Reface DX analysis

To understand the behavior of the reface DX vs DX7 (for example) I decided to make some measurements.

First a table to set modulator amplitude vs DX7 and Reface DX, then some LFO timing:

Then I decided to measure EG rates ... this is at this step that I got some surprises :

1. INIT VOICE

2. Algo : 12

3. OP 1: ON

4. Level: 127, Fixed frequency 9772 Hz

5. EG Levels: 127 0 0 0

6. EG Rates: 127 127 127 0  (very sharp attack and nothing else to get the NOTE ON event)

7. OP 2: ON

8. Level: 127, Fixed frequency 9772 Hz

9. EG Levels: 2 1 127 0

10. EG Rates: 127 89 127 127  (start of sound delayed with low levels L1 > L2, duration is set by R2)

11. OP 3: OFF

12. OP 4: OFF

Audio captured from OUTPUT/MONO with a Tascam DR-05X at 48 kHz.

Output level at Max.

Measurements done with Waveforms from DIGILENT (personnal use)

Note played C5 : the following pictures shows 3 measurements :

To conclude :

It seems that the sync on KEY ON is rather strange, even the OP1 blip is not always the same duration.

The delay induced on OP2 is fluctuating a lot (260 - 380 ms).

Same measurements done with Dexed or Chipsynth OPS7 gives no variation at all between measurement ...

To give some hints, here are the resulst of other measurements:

Perhaps this a choice Yamaha made to give the Reface DX some 'analog variations' to avoid a too much numeric synth ???