Above: nothing startling here, just the usual sound discriminator and Scout reaction tune mods in evidence with the 2.5mm sockets

Above: What have we here? Four more side panel buttons! The top two are used for the sound recorder, the next is for NFM bandwidth toggle. The bottom one is currently unused.

Sound Recorder
An essential item for capturing all kinds of interesting bits of info, surprisingly there hasn't been a module produced to fit into the AR8000. AOR UK was working on a design, which they then abandoned. Implementations on other receivers has often left a bit to be desired, whereby the record mode has to be set up, before it can be invoked. What is needed is a single key-press for instant record and playback.
All such devices seem to use the ISD1000A chip series, intended for use in memo-recorders, and various novelty items that require cheap and cheerful audio facilities. This is a great device, with non-volatile memory (message retention is 100 years!), up to 20 seconds capacity, and it requires very few extra components. To integrate one into the AR8000 seemed a difficult task at first, but it is actually quite easy. I opted to use an existing memo-recorder board (Memokey 320, sold by Maplin Electronics, board type MKP-05), but if you can't find one there are plenty of others using the same technology. Check it's fully working before delving inside. The important thing is that it should use the die version of the chip, if you look on the board you should see it-a small black blob! Any other type may not be possible to squeeze in. Even this board had to be pruned, there was extra circuitry including a microphone, which was removed, and the top 5mm had to be sawn off for it to fit in the only suitable spot I could find. As can be seen from the photo (right) this area is just above the LCD display, on the logic board, with a small sticky pad allowing it to rest on the speaker.
Carefully analyse the track layout from the die chip, and the connections should be obvious. Discard any extra bits and pieces no longer required on the board, including the switches and LED. Remove the two electrolytic caps near the top of the board.
At the bottom of the board are the supply and audio out connections, left to right 0V, AF out, AF ground, and +5V. Just above the +5V pad is a surface mount cap, remove it, the left pad is the line level audio in, which should be DC isolated with an external cap. Audio from the AR8000 comes from J6-3, a connection can be found on the logic board (see the external sockets photo at bottom). The only snag with that is that the audio fed to the recorder is always unmuted, but this is not a major problem in my opinion.
The record and playback switches can be mounted wherever you like, personally I prefer the right side panel. Two press-to-make switches are added which obviously connect to the pads vacated by the original switches. I used a spare left panel (from a broken AR8000), which is perfect for the job (and also gives the option of two more switches), but sadly AOR do not supply this separately.

This is the memo-recorder board squeezed into the area above the LCD display. On the LCD back plate rests a 4013 flip-flop which operates the IF bandwidth toggle.

NAM/NFM IF Bandwidth Switching
A popular mod, which is commercially available and the DIY version has been doing the rounds for years. The idea is very simple, to allow the selection of the narrow SSB/CW IF filter while in AM and NFM modes, and entails swapping the two control voltages from U2. My way to accomplish this is a bit different from the mods I've seen. It requires a flip-flop IC, two diodes and one Supersot FET, the NDC7001C dual FET (one is N-channel, the other P-channel). The latter device is extremely small (see image right lower), even by SMD standards, so you may prefer to use two discrete FETs instead. As can be seen (photo right), I did just that after over-heating the original!
The two drains are joined together and connect to the cathode of a diode; the gates are also connected together, and connect to the Q/NOT Q of a 4013 flip-flop IC via a 10k resistor. The 4013 is in toggle mode and uses a spare momentary push-to-make switch from the mod mentioned above. The source of one FET connects to the junction of R22/C30, the other source connects to the junction of C32/R25/R26.
Two tracks on the IF board need to be cut, I recommend studying the service manual and the board very carefully before doing this. Look to the right of the top row of pins of U6, you'll see three horizontal tracks, the top one and the middle one need to be cut, and the track exposed to create four connection pads. For the top track you need to bridge the connections with a diode (1N914), the cathode (banded end) soldered to the right side pad, which is also connected to a source of the NDC7001C. The middle track left pad connects to the anode of the diode that goes to the gates of the NDC7001C, the right pad connects to the remaining source of the NDC7001C.
I would stress that the PCB track cutting is a slightly tricky procedure, take your time while attempting this, and triple check to make sure you're cutting the right tracks! Do a continuity check to confirm the tracks are actually cut and when you've installed the mod, confirm all connections are correct.
I recommend this mod, it will improve the SNR when listening to weak signals on AM, or those subject to adjacent channel splatter, and it's also very useful to use when listening to low-deviation NFM signals (i.e. those of a covert nature).