Robert Morein wrote:
"ScottW" wrote in message
oups.com...

Robert Morein wrote:
"ScottW" wrote in message
ups.com...

Powell wrote:
"ScottW" wrote

If you must compensate a limited signal
level source with more gain in your preamp
then you are obviously also amplifying the
noise of your source more than should be
necessary and diminishing overall system
signal/noise ratio.

Well, yes and no.

The volume pot is primarily used on players like
CD/DVD, phonograph head amps, tuners, etc.,
to slightly increase or reduce RMS voltage of
the player's line level outputs. For the most
part the consumer electronics industry sets
*fixed outputs/line level* at 1-2 volts.

There are plenty of alternative hybrids that
output much higher by providing preamp output
levels (5-50 Vrms). A few adequate products
were sited. Because there is so little demand
for these hybrids consumers pay a premium
price.

You would unnecessarily burden manufactures
and consumer pocketbooks with unnecessary
expenses for including additional head amp
sections in players. There is no market for this.


A better solution is a source which is capable
of rated output without distortion/clipping or
whatever problem your POS adjustable
output level CD players have.

I wasn't aware there were problems with players
not outputing at line level (1-2 Vrms). There
is no practical use for playing devices outputing
at any higher levels. When they do that's when
a pot is often included on the device.


Moron claims his Sony player doesn't even have the balls for line
level output.

reference his response to Bret's comment:

Most power amps will go full output with 1.5V rms. VTL in their book
specify they design for input sensitivity of 775 mV as I recall.

Morons response:
Yes, but from practical experience with Sony ES players, I can tell you
that
those with 5532 outputs cannot do it cleanly.

So I have a couple issues with Bob's premise.
1) His crappy CD can't even provide std line level output cleanly.
2) Attenuating said output with a pot isn't likely to do anything to
clean it up.
3) Adding extra gain later to compensate will also amplify the noise
floor of the player reducing overall system S/N.

ScottW

Scott, it sounds alot better with the preamp in. That's all I care about.

That's fine. In the future we'll ignore anything but your subjective
appraisals as that is all you care about.

Noise is not a subjective problem in either system.
Without the preamp buffers, the systems sound strained.
I use Sony ES players, known to have excellent DACs, but not the best
output
stages.

So your comments about passive attenuators really only applies to Sony
ES CD players which you find lacking in output performance.

No.

Maybe you
should have said that.

ScottW

It depends upon the player. Most Japanese players, and preamps, use
inadequate ouput circuitry. I disassembled a very fancy Pioneer Elite
preamp, and found 5532 outputs. The power supply was really tiny, using the
78XX regulators in TO-92 package. Some highly thought of Marantz players
also use them. The user has the choicee of modding, or using with a preamp
that has a good line driver output stage.

Do these Marantz players have volume control?
Most preamps have similar input impedance to an amplifier so
adding a preamp won't change anything at the output of a CD player
with fixed levels.
I think you're straining more than your CD player.

ScottW

"François Yves Le Gal" wrote in message
...
On Tue, 13 Dec 2005 18:58:01 -0500, "Robert Morein"
wrote:

I disassembled a very fancy Pioneer Elite
preamp, and found 5532 outputs.

A properly used 5532 is able to swing ± 13 V on a 2 K load with a typical
±
15 V supply voltage...

The power supply was really tiny, using the
78XX regulators in TO-92 package.

At 8 mA of supply current per OP amp and 100 mA of available output
current
per 78XX or 79XXin TO-92 form why should you need anything larger?

IME, 2K is not adequate for more than short runs.

"Robert Morein" wrote in message
...

"Bret Ludwig" wrote in message
oups.com...

Powell wrote:

A "passive preamp" is no such thing at all. It is a
selector/attenuator, acting as a signal switching
box and a variable signal attenuator.

True, and as a result most outboard devices like
CD players, tuners, etc. lack enough RMS
voltage to adequately drive power amps. Most
mainstream preamps will output 5-50 volts.

Most power amps will go full output with 1.5V rms. VTL in their book
specify they design for input sensitivity of 775 mV as I recall.

Yes, but from practical experience with Sony ES players, I can tell you
that those with 5532 outputs cannot do it cleanly.


In fact NE5532's can drive 7.75 volts into a 500 ohm load with exceptionally
low distortion as shown by the following authoritative reference:

http://www.dself.dsl.pipex.com/ampins/webbop/5532.htm

"ScottW" wrote in message
ups.com...

Moron claims his Sony player doesn't even have the balls for line
level output.

The man says a lot of crazy things.

reference his response to Bret's comment:

Most power amps will go full output with 1.5V rms. VTL in their book
specify they design for input sensitivity of 775 mV as I recall.

Morons response:
Yes, but from practical experience with Sony ES players, I can tell you
that those with 5532 outputs cannot do it cleanly.

In fact NE5532's can drive 7.75 volts into a 500 ohm load with exceptionally
low distortion as shown by the following authoritative reference:

http://www.dself.dsl.pipex.com/ampins/webbop/5532.htm

7.75 volts is about 14 dB higher than the input sensitivity of a typical
power amp. IOW if you apply a signal that peaks at 7.75 volts to most power
amps, the amp is way far into clipping.

It's possible that Bob is basing his thesis on equipment that is simply
defective or otherwise not living up to its potential.

So I have a couple issues with Bob's premise.

1) His crappy CD can't even provide std line level output cleanly.

In my experience Bob suffers from hysteria which causes him to leap from
faulty conclusion to faulty conclusion (example given above).

The usual problem with driving power amps directly from CD players is that
while there is more than enough gain to drive the power amp to full output
and maybe a few dB into clipping on the loudest passages, people are used to
working with active preamps with about 20 dB of gain. A lot of this gain is
sacrificed by the fact that most people aren't comfortable turning the gain
full up, to about 5 o'clock. IME most people's perceived comfortable full
output is about 1 o'clock.

2) Attenuating said output with a pot isn't likely to do anything to
clean it up.

Agreed.

3) Adding extra gain later to compensate will also amplify the noise
floor of the player reducing overall system S/N.

Any subsequent linear gain will elevate the signal and the noise
identically, which would maintain system SNR or dynamic range. Losses are
due to any noise that is added by the gain stage itself.

"Arny Krueger" wrote in message
...

said a lot of false things.

"Robert Morein" wrote in message
...

"François Yves Le Gal" wrote in message
...

On Tue, 13 Dec 2005 18:58:01 -0500, "Robert Morein"
wrote:

I disassembled a very fancy Pioneer Elite preamp, and found 5532
outputs.

Good stuff!

A properly used 5532 is able to swing ± 13 V on a 2 K load with a typical
± 15 V supply voltage...

Or, 7.75 vrms with a 500 ohm load with vanishing distortion per Doug Self.

Experienced audio engineers know that a 5532 can do nothing if it can't
drive low impedance loads. If you took the 5532s out of pro audio about 25%
of everything would stop working.

The power supply was really tiny, using the
78XX regulators in TO-92 package.

Note Morein is eyeballing parts with untrained eyes - if a part is too small
for his uneducated, unpracticed eye, it can't handle audio well.

At 8 mA of supply current per OP amp and 100 mA of available output
current
per 78XX or 79XXin TO-92 form why should you need anything larger?

Agreed.

IME, 2K is not adequate for more than short runs.

Note, Morein has ignorantly confused load impedance and source impedance.

I doubt that he can give a cogent explanation of the difference.

Remember, Morien is a guy who places himself over degreed engineers, at
least in his own mind and RAO posts.

"ScottW" wrote in message
ups.com...

Robert Morein wrote:
"ScottW" wrote in message
oups.com...

Robert Morein wrote:
"ScottW" wrote in message
ups.com...

Powell wrote:
"ScottW" wrote

If you must compensate a limited signal
level source with more gain in your preamp
then you are obviously also amplifying the
noise of your source more than should be
necessary and diminishing overall system
signal/noise ratio.

Well, yes and no.

The volume pot is primarily used on players like
CD/DVD, phonograph head amps, tuners, etc.,
to slightly increase or reduce RMS voltage of
the player's line level outputs. For the most
part the consumer electronics industry sets
*fixed outputs/line level* at 1-2 volts.

There are plenty of alternative hybrids that
output much higher by providing preamp output
levels (5-50 Vrms). A few adequate products
were sited. Because there is so little demand
for these hybrids consumers pay a premium
price.

You would unnecessarily burden manufactures
and consumer pocketbooks with unnecessary
expenses for including additional head amp
sections in players. There is no market for this.


A better solution is a source which is capable
of rated output without distortion/clipping or
whatever problem your POS adjustable
output level CD players have.

I wasn't aware there were problems with players
not outputing at line level (1-2 Vrms). There
is no practical use for playing devices outputing
at any higher levels. When they do that's when
a pot is often included on the device.


Moron claims his Sony player doesn't even have the balls for line
level output.

reference his response to Bret's comment:

Most power amps will go full output with 1.5V rms. VTL in their
book
specify they design for input sensitivity of 775 mV as I recall.

Morons response:
Yes, but from practical experience with Sony ES players, I can tell
you
that
those with 5532 outputs cannot do it cleanly.

So I have a couple issues with Bob's premise.
1) His crappy CD can't even provide std line level output cleanly.
2) Attenuating said output with a pot isn't likely to do anything to
clean it up.
3) Adding extra gain later to compensate will also amplify the
noise
floor of the player reducing overall system S/N.

ScottW

Scott, it sounds alot better with the preamp in. That's all I care
about.

That's fine. In the future we'll ignore anything but your subjective
appraisals as that is all you care about.

Noise is not a subjective problem in either system.
Without the preamp buffers, the systems sound strained.
I use Sony ES players, known to have excellent DACs, but not the best
output
stages.

So your comments about passive attenuators really only applies to Sony
ES CD players which you find lacking in output performance.

No.

Maybe you
should have said that.

ScottW

It depends upon the player. Most Japanese players, and preamps, use
inadequate ouput circuitry. I disassembled a very fancy Pioneer Elite
preamp, and found 5532 outputs. The power supply was really tiny, using
the
78XX regulators in TO-92 package. Some highly thought of Marantz players
also use them. The user has the choicee of modding, or using with a
preamp
that has a good line driver output stage.

Do these Marantz players have volume control?
Most preamps have similar input impedance to an amplifier so
adding a preamp won't change anything at the output of a CD player
with fixed levels.
I think you're straining more than your CD player.

Given how easily and thoroughly Francois and I deconstructed Morein, all
he's straining is his credibility, which is pretty well shot already.

"Robert Morein" wrote in message
...

"Arny Krueger" wrote in message
...


"ScottW" wrote in message
ups.com...

Moron claims his Sony player doesn't even have the balls for line
level output.

The man says a lot of crazy things.

reference his response to Bret's comment:

Most power amps will go full output with 1.5V rms. VTL in their book
specify they design for input sensitivity of 775 mV as I recall.

Morons response:

Yes, but from practical experience with Sony ES players, I can tell you
that those with 5532 outputs cannot do it cleanly.

In fact NE5532's can drive 7.75 volts into a 500 ohm load with
exceptionally
low distortion as shown by the following authoritative reference:

http://www.dself.dsl.pipex.com/ampins/webbop/5532.htm

7.75 volts is about 14 dB higher than the input sensitivity of a typical
power amp. IOW if you apply a signal that peaks at 7.75 volts to most
power amps, the amp is way far into clipping.

It's possible that Bob is basing his thesis on equipment that is simply
defective or otherwise not living up to its potential.

So I have a couple issues with Bob's premise.

1) His crappy CD can't even provide std line level output cleanly.

In my experience Bob suffers from hysteria which causes him to leap from
faulty conclusion to faulty conclusion (example given above).

The usual problem with driving power amps directly from CD players is
that while there is more than enough gain to drive the power amp to full
output and maybe a few dB into clipping on the loudest passages, people
are used to working with active preamps with about 20 dB of gain. A lot
of this gain is sacrificed by the fact that most people aren't
comfortable turning the gain full up, to about 5 o'clock. IME most
people's perceived comfortable full output is about 1 o'clock.

2) Attenuating said output with a pot isn't likely to do anything to
clean it up.

Agreed.

3) Adding extra gain later to compensate will also amplify the noise
floor of the player reducing overall system S/N.

Any subsequent linear gain will elevate the signal and the noise
identically, which would maintain system SNR or dynamic range. Losses are
due to any noise that is added by the gain stage itself.

said a lot of false things.

Prove it, Morien. Francois and I have deconstructed you pretty thoroughly.
Live with it!

"François Yves Le Gal" wrote in message
...

On Tue, 13 Dec 2005 21:27:12 -0500, "Robert Morein"
wrote:

IME, 2K is not adequate for more than short runs.

Huh? What do you mean? A typical consumer amp shows an input R of more
than
10 KOhms.

Actually, that's the standard EIA worst case input impedance for consumer
electronics. Many pieces have higher input impedances, often around 100K.

A 5532 can swing nearly all the way to the rails in such a load...

Exactly!

On Wed, 14 Dec 2005 01:23:30 +0100, François Yves Le Gal
wrote:

On Tue, 13 Dec 2005 18:58:01 -0500, "Robert Morein"
wrote:

I disassembled a very fancy Pioneer Elite
preamp, and found 5532 outputs.

A properly used 5532 is able to swing ± 13 V on a 2 K load with a typical ±
15 V supply voltage...

The power supply was really tiny, using the
78XX regulators in TO-92 package.

At 8 mA of supply current per OP amp and 100 mA of available output current
per 78XX or 79XXin TO-92 form why should you need anything larger?

Umm... So you can charge 5 freaking grand for what is essentially a
switch, a buffer amp, and a pot?

It's really amazing how expensive most preamps are, considering how
cheap and easy it is to do that function... Madness.

"Arny Krueger" wrote in message
...

"Robert Morein" wrote in message
...

"Arny Krueger" wrote in message
...


"ScottW" wrote in message
ups.com...

Moron claims his Sony player doesn't even have the balls for line
level output.

The man says a lot of crazy things.

reference his response to Bret's comment:

Most power amps will go full output with 1.5V rms. VTL in their book
specify they design for input sensitivity of 775 mV as I recall.

Morons response:

Yes, but from practical experience with Sony ES players, I can tell you
that those with 5532 outputs cannot do it cleanly.

In fact NE5532's can drive 7.75 volts into a 500 ohm load with
exceptionally
low distortion as shown by the following authoritative reference:

http://www.dself.dsl.pipex.com/ampins/webbop/5532.htm

7.75 volts is about 14 dB higher than the input sensitivity of a typical
power amp. IOW if you apply a signal that peaks at 7.75 volts to most
power amps, the amp is way far into clipping.

It's possible that Bob is basing his thesis on equipment that is simply
defective or otherwise not living up to its potential.

So I have a couple issues with Bob's premise.

1) His crappy CD can't even provide std line level output cleanly.

In my experience Bob suffers from hysteria which causes him to leap from
faulty conclusion to faulty conclusion (example given above).

The usual problem with driving power amps directly from CD players is
that while there is more than enough gain to drive the power amp to full
output and maybe a few dB into clipping on the loudest passages, people
are used to working with active preamps with about 20 dB of gain. A lot
of this gain is sacrificed by the fact that most people aren't
comfortable turning the gain full up, to about 5 o'clock. IME most
people's perceived comfortable full output is about 1 o'clock.

2) Attenuating said output with a pot isn't likely to do anything to
clean it up.

Agreed.

3) Adding extra gain later to compensate will also amplify the noise
floor of the player reducing overall system S/N.

Any subsequent linear gain will elevate the signal and the noise
identically, which would maintain system SNR or dynamic range. Losses
are due to any noise that is added by the gain stage itself.

said a lot of false things.

Prove it, Morien. Francois and I have deconstructed you pretty
thoroughly. Live with it!
I don't think Francois would like to be a party to this. Ask him.

"Arny Krueger" wrote

So I have a couple issues with Bob's premise.

1) His crappy CD can't even provide std line level
output cleanly.

In my experience Bob suffers from hysteria which
causes him to leap from faulty conclusion to faulty
conclusion (example given above).

What is the proper methodology for measuring
Vrms voltage from fixed RCA outputs on players?
Is there anything which would preclude Robert
from measuring it with a handheld volt meter
and test disk?

Arny Krueger wrote:
"ScottW" wrote in message

3) Adding extra gain later to compensate will also amplify the noise
floor of the player reducing overall system S/N.

Any subsequent linear gain will elevate the signal and the noise
identically, which would maintain system SNR or dynamic range. Losses are
due to any noise that is added by the gain stage itself.

Agreed, but running the source at a very low output level will
prevent it from outputting optimal S/N ratio and the additional later
gain will also diminish noise (EMI) immunity.

ScottW

Powell wrote:
"Arny Krueger" wrote

So I have a couple issues with Bob's premise.

1) His crappy CD can't even provide std line level
output cleanly.

In my experience Bob suffers from hysteria which
causes him to leap from faulty conclusion to faulty
conclusion (example given above).

What is the proper methodology for measuring
Vrms voltage from fixed RCA outputs on players?
Is there anything which would preclude Robert
from measuring it with a handheld volt meter
and test disk?

Not that I can think of.

ScottW

"Powell" wrote in message
...

"Arny Krueger" wrote

So I have a couple issues with Bob's premise.

1) His crappy CD can't even provide std line level
output cleanly.

In my experience Bob suffers from hysteria which
causes him to leap from faulty conclusion to faulty
conclusion (example given above).

What is the proper methodology for measuring
Vrms voltage from fixed RCA outputs on players?

EIA load, Test CD, reasonbly high impedance voltmeter with flat frequency
response.

Is there anything which would preclude Robert
from measuring it with a handheld volt meter
and test disk?

The FR of the handheld voltmeter is a potential source of errors. Some are
only designed to work well with line voltage and are already a few dB down
at the standard frequencies of 400 Hz or 1 KHz.

"ScottW" wrote in message
oups.com...

Arny Krueger wrote:
"ScottW" wrote in message

3) Adding extra gain later to compensate will also amplify the noise
floor of the player reducing overall system S/N.

Any subsequent linear gain will elevate the signal and the noise
identically, which would maintain system SNR or dynamic range. Losses are
due to any noise that is added by the gain stage itself.

Agreed, but running the source at a very low output level will
prevent it from outputting optimal S/N ratio and the additional later
gain will also diminish noise (EMI) immunity.

Agreed. It doesn't make sense to unnecessarily throw away signal without
some other larger benefit.

"Arny Krueger" wrote

What is the proper methodology for measuring
Vrms voltage from fixed RCA outputs on players?

EIA load, Test CD, reasonbly high impedance
voltmeter with flat frequency response.

So as I understand it, Robert, based on past
posts of technical capability shouldn't have any
problems generating this data? I’m in general
agreement with him, pots on input devices are
marginal at driving power amps. Providing
data seems like the least he could do to
support his assumption and mine.


Is there anything which would preclude Robert
from measuring it with a handheld volt meter
and test disk?

The FR of the handheld voltmeter is a potential
source of errors. Some are only designed to
work well with line voltage and are already a
few dB down at the standard frequencies of
400 Hz or 1 KHz.

Thank you.

François Yves Le Gal wrote:

On Wed, 14 Dec 2005 14:01:23 GMT, dizzy wrote:

It's really amazing how expensive most preamps are, considering how
cheap and easy it is to do that function... Madness.

Well, you can use fancy parts and components. A quality generic two deck/six
position switch costs around USD4.00, a fancy Elma 2/6 around USD20,00.

Ditto for everything : an op amp costs only pennies in generic form, a high
end model such as the Burr Brown OPA627 costs USD12.25 per 1 K. So it's
pretty easy to reach a USD1,000.00 parts budget, translating into a retail
price of USD10,000.00 or more!

Yes, but a preamp only needs one "big" switch, and just a few op-amp
chips, and 2-4 good pots. Not so "easy" to reach $1,000 parts cost
with the essential components, even when they are "fancy" - unless
they use a ridiculously over-built power supply and/or over-built
casework...

dizzy wrote:

François Yves Le Gal wrote:

On Wed, 14 Dec 2005 14:01:23 GMT, dizzy wrote:

It's really amazing how expensive most preamps are, considering how
cheap and easy it is to do that function... Madness.

Well, you can use fancy parts and components. A quality generic two deck/six
position switch costs around USD4.00, a fancy Elma 2/6 around USD20,00.

Ditto for everything : an op amp costs only pennies in generic form, a high
end model such as the Burr Brown OPA627 costs USD12.25 per 1 K. So it's
pretty easy to reach a USD1,000.00 parts budget, translating into a retail
price of USD10,000.00 or more!

Yes, but a preamp only needs one "big" switch, and just a few op-amp
chips, and 2-4 good pots. Not so "easy" to reach $1,000 parts cost
with the essential components, even when they are "fancy" - unless
they use a ridiculously over-built power supply and/or over-built
casework...

Note that I'm thinking of line-level preamps, here...