Hm LEDs with LDRs? Vactrol based oscillator. Sure, feed the CV to an LED. But it might get very finicky as the current to brightness "conversion" ain't quite a simple calculation. You'd have to trial and error a bit to find the right range etc.

I answered my own question…if I have a gain of 2, both incoming ac and dc bias will be amplified 2 times. But we don’t want the DC bias to be amplified, we want it to be set in stone by the voltage divider. So adding a capacitor in feedback network will be huge impedance at DC and basically no gain at DC.

Hi, it's been 9 years since making this video. Never stopped making music and playing around with synths. I could always try to cook something up.

Good to hear you’re still making music ! Have you got an email I could possibly contact you on to ask a few questions please.

@@monkiemind1596 sure, try [email protected]

for anyone having the same problem. I found the needed folder at C:\Users\{USERNAME}\AppData\Local\LTspice. There you can replace it exactly as it's shown in the video

Hi, the zip file is on the website in the description. The link still seems to work.

I had the same problem. Open the Developer Tools (press F12). Then, go to the Network tab. Refresh the page where the ZIP file is located. You should see the ZIP file appear in the list in the Developer Tools. Click on the ZIP file in the list, and it should download the folder.

Documents > LTSpice > Sym > ind.asy Edit, sorry didn't read well. I can't find that one either for EU

I can't seem to find a proper EU symbol. But when you have the latest LTSpice with updated libraries, you can find one in Documents > LTSpice > lib > sym > contrib > wurth > signal or automotive

@@zanesmith666 Thanks

As the name suggests, the PREamplifier merely boosts up the voltage and prepares the signal for the next stage. Driving a speaker requires a circuit that can also deliver current because a speaker needs power. (Power=voltage x current, we only accounted for the voltage with this preamplifier). The common emitter amp is not meant to do this. It can barely deliver current and thus not drive your speaker to good levels. Follow up the preamplifier with a power amplifier like a push pull configuration or something different. Then attach that to the speaker.

@@trevortjes Do the technical parameters of the amplifier itself matter much if the voltage output of the pre-amp matches with the input range of the amplifier?

Thank you! Hope it helps on your electronics journey

If one is handy with hardware and arduino programming, it's a piece of cake to adapt the project

Probably already figured it out but I was haeing the same issue. I followed the instructions and it didn't pop up. What I fugred out was that where he PICKS the folder ICON, I picked the "+" and then it put a line with a YELLOW Triangle on it. If you look to the right of that line, you can see a FOLDER icon. I picked that it loaded the 3D models. I use WINDOWS and at the top of that diaglog box I picked the 3dModels and it took me to the folders and I picked the part I wanted and it work.

@@schlotdoglaser Will try this tomorrow, thanks for replying.

Is the Dephon an active volume pedal? Does it need power via battery or DC?

I looked into it further. The Holy Grail has a very low output impedance, let's say 500 ohms max. This is R1. The volume pedal is passive. At full volume this means the signal is not traveling through the potentiometer wired as voltage divider in the pedal. The voltage divider creates different voltages at the output depending on pedal position. At full volume the signal "bypasses" the potentiometer, but the potentiometer is still part of the circuit! This can be modelled as a 250kohm resistor to ground. The signal then travels onwards towards the 2i2 with 2Mohm inputs. We got two devices creating a resistance to ground. The Daphon potentiometer of 250k and the 2i2 with 2Mohm. These two resistors are in paralle and together form R2. I wont do the whole calculation, but 250k in parallel with 2M equals about 222k. R2 is now 222kohm! So R1 500 ohms, R2 222kohms. You can see how R2 is WAY bigger than R1. And as stated in the video, this is what you want for optimal voltage transfer!

@@trevortjes Indeed the Daphon low R-in pedal is passive (not powered).Thank you so much for clarifying the parallel nature of the resistors in play. Crystal clear! Mystery solved! I appreciate your prompt and expert reply.