V-SCALE User Guide: Precision Active Buffer & Multiple - Fix Tracking Issues, Accurate Pitch Sharing

video upload by AJH Synth Official

"Not all Buffered Multiples are created equal: The V-SCALE by AJH Synth is a precision active buffer and multiple, which can be used to correct impedance mismatches between instruments, controllers and modules that can cause inaccurate tracking/scaling of pitch CV's, leading to out-of-tune VCO's and synths. It can also compensate for synths, VCO's and VCF's that will not track a 1V/Oct CV signal accurately, by way of 4 adjustable outputs, with fine-tuning trimmers allowing a 5% positive or negative alteration. Also, it will function as a highly accurate buffered multiple, and allow the use of further passive multiples after it in the CV signal chain, without risking a loss of signal strength, which would also lead to tuning or tracking inaccuracies. Unlike many buffered multiples, the V-Scale has a very high input impedance, and a very low output impedance, so it can make the various input and output combinations of different instruments play nicely together.

Index:
00:00 Intro
00:26 Module Overview
02:48 Adjusting VCF/VCO Tracking
07:04 Correcting 1V/Oct Signals
10:30 Usage with Passive Multiples
14:15 Performance Example

Video by DreamsOfWires"

Patch of the Week: Whistle Lead (Tomita/Tangerine Dream) Using self-oscillating Filter/VCF as a VCO

video upload by AJH Synth Official

"This sound is inspired by lead sounds of the 70's/80's from Isao Tomita and Tangerine Dream (Remote Viewing), but will also be reminiscent of Kate Bush's 'All we ever wanted', and even Jeff Wayne's 'War of The Worlds' musical. It uses a filter/VCF in self-oscillation as a VCO, controlling it melodically, with envelopes and noise to help recreate the sounds. No VCO/oscillator is needed in the patch, and white or pink noise is optional, but necessary to get a Tomita-like whistle sound. Tomita originally used a Moog modular system for these sounds, so given that the AJH Synth MiniMod system and it's Transistor Ladder Filter are directly based on the early R.A.Moog version of the Minimoog, it's possible to get very close to such sounds. However, I've not tried to emulate it exactly, but you can see that the basis for this patch is very easily customisable, so it's a very useful synth patch to understand for a variety of musical applications. Patch sheet PDF can be downloaded here: https://kvisit.com/8AE/rv4G

Check out the AJH Synth playlists for module 'User Guides', and 'Patch of The Week' videos, which will be either performances or 'how to' guides, detailing functions/methods, and a range of sounds, some familiar, some less so, containing a patch sheet at the end, with notes below, to show you how to construct it for yourself.

Video by DreamsOfWires

Index:
00:00 Intro
00:29 Performance Example & Overview
02:22 Assembling the patch
03:14 Importance of envelope
03:42 Delayed LFO/Vibrato
05:25 Adding Glide
06:12 Adding Noise
06:56 Mod wheel control of LFO
07:36 Noise as Filter Mod source
08:16 Patch Diagram

Patch Notes:
Green dots show approximate pot and switch positions. Pots and switches that do not have green dots are not used in this patch, and should be left at their zero or off positions.
This is based on the version in the video with noise mixed in as audio, and glide applied to the keyboard CV. For variations without noise or glide, and usage with a mod controller, see the appropriate part of the video (check Index). Only a couple of connections need to be changed for these purposes.
V-Scale: Used here as a simple multiple, but since it's handling Gate signals any passive multiple could be used.
DH-ADSR: Another Contour Generators could be used instead, but the advantage with the DH-ADSR is independent control of both Decay and Release, meaning greater control. It serves as a great companion to the Contour Generators for this reason.
Dual LFO: The Tap Tempo VC-LFO module could also be used here in the same way, as it also has a built-in VCA (level control).
Ladder Filter: The Gemini 2412 would also work well here, it's tracking in self-oscillation is actually better overall. It would just need to have high resonance/self-oscillation enabled by the rear jumpers (see online manual or video user guide). The Ladder Filter struggles to track at lower frequencies, this is an authentic characteristic of the original Minimoog filter, but it's fine for the pitch/note ranges used in this video. The Sonic XV will also self-oscillate, but it's ability to track 1V/Oct is not as tight as the Gemini.
Modules used from left to right: Glide + Noise (Mk I or Mk II), V-Scale, DH-ADSR Envelope, Dual LFO + VCA, Contour Generators, Transistor Ladder Filter, Discrete Cascaded VCA."

MiniMod & Ribbon Controller - AJH Synth Eurorack Ambient with Gemini 2412 'SEM' style Dual Filter

video upload by AJH Synth Official

"A 2-voice ambient performance using the Doepfer ribbon controller with the AJH Synth MiniMod eurorack modular system, here incorporating the Gemini 2412 'SEM-based' dual multimode filter/VCF. Simple 2 note/2 VCO chords are shifted in pitch with the Ribbon, and pressure sensitivity used to control the Gemini's overall frequency, and the level of pitch vibrato from the Dual LFO module, which has a built-in VCA. A third VCO via the Transistor Ladder Filter creates a single oscillator drone sound (a square wave with pulse width modulation/PWM), whilst the Dual LFO also modulates the frequency of this VCF, and both VCF's on the Gemini in position to each other. The Gemini is used as a stereo filter, with both going of it's VCF's going to separate VCA's and audio channels to creates a stereo panning effect.
The Gemini can be used as 2 filters in series, or in stereo with a single audio input signal, but here both filters are processing a different VCO via their individual inputs, whilst the global Dual Frequency CV function of the module's central mix bus section allows them both to be controlled in unison, in addition to, or instead of their own individual CV control. This offers a huge amount of flexibility.
A suitably large reverb is added in post to add a film/movie soundtrack quality to the sound.

Check out the AJH Synth playlists for module 'User Guides', and 'Patch of The Week' videos, which will be either performances or 'how to' guides, detailing functions/methods, and a range of sounds, some familiar, some less so, containing a patch sheet at the end to show you how to construct it for yourself.

Video by DreamsOfWires"

Expanding the Mother 32 Part 2 - More VCO's & Chords, Vocal sounds, External Filter/VCF (Eurorack)

video upload by AJH Synth Official

"The last of 2 videos showing some ways to add more flexibility and sonic power to the Moog Mother 32 using AJH SYNTH modules. The synth is semi-modular and designed with Eurorack compatibility in mind, so this unlocks the huge range of modules in the Eurorack modular ecosystem. Since the Mother 32 has that trademark Moog sound, the AJH Synth MiniMod range sit particularly well with it's vintage analogue synth lineage. The individual elements of the standard MiniMod voice are in fact based directly on the original R.A.Moog version of the Minimoog.

This video shows another example of adding multiple external VCO's to create a big, dense tone with multiple octaves, and also with 2 of the oscillators offset at different pitch intervals to create chords, just as was possible on the original Minimoog synthesizer.

Also shown is an example of using an external filter, in this case the powerful GEMINI 2412 dual multi-mode VCF, which is simply a case of running internal and/or external oscillators and sound sources into the filter, then back into the Ext Audio input, setting the Mother 32's internal ladder filter to maximum frequency (fully open), and reducing resonance to zero. Of course there's no reason why this filter cannot also be used as part of a patch, although the Gemini's two filters can also be run into each other internally (Cascade = in series) in the same way. Finally an example of vocal timbres/formant sounds, which can be achieved by many methods, but here using the wave folder featured on the SONIC XV diode ladder filter, and the FIXED FILTER BANK 914, which really is a go-to tool for tone shaping, allowing the output of 14 individual filters (1 low pass, 12 band pass, 1 high pass), each fixed at a specific frequency, to be mixed together at individual levels in order to dial in a desired tone.

Video by DreamsOfWires

Index:
00:00 Introduction
00:32 Multiple VCO's / 4 stacked octaves
01:20 Chords / VCO Tuning intervals
02:46 Using an External Filter
04:14 Vocal / Formant sounds"

Mother 32 Tracking Correction with the V-SCALE from AJH SYNTH - Fix those out-of-tune External VCO's

video upload by AJH Synth Official

"Following on from last week's video showing some ways to expand the sonic capabilities of your Moog Mother-32, this video details the use of the V-SCALE Eurorack module to fix tracking issues with external VCO's and synths.
Previous video here: [posted here]

The Mother-32 is semi-modular in itself, but it also provides a gateway into Eurorack modular with minimal investment, for those who are unsure if it is for them. Even a single Eurorack module can make a big difference to your sound and capabilities. Since the Mother-32 only has 1 oscillator (and no sub-bass/sub-octave generator), the most obvious choice for many would be adding an external VCO. However, this can result in tuning issues between the synth itself and any external oscillators controlled by the synth's KB output (1V/Oct CV output). This is due to the output impedance, which can cause the 1V/Oct CV signal to become inaccurate, and mean that external VCO's can be out-of-tune within the space of a single octave. This problem gets worse as additional VCO's are loaded onto this pitch CV, affecting it's current.

The V-SCALE is a 5-way active buffer, in it's simplest form serving as an accurate buffered multiple, but more uniquely it is designed to address tracking issues encountered between modules or synths. It has a very high input impedance, and a very low output impedance - this alone can fix many tracking problems simply by connecting it between the misbehaving modules/synths. However, 4 of the 5 outputs are also adjustable - this is particularly useful for synths and modules that simply do not track correctly and need calibrating, something that can be difficult or near-impossible to change depending on the unit. This means it can also be used to to adjust the calibration of anything that needs strong 1V/Oct tracking, such as a self-oscillating filter/VCF when used as a melodic oscillator.

Video by DreamsOfWires

Index
-------
00:00 Intro
00:27 Overview of the issue
01:47 Mother 32 direct to external VCO
04:19 To external VCO via V-SCALE
05:47 3 VCO's via passive multiple
07:13 Passive multiples + V-SCALE
10:24 Testing with a different VCO



more VCOs mother-32 add vco to mother32 suboctave suboctaves subbass audio input ext audio in cv correction fix scaling tracking won't track my synth 1 volt per octave keyboard sequencer problem out of tune issue"

Expanding the Mother 32 - Sub-octaves, wave multipliers & extra VCO's for chords & vintage fatness

video upload by AJH Synth Official

"Here are some ideas for expanding the sonic possibilities and fattening up the sound of the Moog Mother 32 analogue synth - We're sometimes contacted by customers who have, or want to add AJH Synth modules to theirs, as the Mother 32 has great connectivity for Eurorack integration, so hopefully this will video will show a little of what is possible. The Mother 32 has a single oscillator, so the most obvious choice would be to add more VCO's, in order to perform harmonies and simple chords, but also it doesn't have a sub-bass, or sub-octave generator, so this may also be worth considering. In this video we demonstrate both of these options, using the MiniMod Vintage Transistor Core VCO's, the Ring SM to generate sub-octaves and as a CP3 style mixer, but also the Wave Swarm to simulate multiple stacked sawtooth waves. We also use the Sample Hold & Slew to generate rhythmic, random filter modulation, the Precision Voltages as a convenient way to select precise octave and semitone pitch changes of VCO's, and use the V-Scale to address 1V/Oct scaling/tracking issues that may occur when using the Mother 32 to control external VCO's or other instruments via CV.

The AJH SYNTH Eurorack range consists of high-end modules, all hand-made in the UK, most of which are based on classic, vintage designs, authentically recreating the circuitry of much sought-after analogue instruments and technologies of the past, whilst greatly expanding them, and bringing them to modern Eurorack levels of convenience, limitless flexibility, and reliability.

Index:
00:00 Introduction/Overview
00:53 Sub-octaves/sub-bass (Ring SM)
02:40 Sawtooth multiplication (Wave Swarm)
03:50 Ring SM as CP3 Input mixer
04:44 Using it with a sequencer
06:33 Sample & Hold filter mod
08:37 The need for the V-SCALE
09:09 Adding more VCO's
10:25 Using the Precision Voltages
11:19 Multiple VCO's & a sequencer

Check out the AJH Synth playlists for module 'User Guides', and 'Patch of The Week' videos, which will be either performances or 'how to' guides, detailing functions/methods, and a range of sounds, some familiar, some less so, containing a patch sheet at the end to show you how to construct it for yourself: https://youtu.be/89bv0dI8yw4

Video by DreamsOfWires"

Minimoog-style Lead Sounds - Inspired by Rick Wakeman, Keith Emerson, & the sounds of the seventies

video upload by AJH Synth Official

"These are just sound examples, but I am not a keyboardist, so please don't expect any Rick Wakeman/Keith Emerson keyboard wizardry. The intention is just to illustrate the kind of tones that can be created with the basic MiniMod voice in Minimoog configuration (Glide, 3 VCO's, Ladder Filter, etc), along with some overdrive/distortion from driving the audio levels hard.

Generally, input levels significantly beyond 12 O'clock (50%) on the Ladder Filter or Discrete Cascaded VCA should start to apply more overdrive to the audio from the VCO's or other Eurorack level signals. This will noticeably change the character of the sound at extreme settings.

The GAIN SWITCH module is also used a couple of times here, as it conveniently activates the high-gain mode featured on both the Transistor Ladder Filter & Discrete Cascaded VCA modules, which is otherwise set by jumpers on the rear of the modules. Using the Gain Switch just means you don't need to pop the module out to enable/disable the feature. Audio-rate modulation of VCO3 from VCO1 is added at a couple of points... just because it sounds good, not necessarily because it was commonly used in famous lead sounds.

Rick Wakeman has famously used the Minimoog throughout his career, whereas Keith Emerson is equally associated with the Moog modular system that preceded it. Since the AJH Synth MiniMod system is directly based on the early, more desirable R.A.Moog version of the Minimoog, whilst also being fully modular, this makes it an excellent choice for recreating the sounds of those original, iconic instruments, and going way beyond it in the world of Eurorack.

Video by DreamsOfWires"

AJH Synth Low Pass Filters Compared: 3 Eurorack VCF's - Sequences & Sweeps (dry audio/no talking)

video upload by AJH Synth Official

"A purely functional video this week - we're sometimes asked which filter we'd recommend, but really it's a subjective thing, so here's some examples of the current 3 AJH Synth Low Pass filters compared, with both a sequence and static sawtooth sweeps. The settings are mostly kept similar, bearing in mind that it's impossible to get an exact match with different VCF designs. The video timeline has an index, so you can skip to particular sections by using the links below, or by hovering the mouse over the timeline on the video player.

Filters featured:
Transistor Ladder Filter (based on the R.A.Moog Minimoog)
Sonic XV Diode Ladder Wave Filter (based on the 'muSonics' Sonic V)
Gemini 2412 Dual Vintage State Variable Filters (based on the Oberheim SEM)

INDEX:
00:00 Intro
00:29 Video Overview
01:20 Sequence + 1VCO - Ladder Filter
02:18 Sequence + 1VCO - Sonic XV 24dB
03:16 Sequence + 1VCO - Sonic XV 6dB
03:57 Sequence + 1VCO - Gemini 12dB
04:26 Sequence + 1VCO - Gemini 24dB
04:58 Multiple VCO's
06:33 Fast sequence
09:03 Filter Sweeps - Ladder Filter
10:25 Filter Sweeps - Sonic XV
12:56 Filter Sweeps - Gemini 2412

Video by DreamsOfWires

vcf comparison analogue voltage controlled filters compared analog filter shoot out no talking dry audio only examples no fx transistor ladder filter vs sem filter vs diode filter"

See the AJH label below for more.

GEMINI 2412 User Guide Part 3: Using the dual filters together - stereo, formant, 24dB cascaded etc

video upload by AJH Synth Official

AJH Synth Official GEMINI 2412 User Guide posts

"Part 3 of 3. The AJH Synth Gemini 2412 Dual Multi-mode SEM-based VCF explained. The 3-part User Guide will cover this very complex and fully-featured, yet simple to use analogue filter. This final part shows how the functions explained in parts 1 and 2 can be used with both filters working together, with particular attention to creating a 24dB low pass filter, and a 12dB band pass filter, using the Gemini as a single filter in cascade mode. Also, creating formant, or vocal type sounds, evolving patches using an envelope to morph between the output of both filters, then finishing off with various no-talking patch examples, such as using the Gemini as a stereo filter, as part of a 2-voice polyphonic synth, and constantly changing sequencer patterns."

Video by DreamsOfWires

Index:
00:00 Intro
00:27 Overview
01:11 Creating a 24dB Low Pass filter
04:43 Creating a 12dB High Pass filter
08:20 Formant vocal sounds
09:26 Audio Mix & Envelopes
11:34 Patch examples"

'Radiophonic Randomness' - Using the RANDOM VOLTAGE EVENT GENERATOR to make retro scf-fi sounds

video upload by AJH Synth Official

"Just for fun... Some lo-fi sounds/noises created with the help of the Dual RVG Eurorack module, providing random voltages and clock/gate signals, and demonstrating it's ability to multi-function, here providing 4 control signals. It's just an experiment really, since the author of this video is such a fan of the early adopters of analogue synths and the sounds they created, from the BBC Radiophonic Workshop's low-budget TV and radio soundtracks, to the first, less melodic synthesizer experimentations of Klaus Schulze, Tangerine Dream, and others.

Many of these involved the instruments and tools created by a small English company called EMS (Synthi, VCS3), and the Dual RVG by AJH Synth is directly based on one of their rarest products - the Random Voltage Generator. These would be incredibly hard to find now, and expensive, so having the same functionality and vintage circuit design in just 14hp of Eurorack space is a great alternative. The Dual RVG is a limited edition, only 500 units were to be made, but there are still some left as of writing this. It is an authentic vintage design, and it's behaviour faithfully recreates this character - organic in it's uncertainty and anomalies, unlike modern digital modulation sources. A very unique, but useful tool for generative music, experimental sound design, but also melodic composition and performance, especially when used with a quantiser and/or sequencer (see here: [posted here])

Check out the AJH Synth playlists for module 'User Guides', and 'Patch of The Week' videos, which will be either performances or 'how to' guides, detailing functions/methods, and a range of sounds, some familiar, some less so, containing a patch sheet at the end to show you how to construct it for yourself: [posted here]

Video by DreamsOfWires"

'A Space Odyssey' with the LUNAR MODULE - Performance with lo-fi sample processing in eurorack

video upload by AJH Synth Official

"This week's Patch of The Week was inspired by the movie '2001: A Space Odyssey', and uses the LUNAR MODULE by AJH Synth to process audio samples from the film, whilst various other Eurorack modules build the accompanying melodic drone to provide the musical backing.

The Lunar Module is an audio processor and noise generator, which also features distortion, a bit-reduction/bit-crushing effect, and a recreation of the 'Quindar' sounds (beeps) used in the actual NASA Apollo space program/missions of the 1960's to early 70's. In conjunction with the Lunar Module's other sound processing tools this can be used to simulate the lo-fi audio transmissions of the time and then applied to anything. All the features are also useful individually, from a customisable noise source, to adding distortion and bit-reduction to any incoming audio or Eurorack level signals, even melodic sounds. This performance originally appeared at the end of the Lunar Module User Guide video - check it out for all the details on what it can do and how to use it.

Check out the AJH Synth playlists for module 'User Guides', and 'Patch of The Week' videos, which will be either performances or 'how to' guides, detailing functions/methods, and a range of sounds, some familiar, some less so, containing a patch sheet at the end to show you how to construct it for yourself: https://youtu.be/89bv0dI8yw4

Video by DreamsOfWires"

Lunar Module User Guide - Vintage Space Mission Audio/Mic/Sample/Synth Effects for Eurorack

video upload by

"The Lunar Module is a fun Eurorack module for recreating the sound character of early space missions, or adding noise and bandwidth limitation to mics, line-level audio, samples, and synth modules. It's effects can be triggered manually, or from gate signals, and include noise with colour control (a bipolar low pass and high pass filter), hum effects with frequency control, variable distortion, and 'Quindar' - an authentic beep used at the beginning and end of transmissions from the Apollo space capsule back to the NASA Huston control centre.

As with all AJH Synth modules, the Lunar Module is designed to be played, and it's pots and jack sockets are made easily accessible so that live tweaking is not hindered, and controls are all substantial in size and spacing. Most are based on vintage synthesizer circuits and designs, bringing the sounds, behaviour and character of classic synths to Eurorack modular, but with the advantage of modern reliability, compatibility, flexibility, and understanding of the needs of modern musicians.

00:00 Intro
00:13 Overview
00:59 Installation Guide
02:12 Inputs & Controls
09:07 Use with Samples
14:43 Use with Microphones
16:29 Use with Synths
19:43 With Other Audio Devices
22:06 A Patch Clip
23:53 A Short Performance"

Video by DreamsOfWires"

GEMINI 2412 User Guide Part 2: The Mix Bus (Dual Output, Audio, Frequency & CV control of filters)

video upload by AJH Synth Official

"Part 2 of 3. The AJH Synth Gemini 2412 Dual Multi-mode SEM-based VCF explained. The 3-part User Guide will cover this very complex and fully-featured, yet simple to use analogue filter. This part will explain the central mixing bus section of the filter, and how it can be used to control the audio and CV balance, and cutoff frequency of both VCF's simultaneously, and how the dual filter (parallel) and cascaded filter (in series) modes work. Part 1 concentrated on the individual filters and their functions: [posted here] Part 3 will cover using the both filters together with the mixing bus, and how this element enables both VCF's to function together as a single, huge filter, either in series or parallel, along with patch examples, including using the Gemini as a stereo filter.

Video by DreamsOfWires

Index:
00:00 Intro
00:32 Dual Mode
02:17 Cascade Mode
06:01 Invert Function
10:38 Audio Mix
12:25 Mix CV (with an Envelope)
17:20 Mix CV (with an LFO)
22:38 Dual Frequency CV (D-FCV)
28:24 Patch Example (no talking)"

Step Sequencer & Fixed Filter Bank 914 - An alternative to a VCF for sculpting sequences

video upload by AJH Synth Official

"This 'Patch of The Week' shows the Fixed Filter Bank 914 being used instead of a typical voltage-controlled filter to sculpt the sound of a step sequencer pattern, and also how on this particular module the sequencer can also interact with it for more variation and movement. The module is based on the original 914 unit from the vintage Moog modular systems, something Klaus Schulze was very keen on using as part of his 'Big Moog' that he used for much of his music career.
Here the excellent Doepfer Dark Time sequencer is used, but any dual, or combination of 2 step sequences could be used.
Downloadable Patch sheet link and patch notes further down the description.

Check out the AJH Synth playlists for module 'User Guides', and 'Patch of The Week' videos, which will be either performances or 'how to' guides, detailing functions/methods, and a range of sounds, some familiar, some less so, containing a patch sheet at the end to show you how to construct it for yourself.

Video by DreamsOfWires

Index:
00:00 Intro
00:26 Background to this patch
01:42 The Patch
06:56 Patch Sheet/Diagram"

Patch of The Week: 'Melodic Doom' - How to use the Entropic Doom noise oscillator melodically

video upload by AJH Synth Official

"An improvisation using the Entropic Doom noise oscillator as a melodic instrument, controlled by a step sequencer. It's pretty much a voice in it's own right - a noise source, resonant 4, 3, or 2-pole voltage controlled filter, which will self-oscillate and track a 1V/Oct signal, along with a separate XOR based Ring Modulator and a Cmos gate based VCA. In this video I also use the Sync and audio input functions with a VCO. Additionally, I show the Dual RVG module serving as a master clock to the sequencer, and producing random timing for the sequencer steps, as well as additional random voltages for the Entropic Doom's frequency.

Downloadable Patch Sheet: https://kvisit.com/8AE/-vwG

Video by DreamsOfWires

PATCH NOTES:
------------------------
Green dots show approximate pot and switch positions, and where there are 2 dots on the same pot, this indicates the range I adjust them during the video. Pots and switches that do not have green dots are not used in this patch, and should be left at their zero or off positions.
PRECISION VOLTAGES: Used to shift pitch intervals on the Entropic Doom from the incoming sequencer pitch CV. During the video I add 7 semitones and 1 octave at different points using the A switches.
DUAL RVG: This is being used for 2 purposes - To generate random frequency modulation of the Entropic Doom at the start, in addition to the frequency changes generated by the sequencer, which means a wider and more varied range of frequencies can be achieved than just using the pre-chosen frequencies set by the sequencer. It's just to add more randomness and chaos to the initial apocalyptic noises. It is also used to create random sequencer step timing, via it's Time Vary function. It sends gate signals to the sequencer and serves as it's master clock. As I unveil the melody I reduce this time variation until the sequencer timing becomes regular, or normal. The sequencer will need to have some form of Clock Input (perhaps Sync or Gate In), marked here by the green cable. VCO: This is also connected to the sequencer CV out, either by buffered multiple, or by using CV bus via the Glide + Noise as in the video, then the Glide's CV OUT should go to the Precision Voltages IN A. A triangle wave was used as the Sync source (purple cable), and square was used as the audio source. Tuning here is arbitrary, and dependent on your sequencer.
ENTROPIC DOOM: The base pitch of the module will be set by using the Frequency pots (FREQ-C & FREQ-F) to tune it, once the resonance level is high enough, more clearly so in 4-pole mode. FCV-IN here is only used for the random voltages coming from the Dual RVG, which I gradually remove as I unveil the melody from the sequencer.

Index
00:00 Intro
00:26 'Melodic Doom'
06:30 Patch sheet"

GEMINI 2412 User Guide Part 1: The Single Filter (Explaining the individual VCF with audio examples)

video upload by AJH Synth Official

"Part 1 of 3. The AJH Synth Gemini 2412 Dual Multi-mode SEM-based VCF explained. The 3-part User Guide will cover this very complex and fully-featured, yet simple to use analogue filter, starting with looking at one of the individual filters in isolation. There are also some audio examples, both with and without talking, and some example patches for just a single filter at the end.
Part 2 will explain the central mixing bus section of the filter, and Part 3 will cover using the both filters together with the mixing bus, and how this element enables both VCF's to function together as a single, huge filter, either in series or parallel, along with patch examples, including using the Gemini as a stereo filter.

Using the GAIN SWITCH with the Gemini to select High Resonance mode: [posted here]

Featured in this video:
'Assault on Precinct 13': https://youtu.be/fKyEDf2QkV8
'Brass & Blade': https://youtu.be/2KuP930dqcs
'Blade Runner CS-80': https://youtu.be/Tcts4oCyxaI

Video by DreamsOfWires

Index:
00:00 Intro
00:30 Overview
02:13 Physical examination
03:45 Module layout (single filter)
06:41 How it sounds
10:51 Frequency CV control
13:57 Resonance CV control
15:05 Input level & Drive
17:05 High resonance mode/Self oscillation
22:02 Sound examples (no talking)
26:14 Patch examples (no talking)"

Patch of The Week: Analogue Kick Drums in Eurorack with the AJH Synth MiniMod Modular Synth System

video upload by AJH Synth Official

"A simple analogue kick drum patch easily recreated in Eurorack, or even some self-contained synths. This isn't modelled on a particular classic or vintage kick sound, but uses a common process for creating such a sound that is easily tweakable to suit your own ears. Check out our past 'Patch of The Week' videos for other percussion sounds, including analog claps, and using a self-oscillating filter to create various claves, rim shots, cowbell, even a rudimentary kick.

Video by DreamsOfWires

PATCH NOTES:
------------------------
Download PDF with diagram - https://kvisit.com/8AE/qvwG
Green dots show approximate pot and switch positions, and where there are 2 dots on the same pot, this indicates the range I adjust them during the video. Pots and switches that do not have green dots are not used in this patch, and should be left at their zero or off positions.
GLIDE + NOISE: I used the white noise in this patch - not all vintage kick drum sounds used a noise source, but it is optional based on personal taste. I find it gives the sound a more similar character to a real kick drum, whereas without it the sound is more distinctly electronic.
VCO: A good kick sound can be generated using just the filter in self-oscillation, but using a dedicated VCO provides greater flexibility, especially when combining with other audio sources, such as white noise. Base pitch and level of Exp CV from the envelope should be experimented with.
VCF: Envelope control of filter frequency will not make much difference to the sound without the white noise, as then you would only be filtering a triangle wave. This is why I've simply copied the envelope that's also opening the VCA.
ENVELOPE: Ideally there needs to be separate envelopes for the VCO and the VCA/VCF, as one is controlling pitch, and the other volume (& tone), which both have a very different impact on the sound. A pair of DH-ADSR's would offer greater dynamic control, as mentioned in the video, but the CONTOUR GENERATORS is fine too.
VCA: The DISCRETE CASCADED VCA allows a little bit of overdrive when input levels are pushed. Even more so when used with the GAIN SWITCH (See our other videos), but also the MUTING MIXER can be used, as it's built around the same VCA circuit and has a built-in overdrive function."

LFO to Multiple VCO's Simultaneously via CV BUS with PRECISION VOLTAGES & GLIDE MkII Modules

video upload by AJH Synth Official

"Here's a quicker, simpler, more accurate way to send LFO/pitch vibrato to more than one VCO without using a multiple, by using the PRECISION VOLTAGES module with the GLIDE + NOISE MkII. In a previous video we showed how to use the Glide MkII to access the CV bus for convenient pitch control of up to 4 VCO's [2nd video here]. This time we add the Precision Voltages, so that both keyboard/sequencer pitch CV and pitch modulation CV for vibrato can be combined, thus removing the need to multiply the LFO cables to all VCO's, and have to make modulation level adjustments on each individually.

The Precision Voltages is primarily aimed at shifting the pitch of your oscillators, accurately and conveniently, by octave and semitone intervals. However, it is capable of many other uses. In a previous video we showed how to use it to correct the octave range of CV sequencers and keyboard controllers so that you can reach the lowest notes/pitches your VCO's are capable of producing [1st video here].

Doepfer created the CV and Gate Bus system to allow signals to be passed down the bus board/cable to modules equipped to receive these control voltages, such as specific oscillator and envelope generator modules, reducing the number of patch cables, multiples, and simplifying the patching process. AJH Synth VCO's, Contour Generators and DH-ADSR all respond to the CV or Gate bus."

Video by DreamsOfWires

Offset Explanation & Performance with the CV MIX & Multi Burst Envelopes (for Ratcheting effects)

video upload by AJH Synth Official

"This video will explain using a fixed voltage as an Offset on the CV MIX module, and uses it help create variable ratcheting effects during a sequence, using the Multi Burst Envelopes module, which is ideal for this task, especially since you can sync envelope repeats via a sequencer, or other external clock.
In the first part of the video Offset and the built-in attenuation on some modules is explained, then in the second an explanation of the patch I'm using it in, and finally in the third part a short, simple performance.

Index:
00:00 Intro
00:32 Offset Explanation
03:35 Patch Explanation
07:37 Patch Performance

Check out the AJH Synth playlists for module 'User Guides', and 'Patch of The Week' videos, which will be either performances or 'how to' guides, detailing functions/methods, and a range of sounds, some familiar, some less so, containing a patch sheet at the end to show you how to construct it for yourself.

Video by DreamsOfWires

MiniMod Two Voice - A Polyphonic SEM-Inspired Eurorack system layout with the GEMINI 2412

video upload by AJH Synth Official

"This is just a module layout suggestion for how you might create a polyphonic SEM/Oberheim Two Voice-inspired system using the AJH Synth eurorack modular system, and in this example using a typical 6U, 84hp case.

It requires a polyphonic MIDI-CV converter to distribute the notes from a keyboard or sequencer to the two voices. However, this layout also works well when used a huge monosynth, and includes an example of a monophonic patch too. Patch notes and link to downloadable patch sheet below.

Video by DreamsOfWires

Patch Sheet Link: https://kvisit.com/8AE/g_wG

Patch Notes:
This is just how I set up the system for a 6U, 84HP case, not a complete patch example with pot settings, in order to make the diagram easier to see and understand.
I've tried to loosely match the functions of the Oberheim SEM modules used in the original 'Two Voice' synth. Each SEM had a simple LFO, two Attack/Decay/Sustain envelopes, limited VCO waveform and modulation mixing, and a multimode 12dB filter.
I'm using the Glide + Noise Mk2 module to control VCO's 3 & 4, as all are connected to the CV bus on the top row, then I'm using the V-Scale as a buffered multiple to control VCO's 1 & 2 via their 1V/Oct inputs, thus bypassing the CV bus. Aside from this combo of modules fitting the case exactly, having both the Glide and the V-Scale modules became more useful when using the system to create monophonic patches, in which case all 4 VCO's would be controlled via the Glide + Noise input to the CV bus.
Modules: Glide + Noise Mk2, Vintage Transistor Core VCO x4, Contour Generators x2, Discrete Cascaded VCA x2, V-Scale, Dual LFO + VCA, Muting Mixer & VCA x2, Gemini 2412."

PRECISION VOLTAGES & A SEQUENCER - Creating note intervals/chords during a sequence/performance

video upload by AJH Synth Official

"A short performance showing the PRECISION VOLTAGES module by AJH SYNTH to alter the tuning of VCO's, in this case whilst running a sequence from a pattern/step sequencer. This is really useful for introducing pre-tuned note intervals between oscillators, even to create simple chords, adding a whole new dimension of interest to pattern-based performances.

The module can be used to add or subtract multiple octaves or semitones from incoming CV signals, which in itself has a wide range of uses, but it can also generate fixed voltages, either to create continuous VCO pitches, or for adding offsets to CV signals for modulation, etc. It can even be used to combine CV signals, but more about the in the future 'User Guide' video for the module.

I'm using a Doepfer Dark Time sequencer as 2 separate 8-step sequencers. The output of this sequencer can be transposed by MIDI, so I'm using the Keystep simply as a MIDI keyboard for this purpose, but the actual sequencing is from the Dark Time.

Check out the AJH Synth playlists for module 'User Guides', and 'Patch of The Week' videos, which will be either performances or 'how to' guides, detailing functions/methods, and a range of sounds, some familiar, some less so, containing a patch sheet at the end to show you how to construct it for yourself.

DreamsOfWires"