Schematic Elements for Guitar and Effects: Soft Clipping, Overdrive, the Blues Breaker and TS-808

[@BryanDenham]

Nice video, thank you for the break down of this circuit .

[@vitalyluckoanov5024]

Thank You so much! Those explanation videos really helps to understand how the circuits works.

[@thescientificguitarist4228]

I'm glad you find it useful!

[@salt_lick]

This is Gold, thank you very much

[@Splattle101]

Good run through, thank you.

[@thescientificguitarist4228]

Thanks!

[@patrikdunmar8022]

👏👏👏

[@PurposefulPorpoise]

So which section specifically is what gives the TS the "mid hump" vs the Bluesbreaker "flatter" EQ tone?

[@toby8261]

The range of bass/treble frequencies drawn to ground are what create a specific EQ curve. If we use RF filters to pull high and low frequencies to ground, our mids are more accentuated in comparison. We could also use an active tone circuit to amplify certain frequencies rather than diminish them, thus having boosted mids etc. In the tube screamer, this mids hump is caused by a high pass filter (cuts bass, this is the resistor and cap before the clipping circuit) and one low-pass filter (the 51pF capacitor that goes across the diodes + the 51k resistor and 500k potentiometer in series, which cuts highs). These together form a pass-band of mid-range frequencies that will be clipped. As you increase gain by changing the resistance of the 500k pot the attenuation frequency of the low pass filter increases, which helps cut some of the high frequencies that have been clipped by the diodes. This softens the edges of the hard square wave formed by the diodes hard clipping, and means at high gain settings you will attenuate more high frequencies, helping emphasise the mids (when paired with the low pass filter I will mention later) The high pass filter is the .1uf cap and 10k resistor in series, right before the clipping stage, which attenuates frequencies below 720Hz. These frequencies will get less gain and distortion and so will be less present in the distorted signal. That's our low end cut out, with some of the piercing highs that will have been amplified by distortion cut out by the 51pF capacitor + potentiometer by the diodes (acting as a low pass filter). now we need to cut the highs that are present after all of this distortion to get that nice mid peak. The low pass filter is in the tone control section after the clipping stage, again look for a resistor capacitor combo - this time a 220nF cap and a 1k resistor form a low pass filter and start to attenuate frequencies beyond around 720Hz. Plug the numbers in a RC filter calculator to see for yourself! This, combined with the distorted signal that has had its bass cut, forms a narrow band on the EQ curve of mid frequencies that pass through both filters while high and low frequencies are blocked, creating the signature hump.

[@MrJackrockerman]

Can a hard clipping overdrive clean up with guitar roll volume?

[@thescientificguitarist4228]

Yes, as real life diodes aren't perfect clippers. They have what is called an I/V curve that determines how hard the clipping knee is. Most diodes of a certain type (silicon, LED, germanium, etc.) will have general characteristics, but can vary somewhat. You need a special tester to test for this (I'm sure you could homebrew something, but I've never tried).

[@codelicious6590]

Im wondering how you divide the 9v power supply into 4.5v per each OP amp, is this a dumb question? Im just getting into this stuff and trying to wrap my head around it.

[@thescientificguitarist4228]

You divide the 9V rail to create a 4.5V rail. Each opamp gets its bias voltage from the 4.5V rail.

[@codelicious6590]

@@thescientificguitarist4228 yeah, I assumed the 9v needed to be divided, but how do you divide it? Does it require a component to split the voltage or do the opamps just take what they need from a 9v positive line going to both?

[@Linguae_Music]

Can i use diode lasers as diode so it distorts your ears AND your eyes.

[@thescientificguitarist4228]

Believe it or not, I've had this same thought before. Turns out the forward voltage of a laser diode would require redesigning the gain stages to provide higher output in order to distort.