Tube synth diy

Hello,
I found your group by accident and joined up. It looks like a great resource. I am from Ireland and build a few tube guitar amps and have built a few effects pedals from time to time. I am an electrician and an instrumentation technician.

The reason I stumbled upon this group is that I was searching for tube it synth effects. I had an idea to try make some kind of tube synth to play a guitar through into a guitar tube amp. Does anyone have any ideas or plans for anything like that? 

Thanks,
Cian