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Viewmaster · 16th Jun 2018, 8:59 am

I have made a new coil with 750 turns and this has given me the sparks for Bach!

To try it out to see if the sparks will sound loud notes I knocked up a 555 astable sq wave oscillator and was pleased to see and HEAR the sparks sounding off when controlling the two GU81 valves o/p.

I made a cheap and cheerful winding rig to wind the 750 turns. At one point there was small overlap of turns which I didn't notice but the coil seems fine without any arcing over when running the valves at 2.5kv.

To increase spark length I have bought off ebay a HV transmitting variable capacitor to fine tune the primary coil

I will also have to increase ventilation more to get rid of the dangerous ozone produced!

16th Jun 2018, 8:59 am	#6
Viewmaster Hexode Join Date: Jul 2016 Location: Ashby de la Zouch, Leicestershire, UK. Posts: 253	Re: Bach with sparks! I have made a new coil with 750 turns and this has given me the sparks for Bach! To try it out to see if the sparks will sound loud notes I knocked up a 555 astable sq wave oscillator and was pleased to see and HEAR the sparks sounding off when controlling the two GU81 valves o/p. I made a cheap and cheerful winding rig to wind the 750 turns. At one point there was small overlap of turns which I didn't notice but the coil seems fine without any arcing over when running the valves at 2.5kv. To increase spark length I have bought off ebay a HV transmitting variable capacitor to fine tune the primary coil I will also have to increase ventilation more to get rid of the dangerous ozone produced! Attached Thumbnails __________________ "One small step for man".....because he has arthritis. www.retinascope.co.uk Albert.