Seemed more random. Thru the headphone jack.
But yesterday I played through the output jack on the back into an amp and noticed no pops in the sound throughout, so that was nice. The only other problem I had is that the output would slowly go soft and then die out completely. Then after rotating the volume knob a few times, I got the sound back. This happened a few more times. On the last time it happened, no rotating of the volume (or tone) pots alleviated this but I kept playing and eventually it came back.
I have more questions about my mellotron but I will post them in another thread to the group. I can say it was nice playing her again after all these years!