I'm building the VCO.
Built a little kit from maplin as the power supply.
http://www.vellemanusa.com/products/vie ... &id=350481
Put a battery on it. Connected up.
Power supply on.
TM4/5 Centred.
Checked the DC bias using my meter. CORRECT.
It performs like it should like it says in the instructions, I can hear buzzing that changes pitch
But using the sound card scope and the suggested soldered clips it doesnt look very saw like.
Anything I should check or carry on?
How does the I/O fit in?
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How does the I/O fit in?
Last edited by Pish on Wed Jul 17, 2013 6:02 pm, edited 2 times in total.
- antto
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Re: Testing VCO with soundcard scope. Doesnt look the same.
i'd say ignore this, either the scope or soundcard is acting weird
the VCO is biased so it might be clipping in your soundcard inputs
you could try running the probe signal thru a 1Meg pot and adjust it while looking at the scope
the VCO is biased so it might be clipping in your soundcard inputs
you could try running the probe signal thru a 1Meg pot and adjust it while looking at the scope
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Re: Testing VCO with soundcard scope. Doesnt look the same.
Using 7805 tab for both power and scope grounds
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Re: Testing VCO with soundcard scope. Doesnt look the same.
Instead of the 10k pot on the probes?
- mmm
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Re: Testing VCO with soundcard scope. Doesnt look the same.
The scope pics don't even look remotely like the real waveform.
First of all the waveform looks like it has both positive and negative symmetrical components; this shouldn't happen with the sawtooth at all.
In addition it appears as if it has just about 200mV peak to peak; this would be way too small.
I don't know if this is the result of the soundcard scope acting up.
First of all the waveform looks like it has both positive and negative symmetrical components; this shouldn't happen with the sawtooth at all.
In addition it appears as if it has just about 200mV peak to peak; this would be way too small.
I don't know if this is the result of the soundcard scope acting up.
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Re: Testing VCO with soundcard scope. Doesnt look the same.
Any suggestions then?
- antto
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Re: Testing VCO with soundcard scope. Doesnt look the same.
if it sounds fine - my suggestion is to continue forward with the build
you can check the signal again once you put the VCF together
you can check the signal again once you put the VCF together
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Re: Testing VCO with soundcard scope. Doesnt look the same.
Is there anything I can test my soundcard scope against?
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Re: Testing VCO with soundcard scope. Doesnt look the same.
Is it worth making a little frequency generator kit to test it on?
- antto
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Re: Testing VCO with soundcard scope. Doesnt look the same.
well, it's up to you
but IMO you can simply continue and checks things again when you build the VCF section
but IMO you can simply continue and checks things again when you build the VCF section
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Re: Testing VCO with soundcard scope. Doesnt look the same.
Cheers mate.
Ill just make sure I keep logs as i go
Ill just make sure I keep logs as i go
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Re: Testing VCO with soundcard scope. Doesnt look the same.
Got a second hand, hand held Velleman HPS140. I'll give it a go tomorrow.
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Re: Testing VCO with soundcard scope. Doesnt look the same.
Alot more like it!
- mmm
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Re: Testing VCO with soundcard scope. Doesnt look the same.
Definitely!
Let us know how everything else turns out.
Let us know how everything else turns out.
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Re: Testing VCO with soundcard scope. Doesnt look the same.
I was worrying I'd done something wrong but, Ive got the solder bug at the moment so I thought £40 for a £100 scope aint too bad.
Built the VCF but broke the point off the probe D: !!!! Have to find/order one
Built the VCF but broke the point off the probe D: !!!! Have to find/order one
Please be positive and constructive with your questions and comments.