Simulation of the Boss MD-2 Mega Distortion Complementary Common Emitter Stage (Falstad)
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- เผยแพร่เมื่อ 11 ก.ค. 2024
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To try this simulation yourself, paste this text into the window that opens when you select the "File--Import From Text..." menu item in the Falstad simulator at www.falstad.com/circuit
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r 240 448 240 336 0 56000
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c 240 256 176 256 0 0.000047 4.495655197147763 0.001
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w 240 256 240 112 0
32 \0 0 1e-13 0 0 1.5 0 0 2 1 1 0 0 1
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r 240 112 240 0 0 56000
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w 320 448 320 464 0
g 320 464 320 480 0 0
g 320 192 320 208 0 0
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w 288 224 176 224 0
w 176 224 176 0 0
w 240 0 176 0 0
w 176 0 176 -16 0
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o 37 16 0 4099 2.5 0.00009765625 0 2 37 3
0:00 -- Introduction
0:51 -- Op amp gain stages
3:29 -- Complementary common emitter stage
4:05 -- Falstad simulation
5:43 -- What's it for?
In Falstad you can add an audio input (which requires going through a resistor and will need you to select an MP3 file) and an audio output and then listen to your distorted signal. :)
I always wanted to try that audio input! Now I have a simulation which I can use.
My nephew had a MD-2 early on and it struck me as “fine” - it was much more early-2000s nu metal than I cared for, but I also didn’t spend much time trying to dial it in. My impression was that it was more intended to give a bedroom player the vibe of recorded guitars vs the kind of pedal you might actually use if you were playing live & loud with a group. If I’m remembering correctly from 10 years ago, a lot more bass than I would want on my guitar tone.
Long time musician and electronics hobbyist...thank you for your circuit and pedal videos....so far ive modded an orange amplifier preamp. Emg Active guitar circuit. And built a green ringer pedal with silent switching and a blend control. Thank you for being consistent with your content and inspirational to all...
Thank you for your kind words!
falstad is fire
Interesting how symmetrical the output simulates. It occurs to me that a simplified DC path can start to look like a BJT version of a CMOS inverter. It looks like they're running two parallel circuits, but share the biasing, which may be the particular novelty here. Otherwise, there might be no reason to do NPN/PNP transistors.
Thanks for this video. I learned some valuable things from this. I know that discrete op amp is used in the blues driver, where else is it used?
That complementary end pair kind of reminds me of how the CGS lockhart distortion is laid out?
I suspect your summarization is accurate and it's intended to simulate valve distortion. When you overdrive transistors very deeply, it can sound more valve than a valve, so this quasi-complimentary pair provides a transistor to clip each half cycle so it has a good valve sound and a single transistor isn't providing the clipping for both half cycles.
I suspect you're also correct and it's more asymmetrical than the sim is showing, but odd order harmonics do have more sleaze, raunch and decadence than even and the goal of the pedal is to produce metal distortion.
When I hear pinch harmonics out of low, dominating even order harmonics, there's no raunch, sleaze and soul, just valve-like buzzing that reminds you of a synth and triangle waves. I would guess that this setup is also to prevent the dominant, high even order harmonics of semiconductors and a good blend of low even and odd order harmonics.
Boss has the all-around market dominance of analog and digital gear in contrast to other brands' success in both. We've only just entered into digital being a 90% match to tubes, it started about 10-12 years ago, and has only just been in the last 3 to 4 where every brand caught up. I think that's a result of chip engineers being more mindful to provide circuits within the digital microcontroller to be able to produce asymmetrical and dominant low even order harmonics.
Likely a product of everyone inspecting one another's solid-state analog and valve products for decades.
I haven't played a mega distortion, nor do I have any insights, but I'm leaving a comment anyways!
Another incredibly informative video
Thank you for your kind words!
Thanks professor for including the SPICE file of the circuit network.
Since this thing is audio-related, is there a way by which the output of the FALSTAD simulator could be exported as an array of discrete numbers corresponding to the voltages at some appropriate sample rate so that I may use MATLAB to check how it sounds?
That would be the best way to find out about its performance.
it has audio out.
@@AnalogDude_ Oh, really? That's fine, but I cannot find the option. Can you give me the steps?
@@user-qx9bt9tr6t right click, "Outputs and labels" ---> Add audio output, add data output.
Also the "Add labelled node", simplifies schematic by using "labels" instead of wires all over the place and less strain on the computer drawing currents or gives lines colors, like green and red.
@@AnalogDude_ Thanks a lot!
nice
Thanks!
I have a question if that’s okay; so I wanted to make a pedal my self that’s a multi FX type. But I don’t know much about actual pedals and so I wanted to make it maybe with a razzberry pi or somthing like that, the simulation you made could it be used for that type of stuff and if so how can you make these simulations?
Running a full-fledged circuit simulator like this is not practical for real time effects. Search on google for the electrosmash Raspberry Pi Zero guitar pedal project to get ideas (although it's pretty lo-fi). Also google for pi-fx. Also, I highly recommend checking out the Daisy Seed, it's a STM32 platform. Look up the PedalPCB Terrarium, which is a guitar pedal thingy you can plug a Daisy Seed into. And if you want to learn DSP programming, actually a good place to start is writing plugins for a DAW using something like JUCE, or even Cherry Audio's Voltage Modular (which you can get started with for free). You have much research ahead of you.
Are those input jfets in a single package?
Nope, two separate discrete. No idea how much work Roland puts into matching them, if any…
@@Lantertronics probably no effort, mismatch will lead to distortion which is fine.
yes I own a MD-2 since 2002 and play it. Any questions?
What do you think about the sound? How do you like to set your controls?
@@Lantertronics It actually has a quite "organic" distortion-texture, but on the flipside its a bit mushy and lose in the low-end. I mostly have all knobs at noon - not a very sexy answer I know. Sadly I dont have a ds-1 or 2 to compare it to, but I do use mt-2 and hm-2 clones. These sound a lot more aggressive and tight, though a bit more synthetic.
For some reason, the noise floor of the md-2 is a bit higher than that of the two others.
Lastly I might add that it doesnt seem to take boosts as well as my other pedals, so its not as easy to tighten it up.
Its a decent pedal, I just dont get the "mega", because the mt-2 has way more distortion to offer.
I'm using the SF 300 from Behringer, which seems to be based on this pedal (IMHO). It has some sweet spots, which I like.
The SF300 is based on the Boss FZ-2 (which itself is based on a Univox Superfuzz). Great pedal, but the circuit is very different