Sowter TVC LF Oscillation?
#16 Re: Sowter TVC LF Oscillation?
Maybe they all drive Minis Mark..
- Dave the bass
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#18 Re: Sowter TVC LF Oscillation?
I think.... I may have entered a new era of measurement!
Oooo!
Oooo!
"The fat bourgeois and his doppelganger"
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#19 Re: Sowter TVC LF Oscillation?
Flash sod.
Wot is it?
Wot is it?
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
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#20 Re: Sowter TVC LF Oscillation?
Thats a screen grab from AudioTester. I was using a USB soundcard interface I'd built from an EPE magazine a couple of years back. The top 2 traces are a frequency sweep and the same at attenuated level, the lower 2 are the response of a Hagerman iRIAA filter.
I dun learning, with our-Thomas's encouragement.
I dun learning, with our-Thomas's encouragement.
"The fat bourgeois and his doppelganger"
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#21 Re: Sowter TVC LF Oscillation?
Had to look that up, wooo!
Bookmarked ~ a while back I was thinking about some sort of PC 'scope stuff.
Bookmarked ~ a while back I was thinking about some sort of PC 'scope stuff.
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
#22 Re: Sowter TVC LF Oscillation?
Using that front end and a 96/24 m-audio card, you can get down to this sort of floor. Thats on the 200mv range, and 0dB is 100mv RMS. So you can see signals down to about 200nV
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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#23 Re: Sowter TVC LF Oscillation?
Oh, your noise floor looks cleaner than mine Nick, is that using an un-tweaked ATEST and M-Audio Transit?
"The fat bourgeois and his doppelganger"
#24 Re: Sowter TVC LF Oscillation?
Thats a m-audio PCI card, and a atest with copper shielding and andrews tweek to the limiting resistors. It also involves keeping the a-test away from any other source of hum.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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#25 Re: Sowter TVC LF Oscillation?
Ta for the reply, I'm still very much getting grips with the software (which times out after 10 mins of measuring!), I've purchased the license but haven't received the key yet.
Wow, your noise floor trumps mine. This is a 2D FFT with the default 'Rife Vince 3' window selected. Bog standard unshielded un tweaked ATEST + M-Audio USB Transit. EDIT. 200mV range selected.
Wow, your noise floor trumps mine. This is a 2D FFT with the default 'Rife Vince 3' window selected. Bog standard unshielded un tweaked ATEST + M-Audio USB Transit. EDIT. 200mV range selected.
"The fat bourgeois and his doppelganger"
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#26 Re: Sowter TVC LF Oscillation?
Yey, the licence Key has come, I can measure for longer than 10 mns now at a time. So to celebrate I think I've successfully looked at the noise floor of the PCM2902 soundcard interface.
"The fat bourgeois and his doppelganger"
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#27 Re: Sowter TVC LF Oscillation?
Oooo! While I'm on a roll ... I do believe I've just managed to measure/look at the distortion spectra of a little chip amp running into a dummy load. I think I can see the harmonics too.
and here's a freq sweep of the same...
"The fat bourgeois and his doppelganger"
#28 Re: Sowter TVC LF Oscillation?
Looks like you've got the hang of it! Are the soundcard/ audiotester behaving themselves?
I don't fancy that chip amp very much…..I'll have a go measuring mine later
I don't fancy that chip amp very much…..I'll have a go measuring mine later
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#29 Re: Sowter TVC LF Oscillation?
Yeah, its coolio ta Thomas! The Transit USB seems much better behaved after you threatened it with the curse of the spangly pink mouse (and I stopped setting the Audio in/out parameters to a setting that wasn't available, ahem)!
I just re-read a little on the Pete Millett site and 'calibrated' the 'Zero' and 'FS adj' using my sig gen flat out at 2.23V AC @ 50Hz. I'll compare it to a Heater TX another day just to check at say 12V or so too.
A good day.
How's the Plumstead Peril?
I just re-read a little on the Pete Millett site and 'calibrated' the 'Zero' and 'FS adj' using my sig gen flat out at 2.23V AC @ 50Hz. I'll compare it to a Heater TX another day just to check at say 12V or so too.
A good day.
How's the Plumstead Peril?
"The fat bourgeois and his doppelganger"
#30 Re: Sowter TVC LF Oscillation?
That usually seems to work….Dave the bass wrote:Yeah, its coolio ta Thomas! The Transit USB seems much better behaved after you threatened it with the curse of the spangly pink mouse
'Plumstead peril' aka the Matchless G12, my new mid life crisis toy, apart from displaying a worrying tendency to want to bump into things, is doing ok for something of such advanced years, and doesn't seem to leak very much either….
….wait for it…..