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.