a fun one for me when I first started futzing with filters was using a twin t filter to create a bass or tom sound where you get the twin t on the edge of self oscillation so that you can send a transient through it to create the sound. It's been a while but I think I used an unbuffered 4069 or 4049 for the filter portion and a 40106 for a consistently timed input. Though I cant recall, i will have to dig around my basement to find the thing lol.
Different noise spectral shapes are used for testing purposes. C message weighted noise was used for telephone circuits back in the day when that was part of my job.
Back in the late 70s, I think it was General Instruments that produced a neat sound effects generator with VCO(s?) generating waveforms, filters, ADSR envelope generator and some other things. I should still have a chip I bought as a teenager, but it's lost. I'm sad that I didn't buy one of the various experimenter boards that incorporated this chip.
It would be cool to filter the noise separately before mixing it in. Then you could change what type of noise is getting mixed in or get the noise filter to oscillate and create a sine wave as well.
I like the bit of music you use at the end of your videos.. It reminds me of an old made for TV movie called, 'The star wagon' which uses that kind of interesting mysterious music throughout. It starred Dustin Hoffman, and Orson Bean. I first saw it about 20 years ago and it became one of my favorite little films.
Having the input OpAmps could actually solve the inverting behavior of the summing mixer, by turning them into inverting buffers/amplifiers instead of noninverting buffers?
From your hints, I expect you are going to use an OTA (operational transconductance amplifier) like an LM3080. A couple of warnings---do not treat them like an op-amp---treat them like an amplifier block with input and output, with a current controlled gain.. They can be easy to smoke if you aren't paying attention--learned this the hard way. Also, they can only deal with very low signal levels, so you will need a buffer amp to bring them up to your standard voltage level to math the rest other circuits. Just wanted to offer a couple of warnings to prevent your magic smoke from escaping. :)
0:05, you don't need the 3 opamps on the left side, if the output of the previous module/stage sources from a opamp .. or you would place the potentionmeter inside of the opamps setup. check out "Thonk" in the Uk, they have CA3080, some latvian company called "Alfa" cloned CA3080 and so. aswel the ALFA VCO clone of the CEM3340 VCO chip, filter on chip Alfa AS3320 a clone of the 4 pole CEM3320 Filter chip.
@@IMSAIGuy i wonder why Texas Instruments doesn't provide us with a DIP8/soic8 single LM13700, sometimes you just want one and the things i make i try to fit on a 19mm wide x 110 mm high PCB alongside sockets, pots and stuff. the DIP16 is kinda big now the CA3080 is kinda obsolete. i made a Rene Schmidtz Korg MS-20 (2 pole) clone filter with the CA3080, video on my profile and until today it's sounds kinda good. I still would place the pots inside/between the opamps and make the opamps source from the source, so the signal from the source isn't sinked into to ground but directly into to opamp or what is your thought about it
Probably an Automatic Gain Control (AGC) or Audio Limiter. Also, you might want digital Audio recorder and player, so you can say record sound of a say drum or notes of an instrument.
Nice..semi permanent...not breadboarded.. I can see some 2N2646 UJT bring usec... How about dig up TI SN76477...or maybe a newer version...? That chip had some nice oscillator and mixerused... bum Good job...
I have a TENS unit kind of thing that generates out put square wave frequency less that 1khz. I want to run the following ten out puts for 5 to 10 min ea: Hz .52, .2.50, 40.00, 95.00, 376.29, 476.50, 527.00, 665.34, 752.70, 987.23. I think the power in is 4volt and the output power is below 1 miliamp. Any ideas?
If the point of a buffer is to have a high input impedance and low output impedance, I am curious as to why you added the extra 10k resistor on the output of the buffer? Is that to get unity gain with the 2nd stage?
the three 10k resistor are a sum. you can have different gains on each channel. so in this case gain is 1, or actually -1. if one of the buffers had a 5k resistor then that channel would have a gain of -2
@@IMSAIGuy Oh very interesting yeah that is a really good point. I had not considered the 2nd stage mixer's feedback loop relative to its input impedance. I really appreciate the insight!
You've been busy! I'm loving this series.
a fun one for me when I first started futzing with filters was using a twin t filter to create a bass or tom sound where you get the twin t on the edge of self oscillation so that you can send a transient through it to create the sound. It's been a while but I think I used an unbuffered 4069 or 4049 for the filter portion and a 40106 for a consistently timed input. Though I cant recall, i will have to dig around my basement to find the thing lol.
Different noise spectral shapes are used for testing purposes. C message weighted noise was used for telephone circuits back in the day when that was part of my job.
Back in the late 70s, I think it was General Instruments that produced a neat sound effects generator with VCO(s?) generating waveforms, filters, ADSR envelope generator and some other things. I should still have a chip I bought as a teenager, but it's lost. I'm sad that I didn't buy one of the various experimenter boards that incorporated this chip.
Mixers are useful for all sorts of other projects, too.
yes, I tried to make this one pretty generic.
It would be cool to filter the noise separately before mixing it in. Then you could change what type of noise is getting mixed in or get the noise filter to oscillate and create a sine wave as well.
I like the bit of music you use at the end of your videos.. It reminds me of an old made for TV movie called, 'The star wagon' which uses that kind of interesting mysterious music throughout. It starred Dustin Hoffman, and Orson Bean. I first saw it about 20 years ago and it became one of my favorite little films.
thanks, I composed it
nice little circuit, I like it.
Having the input OpAmps could actually solve the inverting behavior of the summing mixer, by turning them into inverting buffers/amplifiers instead of noninverting buffers?
Analog multiplier will allow the development of a wider range of synthesizer. A simple two-quadrant analog multiplier would be fine.
From your hints, I expect you are going to use an OTA (operational transconductance amplifier) like an LM3080. A couple of warnings---do not treat them like an op-amp---treat them like an amplifier block with input and output, with a current controlled gain.. They can be easy to smoke if you aren't paying attention--learned this the hard way. Also, they can only deal with very low signal levels, so you will need a buffer amp to bring them up to your standard voltage level to math the rest other circuits. Just wanted to offer a couple of warnings to prevent your magic smoke from escaping. :)
love this series!!
This is great ! filters will be fun...cheers.
0:05, you don't need the 3 opamps on the left side, if the output of the previous module/stage sources from a opamp .. or you would place the potentionmeter inside of the opamps setup.
check out "Thonk" in the Uk, they have CA3080, some latvian company called "Alfa" cloned CA3080 and so. aswel the ALFA VCO clone of the CEM3340 VCO chip, filter on chip Alfa AS3320 a clone of the 4 pole CEM3320 Filter chip.
yes, this one is robust to create equal channels for different incoming impedances
3080 will be in a future video
@@IMSAIGuy i wonder why Texas Instruments doesn't provide us with a DIP8/soic8 single LM13700, sometimes you just want one and the things i make i try to fit on a 19mm wide x 110 mm high PCB alongside sockets, pots and stuff. the DIP16 is kinda big
now the CA3080 is kinda obsolete. i made a Rene Schmidtz Korg MS-20 (2 pole) clone filter with the CA3080, video on my profile and until today it's sounds kinda good.
I still would place the pots inside/between the opamps and make the opamps source from the source, so the signal from the source isn't sinked into to ground but directly into to opamp or what is your thought about it
@@AnalogDude_ I agree
@@IMSAIGuy alfarzpp.lv/eng/sc/AS3080E.pdf the Lativa / alfa replacement / clone.
Probably an Automatic Gain Control (AGC) or Audio Limiter.
Also, you might want digital Audio recorder and player, so you can say record sound of a say drum or notes of an instrument.
ISD1820-Datasheet.pdf, a pretty cool voice recorder chinese chip, people are suing to build a sampler.
Nice..semi permanent...not breadboarded..
I can see some 2N2646 UJT bring usec...
How about dig up TI SN76477...or maybe a newer version...?
That chip had some nice oscillator and mixerused... bum
Good job...
I have a TENS unit kind of thing that generates out put square wave frequency less that 1khz. I want to run the following ten out puts for 5 to 10 min ea: Hz .52, .2.50, 40.00, 95.00, 376.29, 476.50, 527.00, 665.34, 752.70, 987.23. I think the power in is 4volt and the output power is below 1 miliamp.
Any ideas?
microcontroller, Arduino is an example
If the point of a buffer is to have a high input impedance and low output impedance, I am curious as to why you added the extra 10k resistor on the output of the buffer? Is that to get unity gain with the 2nd stage?
the three 10k resistor are a sum. you can have different gains on each channel. so in this case gain is 1, or actually -1. if one of the buffers had a 5k resistor then that channel would have a gain of -2
@@IMSAIGuy Oh very interesting yeah that is a really good point. I had not considered the 2nd stage mixer's feedback loop relative to its input impedance. I really appreciate the insight!
Are you thinking of putting a sequencer into it?
thought about it, but no
Isn't a voltage controlled amplifier just a JFET? Is that what you have ordered? Sounded more like some type of IC.
I will be doing a video on JFET as a VCA
Dope! I would like to see an equaliser.
Sorry but it's too late, Edward Woodward is dead.
Oh no... Very sorry to hear that. My condolence.
this is a cool chip, "ISD1820" Datasheet to build a LOFI sampler.