LTspice tutorial - EP2 AC simulation and the Baxandall tone control circuit

[@matt55346]

That's how tutorial should be made: direct to the point and crispy voice over that doesn't put you asleep.

[@Remowylliams]

Absolute gold these tutorials. Great pace, good presentation and humor as well as explainations of what and why thanks very much

[@patelpriyank586]

Great video. Simple, precise and accurate.

[@FesZElectronics]

Thank you! I'm glad you liked it

[@Epaniale]

If I could I would hug you... amazingly clear tutorial!

[@FesZElectronics]

I'm happy you enjoyed it! Thank you.

[@geez6666]

Hey, this is horrendously awesome series!! 100% subbed immediately

[@FesZElectronics]

I'm happy you enjoyed it! Therese more simulation videos where this came from!

[@trickytinkerer1070]

This Playlist ist awesome! I will definitely recommend this to all of my students !

[@FesZElectronics]

I'm happy you found this helpful! Let me know if there is anything in particular you would like to see added.

[@harsha9128]

Great tutorial. Learning a lot about LTSPICE. But I would suggest using a different color for the output trace. Blue is not visible in the video!

[@DoctorMangler]

Thanks for posting this great content, you make it easy to understand. Thanks for the great tip on potentiometers.

[@FesZElectronics]

Thank you for watching! If there are any other simulation related problems that you ran into, let me know and I will try to help

[@adana01]

you are the bob ross of ltspice...

[@ShwetaSingh-xv1lb]

Best series for Biggeners. Thinking that sir, you have to publish a book including lots of question in it, will you?? Thankyou once again!! 🤘🏻🤘🏻

[@FesZElectronics]

I'm happy you enjoyed it! I'm not sure about a book, not at the moment at least, but if you have any questions, I can try to answer them of course.

[@bakdiabderrahmane8009]

Great tutorials, simple and concise thank you very much.

[@danielc4361]

Very clear! Thank you and props.

[@lucaholden176]

Hi Fesz, i have a question about the potentiometer, when i get a reading of lets say pot1=45, what value should i put back into my component too re represent that coloured line by itself on my graph? i have tried putting it into the formula and it did not work

[@FesZElectronics]

If you just want to plot a single value for the potentiometer you should use the ".param " definition, and comment the ".step " definition; as long as there are parameters defined using the .step statement, there will be multiple simulation results overlapped.

[@lucaholden176]

@@FesZElectronics hi, thanks for the fast reply, we have now done that. We now wish to get an actual comment value for each thing. Let’s say we have pot2dev= 66 how should we get a resistor value in ohms from that as we need that in a report

[@huguesbelmiro1854]

Thanks mate, this really helps!

[@BrandonDrury]

Outstanding tutorial! Thank you very much.

[@deviantmultimedia9497]

Hey @FesZElectronics what would be the best way to make a differential AC voltage source? I am trying to simulate a balanced audio source signal such as what would be found in a typical 3-pin pro audio line-level interconnect (1: shield, 2: Vin+, 3: Vin- [180° phase inverted copy of Vin+] where Vin+ and Vin- = 3.47 Vpp Ø = 0° and 3.47 Vpp Ø = 180° respectively and Vin common mode= 0.00 Vcm). I am a long-time subscriber and I don't recall you covering this before (my apologies if you have) but you are the go-to channel for anything LTSpice. Thank you for all the great content.

[@FesZElectronics]

Thank you for the kind words! I don't think I ever covered this. When creating signal sources, you can set an initial phase shift - default is 0; In a transient simulation you can create 2 separate sinewave voltage sources from GND to V+ and V- with a 180phase shift on the second one. If you want an AC simulation, the same thing applies - below the input field for AC amplitude, you have a field for AC phase shift. If you want galvanic separation between the signal source and gnd, just add a capacitor between the intersection of the 2 signal sources and gnd. Let me know if this is the sort of thing you where looking for.

[@deviantmultimedia9497]

Would there be any difference between that and putting 2 equal-amplitude AC sources in series, grounding the connection point and tapping off each open end?

[@deviantmultimedia9497]

@@FesZElectronics Update: The 2 supplies in series method sucks. It does create differential signals that appear fine in transient analysis but FFT was showing lots of distortion. Textbook "trap for young players" right there. The method you described, 2 separate supplies, one with initial phase set to 180 is the way to go. Thanks for the tip, man. Much appreciated. Hey, it might make a good video.

[@MN-gp2cu]

Hi, How to get DPDT electromagnetic relay? because there is no in LTSpice database

[@CobraPhobic]

This is my homework in electronics until next week lol

[@FesZElectronics]

Hope you get an A !

[@CobraPhobic]

@@FesZElectronics Thanks, I'll do my best :P

[@YashRaj-ix1dp]

I feel really lucky to find such a series on LTSpice. How can I learn more features of LTSpice?

[@FesZElectronics]

Hello Yash Raj! I think my best advice would be "practice" - the best way to learn to use the program is by working with it; and when there is something that you do not know how to do, just look it up, there is a lot of data on the internet about this program. Of course, you can also look at the other videos in this series, maybe you find something useful!

[@archie6586]

Really Informative video. never knew about potentiometer parameter. Also can you please change the graph waveform color from blue to yellow or something bright. It is not hard to visible. thanks.

[@FesZElectronics]

You can make color related changes under the "Tools" menu -> color preferences ; In later videos I changed the graph background to white to make things more visible. I also increased trace thickness under Tools-> Control Panel-> Waveforms - Trace thickness = 2 Hope this helps!

[@archie6586]

@@FesZElectronics No I am telling you to make change while making videos :P

[@ukaszokapa6782]

Where do you find the SPICE command list?

[@larcomj]

"are you interested? NO! Well im gonna tell you anyways" I with my father lectured my like this.

[@minghuijiang2918]

Brilliant videos and thank u!

[@rohitpal-jn2ql]

Hey, how to rotate the element, like how can I rotate the resistor

[@FesZElectronics]

Ctrl+R rotates and Ctrl+E mirrors

[@spotmark2]

How do you get the measurements to appear? Ive tried both mouse clicks on the VN002 top label without success

[@philippegabathuler7121]

How do you rotate the Resistor symbol?

[@FesZElectronics]

You can rotate any component with Ctrl+R; and you can mirror it with Ctrl+E

[@tebbotebbo309]

keep up the good work !!!!

[@FesZElectronics]

I'm happy you enjoyed it! Thank you for watching!

[@chadmangrum3291]

Great vid! Do you know if there is a spice circuit already built that does what the Duncan Tone Stack Calculator does? Something that can plot and give a single line that moves with the pot deviations? Thanks

[@FesZElectronics]

If I googled the right thing, you are talking about a tone control circuit with 3 inflections (for low, mid and high frequencies). There probably is a spice circuit for it, but since its such a simple circuit, it only involves 4 fixed value components and 3 potentiometeres, it might be much easier to draw it up in the simulator than to try and find it ready made...

[@arunsebastian4035]

LT Spice showing Matrix is singular when iam trying to simulate a TIA why is that ? can u help me ?

[@VvtheD3M0N]

Also, around 4.30 is there a better way to accurately measure the amplitude of the waveforms pk-pk, I used the cursor option that you would normally use in an Oscilloscope, but it does not show the difference in amplitude properly. Thanks in advance.

[@coolman101082]

I want to simulation filter bridge rectifier, pls

[@jazzunk]

Nice video! Thank you for it. The potentiometer explanation is quite useful, however is there not an easier way to analyze thru the potentiometer values without having to plot all of them? like a cursor or something for the visualization? Also, what is C3 exactly doing, since it is not actually needed for the actual baxandall circuit right? Is it for DC decoupling?

[@FesZElectronics]

Hello Jazzunk! Let me start with your second question - C3 is not mandatory, for the simulation at least, but it is a component that is present in practice for DC decopling as you correctly pointed out. On the other hand it does have an influence that is worth simulating since it forms a high pass filter together with R1/2/3/4. If the values or not chosen properly this can have an effect on the circuit performance by filtering out low frequencies, so adding this capacitor should help. Regarding the first part, if I understood correctly what you are asking the short answer is no. LT is not famous for having a friendly user interface unfortunately. You can extract data from multiple simulation runs to add into a secondary graph but that would also be a static representation not something that can be changed without altering the simulation parameters and re-simulating. If you are interested in this filter only, there might be some ready made software somewhere that is more easy to use to generate the output graph.

[@jazzunk]

@@FesZElectronics Thank you for your detailed response! Yeah I have used other software for filter design and simulation but wanted to know what could be done in this sense with LT. Anyway great videos, keep it up man! They do help ;)

[@emilianosaenz2600]

Potato PC haha so funny. Thank you for all your videos!

[@VvtheD3M0N]

around 3.26, can you please explain how you determined the output signal is 10 times smaller than the input signal, even before running the transient analysis, in there we can see the difference of 2v input sinewave vs 200mv output sinewave? I mean the formula on the wiki page was general, it did not specify any values for the input or output voltage. Can you please elaborate on when you said at -20 dB the output signal is 10 times smaller? Also what is that other tainted blue line from the same time stamp (3.26)

[@FesZElectronics]

The AC simulation will give a response in ratio to the input signal (the votlage source with AC=1); since I was measuring -20dB I could calculate that the measured signal in reference to the initial signal is (Vout=Vin*10^(-20/20) - where -20 is the measured value) The AC simulation gives 2 responses - the solid line is the gain value in dB and the dotted line is phase shift in degrees (plotted on right side)

[@VvtheD3M0N]

@@FesZElectronics I'm really sorry, you were measuring -20db with relative to what? I'm missing the point here, why is that -20db level significant. I understand you get 16hz when you hover the cursor above the -20db point, but I don't understand why that -20db is any more relevant than the rest of the points on the Y-axis?. Vout=Vin*10^(-20/20), where did that 10 come from? I should be using the 20log(Vout/Vin) to solve for Vout right? I went through the comments, guess I'm the only one who has this stupid question. 😵‍💫

[@FesZElectronics]

No worries. So, in an "AC analysis" type simulation, the reference signal is a voltage or current source that has, in the advanced settings, the "Small signal AC analysis -> AC amplitude" set to 1. 1=0dB; but you can set other reference values also if needed. Whatever other signal you measure in the circuit is in reference to this signal. So -20dB is in reference to V1. At 16Khz, I think, the filter is producing a -20dB attenuation on the input signal. Or in other words, the output is 10times smaller than the input. The singnificance is that by using an AC simulation rather than a transient, you can look a wide range of frequencies in a single simulation (with transient, you analyze only 1 single frequency at a time). Vout=Vin*10^(gain/20) is the same as gain=20*log(Vout/Vin) ; gain being =-20; its the same equation just re-arranged to not have "log".

[@VvtheD3M0N]

@@FesZElectronics Awesome Thanks!!

[@HasteFrankie]

I'm trying this out on Mac and it will not recognize the pot formulas as models for simulation. Is there another way to do it? any advice would be appreciated:]

[@HasteFrankie]

never mind, I was using () instead of {}, noob mistake

[@Evermoregirl710]

1Kth like by me ..thanks for this

[@kirtynagar476]

Hey.. nice video. I've a doubt about the graph of AC analysis(low pass filter circuit). why exactly are there two slopes while measuring the output? Is it the harmonics? Thanks in advance.

[@FesZElectronics]

Hello. If you are referring to the solid and dashed lines, the solid line is gain (or magnitude) information - plotted on the left side axis in dB and the dashed line is phase information plotted on the right side axis.

[@kirtynagar476]

Thank you so much for the clarification.

[@jman66]

This was great. Thank you!

[@foreverallama]

I have a question. I'm designing a circuit that is taking too long for AC and Noise analysis (it is spending too much time on pseudo-transient analysis). The circuit is basically a bunch of amplifier and filter stages. Simulating these stages separately is fast, but when I combine everything into one big circuit, it is taking too much time. Can I use the simulated results for each stage to speed up the simulation of the whole circuit?

[@FesZElectronics]

I would suggest using ".ic " statements to set initial condition voltages between amplifier stages - this will help with the initial start-up of the circuit (ex: .ic V(n001)=1 sets the initial voltage of net n001 to 1V); Another thing you may try is to set the type of DC operating point solver - LTspice has 4 options, and by default it goes trough them one by one - using the .options statement you can disable one or the other as solver option (see in the help file " .OP -- Find the DC Operating Point " )

[@foreverallama]

@@FesZElectronics I'll check these out. Thanks a lot!

[@alexgeh4875]

Good tutorial, but the lines are practically invisible on the black background in the presentation screen.

[@yasirpunathil7143]

Hii, first of all thanks a lot. Your videos are great and extremey helpful. I was having a doubt. Even though it ran all combinations, only waveforms corresponding to pot2dev = 1 are being displayed. How can I get all waveforms of all combinations displayed?

[@FesZElectronics]

One of the problems other viewers had with this circuit is that they missed the connection between the middle of the 2 resistors corresponding to Pot2 and the line going to output and R5. I would suggest that you check that the components are all interconnected correctly - sometimes when you take a trace over a component pin there is no connection made.

[@yasirpunathil7143]

@@FesZElectronics thanks alot for replying. I have redrawn the circuit properly this time, but still I was getting combinations with fixed value of pot2dev. But when I moved the waveform cursor to right, and then moved the up and down keys there, I got combinations with varying pot2dev values. I didn't understand it clearly yet why is that so though.

[@zanGalant]

Hello, i just started re-learning how to use ltspice and i intend to follow through your playlist. Just a quick question, how did you manage to get that graph output? when i tried it on mine, what appears is a mess off spikes that can hardly be used for any meaningful analysis. thanks!

[@zanGalant]

never mind, i just now noticed that i forgot to ground the voltage source. truly a face palm moment for me. it worked and i got to simulate an output similar to yours thanks!

[@FesZElectronics]

It happens to the best of us. Another topic I would recommend to take caution with is leaving parts of the circuit not connected to ground - like in a transformer circuit; to get the simulator running correctly, all circuit parts need to be connected to GND (both primary and secondary), even if you are using a 100Meg resistor, otherwise it can't calculate voltages correctly.

[@shemjeffs2953]

This doesn't completely work for me. I have two step commands, and I've double checked each one corresponds to each potentiometer, and when the simulation runs it has 121 processes as in the video, but I only get 10 (or so) traces. One of the potentiometer's is changing, increasing by trace between 1 and 99 in steps of 10, the other one if stuck at 1 for every trace. Has anyone else had this issue?

[@FesZElectronics]

Hello @Shem Jeffs . If you want, you can post your netlist View->Spice netlist - this contains the circuit and step commands, maybe we can figure it out.

[@yitingnie1265]

@@FesZElectronics Hi Sir, I have also the same problem. Flowing is the circuit and step commands of the project. Maybe you could help me, thanks a lot! V1 N001 0 AC 1 C1 N002 N001 1000µ C2 N006 N003 22n C3 N008 N006 220n C4 N002 N004 2.2n C5 N009 0 22n R1 N002 N003 10k R2 N003 N005 {pot1*pot1dev/100} R3 N005 N008 {pot1-pot1*pot1dev/100} R4 N008 0 1k R5 output N005 10k R6 N007 N004 {pot2*pot2dev/100} R7 N009 N007 {pot2-pot2*pot2dev/100} R8 0 output 50k .param pot1 100k .param pot2 100k ;.param pot1dev 50 ;.param pot2dev 50 .ac dec 100 10 30k .step param pot2dev 1 99 10 .step param pot1dev 1 99 10 .backanno .end

[@FesZElectronics]

@@yitingnie1265 Well, it seems that you did not connect the output to the middle of Pot 2 (between R6 and R7) - there should be a dot on the line signifying that the lines are inter-connected. Let me know if this fixes it.

[@yitingnie1265]

@@FesZElectronics Hi Fesz, you are right! It works! Tanks a lot for your detailed response, I appreciate it. In addition thanks for the great video, it encourages me to try some things, I can't before! Please keep going and I am gonna follow all of your videos.

[@RockOfGreece]

Amazing tutorial. I am a musician too that studies electronics and this is awesome. Is this tone control used in any amplifier? Also that thing that you do that you click on the symbol of the Vout on your graph and then you choose the curve you want, I can't do it :(. I dont know when I do it the same window as yours opens but it just chooses a random graph and when I move the cursor on the graph window it doesn't change. Any idea why that is?

[@FesZElectronics]

Hello Yanno! This sort of filter is quite commonly used. There is also a version with 3 pot's (high, mid, low); but in simpler designs this 2 pot version is used. I click on a trace name, and then you get a dotted line appearing where the cursor is that measures a specific point; I then select and move that with the mouse. Let me know if this works on your side.

[@RockOfGreece]

@@FesZElectronics I figured it out. It works. Thank you so much you are a legend. I am working on a project to design a guitar amplifier with tube preamp and mosfet class ab power stage and your videos have helped me a ton. Especially the one where you model the triode. I mean all the triode spice models on the web are complete bs but thanks to your video I will try to model my own

[@EnginoIsRunning]

Can somebody give me an oh-yeah? 0:33

[@bobowzki]

Awesome!

[@nottherightone2]

YOur content is good but as a complete beginner from last video, im totally lost. I dont know if its due to my lack of proper knowledge in EE/Advanced Electricity that I am lost or just the way you quickly go from command to command

[@AjayKumar-ul2dg]

Its good, but you're going too fast

[@alterguy4327]

ThankYou

[@aputampuwiraqocha7075]

No sé inglés manos, ahora cómo voy a hacer mi tarea

[@basmaal-ghali9174]

u r awesome

[@electronic10]

Hello, I have tested the circuit, verified values, but the curves are joined below 100 Hz. Here the link drive.google.com/drive/folders/1o25OMr8gWFjkvbNsQ7v-K4luVLQ_r02J?usp=sharing

[@FesZElectronics]

In the picture you attached there seems to be a trace missing that goes between C1 and C2 to between R2 and R3. That should solve the issue.

[@detroit1988]

@@FesZElectronics Yes ! Thanks !

[@philippegabathuler7121]

Your are great, but slightly to fast, hard to follow your cursor and I can’t see what you tip in. I can tell you did the steps 1000000 times already. But thanks for sharing

[@Suprisesbk7551]

You are speaking too fast my guy