Three necessary items;  Click each item for more information. On Transmit I use the Mike, pre-amp/power supply and 6 multiband compressor. 

The Marshall MX990  a NEW Inexpensive ($59) true, phantom powered, condenser microphone.  I use

Or The Behringer B-1 Microphone  ($100)  Slightly more below 60 cycles, My voice fundamentals start at 73 cycles.

You will also need a XLR Microphone cable, male to female with either Mike. And possibly a shock mount and stand. Or hold in your hand to start.

The Behringer UB1002FX  ($80) Mic Preamplifier/Equalizer/Mixer/48 VDC Phantom Power Supply.  

Click here for larger  113K .jpg  The new FX effects chip is verrrry interesting ! These effects alone used to cost $200 ! Built in Monitor. Great for playback and your phone patch. No compressor, limiter. This mixer must be used with a compressor/limiter. A good marriage would be this and the 9024 alone.  Tested by WA2CYT   Who is heard "All the time, on 75 AM".

Or The Behringer Rack mount ULTRAVOICE DIGITAL VX249  ($125) Mic Preamplifier/Voice Processor/48 VDC Phantom Power Supply/Compressor/Limiter. I use the better Compressor/ Limiter in the 9024 below.

Lastly, Add the Behringer DSP-9024 6 band audio Compressor / Limiter. You are allowed to independently select each bands upper and lower limits along with different compressor / limiter parameters. As you can set the output level for each individual band this is the only Equalizer you need, along with the warmth notch and presence rise of the VX249. The final step some day.  Supplies are dwindling with production ended as musicians did not buy them!  This is the poor man's "Orban" limiter/compressor. I use the 9024 very successfully in several AM, FM Radio Stations. First tested by Bill, W3DUQ. I use

My settings for AM Voice  Day time settings

Band 1    35-217              +9 Db                Nighttime Conditions = 0 Db  90-217

Band 2    217-332             -18 Db               Bands 2 reduces Mud frequencies

Band 3    332-470             -5 Db                 Bands 3 reduces Mud frequencies   

Band 4    470-990             +7 Db

Band 5    990-1,900         +16 Db

Band 6    1,900-5,5200    +20 Db                   Nighttime Conditions =  1,900-4,500

Peak limiter -29 Db    Set for no shot noise off channel frequency and or white dots on scope display (approaching carrier cutoff).

Dirk, WA2CYT can help you set the limiter by viewing your signal on his scope. He also uses a 1002 and a 9024.

Run the Virtuoso option at tight or ultra to auto set the thresholds.

     Feeding this audio to old tube transmitters.  Feed this low impedance low level audio into the second audio stages, identified by the mike gain pot feeding its control grid. From its new cathode resistor use a 560 ohm 1/2 watt resistor to ground and add a 47 MFD. coupling cap between the cathode (plus on cathode) through some new shielded RG-58au coax to a newly added RCA connector on the rear chassis. When not using the original mike input connector turn the original mike gain pot all the way down. Don't use old oxidized braid coax.  You must have good RF and audio shielding. Don't start Band one minimum frequency below the distortion free capability of your modulator !

To feed this audio to solid state transceivers or transmitters  here is an example of feeding audio into the balanced modulator directly.  << here >>

03/25/2007