[Richard Crowley]

"Truth" wrote ...
Eeyore wrote:
Truth wrote:
I even got some special power cords for the mic power supplies.

Why ? What did you expect it to do ? AC power doesn't need 'special
cords'.
They're only for gullible 'audiophools'.

Graham

Here are the cables I mentioned for the power supplies.

http://www.silversonic.com/docs/products/PowerPlus.html

Yes, that is exactly what we mean by "snake-oil" products
designed especially for "audiophools" who have more dollars
than sense. Their only remarkable feature is their high price.
Technically, they do absolutely nothing.

And if you *did* have a power-mains-borne noise problem,
that magic cable wouldn't fix it anyway. Those things are much
worse than nothing because they promise what they cannot
deliver and they just take ridiculous amounts of money by
trying to cheat you.

But it seems highly unlikely that your problem has anything to
do with power of any kind. That includes AC power from the
wall plug all the way through the power supply for your mics.

[William Sommerwerck]

I'm coming in late, so sorry if I repeat something some else already said.

If the mic is on a stand, try coiling the cable around the stand. I learned
this about 25 years ago, when experiencing RFI at a concert. Coiling the
cable can introduce enough inductance to "choke" the RF.

[Scott Dorsey]

Truth wrote:
House Power
Ribbon Mic's Power Box
Ribbon Mic's non standard cable, very long about 20 feet( I can't swap
it out to test it with something else)
2 Royer 122V Ribbon Mics

OKAY! So you don't have normal ribbon microphones at all. You have
the 122V.

So, the first question: Do you hear the problem with the 122V turned off?
If turning off the mike stops the noise, the rectification is taking place
inside the mike.

The second question: If you connect up only a single microphone, do you
hear it?
--scott

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

[Scott Dorsey]

Eeyore wrote:
Scott Dorsey wrote:

Eeyore wrote:
Scott Dorsey wrote:
AndyP wrote:

Does a preamp with a transformer balanced input do a better job rejecting
RF?

Almost always. There are some poorly-designed transformer inputs out
there too, though.

What kind of preamp, microphone, and cable are we dealing with here?
And what makes you think it's AM?

He said it was an AM station.

Right, but he said he was hearing a whistle.

AM is also readily demodulated by any diode-like behaviour.

Yes, but then you hear voices.

You got me there. Joke ?

No, when AM radio is demodulated in an audio chain, you can hear the
modulation of the AM signal, which is usually music or an announcer.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Truth wrote:
The cable connecting the ribbon mic to it's dedicated power supply is
a 7 pin cable provided by Royer Labs. Could the problem originate in
the power and get intensified by the Mic's Power Supply and cables, or
the mic itself?

If it's an RF problem, it has nothing to do with the power system.

I'm not so sure it _is_ an RF problem, though.

When you heard this squealing sound on an AM radio tuned to 790, was
your audio gear operating at the time?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Truth]

On Sep 13, 1:27 pm, "William Sommerwerck"
wrote:
I'm coming in late, so sorry if I repeat something some else already said.

If the mic is on a stand, try coiling the cable around the stand. I learned
this about 25 years ago, when experiencing RFI at a concert. Coiling the
cable can introduce enough inductance to "choke" the RF.

Thanks very much for that tip, I will give that a try if the problem
comes back. Right now, I'm not hearing it.

[Truth]

On Sep 13, 12:44 pm, (Don Pearce) wrote:
On Thu, 13 Sep 2007 09:36:00 -0700, Truth
wrote:



On Sep 13, 12:31 pm, Mike Rivers wrote:
On Sep 13, 12:06 pm, Truth wrote:

These are two brand new Royer 122V Tube Ribbon Microphones. I sent
the first two I received back to Royer and they sent me two brand new
replacements. They told me to keep them away from dimmers, motors,
fluorescent lights, etc. They also mentioned that the mics can act
like antennas. If that is the case, then what can be done about it?

Move.

Could the problem originate in the power source and made worse by long
cable runs?

That's the easiest part to RF-proof, and I suspect that they've done a
reasonable job of it, but I don't know for sure. The RF could be being
picked up by the microphone element itself (there's only so much
shielding they can do and still let sound in), but it's not likely
that the cable is the problem. The output of the microphone is a
cathode follower, which I suspect does not go through a transformer,
at least not until it gets into the power supply box. That means an
unbalanced cable run which, even though it's a low impedance source
(the tube in the microphone) can still act as an antenna. The output
of the system is balanced, but it's not clear from the data I have
available where the balancing occurs. So you may very well have a 20
foot antenna ahead of your mic preamp. Or, if the RF field strength is
great enough, the tube in the mic could be acting like a diode and
detecting the radio signal.

You should try taking the mics and a preamp somewhere else. You don't
need the whole computer rig, just a set of headphones.

I'm able to monitor direct from the Pendulum preamp and I hear the
squeal there before it gets to the computer. I'm thinking a shorter
run mic cable between the power box and mic might help.

Before you are forced to anything drastic, try some clamp-on RF
stoppers - the kind you find on the end of your VGA monitor cable. You
can get these in most electronics parts houses. Go for the lowest
frequency spec they have. Put them on all the cables (starting with
the mic cable) close to the preamp, and see which stops, or at least
reduces, the effect.

d
--
Pearce Consultinghttp://www.pearce.uk.com

Ok, I will look into that, thanks.

[Paul Stamler]

"Truth" wrote in message
oups.com...

790 AM
I get lots of squeal/whistle when I tune into that station on a
radio. I'm recording at 96K, 32bits. In reply to Paul Stamler I
listed my recording chain. Mostly digital. The Pendulum is a tube
preamp. When used with the ribbons I sometimes get a squeal. The
Weiss ADC2 can send out analog and digital. I'm sending out a DO to
the Lynx Two's DI.

The Pendulum is an odd duck; it includes a tube in its signal chain, but as
far as I can tell from reading the online stuff its input is
transformerless. That means that the first thing the signal sees is probably
a pair of bipolar transistors, which can demodulate AM if the circumstances
are wrong. Likewise, the Weiss seems to be a transformerless solid-state
preamp. So if the demodulation is happening in the preamp stage, that
wouldn't surprise me in either case. Transformer inputs do help with
situations like this.

But Royer's comment that the mic can act as an antenna sounds to me like
it's a known problem with these microphones. If the tube in the microphone
is accessible, take it out, coat the pins with a thin layer of DeoxIt, put
the tube into the socket again, remove and wait a couple of minutes. Clean
the pins with a Q-tip, reinsert, remove, clean them again, then coat them
with a thin layer of PreservIt. I've gotten rid of annoying AM radio signals
that way, by removing the metal oxide on the tube pins which makes a dandy
demodulating diode.

If the problem is still intractable, consider exchanging the mics for
Royer's similar active ribbon mics incorporating a FET.

Peace,
Paul

[Paul Stamler]

"Truth" wrote in message
oups.com...

The cable connecting the ribbon mic to it's dedicated power supply is
a 7 pin cable provided by Royer Labs. Could the problem originate in
the power and get intensified by the Mic's Power Supply and cables, or
the mic itself?

Much more likely in the mic itself. The transformer in the power supply is
usually pretty good at filtering out RF on the line.

Peace,
Paul

[Mark]

On Sep 13, 1:14 pm, "Paul Stamler" wrote:
"Truth" wrote in message

oups.com...



The cable connecting the ribbon mic to it's dedicated power supply is
a 7 pin cable provided by Royer Labs. Could the problem originate in
the power and get intensified by the Mic's Power Supply and cables, or
the mic itself?

Much more likely in the mic itself. The transformer in the power supply is
usually pretty good at filtering out RF on the line.

Peace,
Paul

I'm gonna guess at this point that the mics power supply has a
switching power supply in there and that the switching freq or
harmonic thereof is beating with the 790 kHz AM station. If you turn
off the mics and the power supplies do you still hear the squeal in
the AM radio on 790?

If you turn off all your audio equipment do you still hear the squeal
in the AM radio?

Does the squeal ever change pitch?

If so what makes it change pitch?

How far away from you is the 790 kHz AM radio stations antennas?

Mark


Mark

[Scott Dorsey]

Paul Stamler wrote:

The Pendulum is an odd duck; it includes a tube in its signal chain, but as
far as I can tell from reading the online stuff its input is
transformerless. That means that the first thing the signal sees is probably
a pair of bipolar transistors, which can demodulate AM if the circumstances
are wrong. Likewise, the Weiss seems to be a transformerless solid-state
preamp. So if the demodulation is happening in the preamp stage, that
wouldn't surprise me in either case. Transformer inputs do help with
situations like this.

I bet a nickel that something is breaking out into oscillation and that the
problem has nothing to do with RF interference.

But Royer's comment that the mic can act as an antenna sounds to me like
it's a known problem with these microphones. If the tube in the microphone
is accessible, take it out, coat the pins with a thin layer of DeoxIt, put
the tube into the socket again, remove and wait a couple of minutes. Clean
the pins with a Q-tip, reinsert, remove, clean them again, then coat them
with a thin layer of PreservIt. I've gotten rid of annoying AM radio signals
that way, by removing the metal oxide on the tube pins which makes a dandy
demodulating diode.

It is a known problem with all microphones, however I did not have any problem
when I reviewed these mikes. I keyed a 1W handie-talkie on 146 MHz up within
a few inches of the mike (which is my regular RF test).
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Eeyore]

Truth wrote:

Eeyore wrote:

A DH Labs DI ? I can't find anything by googling. Is it active or passive ?


Sorry, that wasn't clear. DH labs 12 feet 110 Ohm XLR used as the
connection between the preamps and the sound card.

What the heck is a "DH labs 12 feet 110 Ohm XLR".

Are you using daft audiophool 'snake oil' cables ?

I'd get rid of those straight away and use something sensible and reliable.

Graham

[Eeyore]

Truth wrote:

The cable connecting the ribbon mic to it's dedicated power supply is
a 7 pin cable provided by Royer Labs. Could the problem originate in
the power and get intensified by the Mic's Power Supply and cables, or
the mic itself?

Anyone's guess. For the life of me I don't understand why you'r fixating over the idea
that the AC power is the problem. It's aboutt he leat likely thing ever ! Are you
susceptible to the kind of audiophool nonsense that gave us the Tice Clock and the Shakti
Stone and one way cables ? Hint, the guys selling that stuff are fraudsters and they talk
nothing but garbage. You need to erase everything from your mind that you ever heard in
the 'hi-fi' mags.

So, is the 3 pin XLR mic output on the 'power supply' ? I've looked for the info but
haven't found anything useful.

Graham

[Eeyore]

Truth wrote:

I'm able to monitor direct from the Pendulum preamp and I hear the
squeal there before it gets to the computer.

Your idea that it's 'before' is flawed. Any interconnection can affect these
things even if to you it appears not to be in the obvious signal path. Stuff can
go 'backwards' (i.e from destination to source) down cables you see.

Graham

[Eeyore]

Truth wrote:

Eeyore wrote:

It sounds like they've been pumping you full of nonsense.

No they are correct. When my LCD monitor is on I can hear a definite
hum or buzz. When I turn it off it goes away, so I turn it off while
recording.

That proves the sum total of nothing other than poor product design. I know, I'm a
pro-audio designer and pretty expert in RF interference matters actually.


Because the microphones use magnetism to function they are
prone to these problems.

Rubbish. The fact the mics have a magnet inside is totally and completely irrelevant to
RF pickup. Where the hell do you get this crap from ? What is especially relevant by the
way is inductance and 'loop area'.


They sound good when they work,

As some badly designed equipment (especially esoteric hi-fi) often does.

Graham

[Eeyore]

Truth wrote:

Eeyore wrote:
Truth wrote:
I even got some special power cords for the mic power supplies.

Why ? What did you expect it to do ? AC power doesn't need 'special cords'.
They're only for gullible 'audiophools'.


Here are the cables I mentioned for the power supplies.

http://www.silversonic.com/docs/products/PowerPlus.html

Oh Dear !

" The clarity of an audio signal is greatly affected by the components power
supply " is fairly close to a straight LIE. It's certainly deceptive marketing.
The power supply *can* affects the sound but that's down tot he internal
*components* and circuit design. The power cable is NEVER responsible.

Now you're talking to real professionals we'll put you on the right track.

All that cable does btw is to transfer money out of your bank account and into
someone else's.

Graham

[Eeyore]

Scott Dorsey wrote:

Eeyore wrote:
Scott Dorsey wrote:
Eeyore wrote:
Scott Dorsey wrote:
AndyP wrote:

Does a preamp with a transformer balanced input do a better job rejecting
RF?

Almost always. There are some poorly-designed transformer inputs out
there too, though.

What kind of preamp, microphone, and cable are we dealing with here?
And what makes you think it's AM?

He said it was an AM station.

Right, but he said he was hearing a whistle.

AM is also readily demodulated by any diode-like behaviour.

Yes, but then you hear voices.

You got me there. Joke ?

No, when AM radio is demodulated in an audio chain, you can hear the
modulation of the AM signal, which is usually music or an announcer.

I thought he said he did hear that (and also the heterodynes or whatever) ?

Graham

[Eeyore]

Scott Dorsey wrote:

Truth wrote:
The cable connecting the ribbon mic to it's dedicated power supply is
a 7 pin cable provided by Royer Labs. Could the problem originate in
the power and get intensified by the Mic's Power Supply and cables, or
the mic itself?

If it's an RF problem, it has nothing to do with the power system.

I'm not so sure it _is_ an RF problem, though.

When you heard this squealing sound on an AM radio tuned to 790, was
your audio gear operating at the time?

LOL ! Good point.

Graham

[Eeyore]

Paul Stamler wrote:

But Royer's comment that the mic can act as an antenna sounds to me like
it's a known problem with these microphones.

Absolutely. Why on earth did they do anything so daft as to give a ribbon a
'head amp' ?

Graham

[Scott Dorsey]

Eeyore wrote:
Scott Dorsey wrote:

Truth wrote:
The cable connecting the ribbon mic to it's dedicated power supply is
a 7 pin cable provided by Royer Labs. Could the problem originate in
the power and get intensified by the Mic's Power Supply and cables, or
the mic itself?

If it's an RF problem, it has nothing to do with the power system.

I'm not so sure it _is_ an RF problem, though.

When you heard this squealing sound on an AM radio tuned to 790, was
your audio gear operating at the time?

LOL ! Good point.

I bet a nickel it's an oscillation issue, yes. Not a quarter, but more
than a penny.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[David Morgan \(MAMS\)]

"Truth" wrote...

Here are the cables I mentioned for the power supplies.

http://www.silversonic.com/docs/products/PowerPlus.html


Is there some arrangement that we could make based on a percentage
of savings relative to your current expenses, if I were to come and run
your purchasing department?


--
David Morgan (MAMS)
http://www.m-a-m-s DOT com
Morgan Audio Media Service
Dallas, Texas (214) 662-9901
_______________________________________
http://www.januarysound.com

[Scott Dorsey]

Eeyore wrote:
Paul Stamler wrote:

But Royer's comment that the mic can act as an antenna sounds to me like
it's a known problem with these microphones.

Absolutely. Why on earth did they do anything so daft as to give a ribbon a
'head amp' ?

The head amp is really just a cathode follower. It has no gain, but it
makes driving long cables easier and reduces perceived differences between
preamps due to loading. Also it makes it possible to use a higher ratio
transformer since the transformer has a fixed and known high-Z load.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Paul Stamler]

"Scott Dorsey" wrote in message
...

But Royer's comment that the mic can act as an antenna sounds to me like
it's a known problem with these microphones. If the tube in the
microphone
is accessible, take it out, coat the pins with a thin layer of DeoxIt,
put
the tube into the socket again, remove and wait a couple of minutes.
Clean
the pins with a Q-tip, reinsert, remove, clean them again, then coat them
with a thin layer of PreservIt. I've gotten rid of annoying AM radio
signals
that way, by removing the metal oxide on the tube pins which makes a
dandy
demodulating diode.

It is a known problem with all microphones, however I did not have any
problem
when I reviewed these mikes. I keyed a 1W handie-talkie on 146 MHz up
within
a few inches of the mike (which is my regular RF test).

Yes, but what happens (or doesn't happen) at 146MHz could be very different
from what happens at 790kHz.

Peace,
Paul

[Paul Stamler]

"Eeyore" wrote in message
...

Paul Stamler wrote:

But Royer's comment that the mic can act as an antenna sounds to me like
it's a known problem with these microphones.

Absolutely. Why on earth did they do anything so daft as to give a ribbon
a
'head amp' ?

It's not entirely daft. Many ribbon microphones have loading issues, and
perform much better into a higher-impedance load. Into lower-impedance loads
the response of the mic is overdamped, and high frequencies roll off
extravagantly. That's why AEA's preamp, designed specifically for their
ribbon microphones, has an input Z of 10k. Unfortunately, most modern
preamps have an input Z between 1.2k and 2.5k, way lower than is ideal for
these ribbons. So Royer (and other makers in imitation) chose to include
head amplifiers which terminate the mics the way the want to be terminated,
and send a signal to the preamp which is compatible with modern preamp
designs.

Peace,
Paul

[Paul Stamler]

"Eeyore" wrote in message
...

Sorry, that wasn't clear. DH labs 12 feet 110 Ohm XLR used as the
connection between the preamps and the sound card.

What the heck is a "DH labs 12 feet 110 Ohm XLR".

Are you using daft audiophool 'snake oil' cables ?

I'd get rid of those straight away and use something sensible and
reliable.

Eeyore, you're frothing again, and for no reason. 110 ohm XLR cables are
designed to be compatible with AES/EBU digital signals. They also work fine
for microphones, although they tend to be stiff and thus a bit unruly to
handle. But using them means you can use the same batch of cables for analog
audio or digital signals without worrying that you might grab the wrong
cable by mistake.

Peace,
Paul

[Paul Stamler]

"Eeyore" wrote in message
...

" The clarity of an audio signal is greatly affected by the components
power
supply " is fairly close to a straight LIE. It's certainly deceptive
marketing.
The power supply *can* affects the sound but that's down tot he internal
*components* and circuit design. The power cable is NEVER responsible.

Not entirely true, although nearly so. I once had to rebuild a piece of gear
being used near a UHF-TV transmitter and, along with all the ferrite beads
and ceramic discs needed to clean it up, I found it necessary to use a
shielded power cord. It wasn't any SilverSonic thing, though, but one I
bought from (I think) Mouser Electronics for $3.95.

Peace,
Paul

[Richard Crowley]

"Paul Stamler" wrote ...
"Scott Dorsey" wrote ...
It is a known problem with all microphones, however
I did not have any problem when I reviewed these mikes.
I keyed a 1W handie-talkie on 146 MHz up within
a few inches of the mike (which is my regular RF test).

Yes, but what happens (or doesn't happen) at 146MHz
could be very different from what happens at 790kHz.

But 1W a few inches away is a heckuvalot more RF to
deal with than any AM, FM or TV broadcast transmitter.
Regardless of wavelength.

[Richard Crowley]

"Eeyore" wrote ...
Paul Stamler wrote:

But Royer's comment that the mic can act as an antenna sounds
to me like it's a known problem with these microphones.

Absolutely. Why on earth did they do anything so daft as to give
a ribbon a 'head amp' ?

Same general reason every condensor microphone
(conventional or electret) has a "head amp". i.e.
impedance conversion (even if no signal gain).
In the case of condenser the ultra-high impedance
isn't practical to send down a conventional mic
shielded pair.

And in the case of the ribbon, the impedance is too
low. Or to look at it another way, there's too much
current and not enough voltage for conventional
mic circuits. The traditional way to solve the problem
was to use a step-up transformer. For example
Lundahl LL2912, 2913, 2914

[Richard Crowley]

"Eeyore" wrote ...
Truth wrote:
Eeyore wrote:

It sounds like they've been pumping you full of nonsense.

No they are correct. When my LCD monitor is on I can hear a definite
hum or buzz. When I turn it off it goes away, so I turn it off while
recording.

That proves the sum total of nothing other than poor product design. I
know, I'm a
pro-audio designer and pretty expert in RF interference matters actually.


Because the microphones use magnetism to function they are
prone to these problems.

Rubbish. The fact the mics have a magnet inside is totally and completely
irrelevant to
RF pickup. Where the hell do you get this crap from ? What is especially
relevant by the
way is inductance and 'loop area'.


They sound good when they work,

As some badly designed equipment (especially esoteric hi-fi) often does.

Perhaps you are unaware that Royer has a rather good
reputation on this side of the pond for making good products
with what appears to be decent engineering and good
customer relations, etc. There are more than enough
vendors of shoddy or questionable equipment who are
worthy of your rants, but I don't think Royer is among them.
http://www.royerlabs.com/

[Eeyore]

Scott Dorsey wrote:

Eeyore wrote:
Paul Stamler wrote:

But Royer's comment that the mic can act as an antenna sounds to me like
it's a known problem with these microphones.

Absolutely. Why on earth did they do anything so daft as to give a ribbon a
'head amp' ?

The head amp is really just a cathode follower. It has no gain, but it
makes driving long cables easier and reduces perceived differences between
preamps due to loading. Also it makes it possible to use a higher ratio
transformer since the transformer has a fixed and known high-Z load.

I still don't understand what's wrong with having the ribbon drive the cable.

Graham

[Mike Rivers]

On Sep 13, 1:03 pm, Truth wrote:

That's the thing, I don't know what is the problem yet. It could be
the house lines acting as antenna and not the equipment itself which
is at fault.

Well you have to stop guessing and start doing some troubleshooting.
Start disconnecting things from the microphone back to the computer,
one at a time, until the interference goes away. And start by turning
off the radio.

[Eeyore]

Paul Stamler wrote:

"Scott Dorsey" wrote in message

It is a known problem with all microphones, however I did not have any
problem when I reviewed these mikes. I keyed a 1W handie-talkie on 146 MHz
up
within a few inches of the mike (which is my regular RF test).

AM or FM ?


Yes, but what happens (or doesn't happen) at 146MHz could be very different
from what happens at 790kHz.

Absolutely ! And that band is IME the one which typically causes all the
trouble.

Graham

[Eeyore]

Paul Stamler wrote:

"Eeyore" wrote
Paul Stamler wrote:

But Royer's comment that the mic can act as an antenna sounds to me like
it's a known problem with these microphones.

Absolutely. Why on earth did they do anything so daft as to give a ribbon
a 'head amp' ?

It's not entirely daft. Many ribbon microphones have loading issues,

For any particular reason you know of ?


and perform much better into a higher-impedance load. Into lower-impedance
loads
the response of the mic is overdamped, and high frequencies roll off
extravagantly. That's why AEA's preamp, designed specifically for their
ribbon microphones, has an input Z of 10k. Unfortunately, most modern
preamps have an input Z between 1.2k and 2.5k, way lower than is ideal for
these ribbons. So Royer (and other makers in imitation) chose to include
head amplifiers which terminate the mics the way the want to be terminated,
and send a signal to the preamp which is compatible with modern preamp
designs.

I saw it implied that as a result the cable has an unbalanced signal on it
though which must introduce a whole new set of problems.

Graham

[Eeyore]

Paul Stamler wrote:

"Eeyore" wrote

Sorry, that wasn't clear. DH labs 12 feet 110 Ohm XLR used as the
connection between the preamps and the sound card.

What the heck is a "DH labs 12 feet 110 Ohm XLR".

Are you using daft audiophool 'snake oil' cables ?

I'd get rid of those straight away and use something sensible and
reliable.

Eeyore, you're frothing again, and for no reason. 110 ohm XLR cables are
designed to be compatible with AES/EBU digital signals. They also work fine
for microphones, although they tend to be stiff and thus a bit unruly to
handle. But using them means you can use the same batch of cables for analog
audio or digital signals without worrying that you might grab the wrong
cable by mistake.

I know, I know but I'm sure the OP has been bamboozled to pay over the odds for
this 'magic cable' from a manufacturer that's been blessed by the audiophools.

D-110 AES/EBU Balanced Digital Cable
(XLR termination)
0.5 meter 79.00
1.0 meter 89.00
1.5 meter 99.00
2.0 meter 109.00
Each additional meter 16.50
http://www.silversonic.com/docs/prices.html#D110

I make that $142 !

Whereas all he needs is (for example) 101-066-001 5M £ 11.95 ($24)
http://www.vdctrading.com/products.a...ionID=8&Page=5

Even their digital version is only £13.44 ($27)
http://www.vdctrading.com/products.a...onID=8&Page=10

So he's paying around $115 simply to have the name DH Labs (which means
nothing).

Graham

[Eeyore]

Paul Stamler wrote:

"Eeyore" wrote


" The clarity of an audio signal is greatly affected by the components
power supply " is fairly close to a straight LIE. It's certainly deceptive
marketing. The power supply *can* affects the sound but that's down to the
internal
*components* and circuit design. The power cable is NEVER responsible.

Not entirely true, although nearly so. I once had to rebuild a piece of gear
being used near a UHF-TV transmitter and, along with all the ferrite beads
and ceramic discs needed to clean it up, I found it necessary to use a
shielded power cord. It wasn't any SilverSonic thing, though, but one I
bought from (I think) Mouser Electronics for $3.95.

That is an extreme environment of course and indeed, any decent screened cable
will do the job.

Graham

[Eeyore]

Richard Crowley wrote:

"Eeyore" wrote ...
Paul Stamler wrote:

But Royer's comment that the mic can act as an antenna sounds
to me like it's a known problem with these microphones.

Absolutely. Why on earth did they do anything so daft as to give
a ribbon a 'head amp' ?

Same general reason every condensor microphone
(conventional or electret) has a "head amp". i.e.
impedance conversion (even if no signal gain).
In the case of condenser the ultra-high impedance
isn't practical to send down a conventional mic
shielded pair.

And in the case of the ribbon, the impedance is too
low.

No. That's not a problem at all.


Or to look at it another way, there's too much
current and not enough voltage for conventional
mic circuits. The traditional way to solve the problem
was to use a step-up transformer. For example
Lundahl LL2912, 2913, 2914

It doesn't mean you have to have active circuitry in the mic itself though.

Graham

[Eeyore]

Richard Crowley wrote:

"Eeyore" wrote ...
Truth wrote:
Eeyore wrote:

It sounds like they've been pumping you full of nonsense.

No they are correct. When my LCD monitor is on I can hear a definite
hum or buzz. When I turn it off it goes away, so I turn it off while
recording.

That proves the sum total of nothing other than poor product design. I
know, I'm a pro-audio designer and pretty expert in RF interference matters
actually.


Because the microphones use magnetism to function they are
prone to these problems.

Rubbish. The fact the mics have a magnet inside is totally and completely
irrelevant to RF pickup. Where the hell do you get this crap from ? What is
especially
relevant by the way is inductance and 'loop area'.

They sound good when they work,

As some badly designed equipment (especially esoteric hi-fi) often does.

Perhaps you are unaware that Royer has a rather good
reputation on this side of the pond for making good products
with what appears to be decent engineering and good
customer relations, etc. There are more than enough
vendors of shoddy or questionable equipment who are
worthy of your rants, but I don't think Royer is among them.
http://www.royerlabs.com/

I had other products in mind wrt that comment. Note the reference to hi-fi.

Graham

[Paul Stamler]

"Eeyore" wrote in message
...
Scott Dorsey wrote:

Eeyore wrote:
Paul Stamler wrote:

But Royer's comment that the mic can act as an antenna sounds to me
like
it's a known problem with these microphones.

Absolutely. Why on earth did they do anything so daft as to give a
ribbon a
'head amp' ?

The head amp is really just a cathode follower. It has no gain, but it
makes driving long cables easier and reduces perceived differences
between
preamps due to loading. Also it makes it possible to use a higher ratio
transformer since the transformer has a fixed and known high-Z load.

I still don't understand what's wrong with having the ribbon drive the
cable.

Nothing wrong with having the ribbon drive the cable; it's got a nice low
impedance. But when the signal arrives at the preamp, that's when the signal
hits the fan.

In a separate post, you asked why ribbons might have this particular design
characteristic. I suspect it's a legacy of history; the classic ribbon mic
was originally designed to operate into a transformer which fed the grid of
a vacuum tube with no terminating resistor. (Take a look at schematics for
early RCA mic preamps.) Except for the capacitance of the tube and stray
capacitance in the transformer, the impedance was very high. (Even the tube
capacitance ceased to be an issue in some preamps where RCA used pentodes
instead of triodes.) So the microphone's motor was designed with sufficient
mechanical damping to provide the desired frequency response and damping.

Add a lowish impedance across that motor, and now it's overdamped and the
high-frequency response droops, which is what happens with classic ribbon
mics like RCAs and their AEA clones when operated into modern preamps. (See
Scott Dorsey's review, in "Recording", of the AEA preamp for a report on the
very audible response differences he heard when using a classic ribbon into
that high-Z-input preamp and more conventional modern circuits.) Royer's
microphone designs are descended, technically, from classic ribbon designs,
specifically the B&O ribbons which were popular in the early 1960s. (Royer
has made changes and updates, but the basic motor design comes from the
B&Os.) Rather than change a design which is basically a good one to match
modern preamp inputs, Royer offers the option of using a buffer, either a
FET or a tube, to take the element of preamp loading more-or-less out of the
equation.

In a way, the situation is the mirror image of similar issues with Shure
SM57 mics; those were designed with *low* mechanical damping, with the
expectation they'd feed a low preamp input impedance which provided lots of
electrical damping. Those benefit from an extra loading resistor; classic
ribbons benefit from a higher-input-Z preamp or a buffer. Except that the
buffer may be introducing new problems, hence this thread.

Peace,
Paul

[Paul Stamler]

"Eeyore" wrote in message
...

"Eeyore" wrote

Sorry, that wasn't clear. DH labs 12 feet 110 Ohm XLR used as the
connection between the preamps and the sound card.

What the heck is a "DH labs 12 feet 110 Ohm XLR".

Are you using daft audiophool 'snake oil' cables ?

I'd get rid of those straight away and use something sensible and
reliable.

Eeyore, you're frothing again, and for no reason. 110 ohm XLR cables are
designed to be compatible with AES/EBU digital signals. They also work
fine
for microphones, although they tend to be stiff and thus a bit unruly to
handle. But using them means you can use the same batch of cables for
analog
audio or digital signals without worrying that you might grab the wrong
cable by mistake.

I know, I know but I'm sure the OP has been bamboozled to pay over the
odds for
this 'magic cable' from a manufacturer that's been blessed by the
audiophools.

D-110 AES/EBU Balanced Digital Cable
(XLR termination)
0.5 meter 79.00
1.0 meter 89.00
1.5 meter 99.00
2.0 meter 109.00
Each additional meter 16.50
http://www.silversonic.com/docs/prices.html#D110

I make that $142 !

Whereas all he needs is (for example) 101-066-001 5M £ 11.95 ($24)
http://www.vdctrading.com/products.a...ionID=8&Page=5

Even their digital version is only £13.44 ($27)
http://www.vdctrading.com/products.a...onID=8&Page=10

So he's paying around $115 simply to have the name DH Labs (which means
nothing).

Well, that does look to be the case. Markertek sells a 25' (~7.5 meters) AES
digital cable for $37.95, with good Canare cable and Neutrik plugs, and
lead-free to boot. So I do think he overpaid.

Back to the RF questions.

Peace,
Paul

[Scott Dorsey]

Eeyore wrote:
Scott Dorsey wrote:
The head amp is really just a cathode follower. It has no gain, but it
makes driving long cables easier and reduces perceived differences between
preamps due to loading. Also it makes it possible to use a higher ratio
transformer since the transformer has a fixed and known high-Z load.

I still don't understand what's wrong with having the ribbon drive the cable.

There's some mention of it in Techniques of the Sound Studio.
--scott

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