Re: SSTC Break-Through - 5MHz operation for Ion Tweeter system

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Chris Arnold by way of Terry Fritz <teslalist-at-qwest-dot-net>" <chris_arnold-at-msn-dot-com>

Dan,

That is awesome news!  I have a few questions: What kind of power levels 
were you able to push through it?  Why the need for 10 MHz operation?  It 
would seem to me that once you get above the threshold for noise from the 
arc that higher frequency only complicates things, especially with solid 
state power.

Chris Arnold

PS - I fired my PlasmaSonic SSTC for the first time tonight with a three 
turn primary and 12 vdc input.  It drew around 5-6 amps and was able to 
produce about 0.5" of corona into free air and a power arc over 1" long.
Pretty puny compared to what it will be doing, but still very nice for only 
12 volts in.  Fres was approximately 300 kHz.  I'm going to try the audio 
modulation feature later tonight.


>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: Re: SSTC Break-Through - 5MHz operation for Ion Tweeter system
>Date: Wed, 06 Aug 2003 00:00:48 -0600
>
>Original poster: "Steven Ward by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
><srward16-at-hotmail-dot-com>
>
>Dan,
>
>That is awesome!  how are you managing such high frequencies?!?!?  WOW, 
>5mhz.  Im guessing your little brush discharge is maybe 1cm or so?  How 
>did you manage the gate drive?  Are the gates still square or more of a 
>triangle?  How is heating of the bridge (half? H?).  When will you be 
>updating your website with some info?
>
>Steve Ward
>
>
>>From: "Tesla list" <tesla-at-pupman-dot-com>
>>To: tesla-at-pupman-dot-com
>>Subject: SSTC Break-Through - 5MHz operation for Ion Tweeter system
>>Date: Tue, 05 Aug 2003 22:22:20 -0600
>>
>>Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
>><dhmccauley-at-spacecatlighting-dot-com>
>>
>>Tonight I made a big step towards a Hi-Fi solid state ion tweeter (aka audio
>>modulated SSTC).  The key to creating a Hi-Fi ion tweeter is to run at a
>>frequency of at least
>>3MHz.   The corona formation of anything less than 3MHz can be typically
>>considered "noisy" or "hissy", but once the 3MHz+ limit has been hit, corona
>>discharge is practically silent.
>>Typically tubes are used to easily get switching frequencies well over 12MHz
>>for ion tweeters, but solid state has always been limited to low frequencies
>>(<300kHz typically) due to the
>>inherent complexities of switching a high voltage at relatively high current
>>at high frequencies.  To my knowledge, the highest frequency obtained yet
>>for a solid state ion tweeter
>>has been by a group of doctorate students at Villanova University,
>>Pennsylvania where their SSTCs were operating at 3MHz.
>>
>>However, my initial tests this evening have proven reliable operation at
>>5MHz with some very quiet, continous corona.  I haven't audio modulated yet,
>>but this is the first step.  My goal,
>>however challenging, is to get operation up to about 10MHz switching 170VDC.
>>At these frequencies, I think i can create a ion tweeter approaching Hi-Fi
>>characteristics although probably
>>never achieve the quality (at least in an audiophiles opinion) that tubes
>>can produce.
>>
>>This is exciting news and I will be keeping the group posted.
>>
>>The Captain
>