The Opposite Of A 10db Pad
 

Dear fellow audiophiles,

I'm looking for the opposite of a 10db pad for my unidirectional ECM-66B
lavalier mike. Its output turns out to be quite a bit lower than is ideal
for the Edirol R-1 recorder's mic input, averaging about 10db lower than is
ideal for good SN/R, even with the R-1's input volume set to maximum!

Don't know whether such an animal exists, but I figured this would be a
good place to ask. If a really tiny very portable 10db gain doohinky thingy
doesn't even exist, I'd be open to other suggested solutions. Thanks much.

Cheers,

Charles

The Opposite Of A 10db Pad
 

In article ,
"Charles H. Riggs, III" wrote:
I'm looking for the opposite of a 10db pad for my unidirectional
ECM-66B lavalier mike. Its output turns out to be quite a bit lower
than is ideal for the Edirol R-1 recorder's mic input, averaging about
10db lower than is ideal for good SN/R, even with the R-1's input volume
set to maximum!

Don't know whether such an animal exists, but I figured this would
be a good place to ask. If a really tiny very portable 10db gain
doohinky thingy doesn't even exist, I'd be open to other suggested
solutions. Thanks much.

An ECM 66 is a DIN output standard mic, so it's unlikely it's the problem.
Although I don't know your recorder. How is it connected to it?

--
*If at first you don't succeed, avoid skydiving.*

Dave Plowman London SW
To e-mail, change noise into sound.

The Opposite Of A 10db Pad
 

Has this lavalier possibly got an ancient 30 or 50 Ohm coil? This could
explain its comparatively low o/p. Don't go and measure it on an analogue
multimeter. If yes, you'll need a step-up, approx 1:3 xformer.

The Opposite Of A 10db Pad
 

In article ,
Jim Gregory wrote:
Has this lavalier possibly got an ancient 30 or 50 Ohm coil? This could
explain its comparatively low o/p. Don't go and measure it on an
analogue multimeter. If yes, you'll need a step-up, approx 1:3 xformer.

Sony were the originator of the small high quality personal mic - the
ECM 50. Dunno what ECM actually stands for, but rumour was electret
condenser mic. And I dunno again if they ever made a moving coil personal
- it doesn't make sense these days given how cheap an electret is.

--
*Money isn't everything, but it sure keeps the kids in touch.

Dave Plowman London SW
To e-mail, change noise into sound.

The Opposite Of A 10db Pad
 

Dave Plowman (News) wrote:
In article ,
Jim Gregory wrote:
Has this lavalier possibly got an ancient 30 or 50 Ohm coil? This
could explain its comparatively low o/p. Don't go and measure it on
an analogue multimeter. If yes, you'll need a step-up, approx 1:3
xformer.

Sony were the originator of the small high quality personal mic - the
ECM 50. Dunno what ECM actually stands for, but rumour was electret
condenser mic. And I dunno again if they ever made a moving coil
personal - it doesn't make sense these days given how cheap an
electret is.

Mental note - get replacement MCE2 for the one I broke last week...


--
We are the keepers of the sacred words: Ni, Pang,
and Ni-wom!

The Opposite Of A 10db Pad
 

Dave and Tim,
Didn't realise it was a Sony tieclip dooberry he was complaining about. As
it's an electret it should give stacks more level than your ordinary 200 Ohm
moving coil, assuming the polarising voltage is there.

Chas, must be it's connected up wrongly.

The Opposite Of A 10db Pad
 

In article ,
Jim Gregory wrote:
Didn't realise it was a Sony tieclip dooberry he was complaining about.
As it's an electret it should give stacks more level than your ordinary
200 Ohm moving coil, assuming the polarising voltage is there.

Chas, must be it's connected up wrongly.

My thoughts too. IIRC, the ECM 66 comes with an XLR output battery pack
that will also accept phantom. If that's been removed - as you would for
radio mic use etc - the amp volts have to be provided by other means. Of
course many recorders do supply the volts needed for an electret mic, but
it's a bit of a grey area, standards wise.

--
*I almost had a psychic girlfriend but she left me before we met *

Dave Plowman London SW
To e-mail, change noise into sound.

The Opposite Of A 10db Pad
 

"Dave Plowman (News)" wrote in message
...
An ECM 66 is a DIN output standard mic, so it's unlikely it's the problem.
Although I don't know your recorder. How is it connected to it?

The ECM 66B has a male XLR connector (you probably knew that!). I'm using a
Shure transformer to convert to a male mini stereophone plug to accomodate
the R-1's mic input.

Cheers,

Charles

P.S. By the way, I gave the ECM66B a healthy knock against a cardboard box
within minutes of bringing the brand new mike home with me. Could that have
damaged it and affected its output level?

The Opposite Of A 10db Pad. It's a 10dB Dab!
 

Chas,
Ah, a xformer! If it is not a 1:1 ratio (used merely for isolation), I hope
the *low* side of the given ratio of your device is used at the *mic* end
(ergo it steps up into channel i/p). So if it's about 1:3.2, can we rename
it a 10dB Dab?
But using this interface seems drastic and unnecessary.
Is the mic cell at adequate voltage and where is it located? Is battery
switchable off/on?
At the other end, I imagine the mini jackplug should be mono if your R-1
recorder has Mono pannable inputs, or dual mono (stereo plug with tip & ring
in parallel), if your recorder has Stereo inputs.
The knock's result remains to be seen or heard, or not.
Jim

The Opposite Of A 10db Pad
 

Charles H. Riggs, III wrote:

Dear fellow audiophiles,

I'm looking for the opposite of a 10db pad for my unidirectional
ECM-66B
lavalier mike. Its output turns out to be quite a bit lower than is ideal
for the Edirol R-1 recorder's mic input, averaging about 10db lower than
is ideal for good SN/R, even with the R-1's input volume set to maximum!


Looking at the spec for this device it seems its microphone input is not
very sensitive (-10dBU), although the spec seems not to distinguish between
the mic and line inputs in this respect. It does make a note about
selecting the right position for the mic type switch which appears to
provide power for suitable electret types. If your mic has a built in
battery then I would recommend setting this switch to the dyn position to
avoid sending power to it.

As it is a very small device I assume a full blown mic pre rather defeats
the object. If you only need another 10dB gain then a transformer as
suggested by others should work OK. Just be aware the input impedance of
the R-1 is quoted at 6K8 so a 3:1 ratio transformer will make this look
like about 750 ohms. This is a little low for a nominal 600 ohm mic but
your ECM-66B is likely to have a much lower output impedance so it should
be OK.

Ian

--
Ian Bell

The Opposite Of A 10db Pad
 

"Ian Bell" wrote in message
...
It does make a note about
selecting the right position for the mic type switch which appears to
provide power for suitable electret types. If your mic has a built in
battery then I would recommend setting this switch to the dyn position to
avoid sending power to it.

Interesting. Since the 66B is, so far as I know, a condenser (it certainly
has an internal double AA battery driving it), I just assumed I should set
the R-1 to Condenser rather than Dynamic. But that sounds like an
interesting idea so I'll try it. Thanks.

Cheers,

Charles

The Opposite Of A 10db Pad
 

"Charles H. Riggs, III" wrote in message
...
Interesting. Since the 66B is, so far as I know, a condenser (it
certainly
has an internal double AA battery driving it), I just assumed I should set
the R-1 to Condenser rather than Dynamic. But that sounds like an
interesting idea so I'll try it. Thanks.

I've tried it. I don't have test tones or anything like that to drive it,
but I believe I am getting a slightly higher level, so I'll try it in a for
real situation and see whether it gains me something. Thanks again for the
suggestion.

Cheers,

Charles

The Opposite Of A 10db Pad
 

Charles H. Riggs, III wrote:

"Charles H. Riggs, III" wrote in message
...
Interesting. Since the 66B is, so far as I know, a condenser (it
certainly
has an internal double AA battery driving it), I just assumed I should
set
the R-1 to Condenser rather than Dynamic. But that sounds like an
interesting idea so I'll try it. Thanks.

I've tried it. I don't have test tones or anything like that to drive it,
but I believe I am getting a slightly higher level, so I'll try it in a
for
real situation and see whether it gains me something. Thanks again for
the suggestion.

Cheers,

Charles

My pleasure. One thing to note is that your mic probably has an AC coupled
output via an electroltytic capacitor. If the electret setting send a
voltage to the mike is may just possibly have done some damage to this.
Unlikely but possible nonetheless.

Ian
--
Ian Bell

The Opposite Of A 10db Pad
 

In article ,
"Charles H. Riggs, III" wrote:
An ECM 66 is a DIN output standard mic, so it's unlikely it's the
problem. Although I don't know your recorder. How is it connected to
it?

The ECM 66B has a male XLR connector (you probably knew that!). I'm
using a Shure transformer to convert to a male mini stereophone plug to
accomodate the R-1's mic input.

Ah. Wonder if this transformer is high impedance mic to low impedance
input matcher?

If so, this accounts for the level loss as the mic is a low impedance one.

You need a simple XLR to jack adaptor, not transformer.

P.S. By the way, I gave the ECM66B a healthy knock against a cardboard
box within minutes of bringing the brand new mike home with me. Could
that have damaged it and affected its output level?

They tend to get a fair bit of abuse in my hands and survive. ;-)

With this type of mic, the cable is usually the first thing to go.

--
*A hangover is the wrath of grapes.

Dave Plowman London SW
To e-mail, change noise into sound.

The Opposite Of A 10db Pad. It's a 10dB Dab!
 

In article ,
Jim Gregory wrote:
Ah, a xformer! If it is not a 1:1 ratio (used merely for isolation), I
hope the *low* side of the given ratio of your device is used at the
*mic* end (ergo it steps up into channel i/p). So if it's about 1:3.2,
can we rename it a 10dB Dab?

If it is a transformer, I'd guess it's for matching a high impedance
dynamic mic (Shure make these) to a low impedance input.

Or, indeed, the other way round.

Something like 7:1.

--
*Remember not to forget that which you do not need to know.*

Dave Plowman London SW
To e-mail, change noise into sound.

The Opposite Of A 10db Pad
 

"Dave Plowman (News)" wrote in message
...
"Charles H. Riggs, III" wrote:
The ECM 66B has a male XLR connector (you probably knew that!). I'm
using a Shure transformer to convert to a male mini stereophone plug to
accomodate the R-1's mic input.

Ah. Wonder if this transformer is high impedance mic to low impedance
input matcher?
If so, this accounts for the level loss as the mic is a low impedance one.
You need a simple XLR to jack adaptor, not transformer.

Hmmm. According to B & H, where I purchased this mike, this is what Sony
recommends to convert an XLR to a stereo miniphone. It's called a Shure
A96F Line Matching Transformer. Since it's called Line Matching, does that
mean it is NOT an impedance conversion thingy? I'm not very familiar with
all this terminology (obviously!).

Cheers,

Charles

P.S. By the way, I fed this mike, followed by another mike, into one of my
DAT recorders and the levels were the SAME (using the same transformer).
That would appear to indicate that the problem is with the level inside of
the R-1, not the level coming out of the mike into the device.

The Opposite Of A 10db Pad
 

In article ,
"Charles H. Riggs, III" wrote:
Hmmm. According to B & H, where I purchased this mike, this is what
Sony recommends to convert an XLR to a stereo miniphone. It's called a
Shure A96F Line Matching Transformer. Since it's called Line Matching,
does that mean it is NOT an impedance conversion thingy? I'm not very
familiar with all this terminology (obviously!).

Looking at :-

http://www.shuredistribution.co.uk/s...ssories_23.htm

it suggests this is a convertor from XLR to *mono* mini-jack. How many
rings does the jack end have?

P.S. By the way, I fed this mike, followed by another mike, into one of
my DAT recorders and the levels were the SAME (using the same
transformer). That would appear to indicate that the problem is with the
level inside of the R-1, not the level coming out of the mike into the
device.

I've not seen a dat with a stereo mini jack input - although I have seen
one on a MiniDisc.

--
*He who laughs last, thinks slowest.

Dave Plowman London SW
To e-mail, change noise into sound.

The Opposite Of A 10db Pad
 

"Dave Plowman (News)" wrote in message
...
Looking at :-
http://www.shuredistribution.co.uk/s...ssories_23.htm
it suggests this is a convertor from XLR to *mono* mini-jack. How many
rings does the jack end have?

It has two all right.

I've not seen a dat with a stereo mini jack input - although I have seen
one on a MiniDisc.

This is a Sony TCD-D8 Walkman.

Cheers,

Charles

The Opposite Of A 10dB Pad - 1:3 tranny
 

*Repeating my rec.audio.tech post reply for this NewsGroup*

Plenty of probably Taiwanese step-up transformers, eg, in line 1/4" to 1/4"
or inline XLR barrel to 1/4" here for about $12.
Try Maplin for the latter
http://www.maplin.co.uk/Module.aspx?...TabID=1&source

The Opposite Of A 10dB Pad - 1:3 tranny
 

"Jim Gregory" wrote in message
...
*Repeating my rec.audio.tech post reply for this NewsGroup*

Plenty of probably Taiwanese step-up transformers, eg, in line 1/4" to
1/4"
or inline XLR barrel to 1/4" here for about $12.
Try Maplin for the latter
http://www.maplin.co.uk/Module.aspx?...TabID=1&source



It has been interesting reading this thread and some of the replies
considering the header title "The Opposite Of A 10dB Pad".

A pad is an attenuator - a device that reduces the power level of a signal.
In this case in an impedance matched circuit a 10dB pad would result in a
x10 power loss. So the opposite of a loss is a gain - hey? So would not
10dB of amplification be the answer?

Many have suggested using a transformer. Transformers do not give you a
power gain. If anything, the average transformer may introduce a loss of
0.3dB or possibly more.

Transformers are impedance or voltage conversion devices not amplifiers or
gain devices as it appears to the common misconception in this thread.

If the input to the mixer / amplifier / recorder is high impedance (say
10kohms) and the microphone is a low impedance source (say 600 ohms) then a
step up transformer will solve the problem of low output voltage level.

The Sony ECM-66B has a balanced output impedance of 100 ohms @1kHz.
The Eridol R1 has an unbalanced microphone input impedance of 6.8kohms with
a sensitivity of -10dBu (~345mV) which is quite a high voltage level for a
microphone IMHO.

An impedance matching transformer with a 1:68 impedance transformation ratio
would be ideal and provide more than enough voltage increase to overcome the
problem. Now all that is required is to source a suitable unit.


Not perfect but and inexpensive DIY solution :

If you are handy with a soldering iron (or know someone who is) and want
make a unit for yourself a 600 ohms to 10 kohms tapped microphone
transformer can be found here -
http://www.altronics.com.au/index.as...=item&id=M0705 Specs exceed the
microphone's capability.

Connect your microphone across the red and green wires (600 ohm side) and
the yellow and blue wires (10 kohm side) to the microphone input on the R1.
This should give you a healthy voltage increase. If you need more output
voltage try connecting the microphone across the red and black wires (300
ohm winding).

XLR sockets and 1/8" line jacks can be obtained form the same source as well
as suitable shielded cable and a neat little box to put it all in.

Cheers,
Alan

The Opposite Of A 10dB Pad - 1:3 tranny
 

"Alan Rutlidge iinet.net.au" rutlidge@NO_SPAM wrote in message
...
An impedance matching transformer with a 1:68 impedance transformation
ratio
would be ideal and provide more than enough voltage increase to overcome
the
problem. Now all that is required is to source a suitable unit.

Currently I am using the Shure A96F Line Matching Transformer as a switching
station from the male XLR of the mike to the female stereo miniplug for the
R-1's mic input.

I am not experienced in reading specs for these devices, but here's some of
the information provided with it. Understand that I have attempted to
recreate the formatting WITHOUT invoking HTML formatting in my email client,
since I am not sure whether this newsgroup accepts HTML formatting.
Consequently there is a chance that the below may come out as so much
indecipherable gibberish. Here goes:

Impedance: Low impedance 600 ohms (supplied) or 150 ohms
Medium impedance: 2500 ohms
DC Resistance:
Low Impedance: 600 ohms winding: 56 ohms
150 ohms winding: 28 ohms
Voltage Ratio: 600 ohms
150 ohms
Low Impedance to medium impedance: +6 db +12 db
Maximum Recommended Input Levels
Source Winding Maximum
Impedance Being Driven Level
150 ohms 150 ohms .5 V
600 ohms 600 ohms 1.0 V
2500 ohms 2500 ohms 2.0 V


If you are handy with a soldering iron (or know someone who is) and want
make a unit for yourself a 600 ohms to 10 kohms tapped microphone
transformer can be found here -
http://www.altronics.com.au/index.as...=item&id=M0705 Specs exceed the
microphone's capability.
Connect your microphone across the red and green wires (600 ohm side) and
the yellow and blue wires (10 kohm side) to the microphone input on the
R1.
This should give you a healthy voltage increase. If you need more output
voltage try connecting the microphone across the red and black wires (300
ohm winding).
XLR sockets and 1/8" line jacks can be obtained form the same source as
well
as suitable shielded cable and a neat little box to put it all in.

The above might work very well for me. Unfortunately I am all thumbs at
that stuff, and would probably end up in the emergency room.

However you have given me a sort of crazy idea. What would happen if I take
the low to high impedance converter I got and deliberately plugged it into
the LOW impedance input (the mike input). Would I just blow out the mic
input and be without the R-1 for a few months while they repaired it, would
it probably simply result in a lot of clipping and distortion, or is there a
chance that might be a solution?

Cheers,

Charles

The Opposite Of A 10dB Pad - 1:3 tranny
 

"Charles H. Riggs, III" wrote in message
...
However you have given me a sort of crazy idea. What would happen if I
take
the low to high impedance converter I got and deliberately plugged it into
the LOW impedance input (the mike input). Would I just blow out the mic
input and be without the R-1 for a few months while they repaired it,
would
it probably simply result in a lot of clipping and distortion, or is there
a
chance that might be a solution?

Never mind; I tried it and the hum was godawful. Scratch that idea!

Cheers,

Charles

The Opposite Of A 10dB Pad - 1:3 tranny
 

"Charles H. Riggs, III" wrote in message
...
"Alan Rutlidge iinet.net.au" rutlidge@NO_SPAM wrote in message
...
An impedance matching transformer with a 1:68 impedance transformation
ratio
would be ideal and provide more than enough voltage increase to overcome
the
problem. Now all that is required is to source a suitable unit.

Currently I am using the Shure A96F Line Matching Transformer as a
switching
station from the male XLR of the mike to the female stereo miniplug for
the
R-1's mic input.

I am not experienced in reading specs for these devices, but here's some
of
the information provided with it. Understand that I have attempted to
recreate the formatting WITHOUT invoking HTML formatting in my email
client,
since I am not sure whether this newsgroup accepts HTML formatting.
Consequently there is a chance that the below may come out as so much
indecipherable gibberish. Here goes:

Impedance: Low impedance 600 ohms (supplied) or 150 ohms
Medium impedance: 2500 ohms
DC Resistance:
Low Impedance: 600 ohms winding: 56 ohms
150 ohms winding: 28 ohms
Voltage Ratio: 600 ohms
150 ohms
Low Impedance to medium impedance: +6 db +12 db
Maximum Recommended Input Levels
Source Winding Maximum
Impedance Being Driven Level
150 ohms 150 ohms .5 V
600 ohms 600 ohms 1.0 V
2500 ohms 2500 ohms 2.0 V


If you are handy with a soldering iron (or know someone who is) and want
make a unit for yourself a 600 ohms to 10 kohms tapped microphone
transformer can be found here -
http://www.altronics.com.au/index.as...=item&id=M0705 Specs exceed
the
microphone's capability.
Connect your microphone across the red and green wires (600 ohm side)
and
the yellow and blue wires (10 kohm side) to the microphone input on the
R1.
This should give you a healthy voltage increase. If you need more
output
voltage try connecting the microphone across the red and black wires
(300
ohm winding).
XLR sockets and 1/8" line jacks can be obtained form the same source as
well
as suitable shielded cable and a neat little box to put it all in.

The above might work very well for me. Unfortunately I am all thumbs at
that stuff, and would probably end up in the emergency room.

However you have given me a sort of crazy idea. What would happen if I
take
the low to high impedance converter I got and deliberately plugged it into
the LOW impedance input (the mike input). Would I just blow out the mic
input and be without the R-1 for a few months while they repaired it,
would
it probably simply result in a lot of clipping and distortion, or is there
a
chance that might be a solution?

Cheers,

Charles



Hi Charles,

The Shure A96F Line Matching Transformer
( http://www.shure.com/pdf/userguides/...ories/a96f.pdf ) should
work okay.

Setting the A96F to the 150 ohm option will give you the largest voltage
increase, however if it works okay on the standard setting of 600 ohms just
leave it at the factory default. You will not blow up your R1 recorder
using this device. The voltage levels on the specifications only refer to
the maximum voltages the transformer can handle before the core and windings
become saturated and distortion occurs. They do not indicate the actual
voltages on the windings.

Depending on the wiring of the microphone input socket on the R1, you may
need to cut the wire in the tip / ring / sleeve jack plug as shown in the
diagram on page 2 of the pdf guide in the link above.

Cheers,
Alan

The Opposite Of A 10dB Pad - 1:3 tranny
 

"Alan Rutlidge iinet.net.au" rutlidge@NO_SPAM wrote in message
...
The Shure A96F Line Matching Transformer
( http://www.shure.com/pdf/userguides/...ories/a96f.pdf ) should
work okay.
Setting the A96F to the 150 ohm option will give you the largest voltage
increase

I took a look at the pdf document you mentioned
and right there, in black and white, it says "The A96F can be modified for
microphones rated at 150
 This
modification is only necessary if the output level from the A96F is
insufficient for your recording device." Well, of course, that is PRECISELY
my problem, and there's no doubt that making the modification and treating
the 66B as if it was a 150 ohm mike would appear to precisely solve my
problem.

I even opened up the transformer, precisely as described in the pdf
document. I even successfully identified all the crucial elements, the red
lead, the yellow lead, the location of pin 2, all of it. It was crystal
clear exactly what I had to do, namely cut the red lead, remove the
insulation from the end of the yellow lead and put it on the red lead, and
then solder the yellow lead onto pin 2 in place of the red lead. It would
probably take all of 10 minutes and my problem would be solved.

I opened the whole thing in hopes that I might be able to get
away with making the change while not needing to --

-- solder. You see, I have no soldering iron in the house, no solder, and
I've never touched one in my life, and I would feel like a child attempting
brain surgery. But wrapping lead around a contact is something I could have
gotten into, no problem.

Unfortunately, after close examination, it's obvious there is no way to
connect the lead to the pin except with solder. So there it sits, giving me
inadequate level, and
I'm stuck without the one tool and skill set which would solve this whole
problem.

Looks like this is a job for a soldering friend. Now the challenge is to
find a soldering friend. Which means one more hurdle, namely sweet-talking
a master solderer. I better
start talking!

Alternately, anyone know of a transformer for a mic with an XLR connector to
a stereo miniplug mike input which comes out of the box spitting out at 150
ohms rather than 600 ohms? Inquiring minds want to know.

Cheers,

Charles

The Opposite Of A 10dB Pad - 1:3 tranny
 

Unfortunately, after close examination, it's obvious there is no way to
connect the lead to the pin except with solder. So there it sits, giving me
inadequate level, and
I'm stuck without the one tool and skill set which would solve this whole
problem.

Looks like this is a job for a soldering friend. Now the challenge is to
find a soldering friend. Which means one more hurdle, namely sweet-talking
a master solderer. I better
start talking!

A cheap soldering iron from a hardware store or DIY shed will only cost
you a few quid. Practice on a few bits of scrap wire and then you will
then have acquired a new skill.

Even my 7 year old daughter can do this!....
--
Tony Sayer

The Opposite Of A 10dB Pad - 1:3 tranny
 

In article ,
"Charles H. Riggs, III" wrote:
Looks like this is a job for a soldering friend. Now the challenge is
to find a soldering friend. Which means one more hurdle, namely
sweet-talking a master solderer. I better start talking!

A TV repair shop would do it for you, I'm sure.
Or if you gave your location, perhaps someone on here could help. ;-)

--
*I don't suffer from insanity, I enjoy every minute of it *

Dave Plowman London SW
To e-mail, change noise into sound.

The Opposite Of A 10dB Pad - 1:3 tranny
 

"tony sayer" wrote in message
...
Even my 7 year old daughter can do this!....

Yes, but you see I'm six years old.

Cheers,

Charles

The Opposite Of A 10dB Pad - 1:3 tranny
 

"Dave Plowman (News)" wrote in message
...
A TV repair shop would do it for you, I'm sure.

None in my vicinity, I'm afraid. Everything I need repaired gets sent out
to the manufacturer. True TV repair shops don't really exist any more in
Gotham, or at least certainly not in my 'hood.

Or if you gave your location, perhaps someone on here could help. ;-)

New York City. A little far away, I'm afraid.

Cheers,

Charles

The Opposite Of A 10dB Pad - 1:3 tranny
 

In article ,
"Charles H. Riggs, III" wrote:
A TV repair shop would do it for you, I'm sure.

None in my vicinity, I'm afraid. Everything I need repaired gets sent
out to the manufacturer. True TV repair shops don't really exist any
more in Gotham, or at least certainly not in my 'hood.

I'm surprised - they still exist in London, although may not be shops as
such anymore. Perhaps a search of Yellow Pages etc? It's such a simple job
it doesn't even need a highly skilled technician.

--
*A hangover is the wrath of grapes.

Dave Plowman London SW
To e-mail, change noise into sound.

The Opposite Of A 10dB Pad - 1:3 tranny
 

"Alan Rutlidge iinet.net.au" rutlidge@NO_SPAM wrote in message
...
The Shure A96F Line Matching Transformer
( http://www.shure.com/pdf/userguides/...ories/a96f.pdf ) should
work okay.
Setting the A96F to the 150 ohm option will give you the largest voltage
increase...Depending on the wiring of the microphone input socket on the
R1, you may
need to cut the wire in the tip / ring / sleeve jack plug as shown in the
diagram on page 2 of the pdf guide in the link above.

I found a buddy handy with a soldering iron, and we made the change, as per
http://www.shure.com/pdf/userguides/...ories/a96f.pdf over to an
output for 150 ohms (or is it OF 150 ohms; not sure of the correct
terminology).

AND IT WORKED!!!!!!! My mike level is perfectly fine now going into the
Edirol R-1, and just why the #$%^&* Shure Transformer comes out of the box
set to some exotic mid-impedance level like 600 rather than a normal low
impedance level of 150, and just why the #$%^&* so-and-sos at Shure didn't
add an external switch to effect the impedance change rather than burying it
as a solder job I'll NEVER know.

But thank you, thank you, thank you. I was watching $1200 go down the drain
in recent days and not feeling too happy about it. Really appreciated.

Cheers,

Charles

The Opposite Of A 10dB Pad - 1:3 tranny
 

"Charles H. Riggs, III" wrote in message
...
"Alan Rutlidge iinet.net.au" rutlidge@NO_SPAM wrote in message
...
The Shure A96F Line Matching Transformer
( http://www.shure.com/pdf/userguides/...ories/a96f.pdf )
should
work okay.
Setting the A96F to the 150 ohm option will give you the largest voltage
increase...Depending on the wiring of the microphone input socket on the
R1, you may
need to cut the wire in the tip / ring / sleeve jack plug as shown in
the
diagram on page 2 of the pdf guide in the link above.

I found a buddy handy with a soldering iron, and we made the change, as
per
http://www.shure.com/pdf/userguides/...ories/a96f.pdf over to an
output for 150 ohms (or is it OF 150 ohms; not sure of the correct
terminology).

AND IT WORKED!!!!!!! My mike level is perfectly fine now going into the
Edirol R-1, and just why the #$%^&* Shure Transformer comes out of the box
set to some exotic mid-impedance level like 600 rather than a normal low
impedance level of 150, and just why the #$%^&* so-and-sos at Shure didn't
add an external switch to effect the impedance change rather than burying
it
as a solder job I'll NEVER know.

But thank you, thank you, thank you. I was watching $1200 go down the
drain
in recent days and not feeling too happy about it. Really appreciated.

Cheers,

Charles



Hi Charles,

Glad to read it's finally working and to your satisfaction.

The reason why the Shure transformer probably came set to 600 ohms as the
default impedance, is that 600 ohms is a common impedance for professional
equipment using balanced circuits.
Fortunately Shure had the forethought to design the primary winding of the
transformer with a 150 ohm tap to accommodate lower impedance devices such
as your Sony mic :)

The method behind the madness of a solder joint over a switch is well
founded. In your case, a low level microphone (tens of millivolts) and
having no d.c. present on the circuit, a switch may become noisy over time
and lead to more annoying problems. Now all you should do is add a sticker
to the outside of the case saying "set to 150 ohms" so any other user does
not think it is still on the default of 600 ohms.

Cheers,
Alan

The Opposite Of A 10dB Pad - 1:3 tranny
 

In article ,
Alan Rutlidge wrote:
The reason why the Shure transformer probably came set to 600 ohms as
the default impedance, is that 600 ohms is a common impedance for
professional equipment using balanced circuits.

It's actually rather rare these days. ;-)

IIRC, a common input impedance for a pro balanced mic amp is about 1k.

--
*If horrific means to make horrible, does terrific mean to make terrible?

Dave Plowman London SW
To e-mail, change noise into sound.

The Opposite Of A 10dB Pad - 1:3 tranny
 

Charles H. Riggs, III wrote:

I found a buddy handy with a soldering iron, and we made the change, as
per http://www.shure.com/pdf/userguides/...ories/a96f.pdf over
to an output for 150 ohms (or is it OF 150 ohms; not sure of the correct
terminology).

AND IT WORKED!!!!!!! My mike level is perfectly fine now going into the
Edirol R-1, and just why the #$%^&* Shure Transformer comes out of the box
set to some exotic mid-impedance level like 600 rather than a normal low
impedance level of 150,

Because most dynamic mics work best into an impedance of 600 ohms or
thereabouts. Your electret mic has a built in amplifier with a lower
output impedance that will work happily into 150 ohms and this setting of
the transformer provides a bigger turns ratio so it boost the signal more.


--
Ian Bell

The Opposite Of A 10dB Pad - 1:3 tranny
 

Dave Plowman (News) wrote:

In article ,
Alan Rutlidge wrote:
The reason why the Shure transformer probably came set to 600 ohms as
the default impedance, is that 600 ohms is a common impedance for
professional equipment using balanced circuits.

It's actually rather rare these days. ;-)

IIRC, a common input impedance for a pro balanced mic amp is about 1k.


Has been for a long time. Neve mic inputs in the 70s were 1K2.

Ian
--
Ian Bell

The Opposite Of A 10dB Pad - 1:3 tranny
 

"Alan Rutlidge iinet.net.au" rutlidge@NO_SPAM wrote in message
...
The reason why the Shure transformer probably came set to 600 ohms as the
default impedance, is that 600 ohms is a common impedance for professional
equipment using balanced circuits.

Thank you for the explanation.

The method behind the madness of a solder joint over a switch is well
founded. In your case, a low level microphone (tens of millivolts) and
having no d.c. present on the circuit, a switch may become noisy over time
and lead to more annoying problems.

Now I understand; thank you. I'd STILL like to know why Shure doesn't
include those soldering instructions in the device itself when shipped. If
you hadn't clued me in to Shure's web site instructions I'd never have
known.

Now all you should do is add a sticker
to the outside of the case saying "set to 150 ohms" so any other user does
not think it is still on the default of 600 ohms.

Thoughtful but probably not necessary. I live alone and if anyone else is
using this device I don't know about it!

Cheers,
Charles

The Opposite Of A 10dB Pad - 1:3 tranny
 

"Ian Bell" wrote in message
...
Charles H. Riggs, III wrote:
Because most dynamic mics work best into an impedance of 600 ohms or
thereabouts.

Which I gather means that there are plenty of high-end dynamic mikes that
utilize male XLR connectors, is that correct? I thought most high-end mikes
with XLR connectors were condenser, so that shows you how much I know!

Cheers,

Charles

The Opposite Of A 10dB Pad - 1:3 tranny
 

Charles H. Riggs, III wrote:

"Ian Bell" wrote in message
...
Charles H. Riggs, III wrote:
Because most dynamic mics work best into an impedance of 600 ohms or
thereabouts.

Which I gather means that there are plenty of high-end dynamic mikes that
utilize male XLR connectors, is that correct?

Correct.

I thought most high-end
mikes with XLR connectors were condenser, so that shows you how much I
know!

There are plenty of both but the best are invariably condenser.

Ian
--
Ian Bell

The Opposite Of A 10dB Pad - 1:3 tranny
 

In article ,
"Charles H. Riggs, III" wrote:
Which I gather means that there are plenty of high-end dynamic mikes
that utilize male XLR connectors, is that correct? I thought most
high-end mikes with XLR connectors were condenser, so that shows you how
much I know!

The ubiquitous Shure SM58 is probably the best known example of a dynamic
which uses an XLR.

But an XLR connector isn't just used on mics - it's used for anything with
a balanced input or output. And some things that are unbalanced too. ;-)

--
*Horn broken. - Watch for finger.

Dave Plowman London SW
To e-mail, change noise into sound.