Clipping level dynamically changed by signal envelope

[Vivek]

Somebody posted this vintage article on another group

[Vivek]

Thanks to Sir Teemu K for the name "Rubber Diodes"

[Vivek]

The static clipper looks similar to the rubber diode fuzz from Elektor


https://www.elektormagazine.com/magazine/elektor-198599/46980

The dynamic clipper is interesting!

[11-90-an]

Additional resource posted by @teemuk on this thread...

https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/audio/part2/page3.html

[antonis]

Are we talking about Vbe multipliers or what..??

[teemuk]

That isn't a VBE multiplier / rubber diode. It's just a plain shunt diode referenced to a DC offset, which is sourced from the emitter of a transistor circuit forming a voltage regulator. Two diodes and DC references are used for clipping negative and positive half waves.

[Vivek]

OCR and Google translate:


The new "fuzz
The oldest changing system
the timbre of the electric guitar is
fuzz layout. With the progress of electro
The proposed solutions are increasingly perfect
six versions of this layout. Primary
version, let's call it "static fuzz",
works on the principle of clipping - on
one fixed voltage level
the upper and lower halves of the run
electric generated by gi »
tare. |
| The new version of the system - "regulated
static fuzz "is shown in
fig. 1. The system works as follows
man. Electric guitar output waveform
successive
fading vibrations is
to an amplifier with an integrated circuit
nym US1. The amplifier has adjustable
gain in the range 1..100, for
by the power of the P1 potentiometer. T1 transistors
and T2 with potentiometers P2 and P3
create regulated voltage sources from-
very low resistance
output. Properly strengthened
guitar waveform is cut to
levels determined by
P2 and P3 tenniometers.
Let us consider such an example. It has
my guitar that when it hits
in the strings produces tension between
peak 200 mV. P1 potentiometer
we set such amplification that
the enhanced mileage had a value between
6V peak (gain 30).
Set the value with P2 and P3 potentiometers
reference voltage values ​​+1 Vi — 1V, |
and set the potentiometers P4 and P5 to
minimum resistance. So adjusted
The important attachment cuts the top and bottom
half of the mileage at approx
1.6V, the truncation will continue
until the value of the
the output waveform strengthens
The time will not decrease to 3.2 V.
From the value of the fixed resistance
the color depends on the tenniometers P4 and P5
sound; im the resistance value is
the bigger, the softer the bar-
wa sound.
The cut level of both halves of the
gu can be adjusted separately, co
obviously affects the sound
guitar sound.
After assembling the system it is necessary
selecting the position of the resistor slider
adjustable RS so that there is no
it is a distortion of the cooperating
power amplifier.
The second version of the header system, before
shown in Fig. 2, can be called: "fuzz
dynamic". Characteristic feature
system is that the distortion
the guitar run does not change its own
character with decreasing amplitude
vibration of the guitar strings. System
this one differs from the previous one in that
"| it uses circuits reproducing
_ | the shape of the upper and lower envelopes
_ | guitar run. They are for this purpose
US1 and US3 operational amplifiers
together with cooperating diodes D1i
D3 and C2 and C3 capacitors. Tension-
the envelope adjusts automatically
reference voltage level obtained
on the emitters of transistors T1 and T2.
So the reference voltage decreases with
with a guitar sound, co
causes approximately proportional
truncation of waveforms. The principle works
the system is the same as in the description
previous layout.
The PK1 switch can be changed
the type of work of the attachment with "fuzz dynamics"
"on" to "adjustable static fuzz".
The double potentiometer P1 is used for
regulation of the reference voltage in
if the system is switched to the latter
type of work.
Both systems should be powered from
symmetrical power supply stabilized
with an output voltage of +15 V.
The current consumption of the first circuit is
about 30 mA, the second - about 60 mA.
It is not recommended to use
terrestrial because it decreases
battery voltages change parameters
try "set" by potentiometers and at least
this change is not abrupt, however
the attachment reacts differently over time
"setting the potentiometers.
This enables the use of divisions at
knobs or potentiometers
what is necessary for quick
Attachment regulators lyes.

[Vivek]

That isn't a VBE multiplier / rubber diode. It's just a plain shunt diode referenced to a DC offset, which is sourced from the emitter of a transistor circuit forming a voltage regulator. Two diodes and DC references are used for clipping negative and positive half waves.

Yes you are right !

I corrected the initial post re Rubber diodes.

However the interesting part is the change of clipping levels dynamically

[Vivek]

Are we talking about Vbe multipliers or what..??

My error

It's not vbe multiplier configuration


But the part I was trying to draw attention to was dynamically changing clipping levels

[iainpunk]

i have dabbled in both envelope following clipping and envelope inverting clipping, they are both semi-nice.

the envelope inverting clipping gets really fuzzy and fat and lifeless on the attack and gets more open on the decay, that makes for no/bad attack and not much sustain, and the volume gets quite jumpy, like a bad sounding slow gear. also, when the envelope is to large, both transistors go fully open, create a short circuit and die, so protect them well.

envelope following clipping is less cool, it just retains some dynamics while distorting, which is less cool and or useful, since volume compression is one of the most useful features of overdrive/distortion. there are also some other ways to get the effect without having to finnick and/or fight to get the envelope follower to work, like the half wave precision rectifier i posted in another of your threads.

cheers, Iain

[Kipper4]

I tried some stuff like this but wasn't over impressed with the results of envelope followers increasing or decreasing distortion. Iirc I was never satisfied it was doing what I wanted so I tried introducing a separate distorted signal who's level depended on the envelopes action.
It was better and and Intresting effect at times.

I still prefer something like a honey bee. Where the voice defines which part Of the story goal is distorted.
So I'd like a less distorted bottom end and a more distorted high end.
Adjust to taste to fit in the band mix.

Could just be my ears.