High Voltage Forum

Tesla coils => Dual Resonant Solid State Tesla coils (DRSSTC) => Topic started by: flyingperson23 on November 08, 2022, 02:30:43 AM

Title: Instability
Post by: flyingperson23 on November 08, 2022, 02:30:43 AM
My coil was working seemingly just fine, but now it sounds messy and unstable and has large bursts that aren't in the music I'm trying to play. Any idea what could be causing this?
video here: https://drive.google.com/file/d/1hjojn1vbL6Z8tFSX-wP5lKot-fFEH57g/view?usp=drivesdk
Title: Re: Instability
Post by: Max on November 08, 2022, 08:18:09 AM
I suspect that it‘s the interrupter. I can clearly hear a second, lower voice which might explain some of the behavior. The bursts do match the beat of the music so I do think they are in the MIDI file and get somehow processed by whatever interrupter you got.
Quick way to check this is scoping the interrupter signal.

Kind regards,
Max
Title: Re: Instability
Post by: AeraCura_ on November 08, 2022, 10:43:28 PM
That song has large burst just like youre seeing so I dont believe there is any reason to suspect that its playing eronious notes.
I believe your coil may be out of tune though.
Where are you tapping your primary? How well does it correspond with the calculated turns from JavaTC?
I would start by taping for 10% lower primary frequency and noting if the music sounds better. If not you should reset and go for10% higher primary frequency.
Title: Re: Instability
Post by: flyingperson23 on November 10, 2022, 04:58:51 AM
The bursts aren't in the song; I played the same midi a few times a few weeks ago and never had the bursts. I took off the ud to add better transistor heatsinks and now the arc sounds a lot less clean and has the bursts. My interrupter is a more or less brand new midi stick from TMaxElectronics. I don't have the coil detuned for spark loading but other than that it is about as well tuned as I can get it. I'll scope the ud and interrupter outputs and see if anything is noticeably wrong.
Title: Re: Instability
Post by: AeraCura_ on November 10, 2022, 07:05:52 PM
Its hard for me to know what bursts youre referring to. In the original song there are longer bursts that sound like a tesla coil, this is why everyone likes to play that song.
If its not that than forgive me as everything i'm about to say is based on that assumption.

If its sounding different than the last time you played the song i would look at the instuments feature of the midistick, starting arround 8:20
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Depending on which application you're using you should see a visual reprsentation of the notes playing. I would try muting that channel to see if it appears how you want it.

Title: Re: Instability
Post by: flyingperson23 on December 10, 2022, 03:56:01 AM
if anyone else has this problem, i figured it out - i forgot that i set the max on time to 200us instead of the default 100 but i kept the max duty cycle at 5% so i was running into the duty cycle limiter whenever it tried to play 2 notes at once, leading to a generally much worse sound
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