I have to keep retuning MB

[Thunderroad75]

So I have had my MB for 3 months now and when I first got it The main tune knob would always be at about 11 o'clock to be in tune with 440hz. I now find I have to keep retuning over the course of 2-3 hours.

When I first turn on the MB it will tune up very fast to normal pitch, about 4-5 minutes, and the tune knob is close to 12 o'clock postion.

After 15 mins I have to turn the tune knob down by 1/2 a notch.

After 24 mins I have to turn the tune knob down by 1 1/2 notches.

After 1hr I have to turn the tune knob down to 2 notches.

after 2hrs I have to turn the tune knob down to 2 1/2 notches.

I take it this shouldn't be the case and the tuning should be stable after 15-20 mins. So I shouldn't really have to keep retuning?

I'd be interested in anyone elses findings with their MB.

Thanks.

[stevism]

depends on where you're playing it. temperature changes can play a role in this. is it near a vent/fan/window, etc.?

i retune periodically as well. every couple of hours is pretty stable, for an analog synth with vcos

[Thunderroad75]

When you have to retune are you moving further away everytime from the centred position?

My music room is basically the spare bedroom so only about 10x8 with no room to swing a cat with all my other gear so it does get a little warm.

I spoke to Bruno who asked me to do some tests which I done and sent him the results, just waiting for him to get back to me. He mentioned something about oven temperature. Aparently the MB has a temperature regulator inside it to quickly warm up the VCO so it gets in tune quickly and maybe mines not working as it should.