By “RX8” you mean a Yamaha RX8? I’m just guessing.
If you mean Yamaha RX8 then, yes, assuming you properly recorded the timecode, and your 388 is appropriately reproducing the timecode, and the 388, MTS-30, and RX8 are hooked up correctly and the RX8 is properly configured, yes I believe it is something the RX8 should be able to do.
First of all, how is everything connected? Is it like this?
RX8 MIDI OUT —> MTS30 MIDI IN
MTS30 MIDI OUT —> RX8 MIDI IN
MTS30 TAPE OUT —> 388 BUSS IN 8
388 TAPE OUT 8 —> MTS30 TAPE IN
If so, good. If not, correct it.
Then did you record timecode correctly?
1. dbx on 388 track 8 defeated
2. Play sequence on RX8 and adjust PGM MASTER EVEN fader to achieve a level of about -10VU on the PGM 8 meter
3. Stop RX8 playback
4. Set 388 to record on track 8 and place the 388 into RECORD - PLAY mode
5. Restart the RX8 sequence…record timecode until the sequence is finished.
If you did all that, good…if you didn’t, do it correctly.
Then is the RX8 configured correctly to lock to the incoming timecode? Refer to your RX8 manual page 33.
If you did all that correctly and it’s still not working, if you monitor the timecode track off the 388 does it sound clean and present or is it distorted or dropping out badly? And does the MTS30 display show the timecode reproducing when you reproduce the track on the 388? Are you sure your cables are all in good condition?