can i just put a 1k resistor across pins 2 and 3? to my understanding
this degrades CMRR, since the differential signal is knocked down, but
not the common mode. how much would CMRR degrade in dB with a preamp
with a ~5k input Z?

Du

In article m writes:

can i just put a 1k resistor across pins 2 and 3? to my understanding
this degrades CMRR, since the differential signal is knocked down, but
not the common mode. how much would CMRR degrade in dB with a preamp
with a ~5k input Z?

It's early in the morning so I'm not sure if you're asking the right
question, or if this is the right answer, but off the top of my head,
I wouldn't expect any degradation in common mode rejection since
you're reducing the amplitude of each leg of the signal equally. You
might have a measurable reduction in signal-to-noise ratio since
you're reducing the output level of the microphone, and will need more
gain for the same preamp output level at a given SPL going into the
mic. Purists will add the noise generated by the resistor to your hit
budget.

However, I really don't see that hanging a 1K resistor across the
output of an SM57 is going to help things all that much, if at all.
Why don't you just try it, and see:

1) if it sounds better with the resistor in place and
2) if there's a noticable increase in noise.

Then make your decision as to whether it's a worthwhile modification.

--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article m writes:

can i just put a 1k resistor across pins 2 and 3? to my understanding
this degrades CMRR, since the differential signal is knocked down, but
not the common mode. how much would CMRR degrade in dB with a preamp
with a ~5k input Z?

It's early in the morning so I'm not sure if you're asking the right
question, or if this is the right answer, but off the top of my head,
I wouldn't expect any degradation in common mode rejection since
you're reducing the amplitude of each leg of the signal equally. You
might have a measurable reduction in signal-to-noise ratio since
you're reducing the output level of the microphone, and will need more
gain for the same preamp output level at a given SPL going into the
mic. Purists will add the noise generated by the resistor to your hit
budget.

However, I really don't see that hanging a 1K resistor across the
output of an SM57 is going to help things all that much, if at all.
Why don't you just try it, and see:

1) if it sounds better with the resistor in place and
2) if there's a noticable increase in noise.

Then make your decision as to whether it's a worthwhile modification.

--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

dufus wrote:

can i just put a 1k resistor across pins 2 and 3?

Absolutely. This is not that different from what happens when you add many
mic attenuators. The mic attenuators I've examined provide load impedances
in the 1 to 2.5 Kohm range. Attenuators that are connected across pins 2 &
3 are generally recommended because of their minimal effect on CMRR

to my understanding
this degrades CMRR, since the differential signal is knocked down, but
not the common mode.

The real question is not CMRR, its resistance to externally-generated noise.
Do you have reason to believe that common mode noise is currently a serious
problem with your system? Or, are just worrying about possibilities, as
opposed to realities?

how much would CMRR degrade in dB with a preamp
with a ~5k input Z?

Don't know, because this calculation would be based on the source impedance
of the SM-57, not the input impedance of the preamp.

An interesting related article can be found at
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF

Most interesting is:

"Figure 3 shows the effect of preamp input resistance (and capacitance) on
frequency response of a Shure SM57 with 100 feet of common cable. The upper
curves, 10 kS and 3 kS, are typical of transformer-less mic preamps while
the lower curve, 1.5 kS, is typical of a transformer input mic preamp. Note
the ultra-sonic peaks in response caused by insufficient damping".

This chart gives some insight into the output impedance of a SM57. To
summarize, there is negligible change in response at 3 KHz with load
impedances varying from 1,500 ohms to 10,000 ohms. IOW, the source impedance
of a SM57 in the normal audio range (20 KHz) is quite small. Other sources
give it as being 150 ohms or 310 ohms. It may be even less - perhaps 75
ohms or less. The same charts show an approximate 5 dB range of response at
20 KHz but less than 1 dB variation at 10 KHz. None of this is all that
audibly significant.

aside The high frequency variation relates to a resonance between the
source inductance of the SM57 and a cable capacitance on the order of 0.035
uF. The resonance centers at about 45 KHz, from which the equivalent source
impedance of the SM57 can be calculated.

I would expect less than 1 dB variation due to adding a 1K ohm resistor.
This means that even in your pessimistic estimate, there would be a 1 dB
loss of CMRR which is almost always negligible, even in a high noise
environment.

dufus wrote:

can i just put a 1k resistor across pins 2 and 3?

Absolutely. This is not that different from what happens when you add many
mic attenuators. The mic attenuators I've examined provide load impedances
in the 1 to 2.5 Kohm range. Attenuators that are connected across pins 2 &
3 are generally recommended because of their minimal effect on CMRR

to my understanding
this degrades CMRR, since the differential signal is knocked down, but
not the common mode.

The real question is not CMRR, its resistance to externally-generated noise.
Do you have reason to believe that common mode noise is currently a serious
problem with your system? Or, are just worrying about possibilities, as
opposed to realities?

how much would CMRR degrade in dB with a preamp
with a ~5k input Z?

Don't know, because this calculation would be based on the source impedance
of the SM-57, not the input impedance of the preamp.

An interesting related article can be found at
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF

Most interesting is:

"Figure 3 shows the effect of preamp input resistance (and capacitance) on
frequency response of a Shure SM57 with 100 feet of common cable. The upper
curves, 10 kS and 3 kS, are typical of transformer-less mic preamps while
the lower curve, 1.5 kS, is typical of a transformer input mic preamp. Note
the ultra-sonic peaks in response caused by insufficient damping".

This chart gives some insight into the output impedance of a SM57. To
summarize, there is negligible change in response at 3 KHz with load
impedances varying from 1,500 ohms to 10,000 ohms. IOW, the source impedance
of a SM57 in the normal audio range (20 KHz) is quite small. Other sources
give it as being 150 ohms or 310 ohms. It may be even less - perhaps 75
ohms or less. The same charts show an approximate 5 dB range of response at
20 KHz but less than 1 dB variation at 10 KHz. None of this is all that
audibly significant.

aside The high frequency variation relates to a resonance between the
source inductance of the SM57 and a cable capacitance on the order of 0.035
uF. The resonance centers at about 45 KHz, from which the equivalent source
impedance of the SM57 can be calculated.

I would expect less than 1 dB variation due to adding a 1K ohm resistor.
This means that even in your pessimistic estimate, there would be a 1 dB
loss of CMRR which is almost always negligible, even in a high noise
environment.

"Arny Krueger"

An interesting related article can be found at
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF

Most interesting is:

"Figure 3 shows the effect of preamp input resistance (and capacitance) on
frequency response of a Shure SM57 with 100 feet of common cable. The
upper
curves, 10 kS and 3 kS, are typical of transformer-less mic preamps while
the lower curve, 1.5 kS, is typical of a transformer input mic preamp.
Note
the ultra-sonic peaks in response caused by insufficient damping".

This chart gives some insight into the output impedance of a SM57. To
summarize, there is negligible change in response at 3 KHz with load
impedances varying from 1,500 ohms to 10,000 ohms. IOW, the source
impedance
of a SM57 in the normal audio range (20 KHz) is quite small. Other
sources
give it as being 150 ohms or 310 ohms. It may be even less - perhaps 75
ohms or less. The same charts show an approximate 5 dB range of response
at
20 KHz but less than 1 dB variation at 10 KHz. None of this is all that
audibly significant.


** Fig 3 in the Jensen article shows an overall variation of less than 2dB
at 20kHz for the three load impedances at the end of 100 feet of cable
driven by an SM57. At 15 kHz, or the highest frequency an SM57 actually
reproduces, the variation is less than 1 dB while at 10 kHz that variation
is less than 0.5 dB.

The HF response variation between different samples of the SM57 is a lot
greater than that !!



............. Phil

"Arny Krueger"

An interesting related article can be found at
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF

Most interesting is:

"Figure 3 shows the effect of preamp input resistance (and capacitance) on
frequency response of a Shure SM57 with 100 feet of common cable. The
upper
curves, 10 kS and 3 kS, are typical of transformer-less mic preamps while
the lower curve, 1.5 kS, is typical of a transformer input mic preamp.
Note
the ultra-sonic peaks in response caused by insufficient damping".

This chart gives some insight into the output impedance of a SM57. To
summarize, there is negligible change in response at 3 KHz with load
impedances varying from 1,500 ohms to 10,000 ohms. IOW, the source
impedance
of a SM57 in the normal audio range (20 KHz) is quite small. Other
sources
give it as being 150 ohms or 310 ohms. It may be even less - perhaps 75
ohms or less. The same charts show an approximate 5 dB range of response
at
20 KHz but less than 1 dB variation at 10 KHz. None of this is all that
audibly significant.


** Fig 3 in the Jensen article shows an overall variation of less than 2dB
at 20kHz for the three load impedances at the end of 100 feet of cable
driven by an SM57. At 15 kHz, or the highest frequency an SM57 actually
reproduces, the variation is less than 1 dB while at 10 kHz that variation
is less than 0.5 dB.

The HF response variation between different samples of the SM57 is a lot
greater than that !!



............. Phil

Phil Allison wrote:
"Arny Krueger"

An interesting related article can be found at
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF

Most interesting is:

"Figure 3 shows the effect of preamp input resistance (and
capacitance) on frequency response of a Shure SM57 with 100 feet of
common cable. The upper
curves, 10 kS and 3 kS, are typical of transformer-less mic preamps
while the lower curve, 1.5 kS, is typical of a transformer input mic
preamp. Note
the ultra-sonic peaks in response caused by insufficient damping".

This chart gives some insight into the output impedance of a SM57. To
summarize, there is negligible change in response at 3 KHz with load
impedances varying from 1,500 ohms to 10,000 ohms. IOW, the source
impedance of a SM57 in the normal audio range (20 KHz) is quite
small. Other sources
give it as being 150 ohms or 310 ohms. It may be even less -
perhaps 75 ohms or less. The same charts show an approximate 5 dB
range of response at
20 KHz but less than 1 dB variation at 10 KHz. None of this is all
that audibly significant.

** Fig 3 in the Jensen article shows an overall variation of less
than 2dB at 20kHz for the three load impedances at the end of 100
feet of cable driven by an SM57. At 15 kHz, or the highest frequency
an SM57 actually reproduces, the variation is less than 1 dB while at
10 kHz that variation is less than 0.5 dB.

The HF response variation between different samples of the SM57 is
a lot greater than that !!

This article seems to throw quite a bit of cold water on the many claims of
dramatic sonic differences due to real-world variations in the loading of
SM57s by various preamps and cables.

Phil Allison wrote:
"Arny Krueger"

An interesting related article can be found at
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF

Most interesting is:

"Figure 3 shows the effect of preamp input resistance (and
capacitance) on frequency response of a Shure SM57 with 100 feet of
common cable. The upper
curves, 10 kS and 3 kS, are typical of transformer-less mic preamps
while the lower curve, 1.5 kS, is typical of a transformer input mic
preamp. Note
the ultra-sonic peaks in response caused by insufficient damping".

This chart gives some insight into the output impedance of a SM57. To
summarize, there is negligible change in response at 3 KHz with load
impedances varying from 1,500 ohms to 10,000 ohms. IOW, the source
impedance of a SM57 in the normal audio range (20 KHz) is quite
small. Other sources
give it as being 150 ohms or 310 ohms. It may be even less -
perhaps 75 ohms or less. The same charts show an approximate 5 dB
range of response at
20 KHz but less than 1 dB variation at 10 KHz. None of this is all
that audibly significant.

** Fig 3 in the Jensen article shows an overall variation of less
than 2dB at 20kHz for the three load impedances at the end of 100
feet of cable driven by an SM57. At 15 kHz, or the highest frequency
an SM57 actually reproduces, the variation is less than 1 dB while at
10 kHz that variation is less than 0.5 dB.

The HF response variation between different samples of the SM57 is
a lot greater than that !!

This article seems to throw quite a bit of cold water on the many claims of
dramatic sonic differences due to real-world variations in the loading of
SM57s by various preamps and cables.

Arny Krueger wrote:

Phil Allison wrote:

"Arny Krueger"

An interesting related article can be found at
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF


Most interesting is:


"Figure 3 shows the effect of preamp input resistance (and
capacitance) on frequency response of a Shure SM57 with 100 feet of
common cable. The upper
curves, 10 kS and 3 kS, are typical of transformer-less mic preamps
while the lower curve, 1.5 kS, is typical of a transformer input mic
preamp. Note
the ultra-sonic peaks in response caused by insufficient damping".


This chart gives some insight into the output impedance of a SM57. To
summarize, there is negligible change in response at 3 KHz with load
impedances varying from 1,500 ohms to 10,000 ohms. IOW, the source
impedance of a SM57 in the normal audio range (20 KHz) is quite
small. Other sources
give it as being 150 ohms or 310 ohms. It may be even less -
perhaps 75 ohms or less. The same charts show an approximate 5 dB
range of response at
20 KHz but less than 1 dB variation at 10 KHz. None of this is all
that audibly significant.


** Fig 3 in the Jensen article shows an overall variation of less
than 2dB at 20kHz for the three load impedances at the end of 100
feet of cable driven by an SM57. At 15 kHz, or the highest frequency
an SM57 actually reproduces, the variation is less than 1 dB while at
10 kHz that variation is less than 0.5 dB.


The HF response variation between different samples of the SM57 is
a lot greater than that !!


This article seems to throw quite a bit of cold water on the many claims of
dramatic sonic differences due to real-world variations in the loading of
SM57s by various preamps and cables.

It looks to me as though it's comparing the impact of different loading resistors across the inputs of a particular preamp on the output frequency response of SM57s. Many of the sonic diffrerence claims (and my own experience) show a marked difference between the sound of an SM-57 feeding a high impedance transformerless preamp when compared with that produced by one feeding a transformer-fronted preamp.

Arny Krueger wrote:

Phil Allison wrote:

"Arny Krueger"

An interesting related article can be found at
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF


Most interesting is:


"Figure 3 shows the effect of preamp input resistance (and
capacitance) on frequency response of a Shure SM57 with 100 feet of
common cable. The upper
curves, 10 kS and 3 kS, are typical of transformer-less mic preamps
while the lower curve, 1.5 kS, is typical of a transformer input mic
preamp. Note
the ultra-sonic peaks in response caused by insufficient damping".


This chart gives some insight into the output impedance of a SM57. To
summarize, there is negligible change in response at 3 KHz with load
impedances varying from 1,500 ohms to 10,000 ohms. IOW, the source
impedance of a SM57 in the normal audio range (20 KHz) is quite
small. Other sources
give it as being 150 ohms or 310 ohms. It may be even less -
perhaps 75 ohms or less. The same charts show an approximate 5 dB
range of response at
20 KHz but less than 1 dB variation at 10 KHz. None of this is all
that audibly significant.


** Fig 3 in the Jensen article shows an overall variation of less
than 2dB at 20kHz for the three load impedances at the end of 100
feet of cable driven by an SM57. At 15 kHz, or the highest frequency
an SM57 actually reproduces, the variation is less than 1 dB while at
10 kHz that variation is less than 0.5 dB.


The HF response variation between different samples of the SM57 is
a lot greater than that !!


This article seems to throw quite a bit of cold water on the many claims of
dramatic sonic differences due to real-world variations in the loading of
SM57s by various preamps and cables.

It looks to me as though it's comparing the impact of different loading resistors across the inputs of a particular preamp on the output frequency response of SM57s. Many of the sonic diffrerence claims (and my own experience) show a marked difference between the sound of an SM-57 feeding a high impedance transformerless preamp when compared with that produced by one feeding a transformer-fronted preamp.

In article writes:

This article seems to throw quite a bit of cold water on the many claims of
dramatic sonic differences due to real-world variations in the loading of
SM57s by various preamps and cables.

I didn't see the article you're talking about, but experience has
shown that there's a noticable difference in sound (not necessarily
limited to frequency response) depending on whether an SM57 is
connected to a preamp with an input transformer or without. It
probably has more to do with the transformer in the SM57 than anything
else.

A good illustration would be to plug an SM57 into a Groove Tube ViPRE
and twiddle the input impedance switch. That changes taps on a
transformer, and there may be a "transformerless" setting. But then
we'd get to arguing the benefits of "warm" vs. "transparent."


--
I'm really Mike Rivers - )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article writes:

This article seems to throw quite a bit of cold water on the many claims of
dramatic sonic differences due to real-world variations in the loading of
SM57s by various preamps and cables.

I didn't see the article you're talking about, but experience has
shown that there's a noticable difference in sound (not necessarily
limited to frequency response) depending on whether an SM57 is
connected to a preamp with an input transformer or without. It
probably has more to do with the transformer in the SM57 than anything
else.

A good illustration would be to plug an SM57 into a Groove Tube ViPRE
and twiddle the input impedance switch. That changes taps on a
transformer, and there may be a "transformerless" setting. But then
we'd get to arguing the benefits of "warm" vs. "transparent."


--
I'm really Mike Rivers - )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article ,
Kurt Albershardt wrote:

Arny Krueger wrote:

This article seems to throw quite a bit of cold water on the many claims of
dramatic sonic differences due to real-world variations in the loading of
SM57s by various preamps and cables.

It looks to me as though it's comparing the impact of different loading
resistors across the inputs of a particular preamp on the output frequency
response of SM57s. Many of the sonic diffrerence claims (and my own
experience) show a marked difference between the sound of an SM-57 feeding a
high impedance transformerless preamp when compared with that produced by one
feeding a transformer-fronted preamp.

Bingo. The low end is one place that a transformer loaded preamp can't
be compared to a transformerless preamp. Basically, the input
transformer is not ideal, and since it has a finite number of turns in
its primary and a core of finite permeability, the input inductance may
not be high enough to present the same load at low frequencies as is
presented to the mike at 1KHz.

To a dynamic mike, this will directly influence the mechanics of the
transducer. This load impedance is reflected into the transducer and
will change the damping quite readily. Practically, I have found that
some transformer input preamps like the Groove Tubes VIPRE that use
transformer tap switching (and not high quality resistors) to control
the input impedance can offer a fairly complex input impedance that can
greatly color a 57. In my experience, this coloration is far from
subtle. We're talking 4-8dB of coloration here... hardly the stuff that
needs to be argued over with DBT.

One odd effect I have also noticed with the GT VIPRE is an added peak
around 4-8KHz with low load impedances and a Shure 57/545/547 type of
mike. I don't know why this happens, but it can sound pretty nice
sometimes, and godawful shrill when you don't want it. That's why the
impedance switch is there... right? ;-)

One final observation... I have noticed that you (Arny) seem to have a
bias that prefers not to hear differences between pieces of gear, even
though such differences might be reasonably well known to other
engineers and sometimes exploited on a regular basis by those same
folks. I'm curious as to how this bias helps you get along with
life...? I suppose in the ideal case it more accurately models how
things happen in your world, but I find it odd that it doesn't line up
with what happens in a lot of other folks' worlds who came to some
conclusion without having knowledge that others came to the same
conclusion.


Regards,

Monte McGuire

In article ,
Kurt Albershardt wrote:

Arny Krueger wrote:

This article seems to throw quite a bit of cold water on the many claims of
dramatic sonic differences due to real-world variations in the loading of
SM57s by various preamps and cables.

It looks to me as though it's comparing the impact of different loading
resistors across the inputs of a particular preamp on the output frequency
response of SM57s. Many of the sonic diffrerence claims (and my own
experience) show a marked difference between the sound of an SM-57 feeding a
high impedance transformerless preamp when compared with that produced by one
feeding a transformer-fronted preamp.

Bingo. The low end is one place that a transformer loaded preamp can't
be compared to a transformerless preamp. Basically, the input
transformer is not ideal, and since it has a finite number of turns in
its primary and a core of finite permeability, the input inductance may
not be high enough to present the same load at low frequencies as is
presented to the mike at 1KHz.

To a dynamic mike, this will directly influence the mechanics of the
transducer. This load impedance is reflected into the transducer and
will change the damping quite readily. Practically, I have found that
some transformer input preamps like the Groove Tubes VIPRE that use
transformer tap switching (and not high quality resistors) to control
the input impedance can offer a fairly complex input impedance that can
greatly color a 57. In my experience, this coloration is far from
subtle. We're talking 4-8dB of coloration here... hardly the stuff that
needs to be argued over with DBT.

One odd effect I have also noticed with the GT VIPRE is an added peak
around 4-8KHz with low load impedances and a Shure 57/545/547 type of
mike. I don't know why this happens, but it can sound pretty nice
sometimes, and godawful shrill when you don't want it. That's why the
impedance switch is there... right? ;-)

One final observation... I have noticed that you (Arny) seem to have a
bias that prefers not to hear differences between pieces of gear, even
though such differences might be reasonably well known to other
engineers and sometimes exploited on a regular basis by those same
folks. I'm curious as to how this bias helps you get along with
life...? I suppose in the ideal case it more accurately models how
things happen in your world, but I find it odd that it doesn't line up
with what happens in a lot of other folks' worlds who came to some
conclusion without having knowledge that others came to the same
conclusion.


Regards,

Monte McGuire

Kurt Albershardt wrote:
Arny Krueger wrote:

Phil Allison wrote:

"Arny Krueger"

An interesting related article can be found at
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF

Most interesting is:

"Figure 3 shows the effect of preamp input resistance (and
capacitance) on frequency response of a Shure SM57 with 100 feet of
common cable. The upper
curves, 10 kS and 3 kS, are typical of transformer-less mic preamps
while the lower curve, 1.5 kS, is typical of a transformer input
mic preamp. Note
the ultra-sonic peaks in response caused by insufficient damping".

This chart gives some insight into the output impedance of a SM57.
To summarize, there is negligible change in response at 3 KHz with
load impedances varying from 1,500 ohms to 10,000 ohms. IOW, the
source impedance of a SM57 in the normal audio range (20 KHz) is
quite small. Other sources
give it as being 150 ohms or 310 ohms. It may be even less -
perhaps 75 ohms or less. The same charts show an approximate 5 dB
range of response at
20 KHz but less than 1 dB variation at 10 KHz. None of this is all
that audibly significant.

** Fig 3 in the Jensen article shows an overall variation of less
than 2dB at 20kHz for the three load impedances at the end of 100
feet of cable driven by an SM57. At 15 kHz, or the highest
frequency an SM57 actually reproduces, the variation is less than 1
dB while at 10 kHz that variation is less than 0.5 dB.

The HF response variation between different samples of the SM57 is
a lot greater than that !!

This article seems to throw quite a bit of cold water on the many
claims of dramatic sonic differences due to real-world variations in
the loading of SM57s by various preamps and cables.

It looks to me as though it's comparing the impact of different
loading resistors across the inputs of a particular preamp on the
output frequency response of SM57s.

Right, and that's what I said, isn't it?

Many of the sonic difference
claims (and my own experience) show a marked difference between the
sound of an SM-57 feeding a high impedance transformerless preamp
when compared with that produced by one feeding a transformer-fronted
preamp.

Sure, and the effects of transformer loading are not directly addressed
here. But what is addressed here relates to variations in resistive and
capacitive loading.

We've seen various claims about how preamps with various resistive input
impedances can make SM-57s sound dramatically different, right? It appears
that those claims have now been soaked with cold water by these careful,
real-world measurements. There are substantial measured changes in
performance, but they are all outside the audible range.

The bottom line is that these tests show that a SM-57 presents a relatively
low-impedance source to whatever loads it. They show that SM-57s tend to
perform in an audibly similar fashion with various combinations of
resistance and reactance.

Transformer-input preamps add two dimensions that these tests don't address
directly. First there is the response of the transformer itself. It
obviously acts like a bandpass filter of some kind. Secondly, transformers
can present inductive loads to microphones because the transformers
themselves can have inductance. This is shown as Lt in figure 5 for
example. The article seems to encourage us to ignore both of these, because
it does not mention any effects that are associated with them. It may be
that because of their quality, Jensen transformers have reduced the effects
of these parameters to the point where they can be safely ignored.

Kurt Albershardt wrote:
Arny Krueger wrote:

Phil Allison wrote:

"Arny Krueger"

An interesting related article can be found at
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF

Most interesting is:

"Figure 3 shows the effect of preamp input resistance (and
capacitance) on frequency response of a Shure SM57 with 100 feet of
common cable. The upper
curves, 10 kS and 3 kS, are typical of transformer-less mic preamps
while the lower curve, 1.5 kS, is typical of a transformer input
mic preamp. Note
the ultra-sonic peaks in response caused by insufficient damping".

This chart gives some insight into the output impedance of a SM57.
To summarize, there is negligible change in response at 3 KHz with
load impedances varying from 1,500 ohms to 10,000 ohms. IOW, the
source impedance of a SM57 in the normal audio range (20 KHz) is
quite small. Other sources
give it as being 150 ohms or 310 ohms. It may be even less -
perhaps 75 ohms or less. The same charts show an approximate 5 dB
range of response at
20 KHz but less than 1 dB variation at 10 KHz. None of this is all
that audibly significant.

** Fig 3 in the Jensen article shows an overall variation of less
than 2dB at 20kHz for the three load impedances at the end of 100
feet of cable driven by an SM57. At 15 kHz, or the highest
frequency an SM57 actually reproduces, the variation is less than 1
dB while at 10 kHz that variation is less than 0.5 dB.

The HF response variation between different samples of the SM57 is
a lot greater than that !!

This article seems to throw quite a bit of cold water on the many
claims of dramatic sonic differences due to real-world variations in
the loading of SM57s by various preamps and cables.

It looks to me as though it's comparing the impact of different
loading resistors across the inputs of a particular preamp on the
output frequency response of SM57s.

Right, and that's what I said, isn't it?

Many of the sonic difference
claims (and my own experience) show a marked difference between the
sound of an SM-57 feeding a high impedance transformerless preamp
when compared with that produced by one feeding a transformer-fronted
preamp.

Sure, and the effects of transformer loading are not directly addressed
here. But what is addressed here relates to variations in resistive and
capacitive loading.

We've seen various claims about how preamps with various resistive input
impedances can make SM-57s sound dramatically different, right? It appears
that those claims have now been soaked with cold water by these careful,
real-world measurements. There are substantial measured changes in
performance, but they are all outside the audible range.

The bottom line is that these tests show that a SM-57 presents a relatively
low-impedance source to whatever loads it. They show that SM-57s tend to
perform in an audibly similar fashion with various combinations of
resistance and reactance.

Transformer-input preamps add two dimensions that these tests don't address
directly. First there is the response of the transformer itself. It
obviously acts like a bandpass filter of some kind. Secondly, transformers
can present inductive loads to microphones because the transformers
themselves can have inductance. This is shown as Lt in figure 5 for
example. The article seems to encourage us to ignore both of these, because
it does not mention any effects that are associated with them. It may be
that because of their quality, Jensen transformers have reduced the effects
of these parameters to the point where they can be safely ignored.

Monte McGuire wrote:

One final observation... I have noticed that you (Arny) seem to have a
bias that prefers not to hear differences between pieces of gear, even
though such differences might be reasonably well known to other
engineers and sometimes exploited on a regular basis by those same
folks.

Monte, I guess this means that you think that the principles of science and
audio engineering are up for a vote, a vote that involves only the people
you choose.

I'm curious as to how this bias helps you get along with life...?

That bias is a figment of your imagination Monte, so the question falls back
on you. How do you find that making false claims about people based on
taking their discussions well outside of their intended domain, helps you
get along in life?

I've got no problem with disagreeing with people who are poorly-informed,
have tightly held beliefs based on weak or non-existent proof, and don't do
their homework.

I suppose in the ideal case it more accurately models how
things happen in your world, but I find it odd that it doesn't line up
with what happens in a lot of other folks' worlds who came to some
conclusion without having knowledge that others came to the same
conclusion.

I think that you just don't get the truth and honesty thing, Monte. I made
comments that are based on well-documented, well-supported high frequency
differences, and you tried to falsify them with a bunch of unsupported,
undocumented assertions about low frequency differences. Then you
extrapolate from that weirdness to some other assertions that border on
personal attacks, relating to whether or not I like to hear differences.

For the record, I like to hear differences that are not figments of people's
imaginations, since so many of them are.

Monte I guess you need to be reminded hat I said:

"This article seems to throw quite a bit of cold water on the many claims of
dramatic sonic differences due to real-world variations in the loading of
SM57s by various preamps and cables."

Monte, I didn't say "all claims", I said "many claims". You obviously
extrapolated "many claims" to "all claims" and started waving your
defensiveness flag. Your bad, not mine.

Hey Monte, if this sort of thing helps you get through the day, fine. Just
don't expect me to suffer silently through this kind of poorly-reasoned and
poorly-supported abuse. When you've got some support for your claims that
are as thoroughly documented and complete as Bill Whitlock's paper,
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF
be sure to share it. I mean it!

I haven't been following whatever you and Monte have been kicking
around. However, after briefly peaking at the post below - ouch - I
wanted to comment.

Monte is a pro in this field with lots of happy clients. You Arny seem
more interested in debating stuff rather than recording and mixing
stuff.

If I am wrong about this, then get out there and smell the salt air.
[It was a beautifully warm and humid day here in SE New England - my
studio is close to the water and the thick humid air this evening
smelled great!] Happy clients don't care in theory. Their do care
tremendously about the sound of their final product. Great sounding
final products don't fall off trucks or appear by happenstance. Nor may
I add does longtime success in this industry.

Also, I had to wince about your comment to him about truth and honesty.
I have only spoken with Monte in person once and found him as measured,
reasonable and pleasant as his years of posts both here and on the
dawmac list.

I guess what I'm really saying is I wanted to stand up for Monte. Even
while sitting down typing this.




David Correia
Celebration Sound
Warren, Rhode Island


www.CelebrationSound.com





In article , Arny Krueger
wrote:

Monte McGuire wrote:

One final observation... I have noticed that you (Arny) seem to have a
bias that prefers not to hear differences between pieces of gear, even
though such differences might be reasonably well known to other
engineers and sometimes exploited on a regular basis by those same
folks.

Monte, I guess this means that you think that the principles of science and
audio engineering are up for a vote, a vote that involves only the people
you choose.

I'm curious as to how this bias helps you get along with life...?

That bias is a figment of your imagination Monte, so the question falls back
on you. How do you find that making false claims about people based on
taking their discussions well outside of their intended domain, helps you
get along in life?

I've got no problem with disagreeing with people who are poorly-informed,
have tightly held beliefs based on weak or non-existent proof, and don't do
their homework.

I suppose in the ideal case it more accurately models how
things happen in your world, but I find it odd that it doesn't line up
with what happens in a lot of other folks' worlds who came to some
conclusion without having knowledge that others came to the same
conclusion.

I think that you just don't get the truth and honesty thing, Monte. I made
comments that are based on well-documented, well-supported high frequency
differences, and you tried to falsify them with a bunch of unsupported,
undocumented assertions about low frequency differences. Then you
extrapolate from that weirdness to some other assertions that border on
personal attacks, relating to whether or not I like to hear differences.

For the record, I like to hear differences that are not figments of people's
imaginations, since so many of them are.

Monte I guess you need to be reminded hat I said:

"This article seems to throw quite a bit of cold water on the many claims of
dramatic sonic differences due to real-world variations in the loading of
SM57s by various preamps and cables."

Monte, I didn't say "all claims", I said "many claims". You obviously
extrapolated "many claims" to "all claims" and started waving your
defensiveness flag. Your bad, not mine.

Hey Monte, if this sort of thing helps you get through the day, fine. Just
don't expect me to suffer silently through this kind of poorly-reasoned and
poorly-supported abuse. When you've got some support for your claims that
are as thoroughly documented and complete as Bill Whitlock's paper,
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF
be sure to share it. I mean it!

david wrote:
I haven't been following whatever you and Monte have been kicking
around. However, after briefly peaking at the post below - ouch - I
wanted to comment.

David, I'm sad to see that you think that Monte can't stand up for himself.

Arny Krueger wrote:

This article seems to throw quite a bit of cold water on the many claims of
dramatic sonic differences due to real-world variations in the loading of
SM57s by various preamps and cables.

This is a PSA.

If you hook a 57 to a Mackie 1202, and then hook it to a GRE MP2 and
can't hear a difference, please see your audiologist.
--
ha

david wrote:

I guess what I'm really saying is I wanted to stand up for Monte. Even
while sitting down typing this.

Monte is a professional recordist, mixer, and producer. He had the balls
to try simultaneous FOH, mons, and live recording all from one PT rig
before the hard and soft ware was up to it. Once the kit would float, he
did it, and the result is product. He makes daily decisons based on what
he gets from his ears, and by invoking actions based on those decision,
he makes his living. Enough said.

--
ha

Arny Krueger wrote:

david wrote:
I haven't been following whatever you and Monte have been kicking
around. However, after briefly peaking at the post below - ouch - I
wanted to comment.

David, I'm sad to see that you think that Monte can't stand up for himself.

Surely you must have heavier **** to be sad about. I doubt Monte has all
that much time to **** with theory. He's making his living as an audio
pro, in the real field, in real time.

--
ha

hank alrich wrote:
Arny Krueger wrote:

This article seems to throw quite a bit of cold water on the many
claims of dramatic sonic differences due to real-world variations in
the loading of SM57s by various preamps and cables.

This is a PSA.

If you hook a 57 to a Mackie 1202, and then hook it to a GRE MP2 and
can't hear a difference, please see your audiologist.

Well Hank you charming devil, if you think this discussion suggests that
there can't or shouldn't possibly be an audible difference in that
situation, then you need to learn the difference between a console and a
stand-alone mic preamp.

;-)

"Arny Krueger" wrote in message
...
hank alrich wrote:
Arny Krueger wrote:

This article seems to throw quite a bit of cold water on the many
claims of dramatic sonic differences due to real-world variations in
the loading of SM57s by various preamps and cables.

This is a PSA.

If you hook a 57 to a Mackie 1202, and then hook it to a GRE MP2 and
can't hear a difference, please see your audiologist.

Well Hank you charming devil, if you think this discussion suggests that
there can't or shouldn't possibly be an audible difference in that
situation, then you need to learn the difference between a console and a
stand-alone mic preamp.

Same difference tends to apply to a Sytek and a Great River. The SM57 really
seems to react differently to a resistive load than to a transformer.

Peace,
Paul

"Arny Krueger" wrote in message ...
Phil Allison wrote:
"Arny Krueger"

An interesting related article can be found at
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF

Most interesting is:

"Figure 3 shows the effect of preamp input resistance (and
capacitance) on frequency response of a Shure SM57 with 100 feet of
common cable. The upper
curves, 10 kS and 3 kS, are typical of transformer-less mic preamps
while the lower curve, 1.5 kS, is typical of a transformer input mic
preamp. Note
the ultra-sonic peaks in response caused by insufficient damping".

This chart gives some insight into the output impedance of a SM57. To
summarize, there is negligible change in response at 3 KHz with load
impedances varying from 1,500 ohms to 10,000 ohms. IOW, the source
impedance of a SM57 in the normal audio range (20 KHz) is quite
small. Other sources
give it as being 150 ohms or 310 ohms. It may be even less -
perhaps 75 ohms or less. The same charts show an approximate 5 dB
range of response at
20 KHz but less than 1 dB variation at 10 KHz. None of this is all
that audibly significant.

** Fig 3 in the Jensen article shows an overall variation of less
than 2dB at 20kHz for the three load impedances at the end of 100
feet of cable driven by an SM57. At 15 kHz, or the highest frequency
an SM57 actually reproduces, the variation is less than 1 dB while at
10 kHz that variation is less than 0.5 dB.

The HF response variation between different samples of the SM57 is
a lot greater than that !!

This article seems to throw quite a bit of cold water on the many claims of
dramatic sonic differences due to real-world variations in the loading of
SM57s by various preamps and cables.

I was under the impression that the interesting loads for the SM-57
were reactive rather than resistive. I think Mark McQ added some
reactive load (a low pass filter on the input for RF rejection) to his
RNP in part for this reason.

rossi

hank alrich wrote:
Arny Krueger wrote:

This article seems to throw quite a bit of cold water on the many claims of
dramatic sonic differences due to real-world variations in the loading of
SM57s by various preamps and cables.

This is a PSA.

If you hook a 57 to a Mackie 1202, and then hook it to a GRE MP2 and
can't hear a difference, please see your audiologist.

And, it's measurable. I've only done frequency response, not impulse
response, though. Anyone who gets a good set of impulse responses with
different loads should be able to get a nice JAES paper out of it.

Be aware that the GRE MP2 input is reactive, too!
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Chris Rossi wrote:
"Arny Krueger" wrote in message
...
Phil Allison wrote:
"Arny Krueger"

An interesting related article can be found at
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF

Most interesting is:

"Figure 3 shows the effect of preamp input resistance (and
capacitance) on frequency response of a Shure SM57 with 100 feet of
common cable. The upper
curves, 10 kS and 3 kS, are typical of transformer-less mic preamps
while the lower curve, 1.5 kS, is typical of a transformer input
mic preamp. Note
the ultra-sonic peaks in response caused by insufficient damping".

This chart gives some insight into the output impedance of a SM57.
To summarize, there is negligible change in response at 3 KHz with
load impedances varying from 1,500 ohms to 10,000 ohms. IOW, the
source impedance of a SM57 in the normal audio range (20 KHz) is
quite small. Other sources
give it as being 150 ohms or 310 ohms. It may be even less -
perhaps 75 ohms or less. The same charts show an approximate 5 dB
range of response at
20 KHz but less than 1 dB variation at 10 KHz. None of this is all
that audibly significant.

** Fig 3 in the Jensen article shows an overall variation of less
than 2dB at 20kHz for the three load impedances at the end of 100
feet of cable driven by an SM57. At 15 kHz, or the highest
frequency an SM57 actually reproduces, the variation is less than 1
dB while at 10 kHz that variation is less than 0.5 dB.

The HF response variation between different samples of the SM57 is
a lot greater than that !!

This article seems to throw quite a bit of cold water on the many
claims of dramatic sonic differences due to real-world variations in
the loading of SM57s by various preamps and cables.

I was under the impression that the interesting loads for the SM-57
were reactive rather than resistive. I think Mark McQ added some
reactive load (a low pass filter on the input for RF rejection) to his
RNP in part for this reason.

Check figure 4 in the reference:
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF
for information about the effects of reactive loads on the SM-57.

Basically, with a load on the order of a relatively large 25,000pF there a
mere 2 dB increase at 15 KHz. A large 2,500 pF load gives just a 1.2 dB
increase at 20 KHz. Both peaks are fairly narrow and lightly damped, so
their effects in the main part of the audible range (10 KHz) are less than
1.5 dB (25,000 pF) or less than 0.3 dB (2,500 pF).

Since the RNP and the GRE have been mentioned, perhaps people who have them
can see what's inside the box in this area. Compared to the mic's response
variations in the same frequency ranges, this is all chump change.

Arny Krueger wrote:

Well Hank you charming devil, if you think this discussion suggests that
there can't or shouldn't possibly be an audible difference in that
situation, then you need to learn the difference between a console and a
stand-alone mic preamp.

Take the Mackie's pre out via the insert and get back to me or to your
audiologist. g

(I've had consoles: Sony, Altec, a custom one we built around API
components, Midas, Sphere, Soundcraft, Mackie, Allen & Heath. I've
driven a few dozen consoles that weren't mine.)

The point is that generalizing from spec sheets and theory doesn't
always hold up well in the practical world of real audio, where the
invoice meets the payment. While Jensen's calculations demonstrate the
likely variance in response for changes in resistive loading of a
microphone they certainly do not exclude the possibility that mic
response will be altered by interaction with various preamps, resistive
load being only a portion of the equation. When people discuss the
variations in mic response with different mic cables, they are generally
talking about the effects of capacitance.

--
ha

hank alrich wrote:

The point is that generalizing from spec sheets and theory doesn't
always hold up well in the practical world of real audio, where the
invoice meets the payment.

Well established theories are generally right, but our applications of them
are often more flawed. Is that the fault of the theory? Does pooh-poohing
theories that disagree with or challenge our long held-beliefs really help
anybody?

While Jensen's calculations demonstrate the
likely variance in response for changes in resistive loading of a
microphone they certainly do not exclude the possibility that mic
response will be altered by interaction with various preamps,
resistive load being only a portion of the equation.

In this case, both resistive loading and capacitive loading were discussed
by Whitlock.

When people
discuss the variations in mic response with different mic cables,
they are generally talking about the effects of capacitance.

The irony of all this is that while Figure 3 in the Whitlock paper covered
the effect of resistive loads on a SM57, the next figure, figure 4 covered
the effect of various cable lengths on a SM57. As I covered in detail in
another post, the capacitive load study had similar results to the resistive
load study. So Hank, you're arguing against a straw man.

I'm really disappointed in all the people who have made this same straw man
argument, when the full text of the paper was just one click away. It's not
a long paper, and it is written very practically. In fact, its not a
theoretical paper at all, but a paper of real-world practical results.
People seem to have time to attack the paper on bogus grounds, but they
don't have time to even glance at it for a moment or two.

"Arny Krueger" wrote in message ...
Chris Rossi wrote:
"Arny Krueger" wrote in message
...
Phil Allison wrote:
"Arny Krueger"

An interesting related article can be found at
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF

Most interesting is:

"Figure 3 shows the effect of preamp input resistance (and
capacitance) on frequency response of a Shure SM57 with 100 feet of
common cable. The upper
curves, 10 kS and 3 kS, are typical of transformer-less mic preamps
while the lower curve, 1.5 kS, is typical of a transformer input
mic preamp. Note
the ultra-sonic peaks in response caused by insufficient damping".

This chart gives some insight into the output impedance of a SM57.
To summarize, there is negligible change in response at 3 KHz with
load impedances varying from 1,500 ohms to 10,000 ohms. IOW, the
source impedance of a SM57 in the normal audio range (20 KHz) is
quite small. Other sources
give it as being 150 ohms or 310 ohms. It may be even less -
perhaps 75 ohms or less. The same charts show an approximate 5 dB
range of response at
20 KHz but less than 1 dB variation at 10 KHz. None of this is all
that audibly significant.

** Fig 3 in the Jensen article shows an overall variation of less
than 2dB at 20kHz for the three load impedances at the end of 100
feet of cable driven by an SM57. At 15 kHz, or the highest
frequency an SM57 actually reproduces, the variation is less than 1
dB while at 10 kHz that variation is less than 0.5 dB.

The HF response variation between different samples of the SM57 is
a lot greater than that !!

This article seems to throw quite a bit of cold water on the many
claims of dramatic sonic differences due to real-world variations in
the loading of SM57s by various preamps and cables.

I was under the impression that the interesting loads for the SM-57
were reactive rather than resistive. I think Mark McQ added some
reactive load (a low pass filter on the input for RF rejection) to his
RNP in part for this reason.

Check figure 4 in the reference:
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF
for information about the effects of reactive loads on the SM-57.

Basically, with a load on the order of a relatively large 25,000pF there a
mere 2 dB increase at 15 KHz. A large 2,500 pF load gives just a 1.2 dB
increase at 20 KHz. Both peaks are fairly narrow and lightly damped, so
their effects in the main part of the audible range (10 KHz) are less than
1.5 dB (25,000 pF) or less than 0.3 dB (2,500 pF).

Since the RNP and the GRE have been mentioned, perhaps people who have them
can see what's inside the box in this area. Compared to the mic's response
variations in the same frequency ranges, this is all chump change.

Is simply measuring frequency response a reliable way of
characterizing the sound of a mic?

rossi

Chris Rossi wrote:
"Arny Krueger" wrote in message
...
Chris Rossi wrote:
"Arny Krueger" wrote in message
...
Phil Allison wrote:
"Arny Krueger"

An interesting related article can be found at
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF

Most interesting is:

"Figure 3 shows the effect of preamp input resistance (and
capacitance) on frequency response of a Shure SM57 with 100 feet
of common cable. The upper
curves, 10 kS and 3 kS, are typical of transformer-less mic
preamps while the lower curve, 1.5 kS, is typical of a
transformer input mic preamp. Note
the ultra-sonic peaks in response caused by insufficient
damping".

This chart gives some insight into the output impedance of a
SM57. To summarize, there is negligible change in response at 3
KHz with load impedances varying from 1,500 ohms to 10,000 ohms.
IOW, the source impedance of a SM57 in the normal audio range
(20 KHz) is quite small. Other sources
give it as being 150 ohms or 310 ohms. It may be even less -
perhaps 75 ohms or less. The same charts show an approximate 5 dB
range of response at
20 KHz but less than 1 dB variation at 10 KHz. None of this is
all that audibly significant.

** Fig 3 in the Jensen article shows an overall variation of
less than 2dB at 20kHz for the three load impedances at the end
of 100 feet of cable driven by an SM57. At 15 kHz, or the highest
frequency an SM57 actually reproduces, the variation is less than
1 dB while at 10 kHz that variation is less than 0.5 dB.

The HF response variation between different samples of the SM57
is a lot greater than that !!

This article seems to throw quite a bit of cold water on the many
claims of dramatic sonic differences due to real-world variations
in the loading of SM57s by various preamps and cables.

I was under the impression that the interesting loads for the SM-57
were reactive rather than resistive. I think Mark McQ added some
reactive load (a low pass filter on the input for RF rejection) to
his RNP in part for this reason.

Check figure 4 in the reference:
http://www.eetasia.com/ARTICLES/2002...MSD_POW_AN.PDF
for information about the effects of reactive loads on the SM-57.

Basically, with a load on the order of a relatively large 25,000pF
there a mere 2 dB increase at 15 KHz. A large 2,500 pF load gives
just a 1.2 dB increase at 20 KHz. Both peaks are fairly narrow and
lightly damped, so their effects in the main part of the audible
range (10 KHz) are less than
1.5 dB (25,000 pF) or less than 0.3 dB (2,500 pF).

Since the RNP and the GRE have been mentioned, perhaps people who
have them can see what's inside the box in this area. Compared to
the mic's response variations in the same frequency ranges, this is
all chump change.

Is simply measuring frequency response a reliable way of
characterizing the sound of a mic?

Depends. Consider the same mic connected to 2 different mic preamps first
one, then the other. Let's presume adequate overload and noise
characteristics for both preamps, and low distortion. IOW both preamps are
high quality pieces with very good performance. We find that there are no
important difference in the measured frequency response for the mic-preamp
combination when the mic is connected to either preamp. How different do you
expect them to sound?

Arny Krueger wrote:

The irony of all this is that while Figure 3 in the Whitlock paper covered
the effect of resistive loads on a SM57, the next figure, figure 4 covered
the effect of various cable lengths on a SM57. As I covered in detail in
another post, the capacitive load study had similar results to the resistive
load study. So Hank, you're arguing against a straw man.

The SM-57 wants an inductive load. This actually shouldn't be hard to do
with lumped sum inductors (which should be a lot cheaper than a transformer).
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

in article ,

Arny Krueger wrote:

The irony of all this is that while Figure 3 in the Whitlock paper covered
the effect of resistive loads on a SM57, the next figure, figure 4 covered
the effect of various cable lengths on a SM57. As I covered in detail in
another post, the capacitive load study had similar results to the resistive
load study. So Hank, you're arguing against a straw man.

Scott Dorsey at wrote on 6/14/04 10:41 AM:
The SM-57 wants an inductive load. This actually shouldn't be hard to do
with lumped sum inductors (which should be a lot cheaper than a transformer).
--scott


'wants and inductive load'... hmmm... how many transformers in a line want
more transformers after them? meaning: old question but... what's the take
on 57's with and without internal xfrmrs?
Not meant to be a leading question, now that I look at what I wrote and
think, since indeed a 57 by design/definition HAS a xfrmr in it... as does
most EVERY popular SHURE mic,
just that there are family members that DON'T... 57L, 545L, some of the
other cousins past and present (SM78), that come wired cartridge-to-pins...

and has anyone looked at the 57/preamp/sonics compare/contrast thing
including (oh the test variables...) identical 57's with and without?


--
John I-22
(that's 'I' for Initial...)
Recognising what's NOT worth your time, THAT'S the key.
--

JoVee wrote:

'wants and inductive load'... hmmm... how many transformers in a line want
more transformers after them? meaning: old question but... what's the take
on 57's with and without internal xfrmrs?

Taking the internal transformer out of the SM-57 turns it into a totally
different mike with a very different sound. This used to be a common thing
for drum miking back in the eighties.

Not meant to be a leading question, now that I look at what I wrote and
think, since indeed a 57 by design/definition HAS a xfrmr in it... as does
most EVERY popular SHURE mic,
just that there are family members that DON'T... 57L, 545L, some of the
other cousins past and present (SM78), that come wired cartridge-to-pins...

I believe these also have different coil designs on the element, though.

and has anyone looked at the 57/preamp/sonics compare/contrast thing
including (oh the test variables...) identical 57's with and without?

57s sound more like than they sound different, even the newer Mexican ones.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

in article , Scott Dorsey at
wrote on 6/14/04 4:07 PM:

JoVee wrote:

and has anyone looked at the 57/preamp/sonics compare/contrast thing
including (oh the test variables...) identical 57's with and without?

57s sound more like than they sound different, even the newer Mexican ones.
--scott

not quite what I meant to ask, was wondering about how a 57 sans-tran
interacts with various preamps (different loadings etc = different sounds)
vs a 57 avec.

did SHURE ever pot the trannies? some of my (bought-used) 57's have
xfrmr-in-caulk, most don't.

I sorta wish the most common mic failure (outside of obvious destruction)
wasn't internal wire-breaks... then I wouldn't have had to learn about all
this and could just relax...


--
John I-22
(that's 'I' for Initial...)
Recognising what's NOT worth your time, THAT'S the key.
--

JoVee wrote:
in article , Scott Dorsey at
wrote on 6/14/04 4:07 PM:

JoVee wrote:

and has anyone looked at the 57/preamp/sonics compare/contrast thing
including (oh the test variables...) identical 57's with and without?

57s sound more like than they sound different, even the newer Mexican ones.

not quite what I meant to ask, was wondering about how a 57 sans-tran
interacts with various preamps (different loadings etc = different sounds)
vs a 57 avec.

Dunno, but it will be different, because the transformer is not a 1:1 device,
so the optimal load impedance will be different at the very minimum.

did SHURE ever pot the trannies? some of my (bought-used) 57's have
xfrmr-in-caulk, most don't.

The newer ones have some gunk to hold the transformer in place, but I have
not seen any that were properly potted. Potting is a good idea for larger
transformers because it reduces distortion from the windings shifting in
place under load. I don't know if it's much of a win on small ones other
than just mechanical stability.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

in article , Scott Dorsey at
wrote on 6/15/04 9:37 AM:

JoVee wrote:

did SHURE ever pot the trannies? some of my (bought-used) 57's have
xfrmr-in-caulk, most don't.

The newer ones have some gunk to hold the transformer in place, but I have
not seen any that were properly potted.

ack... right.. potted is wind-sealed... i WAS talking about 'glued-down'



Potting is a good idea for larger
transformers because it reduces distortion from the windings shifting in
place under load. I don't know if it's much of a win on small ones other
than just mechanical stability.
--scott

Chris Rossi wrote:
were reactive rather than resistive. I think Mark McQ added some
reactive load (a low pass filter on the input for RF rejection) to his
RNP in part for this reason.

Sorry to change the subject here, but this may relate. As I understand
it, the RNP is a transformerless mic pre. According to a little
birdie who told me things, the blocking capacitors, necessary in
transformerless pres to protect the input from phantom power, cause a
certain amount of signal degradation, particularly in the top end.

However, this supposedly is not a factor when it comes to condensors
since when the phantom is switched on, the biasing to the capacitors
that results, somehow negates this problem.

Assuming any of this is true, has anyone ever tested with a dynamic
mic, plugged into a transformerless pre, whether or not the sound
improves (more clarity in the top end) by switching on the phantom
power!?

It may not matter with most dynamics, but what about some of the better
ones such as the 441 or RE20? And dare I say it...what about ribbon
mics, where switching on phantom is generally considered a no-no?

Rob R.

Rob Reedijk wrote in message ...
Chris Rossi wrote:
were reactive rather than resistive. I think Mark McQ added some
reactive load (a low pass filter on the input for RF rejection) to his
RNP in part for this reason.

Sorry to change the subject here, but this may relate. As I understand
it, the RNP is a transformerless mic pre. According to a little
birdie who told me things, the blocking capacitors, necessary in
transformerless pres to protect the input from phantom power, cause a
certain amount of signal degradation, particularly in the top end.

However, this supposedly is not a factor when it comes to condensors
since when the phantom is switched on, the biasing to the capacitors
that results, somehow negates this problem.

Assuming any of this is true, has anyone ever tested with a dynamic
mic, plugged into a transformerless pre, whether or not the sound
improves (more clarity in the top end) by switching on the phantom
power!?

You will hopefully get some better technical answers, but for now I'll
just say that it's my understanding that any good designer is going to
make sure any electrolytics in his/her design are properly biased.
I've noted in other discussions a belief by some of the electronic
whizzes of today that the bad name given to capacitors is largely a
result of early poor design resulting from a lack of understanding of
how to properly bias the caps. In general, today, designers today
don't make those mistakes. Anyway, a mic pre that behaved in the
manner you describe would indicate to me a bad design. I do have an
RNP and don't recall having ever encountered a difference in sound
with phantom engaged or not on a dynamic mic. I'll give it a shot
this week, though, just for grins.

rossi