Re: VTTC output

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

Original poster: "David Trimmell by way of Terry Fritz <twftesla-at-uswest-dot-net>" <davidt-at-pond-dot-net>


Hi,



> able to get deafening audio out of the spark with only 3-4" brush
- So, ear protection is a MUST
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Not a bad idea for hi Vol testing...
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> but would produce noticable clipping of audio and as seen on the scope.
- Did you continue to operate the tube in C mode or did you reduce
the gridleak resistor in order to drive it in A mode?
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I found that I got best responce (less distortion) with a high value of
resistance in the grid. Around 40 to 50K worked very well for 833's and
304TL's (and 304TH). Very little DC current would flow, around 10 to 20
mA.
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> You might try a signal generator run through a amp for testing,
would be great way to test audio responce...
- Where should I pick the modulated signal? Across the 5 Ohm
resistor connected between the base of the secondary and rf
ground?
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Not to sure of what you mean. Last night I setup my Audio Mod VTTC lashup,
unfortunatly I have been having a bear of a time trying to find the best
bias for the output tubes on my Audio Amp, but thats another story...
I ran the output of the Audio Signal generator into the amp input and the
4 ohm output whent to the Audio coupling transformer. Preliminary testing
(low audio power untill I get the amp working corectly) does verify that
the spark has a harder time reproducing low frequency 
signals(<1000-500Hz) without distortion. This I need to do more work on 
though...

I am in the process of designing a Audio Mod research coil that will use a
304TL and a small 2400V PT (a MOT with shunts removed can be used also), I
just need a functional Audio Amp! Really, one does not need a very big
spark, to get decent Audio.

Herwig, do have Schematics of your VTTC?

Regards,

David Trimmell
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Regards,

Herwig