AMSynths AM8705 Dual ADSR Envelope & AM8060 JP6 Multi-Mode VCF

via AMSynths

"This module is a Dual ADSR similar to the envelope generators in the Roland 700 and 100M modular analog synthesizers. The AM8705 contains two identical traditional ADSR format envelope generators with variable Attack, Decay, Sustain and Release. The module uses 30mm travel slide potentiometers and has toggle switches to switch between 2 different set of timings - slow or fast."



"This module contains two envelope generators each with 3 timed stages: Attack, Decay, Release. The Sustain control adjusts the level to which the Decay time reduces to. Both ADSR's are triggered together by an internal gate signal from the standard Doepfer 16 pin bus, or a front panel push button (MANUAL GATE), or individually via a gate signal connected to the front panel Gate jacks (GATE1, GATE2).

The standard duration of each stage is 10 seconds, but each ADSR can be switched using the TIME toggle switch into a fast timing 1/10 the duration. This enables fast envelopes to be generated. Two identical control voltages are available for each ADSR, making it easy to patch an ADSR into both a VCF and VCA simultaneously. The gate signal is displayed for each ADSR via a dedicated LED. Each ADSR generates a control signal from 0V to +10V.

There is a Red gate LED for ADSR1 and a Blue gate LED for ADSR2. The toggle switches have colour coded caps (Blue and Red) and the single gate switch is a Red push button button."


"This module is a replication of the Jupiter 6 voltage controlled filter which comprises two 2-pole OTA filters in series, and was launched in 1983. Each 2-pole filter can be switched into either Low Pass or High Pass modes providing three VCF modes all with variable resonance:

24dB Low Pass Filter
24dB High Pass Filter
12dB Band Pass Filter

This voltage controlled filter has a more aggressive sound than a simple 4 pole OTA based filter, along with a lot more flexibility...

This module is a multi-mode voltage controlled filter with front panel controls for adjusting the Cutoff Frequency and Resonance as well as the level of 2 control voltages and 3 audio signal inputs. There are six 3.5mm jack sockets on the right of the front panel; the filters audio output, 2 control voltages and 3 audio inputs. The filter topology can be adjusted using two front panel latching push buttons.

The filter has two 2-pole OTA filters in series, and the blue and grey push buttons select from 4 filter modes, each sounding different:

24dB Low Pass Filter - Blue and Grey OUT
24dB High Pass Filter - Blue and Grey IN
12dB Band Pass Filter - Grey IN and Blue IN
12dB Band Pass Filter - Grey OUT and Blue IN"

See http://www.amsynths.co.uk for more.

AM8071 Snow Fall VCF

via AMSynths

"This module is a traditional diode ladder low pass filter similar to that in the EMS VCS3, Roland SH-3, System 100 and the PE Minisonic 2. The filter has a 4-pole ladder with an 18dB like response, thanks to the characteristics of diodes. A fifth pole can be switched in to give a steeper 24dB response using the Slope switch. The control voltages can be smoothed out using the Lag switch, to give a more fluid modulation.

The filter has adjustable Cutoff Frequency and Resonance, along with a resonance CV input, 2x Signal inputs and 2x Frequency Cutoff CV inputs. The panel design is a mix of rotary and slide potentiometers. The filter was developed during the heavy snowfalls across the UK in February 2010, hence the name."


via the AMSynths blog: "Back in the late Winter of 2009/2010 there were heavy snow falls in south east England for the first time in many years. During this "white out" I designed a diode ladder voltage controlled filter similar to the ones that appeared in a number of analog synths in the 1970's, and named this new module "Snow Fall". In 2009 I had already built a number of prototype 4-pole diode filters from the EMS VCS3, Roland SH-3 and the Practical Electronics Minisonic 2. I improved the designs with modern components and added a fifth pole and slew delay on the CV input. This AM8071 protptype was very sucessful and delivered a great sounding and flexible VCF.

During Summer of 2011 the prototype was worked up into a production design using the new AMSynths panel design which has a mix of rotary and slide pots, with momentary push buttons. The production units were launched on 20 September 2011 and this EuorRack module is available to purchase from AMSynths web site."

Snow Fall - EMS VCS3 Filter Clone

via AMSynths

AM8071 Module - "Snowfall" Diode Low Pass Filter

"During the exceptionally snowy weeks of early 2010 I built a redesigned version of this classic filter which was used in the EMS VCS3 and AKS synthesizers in the 1970’s. With snow falling and the wonderful bubbly sound of the filter, I named this module - Snow Fall. It was a 4-pole diode ladder low pass filter using all discrete and rather old components. The Roland SH-3 filter (AM8003) and PE Minisonic 2 (AM8050) filters are close copies of this legendary design.

EMS originally (in 1970) described the filter as Low Pass and with a cutoff rate 12dB for the first octave and then 18dB per octave thereafter, with band pass filter response at medium Resonance levels and a maximum Q of 20. From early 1974 EMS updated the filter with an extra capacitor at the base of the diode ladder to provide a steeper 24dB per octave response, this appears to have changed the character of the filter. The filter frequency response is stated as 5Hz to 10kHz.

In terms of electronic design the standard filter is 4-pole but the characteristics of diode ladders makes this sound more like 18dB, and the 24dB version is really 5-pole. No matter, the filter sounds fantastic....

Visit the AMsynths web site for the full story here..." You will find samples there as well.
Be sure to see the rest of AMSynths for more DIY clones and projects.
via VICMOD

AMSynths: AM8109 Test Movie - DIY Roland Jupiter-8 VCF Module

YouTube via amsynths | August 06, 2010

"AM8109 Jupiter 8 VCF"
http://www.amsynths.co.uk/

AM8060 Module - Roland Jupiter 6 Multi-Mode VCF Clone

Full details on Analog Metropolis Synthesizers. Be sure to see the site for more DIY projects including an ARP 2600 replica.

On the AM060: "This module is a clone of the Roland Jupiter 6 voltage controlled filter which comprises two 2-pole OTA filters in series, and was launched in 1983. Each 2-pole filter can be switched into either Low Pass or High Pass modes providing three VCF modes all with variable resonance:

* 24dB Low Pass Filter
* 24dB High Pass Filter
* 12dB Band Pass Filter"

Update: "The PCB is 80x100mm, and currently available in 15V format. I plan to have a limited run of completed 12V EuroRack modules in the summer, thanks to a Roland MKS10. The web page now has the project notes and Eagle CAD files for download.

http://www.amsynths.co.uk/Filter_Bank2/AM8060/am8060.html

Regards - Rob
www.amsynths.co.uk"