"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