Are you a proud owner of an IC-R7000 receiver which has no voice synthesizer installed?
Do you wish it had a little more in the way of selectivity and noise-fighting features, a la its later siblings the R8500 and R9500?
Fret not. There's a mod(ule) for that.
Disclaimer: One could always plug a Timewave DSP-599 into the '7000's Speaker Out jack, but the following solution is about half the the price...and goes everywhere the radio does.
SGC makes it: http://www.sgcworld.com/ADSPProductPage.html
Those wishing to duplicate my efforts will want to order the "low" module. The "high" unit has an onboard audio amp, and it isn't necessary for this application.
Examine your R7000 carefully. See that useless "speech" push-button on the front panel? It and the "Record Speech" control on the rear are going to be co-opted to control the SGC ADSP2's filter functions.
Note: The ADSP2 unit will mount with double-sided tape in the bottom half of the radio, where the IC-EX310 voice synthesizer attaches if it were installed. Reference all wiring runs accordingly.
Start by removing both covers and the rear bulkhead assembly. Remove the switch/connector daughterboard from the rear bulkhead and identify the "Record Speech" switch (second locking push-button down). Locate the black and blue wires which run to solder terminals and eventually the switch in question. Desolder them from the board and then solder them together, covering the connection with a piece of heat shrink tubing. Next, clip the dual microswitch from the small red/yellow/black wires running from the ADSP2 unit; connect the small-gauge yellow wire from the ADSP2 unit to one of the outer terminals of the "Record Speech" switch that you previously isolated. Connect the small-gauge red wire from the ADSP2 to the other outer terminal then connect an 18" piece of similarly sized wire to the center (common) terminal of the "Record Speech" switch. Reinstall daughterboard then bulkhead. Route added wire towards front of radio; you will connect it later.
Remove front panel sub-assembly attaching screws (2 each side) and pull front panel sub-assembly free of main chassis. Locate the SW3 board; remove it (3 screws) and locate the orange and green wires which attach to solder pads on one edge of the board. Desolder them and insulate each with heat-shrink tubing; tuck out of the way. Locate D31 (a diode which attaches to one leg of the "Speech" push-button) and desolder one lead. Next, attach the wire you ran from the rear bulkhead switch to one terminal of the "Speech" switch which you just isolated. Connect the small-gauge black wire from the ADSP2 unit to the other terminal of the "Speech" switch. Examine your work then reinstall SW3 board and front subassembly.
Remove the "Main" board - it has an audio amplifier chip and a couple of relays attached and is on the left side of the radio. Desolder C63, a 0.47uF electrolytic which connects to Pin 1 of the LA2600 audio preamp and serves as an intra-stage coupling capacitor. Run two small shielded audio cables from the IN/OUT ports on the ADSP2 board through the chassis cutout immediately behind the small shielded assembly adjacent to the "Main" board. The sub-miniature shielded cable which connects to the Output" solder pad of the the ADSP2 board goes to the now-vacant hole which connects via board trace to Pin 1 of the LA2600 IC; the other sub-miniature shielded cable (which runs from the "Input" pad of the ADSP2) connects to the other hole where C63 was formerly mounted.
Each shield of the shielded cables gets connected to a convenient grounded foil area on the "Main" board. Leave the far end shields free from anything (and each other).
Power and ground for the SGC board are obtained from IC6, a 7809 regulator - center terminal is ground, and the side which faces away from the reed relay is +9v out. Using this regulator as a power source puts AF preamp, DSP unit and AF PA at the same power/ground reference levels and eliminates ground loops. Dress the power leads for the ADSP2 unit out of the front chassis cutout where the "Main" board mounts then run them to the ADSP2 and solder into place.
Check your work for solder bridges then reinstall the "Main" board and sticky-tape the ADSP2 unit to the R7000's bottom metal bulkhead.
The "Record Speech" button on the back panel now serves to select the DSP mode (NR/notch or audio filter) and the front-panel "Speech" button steps through the filter settings or aggressiveness levels as required by the operator.
All of this is reversible if need be. The rig's appearance is unaltered as well.
My other R7000 will get the conversion over the XMas holidays. If anyone wants to see more info about the process I'll take a bunch of pix and post them as a follow-up to this thread.
