Showing posts with label A-110. Show all posts
Showing posts with label A-110. Show all posts

Thursday, October 10, 2013

SiteTip: Mheontube YouTube Channel

It looks like another Eurorack fan has hit YouTube...
Mheontube started to upload interesting short Eurorack snippets since yesterday, basic patches made with a small setup of only 4 Doepfer modules (so far)...

Check the full playlist (the last 7 videos were uploaded in one day) HERE

Video 1: Chirp Chirp Analogue by mheontube

-no description available

Video 2: Android's Talk by mheontube

-no description available

Video 3: Grumpy Android by mheontube

-no description available
Uploaded by mheontube (subscribe!)

Sunday, July 14, 2013

A-110 Tuning Knob Modification

Triggered by a photo by Scott Rogers that popped up on Flickr a few weeks ago, I decided to re-create the A-110 Oscillator modification that he made.
Scott simply added a resistor in parallel with R5 to increase the tune knob range to a bit more than an octave up and down.

Locating R5 on the A-110 VCO
On Scott's blog he writes:
" I’ve already made my first modification to my Doepfer A-110 Oscillators.
For some reason they have set the Tune knob range to only a single tone up or down. 
One thing I do a lot is offset the oscillators by a fifth so this wasn't going to do!

So I contacted Doepfer and they told me (more or less) what to do.
So what I did was this: located resister R5 on the circuit board and added a second resister in parallel with it to reduce it’s value.

Locating R5 on the A-110 VCO
on the other side
I added a 100K resister and this now gives me a range of an octave and a third up and a bit more than an octave down. 
So now it’s a bit more difficult to fine tune, but now I have a huge tuning range that lets me do a lot more! "

The modification is also described in the A-110 service manual on the Doepfer website:
" From the factory the range is about 2 semitones to enable a fine tuning of the VCO.
If you are a bit familiar with soldering you may modify the A-110: shorten R9 (this increase the range about by a factor 3) or reduce the value of R5 (1M).
You may solder e.g. a second resistor in parallel to the existing R5 (1M). The smaller the value of the resistor the higher the range."

A 100K, 5% resistor in paralel with R5
Re-creating this modification was not difficult, after locating the R5 resistor, soldering the 100K, 5% resistor in parallel to it was a piece of cake.

I don't have any test-equipment, but after listening to the result, it changed the range of the tune knob on my A-110 from around 3 or 4 semitones up/down to a little bit over 1 octave /around 15 semitones, so the results seem to vary a little bit per A-110... which probably has to do with different internal potmeter settings on the PCB.

Thanks to Nicholas Keller for additional support, info and links!

The mods described on this site will most likely void any warranty and, if not done carefully, can damage the circuit board, IC chips, and faceplates.

Tuesday, April 03, 2012

Doepfer A-110-2 Low-Cost VCO Announced

A-110-2 Basic VCO
Always nice, those unexpected new module announcements.

Doepfer announced the A-110-2 on their site recently, a low cost VCO, similar to A-110, but sawtooth, triangle and rectangle with PWM only.
The module will have a 3-position octave switch (instead of the rotary switch of A-110), Soft and Hard Sync inputs, linear FM input.
This should all fit on a 8 HP front panel, the 'original' A-110 is 10 HP wide.

The module is planned for fall 2014 and will be priced at around Euro 110.00
(The A-110 costs 140 Euro's)

Power consumption:
- 150 mA +12V
- 150 mA -12V

- 50 mm Depth

Update Oktober 13, 2014: 
Dieter Doepfer in the A-100 Usergroup 
"...the A-110-2 is planned still for this year.
I hope the first units will be available end of November. 
The pcbs are already made. 
We are waiting only for the front panels."

Saturday, October 01, 2011

A-110 VCO Tutorials from Raul Pena

Raul Pena, who already brought us the A-188-1 BBD tutorials, recently published six new video tutorials.
This time the focus is on the A110 VCO:

Video 1 : Doepfer A110 Features and Functions
http://www.youtube.com/watch?v=E2BV4iYBpOY
" Explanation of Features and Functions of the Doepfer A-110 Standard VCO Module.
Next in this series Audio Demonstration of Waveforms and Pulse Width Modulation.Sound and Video by Raul Pena. "


More video after the break:

Wednesday, November 17, 2010

Busboard Access

Updated August 25th 2011

A good patch can sometimes turn out to a whole spaghetti of patchcables.
Luckily Doepfer provided the A-100 system with a subsystem that makes the routing of some Gate and CV signals through the internal busboard-system possible.

It's too bad that not all modules have this ability, but for some modules this is a good way to avoid "over-wiring" your system with patch-cables.

Only modules A-110 (Standard VCO), A-111 (High end VCO), A-111-5 (Mini Synth. Voice), A-140 (ADSR), A-164-1 (Manual Gate), A-185-1 (Bus Access), A-185-2 (Precision Adder) and A-190-1,2,3 and 4 (Midi Interfaces) have access to the CV or Gate signal of the A-100 busboard.

The A-164-1, A-185 (-1 and 2) and A-190 (-1,2 and 3) can be used to "write" the busboard, i.e. they can output the signals to the bus.

The others are able to "read" the busboard, i.e. they pick up the signals CV (A-110, A-111, A111-5) resp. Gate (A-140, A-164-1) from the bus.
The A-111-5 can pick up CV and Gate from the bus. Also the planned A-143-4 Quad VCLFO/VCO will be able to read the A-100's busboard.
For details please refer to the user manuals of these Doepfer modules.

Most of the modules come with jumpers inside that can connect or disconnect the signal from and to the busboard. If other modules should be able to "write" or "read" the bus some of them can be modified. More on this in a future modding blogpost.

Doepfer warns on their DIY-site for shortcircuiting modules and/or busboard, so please take note:
Pay attention that only one module is allowed to "write" to the same bus signal.  If two or more modules write to the bus this leads to a short circuit of the corresponding outputs.
Please let me know if i forgot some modules in the Feedback section of this post, thank you!

Tuesday, November 02, 2010

Oscillator Synchronizing


Interesting sound-effects can be obtained by the synchronising of (multiple) oscillators.
In a typical setup, one oscillator (master) restarts the cycle-period of the other one (slave) , what results in equal base frequencies on both oscillators. This is called Hard Sync.

The result is an irregular waveform with it's own harmonic spectrum, completely different from 'standard' waveforms

Soft Sync is a more general name for all kinds of oscillator synchronisation.
This form is very similar to Hard Sync, but here the slave oscillator is forced to reset to zero with every cycle of the master regardless of position or direction of the slave waveform, which often generates asymmetrical shapes.

In Soft Sync, rather than resetting to zero, the wave is inverted;  its direction is reversed.
Further variations to the sound can be made by comparing the sounds with different comparison tresholds. For more info see the Wikipedia page on Oscillator Synchronisation
Soft Sync sounds smoother  and distinctly different from hard-sync.
It is difficult to replicate this effect on digital synths, due to aliasing problems.

Soft Sync-like effects can also be created with other modules, for example a phaser or a Phase Locked Loop (PLL) Module.

Tuesday, October 19, 2010

Never Enough VCO's


The engines or hearts of all modular synthesizers are definetely the VCO's. As main sound source for your patches it seems you never have enough of them.

I own 5 VCO's at the moment, One A-111 High End VCO plus four A-110 Standard VCO's. Ideal for stacking layers of waveforms to make extra- fat sounds, and also very useable for multiple A-100 melodylines

The A-111 is the one i use most because of its extended possibilities. 
This VCO has an extended frequency range, improved waveforms, FM and Soft Sync inputs plus an extra fine-tune-controller. Ideal for controllerfreaks like me. 
It produces sine, triangle, pulse and sawtooth waveforms, which are all derived from the triangle oscillator, what does make it hard to produce perfect sine-waves ( but a little better as the A-110's sine wave )
One of the best things is that all 4 waveforms are all simultanously available at the outputs for your mixing pleasure.

The much cheaper A-110  has less controls and is based on a sawtooth oscillator. All outcoming waveforms of this module are derived from this sawtooth by internal waveform converters. This module also generates sinewaves that are not completely perfect, but to 'normal' ears this is hardly audible

I never noticed, and i guess most of us don't care and never noticed the imperfect-ness of the sinewaves of both modules.
Even on an oscilloscope it is hardly visible that the sinewaves are nothing more than rounded sawtooth-waves.
For a perfect sine wave Doepfer recommends the A-143-9 Quadrature LFO/VCO, another interesting module, that i will highlight in a future blogpost.

Note: As the special circuit CEM3340 used in the A-111 High End VCO module is no longer available the module has to be discontinued. Sales at Doepfer while stocks last !

Thursday, September 30, 2010

A-115 Audio Divider

A module that i use a lot in my patches to get a fatter sound is the A-115 Audio Divider.

This module adds 4 seperately mixable sub-octaves to your original signal,
where F/2 = half the frequency = first sub-octave,
           F/4 = quarter frequency = second sub-octave,
and so on...

It is a perfect module for making nasty low bass sounds.
Especially the F/16 output can sound very dirty ( but very gritty ) if you turn its volume up.

Most of the times i feed a signal directly from an A-110 VCO Voltage Controlled Oscillator into the Divider module.
To make optimal use of all of the sub-octaves, i turn the footage (or octave-) switch of the original oscillator up one or 2 octaves.
( An option is to leave the original signal out of the mix )
This makes even the lowest octave (F/16) a bit useable in my setup.

Note that all 4 sub-octaves outputs are all true square waves, so the output provides 4 square waves plus the original signal.