereo
downstream (home installation, not studio); if I want stereo again,
i'll just plug in a stereo cable.

The pot on the integrated amp is probably (the board won't be here
until Tuesday and i can't read the spec on the piccie) 50K Alps but I
can replace it with a DACT of which I have a good selection of values.

So what value resistors would you use for monoing?

How many? Only two, or three?

With your choice of values, what can I expect to lose from the monoing
in bandwidth as distinct from gain?

Andre Jute
Visit Jute on Amps at
http://www.audio-talk.co.uk/fiultra/
"wonderfully well written and reasoned information for the tube audio
constructor"
John Broskie TubeCAD& GlassWare
"an unbelievably comprehensive web site containing vital gems of
wisdom"
Stuart Perry Hi-Fi News& Record Review
#

I would use 3 resistors, all 10K. I think you can guess how to wire them. The
important thing is to
place them at the amp end.

There is only one logical way to connect the first two resistors, and
then seemingly only one place to connect the odd resistor, but what is
the point of including the third 10k resistor?

--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/

[Ian Jackson]

In message , John Byrns
writes
In article ,
Ian Bell wrote:

Andre Jute wrote:
Time to return to tech-talk.

In a modest-sized room (by horn standards anyway) I want to rig up a
singleton of my modded semi-Fidelio bicor horns for Lowther PM6A. I
thought I'd do the monoing in a specially made 1 metre cable between
the CD player and the power amp.

The QUAD CD expects to see at least 10K impedance on its outputs.
Output of the CD player is 2Vrms and about 0.5Vrms of that is required
to drive the amp to enough power to handle the horns, so high value
resistors can be used in the monomaker if there is any advantage to be
gained.

However, the sound is NOT intended to be reprocessed as stereo
downstream (home installation, not studio); if I want stereo again,
i'll just plug in a stereo cable.

The pot on the integrated amp is probably (the board won't be here
until Tuesday and i can't read the spec on the piccie) 50K Alps but I
can replace it with a DACT of which I have a good selection of values.

So what value resistors would you use for monoing?

How many? Only two, or three?

With your choice of values, what can I expect to lose from the monoing
in bandwidth as distinct from gain?

Andre Jute
Visit Jute on Amps at
http://www.audio-talk.co.uk/fiultra/
"wonderfully well written and reasoned information for the tube audio
constructor"
John Broskie TubeCAD& GlassWare
"an unbelievably comprehensive web site containing vital gems of
wisdom"
Stuart Perry Hi-Fi News& Record Review
#

I would use 3 resistors, all 10K. I think you can guess how to wire
them. The
important thing is to
place them at the amp end.

There is only one logical way to connect the first two resistors, and
then seemingly only one place to connect the odd resistor, but what is
the point of including the third 10k resistor?

One assumes that the output impedance of the CD player is low compared
with the 10k input impedance of the amplifier (100 ohms to 1k?).

Provided 'relatively low' is not 'really low', you'll probably get away
with simply paralleling the two outputs. However, just in case, you need
the two resistors to prevent one output more-or-less shorting out the
other (and vice versa). Something like a couple of 5 to 10k resistors
(preferably at the amplifier end) should work just fine, at the expense
of a little audio level.

There is absolutely no virtue in having a third resistor. It will serve
no purpose, and only lower the audio level further.
--
Ian

[Eiron]

On 07/09/2010 17:19, Ian Jackson wrote:
In message , John Byrns
writes
In article ,
Ian Bell wrote:

Andre Jute wrote:
Time to return to tech-talk.

In a modest-sized room (by horn standards anyway) I want to rig up a
singleton of my modded semi-Fidelio bicor horns for Lowther PM6A. I
thought I'd do the monoing in a specially made 1 metre cable between
the CD player and the power amp.

The QUAD CD expects to see at least 10K impedance on its outputs.
Output of the CD player is 2Vrms and about 0.5Vrms of that is required
to drive the amp to enough power to handle the horns, so high value
resistors can be used in the monomaker if there is any advantage to be
gained.

However, the sound is NOT intended to be reprocessed as stereo
downstream (home installation, not studio); if I want stereo again,
i'll just plug in a stereo cable.

The pot on the integrated amp is probably (the board won't be here
until Tuesday and i can't read the spec on the piccie) 50K Alps but I
can replace it with a DACT of which I have a good selection of values.

So what value resistors would you use for monoing?

How many? Only two, or three?

With your choice of values, what can I expect to lose from the monoing
in bandwidth as distinct from gain?

Andre Jute
Visit Jute on Amps at
http://www.audio-talk.co.uk/fiultra/
"wonderfully well written and reasoned information for the tube audio
constructor"
John Broskie TubeCAD& GlassWare
"an unbelievably comprehensive web site containing vital gems of
wisdom"
Stuart Perry Hi-Fi News& Record Review
#

I would use 3 resistors, all 10K. I think you can guess how to wire
them. The
important thing is to
place them at the amp end.

There is only one logical way to connect the first two resistors, and
then seemingly only one place to connect the odd resistor, but what is
the point of including the third 10k resistor?

One assumes that the output impedance of the CD player is low compared
with the 10k input impedance of the amplifier (100 ohms to 1k?).

Provided 'relatively low' is not 'really low', you'll probably get away
with simply paralleling the two outputs. However, just in case, you need
the two resistors to prevent one output more-or-less shorting out the
other (and vice versa). Something like a couple of 5 to 10k resistors
(preferably at the amplifier end) should work just fine, at the expense
of a little audio level.

There is absolutely no virtue in having a third resistor. It will serve
no purpose, and only lower the audio level further.

You didn't read the original question very carefully, did you?
It's always a good idea to attenuate a CD output so that you can
turn the volume up to 11 without clipping or overdriving the speakers.
Because there may be teenagers in the house when you're out....

--
Eiron.

[Arny Krueger]

"Andre Jute" wrote in message

Time to return to tech-talk.

In a modest-sized room (by horn standards anyway) I want
to rig up a singleton of my modded semi-Fidelio bicor
horns for Lowther PM6A. I thought I'd do the monoing in a
specially made 1 metre cable between the CD player and
the power amp.

The QUAD CD expects to see at least 10K impedance on its
outputs.

So what value resistors would you use for monoing?

I would use 2 10K resistors, one in series with each source.

[Mike Coatham]

On 7/09/2010 12:34 p.m., Andre Jute wrote:
On Sep 6, 3:26 pm, "Arny wrote:
"Eeyore"rabbitsfriendsandrelati...@removethishotm ail.com
wrote in . com

Andre Jute wrote:
The QUAD CD expects to see at least 10K impedance on its
outputs.
I suspect you are misreading the spec. I expect that is
the 'nominal' load but I'd be VERY surprised if it can't
drive a lower impedance. Without schematics to hand I
couldn't give a precise figure.

For openers, the title "QUAD CD" does not describe a single piece of
equipment, or even a single family of related products. There are at two
families of Quad CD players, the 67 family and the 99 family. The Quad 99
series players further compound the situation by having two different sets
of outputs with very difference performance specs.

I suspect that Jute is basing his alleged specification on the standard IHFM
line level load which includes a 10K resistive component. If that's the case
then he's still in error because the proper way to address that load is with
a device that expects to see 10K or *less*.

You're a blustering idiot, Krueger. This is from the QUAD official
literature of the CD66 and it states "10K minimum*: " Audio Output:
2Vrms maximum. 300mV on normal progamme material. Minimum load
impedance 10kR."

What part of "minimum load impedance 10KR" do you fail to understand,
Krueger?

We have three idiots pontificating about a simple number, which all
three have got it wrong -- but not one of them has bothered to look it
up! But meaningwhile these three morons are smacking their chops in
glee that someone else got it "wrong." How childish. No wonder these
newsgroups remain in intensive care.

Andre Jute
"The brain of an engineer is a delicate instrument which must be
protected against the unevenness of the ground." -- Wifredo-Pelayo
Ricart Medina

I am surprised that someone who purports to design & build amplifiers etc.
would have to ask such a basic question. This is electronics 101.......
However in the interests of being helpful, read this link and learn a
little http://www.rane.com/note109.html

[Andre Jute[_2_]]

On Sep 8, 5:00*am, Mike Coatham wrote:
On 7/09/2010 12:34 p.m., Andre Jute wrote:





On Sep 6, 3:26 pm, "Arny *wrote:
"Eeyore"rabbitsfriendsandrelati...@removethishotm ail.com
wrote in . com

Andre Jute wrote:
The QUAD CD expects to see at least 10K impedance on its
outputs.
I suspect you are misreading the spec. I expect that is
the 'nominal' load but I'd be VERY surprised if it can't
drive a lower impedance. Without schematics to hand I
couldn't give a precise figure.

For openers, the title "QUAD CD" *does not describe a single piece of
equipment, or even a single family of related products. There are at two
families of Quad CD players, *the 67 family and the 99 family. * The Quad 99
series players further compound the situation by having two different sets
of outputs with very difference performance specs.

I suspect that Jute is basing his alleged specification on the standard IHFM
line level load which includes a 10K resistive component. If that's the case
then he's still in error because the proper way to address that load is with
a device that expects to see 10K or *less*.

You're a blustering idiot, Krueger. This is from the QUAD official
literature of the CD66 and it states "10K minimum*: " Audio Output:
2Vrms maximum. 300mV on normal progamme material. Minimum load
impedance 10kR."

What part of "minimum load impedance 10KR" do you fail to understand,
Krueger?

We have three idiots pontificating about a simple number, which all
three have got it wrong -- but not one of them has bothered to look it
up! But meaningwhile these three morons are smacking their chops in
glee that someone else got it "wrong." How childish. No wonder these
newsgroups remain in intensive care.

* Andre Jute
* "The brain of an engineer is a delicate instrument which must be
protected against the unevenness of the ground." -- Wifredo-Pelayo
Ricart Medina

I am surprised that someone who purports to design & build amplifiers etc..
would have to ask such a basic question. This is electronics 101.......

Here's a fourth clown who just can't resist pursing his lips and
passing a spiteful judgement.

However in the interests of being helpful, read this link and learn a
little *http://www.rane.com/note109.html

I've had that Rane note since it first appeared. To be "helpful" in
"Electronics 101" it should show how the numbers he mentions are
derived. It doesn't. Read my question, then read the Rane note again.

Andre Jute
Visit Jute on Bicycles at
http://www.audio-talk.co.uk/fiultra/...20CYCLING.html

[Ian Bell[_2_]]

Eiron wrote:
On 06/09/2010 20:48, Ian Bell wrote:
Andre Jute wrote:
Time to return to tech-talk.

In a modest-sized room (by horn standards anyway) I want to rig up a
singleton of my modded semi-Fidelio bicor horns for Lowther PM6A. I
thought I'd do the monoing in a specially made 1 metre cable between
the CD player and the power amp.

The QUAD CD expects to see at least 10K impedance on its outputs.
Output of the CD player is 2Vrms and about 0.5Vrms of that is required
to drive the amp to enough power to handle the horns, so high value
resistors can be used in the monomaker if there is any advantage to be
gained.

However, the sound is NOT intended to be reprocessed as stereo
downstream (home installation, not studio); if I want stereo again,
i'll just plug in a stereo cable.

The pot on the integrated amp is probably (the board won't be here
until Tuesday and i can't read the spec on the piccie) 50K Alps but I
can replace it with a DACT of which I have a good selection of values.

So what value resistors would you use for monoing?

How many? Only two, or three?

With your choice of values, what can I expect to lose from the monoing
in bandwidth as distinct from gain?

Andre Jute
Visit Jute on Amps at
http://www.audio-talk.co.uk/fiultra/
"wonderfully well written and reasoned information for the tube audio
constructor"
John Broskie TubeCAD& GlassWare
"an unbelievably comprehensive web site containing vital gems of
wisdom"
Stuart Perry Hi-Fi News& Record Review
#

I would use 3 resistors, all 10K. I think you can guess how to wire
them. The important thing is to place them at the amp end.

Can't guess how to wire them to give the desired attenuation.



One each in series with each output and the third across them to ground.

Cheers

ian

[Ian Bell[_2_]]

John Byrns wrote:
In ,
Ian wrote:

Andre Jute wrote:
Time to return to tech-talk.

In a modest-sized room (by horn standards anyway) I want to rig up a
singleton of my modded semi-Fidelio bicor horns for Lowther PM6A. I
thought I'd do the monoing in a specially made 1 metre cable between
the CD player and the power amp.

The QUAD CD expects to see at least 10K impedance on its outputs.
Output of the CD player is 2Vrms and about 0.5Vrms of that is required
to drive the amp to enough power to handle the horns, so high value
resistors can be used in the monomaker if there is any advantage to be
gained.

However, the sound is NOT intended to be reprocessed as stereo
downstream (home installation, not studio); if I want stereo again,
i'll just plug in a stereo cable.

The pot on the integrated amp is probably (the board won't be here
until Tuesday and i can't read the spec on the piccie) 50K Alps but I
can replace it with a DACT of which I have a good selection of values.

So what value resistors would you use for monoing?

How many? Only two, or three?

With your choice of values, what can I expect to lose from the monoing
in bandwidth as distinct from gain?

Andre Jute
Visit Jute on Amps at
http://www.audio-talk.co.uk/fiultra/
"wonderfully well written and reasoned information for the tube audio
constructor"
John Broskie TubeCAD& GlassWare
"an unbelievably comprehensive web site containing vital gems of
wisdom"
Stuart Perry Hi-Fi News& Record Review
#

I would use 3 resistors, all 10K. I think you can guess how to wire them. The
important thing is to
place them at the amp end.

There is only one logical way to connect the first two resistors, and
then seemingly only one place to connect the odd resistor, but what is
the point of including the third 10k resistor?



To provide some attenuation to get the 2V rms output closer to the 0.5V rms input requirement.

Cheers

Ian

[Arny Krueger]

"Mike Coatham" wrote in message


I am surprised that someone who purports to design &
build amplifiers etc. would have to ask such a basic
question.

Good point. Every Jute amplifier schematic I've seen looked like it was
copied from someplace.

This is electronics 101....... However in the
interests of being helpful, read this link and learn a
little http://www.rane.com/note109.html

Jute says he's read it, which only makes him look even more strange.

[David Looser]

"Ian Bell" wrote in message
...
John Byrns wrote:

There is only one logical way to connect the first two resistors, and
then seemingly only one place to connect the odd resistor, but what is
the point of including the third 10k resistor?



To provide some attenuation to get the 2V rms output closer to the 0.5V
rms input requirement.


If the idea is to prevent overload of the amplifier then the shunt resistor
should be a lot lower, 1.67k to be exact.

David.

[Andre Jute[_2_]]

Only two cycles of messages from an innocent question to the resident
circlejerk of mutual masturbators launching a full-scale personal
attack on the poster. Is anyone surprised that i treat this malicious
scum with open contempt? -- Andre Jute

On Sep 8, 12:12*pm, "Arny Krueger" wrote:
"Mike Coatham" wrote in message



I am surprised that someone who purports to design &
build amplifiers etc. would have to ask such a basic
question.

Good point. Every Jute amplifier schematic I've seen looked like it was
copied from someplace.

This is electronics 101....... However in the
interests of being helpful, read this link and learn a
little *http://www.rane.com/note109.html

Jute says he's read it, which only makes him look even more strange.

[Andre Jute[_2_]]

On Sep 8, 12:41*pm, "David Looser"
wrote:
"Ian Bell" wrote in message

...

John Byrns wrote:

There is only one logical way to connect the first two resistors, and
then seemingly only one place to connect the odd resistor, but what is
the point of including the third 10k resistor?

To provide some attenuation to get the 2V rms output closer to the 0.5V
rms input requirement.

If the idea is to prevent overload of the amplifier then the shunt resistor
should be a lot lower, 1.67k to be exact.

David.

I agree with Ian, with John, *and* with you! Savour the moment!

See. Ian is right, the third resistor shunted to ground across the
junction of the other two is the traditional way to do it on 600 ohm
networks, where everything was matched, but the pot was at the
beginning of the chain, under the engineer's control.

See, next, John is right too, because the form of the question is:
There's an unknown pot following (for whatever reason). Maybe in this
case better to leave off the shunt resistor and content yourself with
the two series resistors.

See, finally, you're right, because that shunt resistor is in parallel
with the unknown pot. But rather than make it very low, I'd make it
very high.

On the whole, I think I'd leave off the shunt resistor and avoid the
uncertainty.

BTW, cutting the signal level isn't primarily to protect the amp from
overload but to limit the output beyond the poweramp to protect the
Lowther driver which unloads right smartly below about 32Hz. That's
another reason why John's suggestion about putting the monoing network
in the amp end of the cable is smart: it's not the high frequency we
want to roll off... Limiting the signal level before the amp also
keeps the output centred in the lowest distortion section of the
transfer curve.

Andre Jute
Visit Jute on Amps at
http://www.audio-talk.co.uk/fiultra/
"wonderfully well written and reasoned information for the tube audio
constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site containing vital gems of
wisdom"
Stuart Perry Hi-Fi News & Record Review

[Iain Churches[_2_]]

"Andre Jute" wrote in message
...
Time to return to tech-talk.

In a modest-sized room (by horn standards anyway) I want to rig up a
singleton of my modded semi-Fidelio bicor horns for Lowther PM6A. I
thought I'd do the monoing in a specially made 1 metre cable between
the CD player and the power amp.

The QUAD CD expects to see at least 10K impedance on its outputs.
Output of the CD player is 2Vrms and about 0.5Vrms of that is required
to drive the amp to enough power to handle the horns, so high value
resistors can be used in the monomaker if there is any advantage to be
gained.

However, the sound is NOT intended to be reprocessed as stereo
downstream (home installation, not studio); if I want stereo again,
i'll just plug in a stereo cable.

The pot on the integrated amp is probably (the board won't be here
until Tuesday and i can't read the spec on the piccie) 50K Alps but I
can replace it with a DACT of which I have a good selection of values.

So what value resistors would you use for monoing?

How many? Only two, or three?

With your choice of values, what can I expect to lose from the monoing
in bandwidth as distinct from gain?

Andre Jute
Visit Jute on Amps at
http://www.audio-talk.co.uk/fiultra/
"wonderfully well written and reasoned information for the tube audio
constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site containing vital gems of
wisdom"
Stuart Perry Hi-Fi News & Record Review


Hello Andre.

Good to see you posting again.

I would try three R's arranged as a Y, with the
top two arms (R=10K each) connected at the sources,
and the bottom leg (R=2k2) to ground,
with the mono output taken from the junction of
the three resistors.

In the prototype you could make the 2k2 a
trimmer, to allow you to adjust the attenuation
precisely, and then replace it with the equivalent
fixed value resistor.


Best regards
Iain

[Iain Churches[_2_]]

"Arny Krueger" wrote in message
...

Good point. Every Jute amplifier schematic I've seen looked like it was
copied from someplace.

Oh Arny! You are such a *nice* Christian.

Iain

[TonyL]

Andre Jute wrote:
Only two cycles of messages from an innocent question to the resident
circlejerk of mutual masturbators launching a full-scale personal
attack on the poster. Is anyone surprised that i treat this malicious
scum with open contempt? -- Andre Jute

Jute,

Just to delurk for a moment.....

Why not just wire the frigging resistors in and see what it sounds like ?

Would be much quicker than messing about in here.

[Arny Krueger]

"Iain Churches" wrote in message

"Arny Krueger" wrote in message
...

Good point. Every Jute amplifier schematic I've seen
looked like it was copied from someplace.

Oh Arny! You are such a *nice* Christian.

And piling on like this somehow makes you better than me?

No, it makes you lower than me because you could have kept out of it.

Love ya Iain - you've never saw an opportunity to make trouble that you
could avoid.

[Ian Bell[_2_]]

David Looser wrote:
"Ian wrote in message
...
John Byrns wrote:

There is only one logical way to connect the first two resistors, and
then seemingly only one place to connect the odd resistor, but what is
the point of including the third 10k resistor?



To provide some attenuation to get the 2V rms output closer to the 0.5V
rms input requirement.


If the idea is to prevent overload of the amplifier then the shunt resistor
should be a lot lower, 1.67k to be exact.

David.



The idea is not to prevent overload but rather to get the power amp volume control in more user
friendly region.

Cheers

Ian

[Andre Jute[_2_]]

On Sep 9, 9:39*am, "TonyL" wrote:
Andre Jute wrote:
Only two cycles of messages from an innocent question to the resident
circlejerk of mutual masturbators launching a full-scale personal
attack on the poster. Is anyone surprised that i treat this malicious
scum with open contempt? -- Andre Jute

Jute,

Just to delurk for a moment.....

Why not just wire the frigging resistors in and see what it sounds like ?

Would be much quicker than messing about in here.

I was deliberately making a simple talking point. That has succeeded.
There was also the salutary secondary effect of proving once more that
the self-appointed gatekeepers (the jerks I refer to collectively as
"the scum") keep out newbies by making any discussion personally
unpleasant. Who'd want to ask a question if you were treated as I've
been treated by Poopie Stevenson, "Eiron", that New Zealand jerk
Coatham (who actually had the effrontery to label his abuse as
"helpful"!), and the ever-wretched Krueger?

Andre Jute
Noblesse oblige

[Arny Krueger]

"Andre Jute" wrote in message

Who'd want to ask a question if
you were treated as I've been treated by Poopie
Stevenson, "Eiron", that New Zealand jerk Coatham (who
actually had the effrontery to label his abuse as
"helpful"!), and the ever-wretched Krueger?

Trust me Andre, we save our *special treatment* for know-it-alls like you.

We give far better treatment to those who we recognize as being fellow
members of the human race. ;-)

[Andre Jute[_2_]]

On Sep 9, 6:59*am, "Iain Churches" wrote:
"Andre Jute" wrote in message

...





Time to return to tech-talk.

In a modest-sized room (by horn standards anyway) I want to rig up a
singleton of my modded semi-Fidelio bicor horns for Lowther PM6A. I
thought I'd do the monoing in a specially made 1 metre cable between
the CD player and the power amp.

The QUAD CD expects to see at least 10K impedance on its outputs.
Output of the CD player is 2Vrms and about 0.5Vrms of that is required
to drive the amp to enough power to handle the horns, so high value
resistors can be used in the monomaker if there is any advantage to be
gained.

However, the sound is NOT intended to be reprocessed as stereo
downstream (home installation, not studio); if I want stereo again,
i'll just plug in a stereo cable.

The pot on the integrated amp is probably (the board won't be here
until Tuesday and i can't read the spec on the piccie) 50K Alps but I
can replace it with a DACT of which I have a good selection of values.

So what value resistors would you use for monoing?

How many? Only two, or three?

With your choice of values, what can I expect to lose from the monoing
in bandwidth as distinct from gain?

Andre Jute
Visit Jute on Amps at
http://www.audio-talk.co.uk/fiultra/
"wonderfully well written and reasoned information for the tube audio
constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site containing vital gems of
wisdom"
Stuart Perry Hi-Fi News & Record Review

Hello Andre.

Good to see you posting again.

I would try three R's *arranged as a Y, with the
top two arms (R=10K each) connected at the sources,
and the bottom leg (R=2k2) to ground,
with the mono output taken from the junction of
the three resistors.

I don't get this, Iain. You and David both want a low value resistor
shunted to ground. But it seems to me you're looking backward to the
series resistors whereas the important direction is forwards to the
unknown pot, with which the shunt resistor will be in parallel. If the
shunt resistor is low, the parallel combination will be grotesquely
low.

In the prototype you could make the 2k2 a
trimmer, *to allow you to adjust the attenuation
precisely, and then replace it with the equivalent
fixed value resistor.

Nice touch. However, precision isn't all that important; we just want
to be in the ballpark of not overloading the speaker.

Andre Jute
http://www.audio-talk.co.uk/fiultra/Andre%20Jute's%20Utopia%20Kranich.pdf

[Paul G.]

On Thu, 9 Sep 2010 11:57:28 -0700 (PDT), Andre Jute
wrote:

On Sep 9, 6:59*am, "Iain Churches" wrote:
"Andre Jute" wrote in message
......[snip!].....

In a modest-sized room (by horn standards anyway) I want to rig up a
singleton of my modded semi-Fidelio bicor horns for Lowther PM6A. I
thought I'd do the monoing in a specially made 1 metre cable between
the CD player and the power amp.

The QUAD CD expects to see at least 10K impedance on its outputs.
Output of the CD player is 2Vrms and about 0.5Vrms of that is required
to drive the amp to enough power to handle the horns, so high value
resistors can be used in the monomaker if there is any advantage to be
gained.

However, the sound is NOT intended to be reprocessed as stereo
downstream (home installation, not studio); if I want stereo again,
i'll just plug in a stereo cable.

The pot on the integrated amp is probably (the board won't be here
until Tuesday and i can't read the spec on the piccie) 50K Alps but I
can replace it with a DACT of which I have a good selection of values.

So what value resistors would you use for monoing?

How many? Only two, or three?

With your choice of values, what can I expect to lose from the monoing
in bandwidth as distinct from gain?

Andre Jute
Visit Jute on Amps at
http://www.audio-talk.co.uk/fiultra/
"wonderfully well written and reasoned information for the tube audio
constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site containing vital gems of
wisdom"
Stuart Perry Hi-Fi News & Record Review

Hello Andre.

Good to see you posting again.

I would try three R's *arranged as a Y, with the
top two arms (R=10K each) connected at the sources,
and the bottom leg (R=2k2) to ground,
with the mono output taken from the junction of
the three resistors.

I don't get this, Iain. You and David both want a low value resistor
shunted to ground. But it seems to me you're looking backward to the
series resistors whereas the important direction is forwards to the
unknown pot, with which the shunt resistor will be in parallel. If the
shunt resistor is low, the parallel combination will be grotesquely
low.

In the prototype you could make the 2k2 a
trimmer, *to allow you to adjust the attenuation
precisely, and then replace it with the equivalent
fixed value resistor.

Nice touch. However, precision isn't all that important; we just want
to be in the ballpark of not overloading the speaker.

Andre Jute
http://www.audio-talk.co.uk/fiultra/Andre%20Jute's%20Utopia%20Kranich.pdf

The value seems rather low, but let's figure it out with a few
assumptions:
1- impedance (looking back into CD player) is low - quite valid if
it has considerable feedback.
2- Both channels are going full out (2V), and both have identical
signals (worst case scenario for highest mono output level)
3- 10K (or so) are recommended resistors that "Y" the two CD player
outputs.
4- the impedance of the amp is very high

Effectively, your signal source appears as 2v in series with 5K. To
attenuate the signal to 0.5 volts, Vout/Vin for your attenuator is
0.25, and the resistor to ground works out to about 1.66K .
But.... assumption 1 is probably not valid, and 4 isn't either
(input pot). So with a bit of juggling of values, I'd say that 2-2.5k
is quite reasonable, as suggested above.
The other consideration is that you may get recordings that will not
put out the maximum 2V (they don't always max out just shy of the
maximum possible from the DAC circuits). In such cases you won't be
able to run your system full out, whereas if you had more of a gain
margin you could get it. That would suggest even higher values for the
resistor to ground, or even no resistor to ground.
On the other hand, since it takes a factor or 10 times the power to
sound twice as loud, I don't think it's going to make a big difference
to the sound level if the resistor to ground varies a bit. If I were
you, my primary concern would be if someone (like the kids) turn
everything up full out, then you could burn out your speakers. In that
case, I'd use the 1.66K (or thereabouts) to be on the safe side.
Are your horns rated for continuous RMS (rare for home systems) or
some other standard where there is a peak level for a short duration?
If the latter, I would be much more worried if I were you, especially
if they are expensive or "one of a kind". If your speakers are rated
for short peak levels, the above calculations would not be
conservative enough.
Getting somewhat off topic, what is the best way to protect a
speaker from destruction if the amp is sufficiently powerful, and you
have no control over volume? It happens.... the kids have fun with
your stereo, the grounds come loose on the inputs (huge buzz), the
system oscillates, etc.


Paul G.

[Iain Churches[_2_]]

"Andre Jute" wrote in message
...
On Sep 9, 6:59 am, "Iain Churches" wrote:
"Andre Jute" wrote in message

...





Time to return to tech-talk.

In a modest-sized room (by horn standards anyway) I want to rig up a
singleton of my modded semi-Fidelio bicor horns for Lowther PM6A. I
thought I'd do the monoing in a specially made 1 metre cable between
the CD player and the power amp.

The QUAD CD expects to see at least 10K impedance on its outputs.
Output of the CD player is 2Vrms and about 0.5Vrms of that is required
to drive the amp to enough power to handle the horns, so high value
resistors can be used in the monomaker if there is any advantage to be
gained.

However, the sound is NOT intended to be reprocessed as stereo
downstream (home installation, not studio); if I want stereo again,
i'll just plug in a stereo cable.

The pot on the integrated amp is probably (the board won't be here
until Tuesday and i can't read the spec on the piccie) 50K Alps but I
can replace it with a DACT of which I have a good selection of values.

So what value resistors would you use for monoing?

How many? Only two, or three?

With your choice of values, what can I expect to lose from the monoing
in bandwidth as distinct from gain?

Andre Jute
Visit Jute on Amps at
http://www.audio-talk.co.uk/fiultra/
"wonderfully well written and reasoned information for the tube audio
constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site containing vital gems of
wisdom"
Stuart Perry Hi-Fi News & Record Review

Hello Andre.

Good to see you posting again.

I would try three R's arranged as a Y, with the
top two arms (R=10K each) connected at the sources,
and the bottom leg (R=2k2) to ground,
with the mono output taken from the junction of
the three resistors.

I don't get this, Iain. You and David both want a low value resistor
shunted to ground. But it seems to me you're looking backward to the
series resistors whereas the important direction is forwards to the
unknown pot, with which the shunt resistor will be in parallel. If the
shunt resistor is low, the parallel combination will be grotesquely
low.

My idea was to use a Y pad to attenuate the signal so that you
would be able to use the pot at 2 o'clock instead of just-about-off-
the-stop.

In the prototype you could make the 2k2 a
trimmer, to allow you to adjust the attenuation
precisely, and then replace it with the equivalent
fixed value resistor.

Nice touch. However, precision isn't all that important; we just want
to be in the ballpark of not overloading the speaker.

If I were going to make a bespoke cable, I would consider it
a minor additional task to build in precisely the attenuation
needed.

Many classical CD's still follow the early (and prudent) practice
or peaking at -10dBFS, but a huge amount of pop material
is heavily compressed at 0dBFS. I know from earlier discussion
with you, that your music taste is hardly likely to include the
latter, but there might be someone else in the house to whom this
kind of music appeals.

Best regards
Iain

[Iain Churches[_2_]]

"Arny Krueger" wrote in message
...
"Andre Jute" wrote in message

Who'd want to ask a question if
you were treated as I've been treated by Poopie
Stevenson, "Eiron", that New Zealand jerk Coatham (who
actually had the effrontery to label his abuse as
"helpful"!), and the ever-wretched Krueger?

Trust me Andre, we save our *special treatment* for know-it-alls like you.

We?

We give far better treatment to those who we recognize as being fellow
members of the human race. ;-)

We?

The use of the personal pronoun in the 1st person plural
is reserved for:

1. Those who speak on behalf of others.
2. Royalty.

Despite what you may wish us to believe, Arny,
you qualify in neither category:-)

Iain

[Iain Churches[_2_]]

"Arny Krueger" wrote in message
...
"Iain Churches" wrote in message

"Arny Krueger" wrote in message
...

Good point. Every Jute amplifier schematic I've seen
looked like it was copied from someplace.

Oh Arny! You are such a *nice* Christian.

And piling on like this somehow makes you better than me?

I am hard-pressed to think of a single person whom
I do not consider to be better than you:-)


No, it makes you lower than me because you could have kept out of it.


So you want me to stand by, while you cast aspersions
upon one of the most helpful and interesting contributors
to Usenet tube-audio discussion?

Not a chance!


Iain