If the modern HiFi amplifier or tube amplifier clips when you use it to play back audio recording, you are doing it wrong. With tube guitar amplifiers pushing it to clipping to get certain distorted sound is often intentional. Modern take to get the same guitar sound is to use DSP based effect pedals to get the right distorted sound that is fed to modern class D amplifier. Nothing is run physically to clipping.
Here are some links to information on guitar effects:
Most DISTORTED Guitar Tone Possible?!
https://www.youtube.com/watch?v=TkO-yau7jdQ
What does distortion look like?
https://www.youtube.com/watch?v=pFSX93aPzmw
Understanding Distortion (Pt2) – Diode Clipping circuits
https://www.youtube.com/watch?v=6Qs1H2qTAWI
Demonstration of Overdrive, Distortion and Fuzz effects on oscilloscope and with a guitar signal
https://www.youtube.com/watch?v=8NjeHHroOgI
The World’s Largest Guitar Pedalboard (world record)
https://www.youtube.com/watch?v=iWRfLuJ_NKw
She sings through guitar pedals and it sounds AMAZING
https://www.youtube.com/watch?v=77iUH208XaI
Modeling A Guitar For Circuit Simulation
https://hackaday.com/2023/08/19/modeling-a-guitar-for-circuit-simulation/
Guitar effects have come a long way from the jangly, unaltered sounds of the 1950s when rock and roll started picking up steam. Starting in large part with [Jimi Hendrix] in the 60s, the number of available effects available to guitarists snowballed in the following decades step-by-step with the burgeoning electronics industry. Now, there are tons of effects, from simple analog devices that would have been familiar to [Hendrix] to complex, far-reaching, digital effects available to anyone with a computer. Another thing available to modern guitarists is the ability to model these effects and guitars in circuit simulators, as [Iain] does.
[Ian] plays a Fender Stratocaster, but in order to build effects pedals and amplifiers for it with the exact desired sound, he needed a way to model its equivalent circuit. For a simple DC circuit, this isn’t too difficult since it just requires measuring the resistance, capacitance, and inductance of the overall circuit and can be done with something as simple as a multimeter. But for something with the wide frequency range of a guitar, a little bit more effort needs to go into creating an accurate model. [Iain] is using an Analog Discovery as a vector network analyzer to get all of the raw data he needs for the model before moving on to some in-depth calculations.
Guitar Pickup Equivalent Circuits
https://macalisterelectronics.com/guitar-pickup-equivalent-circuits.html
An equivalent circuit of a guitar’s pickups, tone/volume controls and cable is useful when designing input stages for effects pedals or amplifiers. It makes simulations or calculations of how input networks modify the spectrum of the guitar’s output more realistic. This article covers some background on the topic and then goes into a technique for measuring the output impedance of a guitar and how to deduce the values of an equivalent circuit from the measurement. The equivalent circuit of a Stratocaster are given in the Conclusion at the end of this page.
Sebastian of Baltic Lab demonstrates how to implement overdrive and distortion effect DSP algorithms on the Arduino GIGA R1 WiFi
https://baltic-lab.com/2023/08/dsp-diode-clipping-algorithm-for-overdrive-and-distortion-effects/
Open Source Analog Effects Pedal
A modular platform for developing and trading guitar (and other) audio effects. Focus on, but not limited to, pure analog signal path.
https://hackaday.io/project/2311-open-source-analog-effects-pedal
Guitar Distortion With Diodes In Code, Not Hardware
https://hackaday.com/2023/08/23/guitar-distortion-with-diodes-in-code-not-hardware/
Guitarists will do just about anything to get just the right sound out of their setup, including purposely introducing all manner of distortion into the signal. It seems counter-intuitive, but it works, at least when it’s done right. But what exactly is going on with the signal? And is there a way to simulate it? Of course there is, and all it takes is a little math and some Arduino code.
https://baltic-lab.com/2023/08/dsp-diode-clipping-algorithm-for-overdrive-and-distortion-effects/
Guitar Effects With No (Unwanted) Delay
https://hackaday.com/2021/03/15/guitar-effects-with-no-unwanted-delay/
Raspberry Pi Pico – Guitar To MIDI
https://www.youtube.com/watch?v=Fu0Qsz2h3HE
68 Comments
Tomi Engdahl says:
https://www.electrosmash.com/pedalshield-uno-start
Tomi Engdahl says:
Temu’s Pedals Exposed: The Verdict
https://www.youtube.com/watch?v=1vI4ZFx-RZQ
Temu asked me to make a video on their guitar pedals, so, here you go, this is what the effects pedals on Temu’s app sound like and how they compare to effects pedals 4x their price. How did the Temu pedals hold up? Let me know in the comments section below.
00:00 INTRO
01:02 Touchy Subject
03:00 Unboxing
05:32 Recording Setup
07:47 Green Martian
11:28 Green Martian Hi Gain
12:55 The Dumbler
17:35 Dolamo Distortion
20:34 Heavy Thunder
24:12 Heavy Thunder vs. HM-2
25:09 M-Wave
29:12 Quick Run-Thru
30:50 Final Thoughts
Tomi Engdahl says:
Are Temu Guitar Pedals Any Good or Straight Trash?
https://www.youtube.com/watch?v=SqDNfF74s-g
Tomi Engdahl says:
I Tried the Cheapest Music Gear on Temu
https://www.youtube.com/watch?v=Tx_2n4yULZY
CHAPTERS
0:00 – intro
01:24 – first item
03:24 – second item
04:27 – third item
06:54 – fourth item
08:25 – fifth item
Tomi Engdahl says:
Guitar Pedals For Beginners – In Less Than 10 Minutes
https://www.youtube.com/watch?v=RttNJxF0eU0
In this video I’m going to talk about what I wish I knew about guitar pedals when I first started as a guitarist. There’s so many guitar pedals out there on the market so it’s tough to know what each effect does as a beginner. However it’s actually much simpler than you think! In this video I break it down using a simple analogy that everyone can relate with. We’ll cover gain/drive pedals, modulation pedals like flanger/chorus and essential effects like reverb and delay and you’ll hear how each pedal and effect changes the tone of my guitar. There are ofcourse many more effects and pedal types out there but I feel like the ones I talk about in this video can cover most guitar tones out there.
Tomi Engdahl says:
All guitar effects demonstration in one video (Most popular guitar effects demo)
https://www.youtube.com/watch?v=Pg6QaQpSoUc
10 Guitar Effects Essential To Rock!
https://www.youtube.com/watch?v=WmOQFOpLlO4
Tomi Engdahl says:
6 Guitar Effects You Should Know | 6 songs + tabs
https://www.youtube.com/watch?v=T445rnloHjc
Tomi Engdahl says:
https://hackaday.com/2025/08/13/running-guitar-effects-on-a-playstation-portable/
Tomi Engdahl says:
https://www.thomann.de/blog/en/ac-dc-guitars-and-amps/?utm_medium=paidsocial&utm_source=meta&utm_campaign=daily&utm_content=blog&fbclid=IwQ0xDSwMPwAJleHRuA2FlbQEwAGFkaWQBqyTwd7_OfgEe5T0sOgRRvFncrnxdEnISIjgrbOeJYmJFkc-SjAFDRV76NF2w3O-y7XSIkLc_aem_GRdc37jTsYjQ8LYnHZskLQ&utm_id=120226402789990030&utm_term=120226402789980030
Tomi Engdahl says:
Let’s Build a Complete Pedalboard!
https://m.youtube.com/watch?v=xumUvY-lmlk&fbclid=IwQ0xDSwMRekFleHRuA2FlbQIxMAABHrbBqLEcqWrI0pcMNUHmZ7eJCPhWy5i1kvKm31xMNzfCnHynDGsPuw8P6x9A_aem_x-y0pDqUg6xgvWGP_XhU7A
Tomi Engdahl says:
https://www.premierguitar.com/features/gear-features/keeley-electronics
Tomi Engdahl says:
A guitar cable’s length and quality can noticeably affect the tone of an electric guitar, primarily due to capacitance and resistance. Longer cables, especially with higher capacitance, can attenuate high frequencies, leading to a darker, muddier tone. While less noticeable with short, high-quality cables, the effect can be significant with longer runs or cheaper cables.
Here’s a more detailed breakdown:
Capacitance:
All cables have capacitance, which increases with length. This capacitance acts as a low-pass filter, reducing high frequencies and resulting in a less bright, potentially muddy tone.
Resistance:
Longer cables also have higher resistance, which can further contribute to signal loss, particularly in the high frequencies.
Cable Length:
The audible effect of cable length is more pronounced with passive pickups (common in most guitars) than with active pickups.
Cable Quality:
Cheaper cables may have higher capacitance and resistance than high-quality cables, leading to a more noticeable impact on tone.
Active vs. Passive:
Active pickups (with a built-in preamp) are less susceptible to the effects of cable capacitance and resistance than passive pickups.
Interference:
Poorly constructed cables can also be more susceptible to interference, adding noise to your signal.
Buffer Pedals:
If you’re using many pedals, a buffer pedal can help counteract the capacitance and resistance issues of long cable runs between them
Tomi Engdahl says:
The output impedance of a passive electric guitar pickup is typically high, ranging from 6k to 10k ohms. Active pickups, on the other hand, have a much lower output impedance, around 100 ohms. This difference in impedance is important when considering how a guitar interacts with other equipment like amplifiers and effects pedals.
Elaboration:
Passive Pickups:
Passive pickups, like those found in most vintage and many modern guitars, rely on the magnetic field created by the vibrating strings to induce a voltage in a coil of wire. This coil has inherent resistance and inductance, resulting in a high output impedance.
Active Pickups:
Active pickups incorporate a built-in preamplifier, often powered by a battery. This preamp lowers the output impedance significantly, making it easier to drive long cables and interact with various effects pedals and amplifiers.
Impedance Matching:
The concept of impedance matching is crucial for optimal signal transfer. Ideally, the output impedance of a source (like a guitar) should be much lower than the input impedance of the load (like an amplifier).
Consequences of Mismatch:
If the output impedance of the guitar is too high relative to the amplifier’s input impedance, it can lead to a loss of signal strength, particularly in the higher frequencies, resulting in a duller, less vibrant tone.
Example:
A passive guitar (high output impedance) paired with a mixing console (lower input impedance) might benefit from a DI (Direct Injection) box. The DI box acts as an impedance converter, matching the guitar’s output impedance to the mixing console’s input impedance.
Tomi Engdahl says:
https://www.diystompboxes.com/smfforum/index.php?topic=119353.0
t seems to me that choosing the input impedance of a DIY box is a bit of a minefield. I measured the resistance of my Epiphone SG dual Humbucker pick up guitar and it goes from 3.7 K to 470 K depending on the switch, tone and volume control settings. :icon_confused: Hoping for some inspiration I looked at the input circuit of my early 70′s Orange Matamp OR100 but notice there was a modification on the site that said later models had 220 K resistors added. This mod on the later unit changed the input resistance from 1.068 M down to 182 K :icon_confused: so no enlightenment from that. :icon_rolleyes:
I can see that you want a high input impedance like 1 M ideally but in the real world there can be a significant distance from the guitar to the pedal to allow movement on the stage like 10 or 20 foot cable so I wonder if Orange added the resistor to combat noise pick up. Over 200 K would suit my needs and simplify the circuit I want to build since it wouldn’t require an extra input buffer and is better than existing Orange Amps being sold. Any thoughts on whether > 200K would be too low or not?
Tomi Engdahl says:
I measured the resistance of my Epiphone SG dual Humbucker pick up guitar and it goes from 3.7 K to 470 K depending on the switch, tone and volume control settings.
That’s because you’re not measuring the pickup itself, but one or more pickups in various combinations and possibly splits, depending on what the switching does, as well as the tone and/or volume controls. And because resistance is not what you need to measure.
Humbucker pickups by themselves mostly measure 4K and up, not far from your 3.7K minimum. That goes through the switches, then the volume pot. When volume is max, the volume pot is in parallel with the pickup, and so you have the volume pot end-to-end resistance (250K to 2M, generally) parallel to the 4K-ish bucker.
But what you need to know is not DC resistance, but what the AC impedance is over the usable frequency range, up to 5K to 10K Hz. Those pickups are actually high-value inductors, usually 2H to 4H for ‘buckers, and so their impedance rises linearly with frequency, and is in the range of 100K to 400K at the high end of audio. Amps and pedals will subtract treble more than bass if they’re less than about 10x the AC impedance at treble, so you really need on the order of 1M and up in whatever the pickup is driving. In fact, one old trick to fake a pickup is to use a biggish inductor, or a transformer primary of a few Henries to get the same kind of rolloff.
https://www.diystompboxes.com/smfforum/index.php?topic=119353.0
You don’t have to match the impedance.
The load affects the high frequency response.
Adding resistor will not “combat noise pick up”.
Put 220K across your guitar and play. Is the tone OK? Top-end all there? ALL your guitars? Now, and the one you buy next month? Then go for it. Quite a few amps are in this zone. Maybe to cut some harshness (but different cut for different guitars).
The use of 20 30 40 foot cables clobbers highs more than a few hundred K of loading. But guitar-amplifier interfacing has always been a “good enough” bodge, and a 50 foot cable is so cool.
Thanks for your replies and thanks to Rob for the link about pickups where the guy has an interesting method of investigating the frequency response of pickups using an external magnetic driver. I looked at some pedals and some are as low as 80K on the input then I tried putting resistors across the guitar lead and watched on the oscilloscope. 47 K knock the signal right down to roughly 25% and 820 K took it to 80% but it says nothing about the frequency content other than I can’t see any change in wave shape. Going by what people say when they modify Orange amps from 180 K input load back to 1 M like the original 70′s amps the amplifier gain is the only change and there is no mention of any change in frequency content perhaps because it is so insignificant. I guess with a distortion pedal it doesn’t matter what it does to the signal so long as it sounds like what you want.
When folk speak of low amplifier input impedance not having a noticeable cut of their highs, you have to ask what they are playing with.
They may always have a buffered pedal between guitar and amp. That stops the amp input impedance load for changing the guitar tone.
They may have active pickups or tone control. Ditto as above.
They may have low impedance pickups on a passive guitar. These can be tolerant of load down to 100k or less. Without doing any measurement, the value of volume control in the guitar is a guide. If it’s 500k to 1M, then the amp impedance must be as high as is practical – usually 1M. If its 100k to 250k, then it probably can tolerate less that 1M input impedance.
There may be treble loss, but the players amp & cab design or eq choices won’t show it up.
The player has severe hearing damage and wouldn’t notice treble loss if it walked up and smacked them around the head.
Normally, I wouldn’t expect that much attenuation, maybe a few dB. You might be seeing changes in peaks as opposed to the perceived level. The 470k DC resistance you measured before might also have something to do with it.
Going by what people say when they modify Orange amps from 180 K input load back to 1 M like the original 70′s amps the amplifier gain is the only change and there is no mention of any change in frequency content perhaps because it is so insignificant.
Normally it would just give you a little more highs. For most pickups 180k would have an audible roll-off. At about 330k it’s hard to tell. And 1MEG is usually a good upper bound. If you consider the guitar has a 250k volume control and a 250k tone control in parallel with it, the pickup is seeing at least 125k, loads like 1MEG only change the total load by a small amount, like 10% – that’s why you can’t hear much change beyond 1MEG.
> resistors across the guitar lead and watched on the oscilloscope
Your ears/brain are much smarter than a ‘scope!
Bass is big. Treble is small. You can cut everything over 800Hz and hardly see a difference in the total. But your ears will feel like they are full of wool. Very dull sound. No sing no zing.
*Listen* with various loadings. As you come down from a Meg, the treble goes out first. Playing through a blanket. Because much guitar technique is about managing those higher partials (and because you need the scream to cut through a band), you really want to preserve these highs as much as possible.
The 470k DC resistance you measured before might also have something to do with it.
Yeah you shouldn’t see a resistance anywhere near that across the output of any common, passive pickup guitar. Usually below 20k. You might have an open pickup, and you’re reading a volume pot with nothing in parallel. It can still making sound, thin and weak, via a capacitive coupling in the coil.
No, not if its wired pickup to wiper of volume pot, which some guitars are – mostly 2 pickup/separate control guitars but some single pickup versions do the same, even though they could be wired wiper to jack. Think about it, if 2 volume pots are wired wiper to jack, then turning one down would turn the other down too. Although there is probably more treble loss with low volume control settings (due to the lower wiper resistance to ground loading the treble out), some manufacturers and players prefer the lack of interaction between controls by wiring it that way. With 2 pickup bass guitars, pick up to volume wiper is pretty much the standard way – Fender, Rickenbacker etc.
Well, let me re-phrase. In any factory-wired Gibson or Epiphone “standard” LP/SG/similar that I’m aware of, a 470k DC resistance reading across the output jack would indicate an open or disconnected pickup.
Wiring the pickup hot to the volume pot wiper is a noise problem, and fairly rarely done. But it’s certainly possible.
Tomi Engdahl says:
https://ironstone-guitar-pickups.co.uk/guitar-impedance-matching-lcr/?srsltid=AfmBOorcu6nW2aGqqoOfgL-NcdkLlYCxA0XawE-mqjYgmvAnV8AjsQpR
Tomi Engdahl says:
Suosittelen ehdottomasti JHS-pedalsin Short circuit sarjaa, jossa käydään läpi ppedaalien perusasioita erittäin havainnollisesti ja ehdottomalla intohimolla yksityiskohtiin.
https://www.youtube.com/playlist?list=PL_cgYn-EP29auNC4wm9fkpeqbSylf3qQV
Tomi Engdahl says:
https://geekstands.com/blogs/news/the-impact-of-guitar-cable-quality-on-sound-what-you-need-to-know?srsltid=AfmBOorY9sKFhA_9hu8soxWcngzo6O3OjhaBtb4eg2aBdLZxsKCcZTLp