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Hello, I'm wondering if I could impose upon you for a little help with my Teezer.

First let me thank you for all the great circuits you have shared and your website.

I just assembled a Teezer u ...

I built a T.H. VCF-1 and really like it. I have a question about self resonance. The filter does all the things I expected including pretty nice V/O tacking and it pings really nicely.

But, if the ...

Well, it's pretty well fixed. The simulation you did was brilliant and pointed to the lack of gain at IC3d as the problem. Thanks so much for that.

We had to expect that with a set of symptoms as g ...

Yep, I did a good deal of mispoking around the time I gave those resistor values. Rolling Eyes

Wow, I love the simulation. I think we're on the same page now. Still confused but at a much higher level ...

I hope you don't have too bad a reaction from that booster. I've gone back and forth on covid vaccine reactions.

I don't feel picked on. When I make a mistake, I value having it corrected. Just a ...

Here's a pic of the output at pin 5 IC2. DC coupled. I'm not too worried about the offset as I see the compensation for that at IC3D, I think. But 5.xV PP seems too low to me. (Ignore the slight slew ...

Well that's embarrassing.
Sorry for the brain fart in computing voltage dividers. I've been trouble shooting this thing all day as well as being eyeball deep in some complex CAD work for a customer. ...

Again, I really appreciate your input.

I don't think we're looking at the same schematic.

Mine has a 10K/4.7K at pin 3 IC2. So 4.7K/10K= 0.47 X 15V = 7.05V. These are also the values on the sc ...

It would be useful to see what the signal looks like at pin 8 of IC3. If *that* looks normal, then the problem is somewhere around IC3d which scales and offsets the triangle.

The signal at pin 8 I ...

Lastly my poor sine wave. It looks like it's turned half a triangle wave into half a sine wave.

Here's the sawtooth. It's totally unaffected. I think this is because the shape of the sawtooth is created totally by the 555 and is not derived from the triangle like the other waveforms.

Here's the triangle

Thanks again for your time. I pretty happy with you just throwing out ideas. It's a pesky trouble shooting problem and I can't expect anyone to take it on or spend a lot of time on it.

It's a great ...

Thanks again for the continued interest in my little problem. When I first built it I looked at and measured all the waveforms using my o-scope. I did a distortion measurement on the sine wave and loo ...

Thanks for the reply. Pin 3 shows an almost 50% duty cycle square wave 0V-14.7V.

Spence

I keep thinking of things I've already checked. The 5V+ and 1.5V- magnitude of the triangle wave is present at pin 5 of the 13007, which has been replaced. This tells me what ever happened is not *now ...

I should add that all PS voltages at the various IC pins are correct and I don't detect any solder bridges or shorts by visual inspection.

Thanks,
Spence

I my finished PCB of the VCO-555 was working perfectly but I needed to rewire the connections from the PCB to the pots and jacks when I mounted it to the panel.

After doing so I found everything wo ...

Author	Message
Topic: TZFM SAW VCO
gimble88 Replies: 536 Views: 602479	Posted: Mon Sep 05, 2022 9:33 pm Subject: TZFM SAW VCO Forum: DIY Hardware and Software
gimble88 Replies: 536 Views: 602479	Hello, I'm wondering if I could impose upon you for a little help with my Teezer. First let me thank you for all the great circuits you have shared and your website. I just assembled a Teezer u ...
Topic: VCF-1 self oscillation
gimble88 Replies: 0 Views: 2826	Posted: Wed Jun 29, 2022 8:34 am Subject: VCF-1 self oscillation Forum: DIY Hardware and Software » Thomas Henry designs
gimble88 Replies: 0 Views: 2826	I built a T.H. VCF-1 and really like it. I have a question about self resonance. The filter does all the things I expected including pretty nice V/O tacking and it pings really nicely. But, if the ...
Topic: The VCO-555
gimble88 Replies: 479 Views: 569559	Posted: Sat May 28, 2022 6:47 pm Subject: The VCO-555 Forum: DIY Hardware and Software » Thomas Henry designs
gimble88 Replies: 479 Views: 569559	Well, it's pretty well fixed. The simulation you did was brilliant and pointed to the lack of gain at IC3d as the problem. Thanks so much for that. We had to expect that with a set of symptoms as g ...
Topic: The VCO-555
gimble88 Replies: 479 Views: 569559	Posted: Sat May 28, 2022 4:13 pm Subject: The VCO-555 Forum: DIY Hardware and Software » Thomas Henry designs
gimble88 Replies: 479 Views: 569559	Yep, I did a good deal of mispoking around the time I gave those resistor values. Wow, I love the simulation. I think we're on the same page now. Still confused but at a much higher level ...
Topic: The VCO-555
gimble88 Replies: 479 Views: 569559	Posted: Sat May 28, 2022 1:31 pm Subject: The VCO-555 Forum: DIY Hardware and Software » Thomas Henry designs
gimble88 Replies: 479 Views: 569559	I hope you don't have too bad a reaction from that booster. I've gone back and forth on covid vaccine reactions. I don't feel picked on. When I make a mistake, I value having it corrected. Just a ...
Topic: The VCO-555
gimble88 Replies: 479 Views: 569559	Posted: Sat May 28, 2022 12:21 am Subject: The VCO-555 Forum: DIY Hardware and Software » Thomas Henry designs
gimble88 Replies: 479 Views: 569559	Here's a pic of the output at pin 5 IC2. DC coupled. I'm not too worried about the offset as I see the compensation for that at IC3D, I think. But 5.xV PP seems too low to me. (Ignore the slight slew ...
Topic: The VCO-555
gimble88 Replies: 479 Views: 569559	Posted: Sat May 28, 2022 12:10 am Subject: The VCO-555 Forum: DIY Hardware and Software » Thomas Henry designs
gimble88 Replies: 479 Views: 569559	Well that's embarrassing. Sorry for the brain fart in computing voltage dividers. I've been trouble shooting this thing all day as well as being eyeball deep in some complex CAD work for a customer. ...
Topic: The VCO-555
gimble88 Replies: 479 Views: 569559	Posted: Fri May 27, 2022 8:41 pm Subject: The VCO-555 Forum: DIY Hardware and Software » Thomas Henry designs
gimble88 Replies: 479 Views: 569559	Again, I really appreciate your input. I don't think we're looking at the same schematic. Mine has a 10K/4.7K at pin 3 IC2. So 4.7K/10K= 0.47 X 15V = 7.05V. These are also the values on the sc ...
Topic: The VCO-555
gimble88 Replies: 479 Views: 569559	Posted: Fri May 27, 2022 5:37 pm Subject: The VCO-555 Forum: DIY Hardware and Software » Thomas Henry designs
gimble88 Replies: 479 Views: 569559	It would be useful to see what the signal looks like at pin 8 of IC3. If that looks normal, then the problem is somewhere around IC3d which scales and offsets the triangle. The signal at pin 8 I ...
Topic: The VCO-555
gimble88 Replies: 479 Views: 569559	Posted: Fri May 27, 2022 3:20 pm Subject: The VCO-555 Forum: DIY Hardware and Software » Thomas Henry designs
gimble88 Replies: 479 Views: 569559	Lastly my poor sine wave. It looks like it's turned half a triangle wave into half a sine wave.
Topic: The VCO-555
gimble88 Replies: 479 Views: 569559	Posted: Fri May 27, 2022 3:18 pm Subject: The VCO-555 Forum: DIY Hardware and Software » Thomas Henry designs
gimble88 Replies: 479 Views: 569559	Here's the sawtooth. It's totally unaffected. I think this is because the shape of the sawtooth is created totally by the 555 and is not derived from the triangle like the other waveforms.
Topic: The VCO-555
gimble88 Replies: 479 Views: 569559	Posted: Fri May 27, 2022 3:16 pm Subject: The VCO-555 Forum: DIY Hardware and Software » Thomas Henry designs
gimble88 Replies: 479 Views: 569559	Here's the triangle
Topic: The VCO-555
gimble88 Replies: 479 Views: 569559	Posted: Fri May 27, 2022 3:13 pm Subject: The VCO-555 Forum: DIY Hardware and Software » Thomas Henry designs
gimble88 Replies: 479 Views: 569559	Thanks again for your time. I pretty happy with you just throwing out ideas. It's a pesky trouble shooting problem and I can't expect anyone to take it on or spend a lot of time on it. It's a great ...
Topic: The VCO-555
gimble88 Replies: 479 Views: 569559	Posted: Fri May 27, 2022 12:30 pm Subject: The VCO-555 Forum: DIY Hardware and Software » Thomas Henry designs
gimble88 Replies: 479 Views: 569559	Thanks again for the continued interest in my little problem. When I first built it I looked at and measured all the waveforms using my o-scope. I did a distortion measurement on the sine wave and loo ...
Topic: The VCO-555
gimble88 Replies: 479 Views: 569559	Posted: Fri May 27, 2022 9:12 am Subject: The VCO-555 Forum: DIY Hardware and Software » Thomas Henry designs
gimble88 Replies: 479 Views: 569559	Thanks for the reply. Pin 3 shows an almost 50% duty cycle square wave 0V-14.7V. Spence
Topic: The VCO-555
gimble88 Replies: 479 Views: 569559	Posted: Sun May 22, 2022 12:32 pm Subject: The VCO-555 Forum: DIY Hardware and Software » Thomas Henry designs
gimble88 Replies: 479 Views: 569559	I keep thinking of things I've already checked. The 5V+ and 1.5V- magnitude of the triangle wave is present at pin 5 of the 13007, which has been replaced. This tells me what ever happened is not *now ...
Topic: The VCO-555
gimble88 Replies: 479 Views: 569559	Posted: Sun May 22, 2022 10:43 am Subject: The VCO-555 Forum: DIY Hardware and Software » Thomas Henry designs
gimble88 Replies: 479 Views: 569559	I should add that all PS voltages at the various IC pins are correct and I don't detect any solder bridges or shorts by visual inspection. Thanks, Spence
Topic: The VCO-555
gimble88 Replies: 479 Views: 569559	Posted: Sat May 21, 2022 7:03 pm Subject: Odd behavior of previously working VCO-555 Forum: DIY Hardware and Software » Thomas Henry designs
gimble88 Replies: 479 Views: 569559	I my finished PCB of the VCO-555 was working perfectly but I needed to rewire the connections from the PCB to the pots and jacks when I mounted it to the panel. After doing so I found everything wo ...