New AMSynths DIODE-01 Based on the Roland System 101 + 102 Extras

AMSynths, makers of various Roland clone modules is coming out with a complete desktop synth based on the Roland System 101, named the DIODE-01. Some info and pics follow.

"NEW SYNTH ALERT: Here is the aluminium panel for the AMSynths DIODE-01 analog synthesizer. It is an accurate replica of the Roland System 101 with its diode ladder filter, combined with the extra features of the 102 (Ring Mod, S&H). The prototype will be ready in October. What do you think?"

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AMSynths March News Letter

"Newsletter March 2013
Latest News: At last a new AMSynths newsletter after nearly 6 months! We can only say we have been really busy....here is the latest news and plans for 2013.

Xmas was a busy time and we shipped over 25 modules to customers and completed the design of the AM8328 Mirage Filter - which has been shipping since early January. Customer demand has increased in 2013 , so we are we have restarted our sales to the SDIY market with panels, and blank PCB's now in stock and on sale in the online store. We have also added a free online reservation system here from the web store, so customers can be sure they will get a module. Production volumes have slipped back in February due to various holidays and a busy day job, but March and April will see more modules shipping and new products arriving.

Module Plans
The popular AM8012, AM8075, AM8071 and AM8109 filter modules are in production but there is a queue of reservations to satisfy before they will appear in the online store in large volumes. The new AM8328 Miarge Filter will see another 10 modules built in March, along with the arrival of the AM8044 VCF & VCA which has cleared testing and is going into production. It is the first module we have implemented with both a filter and final stage VCA, so all it needs is a dual ADSR and dual VCO to create some fantastic sounds. A special Dave Rossum tribute VCF, the AM8040 will be launched as a PCB sets for the SDIY market initially. It will have both 2 and 4 pole modes, and can use either a rare SSM2040 chip or the HM2040 replica. If there is sufficient customer demand it will be introduced as a completed EuroRack module based on the HM2040 chip, it will have the same panel design as an AM8109 JP8 VCF and provides the sounds of the SCI Prophet 5 early models as well as the original E-mu Systems Audity 16 voice synthesizer.

The versatile dual SVF filter, the AM8060SE, is completing it's first production PCB build this weekend and if this goes ok we can start manufacturing modules for a 24 March 2013 launch. I have put some photos of the prototype on the web store, and I will add some new demos soon. The Dual ADSR AM8140 is the other product launch for late March, with a first production build to check everything is ok. Then there is the AM8005 Diode VCF to finalise on 12V and get into production, I know alot of customers are waiting on this module, so it is top of the list!

The dual VCO's remain in development with the ARP version (AM8027) about to go into a final production stage, the reason for the delay is we had to find some switched vertical jack sockets that fit the design, which we now have. The JP8 Dual VCO is at design stagee with a few more months work to get all the extra features loaded, such as the quantiszed picth knob (using a PIC) and the in-built analog LFO. The VCO designs have been switched to dual rather than single to reduce the overall costs of 2 VCO's, which everyone needs.

A set of new modules planned for 2H2013 are waiting on the arrival of the right log response vertical pots from Small Bear. This includes a dual linear and expo response VCA (AM8164) and the AM83272 Ambient VCF (using the CEM3372). The AM8706 LFO can now more forward with the right vertical jack sockets, so expect this module and the AM8019 ARP style VCA to appear by mid 2013.

Customer Feedback
AMSynths really appreciates customer feedback and ideas. Just send an email to me at sales@amsynths.co.uk. The recently launched AM8328 Mirage Filter was all down to one of our customers, Adam, asking us to make this module using CEM3328 chips. This had led onto the idea of a Key Track pot on some new modules (AM8040) which enables filter cutoff to be varied up or down by the note played on the keyboard. So do let me know of the features and modules you would like to see. For example we have new ideas floating around at AMSynths HQ, for an audio mixer, ring modulator and noise source module, which kinda replicates the middle of an Roland SH-5 (AM8002) and a programmable ADSR with 64 patches which can be voltage controlled (AM8056). And if anybody on the list writes coolt DSP code, we would love to launch a Z-plane digital filter.

Future Plans
Our biggest problem is manufacturing enough modules to meet the increasing customer demand, and that is before we do any press marketing or shows! So we are completeing reaseach into larger scale assembly and manufacturing for some modules, to see what it does to the margins and retail prices. AMSynths have launched a partnership with SynthCube, where you buy my designs in MOTM, FracRac and other non-Euro formats. The AM4023 2 pole OTA filter is the first SynthCube module to hit production, but many more will follow in 2013. The web store will move to a new platform in late 2013 to provide a better presentation and more features. We will continue to operate 2 web sites, one as a secure store and one as a blog and information portal. And Finally, many thanks to all our customer for purchasing AMSynths products and your patience in trying to buy more. I will get more newsletters out this year, timed with product launches."

Left: "AM8328 VCF PCB Set

This is a PCB kit for the AM8328 Mirage VCF which enables you to build a EuroRack Module with a 16-pin 12V Doepfer Bus power connector. It may also work on 15V but I have not tried it out.

The AM8328 is a 4 pole Low Pass Filter that uses the CEM3328 filter chip to produce a amazing sounding VCF.

Project Notes:

Kit Components
The AM8328 PCB kit contains:
AM8328 POT PCB (ROHS compliant, blue solder mask).
AM8328 VCF PCB (ROHS compliant, blue solder mask).
You can also purchase Pot Brackets (x7), Jack PCB and an AMSynths factory AM8328 EuroRack panel.
Kits EXCLUDE the CEM3328 chip. You will need to locate one on eBay. An Ensoniq Mirage has 8x inside."

Above: "AM8328 The Mirage Filter

This module is based around the CEM3328 4-pole Low Pass Filter chip that was released in 1984, as one of the last filter chips and with some great features. It has differential signal inputs, an accurate exponential scale over 14 octaves and voltage controlled resonance. It has a unqiue feature, the signal level is automatically increased as the resonance goes up, thereby avoiding the usual signal level dropping off as resonance comes in. The CEM3328 was late onto the analog stage, just before digital filters appeared, so it only made it into the BIT01 and Ensoniq Mirage (and a few drum machines). So this chip has never really seen action, and was never under analog pot control, just lonely digital parameter access! In the Mirage it was not even allowed to oscillate…..We just love giving it a new lease of life in a new analog module!"

AMSynths Newsletter - AM8019 Athena VCA & AM8328 Mirage VCF

"Newsletter March 2014
Latest News: Spring has at last arrived in the UK with the first few days of sunshine after many months of rain and floods. Over the last few weeks we have been developing new exciting modules, as well as refining some of the existing range, and shipping modules to customers! The new AM8105 Super JX VCF & VCA will be available in April, providing a really nice sounding 4-pole VCF with smooth oscillation and a VCA, all in one EuroRack module. It uses the IR3R05 Roland chip that appeared in the legendary MKS80 and MKS70.

Updated AM8012 and AM8075 filters will be shipping in April, with new vertical jacks and revised electronics, along with the new AM8125 Analog VCO which has 3 waveforms and sync.This month we are shipping AM8019 VCA's, AM8109 VCF's and a final run of AM8319 Diode Array Filters. The AM8019 is in stock now, the others will appear over the next 2 weeks, along with some AM8140 Dual ADSR's.

In the workshop we are continuing to develop the amazing Athena synthesizer, a PCB and panel project for Synthesizer DIY, as well as testing dual VCO EuroRack modules and a new LFO module based on the Jupiter 8 with variable delay and five waveforms.

This year we plan to continue to bring new modules to market and to increase the production volumes from the 115 we shipped in 2013.

Best Wishes and thanks to all our customers.

Rob Keeble
Owner and Designer, AMSynths"

http://www.amsynths.co.uk

"The AM8019 is a replica of the ARP 2600 Voltage Controlled Amplifier, which is a transistor VCA dating back to the ARP2500 and 1970. This EuroRack module makes use of matched transistor arrays and a high quality buffer Op Amp at the output stage. The VCA is designed to be used with the Athena VCO and VCF's, enabling a replica of the 2600P or Odyssey in a rack format to be achieved.

This 16HP wide module has have enhanced from the original 1970 ARP design with high quality components and additional control inputs, the circuit has been adjusted to provide a better HF response than the original design. The VCA is based on a Wilson Current mirror, and the AMSynths version uses matched transistor arrays to replace the discrete transistors. There are two signal inputs with level controls, one inverted and both pass through a 470nF capacitor which acts as a high pass filter at 10 Hz, thereby blocking any DC offsets.
The ARP 2600 VCO's have a DC offset which is effectively removed via this input (post VCF mixer) and thereby eliminates ADSR thumps. This means the AM8019 is not designed to be used as a ring modulator - see the AM1005 for this application. There are 2x linear control inputs and 2x exponential control inputs, all adjustable by front panel slider potentiometers. There is also a GAIN slider pot on the upper right hand panel, with an amber LED output signal level indicator. The slide potentiometers have been especially manufactured for AMSynths and we have used coloured plastic caps to give the VCA that vintage look and feel.

The discrete transistor VCA is a product of the 1960's before integrated circuits were affordable and the use of the CA3080 OTA chip. This modern and updated version takes the design into the modern era and provides a versatile and clean VCA. The Wilson current mirror and discrete VCA is used in a number of other AMSynths modules such as the AM8047 Multi-Mode Filter."

AM8122 Dual SVF (100M)

AM8122 BRIEF DEMO video upload by AMSynths

via AMSynths

"Overview The original Roland 100M (1978) has only one type of voltage controlled filter, 24dB low pass. This rather limits the range of sounds that can be created with the synthesizer and it is strange that Roland never ported the 703 2-pole OTA SVF into the 100M format. The AM8122 closes this gap and provides two 2-pole State Variable Filters in one 16HP module.

AMSynths Design The AS3320 chip is used to create the SVF, rather than the CA3080 OTA in the original 703 module. This is partly down to the limited PCB space for two filters and partly because the 3320 chip in SVF mode sounds very good, think Oberheim OBX. An alternative approach would be to build a dual Jupiter 6 SVF with AS3109’s, but this is tricky to achieve given the limited PCB space and we already produce a Jupiter 6 module – the AM8060 module.

The AM8122 circuit reuses the 2-pole SVF in the AM8325 and adds the BP mode and voltage controlled resonance. The third CV input is used as the Resonance CV input. The front panel design follows the Behringer 121 module with signal and CV input trimmers, frequency and resonance on 30mm sliders and green and red indicator LED’s.

Each filter has two outputs, with a slide switch selecting which filter output goes to which jack socket. The upper jack socket (OUT) can be set to either LP, BP or HP and the lower jack socket (REV OUT) follows the reverse (HP, BP, LP). This approach ensure the LED’s track the filter mode selected by the switch, whilst still providing individual outputs of each filter mode. The three signal inputs of the second filter are normalised to the outputs of the first filter (HP, BP and LP), so that the filter modes can be mixed together and filtered again!

Front Panels The panels use the same manufacturing process as the earlier AMSynths 100Mmodules, with a white silk screen over a dusty grey powder coated panel.

Outcome & Availability The module and panel were designed in December 2022. In 1Q23 the prototype PCB’s were debugged, with the revised LED drive and increased filter output levels so they are all the same (10V p-t-p). Production modules will be availble in 3Q23. The AM8122 will be the first AMSynths module to use SMD manufacturing processes (JLCPCB) for the PCB’s."

Roland Jupiter-6 Synthesizer Filter VCF Build - Demo 01

Published on Feb 7, 2017 gstormelectro

"Audio and Video by G-Storm Electro c.2017

This video demos a Roland Jupiter-6 synthesizer clone filter VCF. This breadboard build took two days, and for me is the largest one I've built yet. Does this circuit sound as good as the original? You be the judge. Anyway, I really wanted to hear what it sounded like before deciding about building my own module.

I came across schematics for the Roland Jupiter-6 at amsynths.co.uk. They actually sell completed modules and PCBs, however they seem to be perpetually out of stock. This will be a nice companion multi-mode filter to go next to my SEM module. IMHO the SEM sounds buttery and creamy, and the Jupiter-6 is a complete savage with outrageous low end."

Update:

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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."

Behringer's Cool Audio Clones the Roland BA662A

This one is in via Jose of sonicplug.com, spotted on Future Music Spain.

Per Behringer:

"Great news. Our sister company Coolaudio who designs mixed architecture semiconductors has just released the holy grail of synthesizer chips - a clone of the BA662A.

It is the THE chip responsible for the unique sound of so many classic synths.

Not only has Coolaudio cloned the BA662 “A” version, which is the highest specified version, they also managed to greatly improve noise performance and included even two chips in one packaging.

We’re beyond excited:-)"

The BA662 was used in the Juno-6/60/106, JX-3P and TB-303, Jupiter-4, and Jupiter-8.

via AMSynths:

"The BA662 is a custom made DC controlled variable transconductance amplifier (or OTA) that Roland had manufactured by Rohm from the late 1970’s and is now obsolete. There are two types of chip with different suffices; the A version has been selected for lower offset than the B version. They are further classified by gain/gm. The BA662B can only replace another BA662B, whilst an A can be used in either application.

To quote Roland from the 100M Service Manual: 'Color has great importance in circuits of some models'. However there is nothing mystical about the sound of the BA662, it is just a reasonable good OTA chip which is often carefully matched and selected."

Note Open Music Labs made a clone as well (last edited in 2014):

"They just don’t make IC’s like they used to, and is this case, they just don’t make them at all! So, we decided to bring the BA662 back to life, in all it’s Frankenstein glory. This is a direct replica (to the best of our knowledge) of the now obsolete OTA, made from well matched transistor pairs. It can be used as a drop-in replacement for most applications. So if you have an old synth or effects pedal that is no longer synth’ing or effecting, this just might be the cure...

The BA662 clone is a replica of the very rare BA662 OTA which was used by Roland in a number of their synthesizers and effects pedals from the 80's. The internal wiring of the BA662 was reverse engineered from an original part by applying external voltages and currents, and seeing how it responded. For example, you can find out how many transistors are at the top and bottom of the output stage by measuring the saturation voltages. From this it was found that they used Wilson current mirrors. Also, by measuring the current consumption under varying signal levels, the value of the emitter resistor on the buffer stage was found. A fair bit of the anaylsis was based on recollections from seeing a datasheet a long time ago, and the fact that OTA's have very similar topologies."

AMSynths AM8400 Jupiter-4 VCO Clone Waveforms

AM8400DemoMovie Published on Mar 11, 2018 AMSynths

"Quick demo of the various wave shapes from my Jupiter VCO clone, note the sawtooth waveform, is composed of curved steps."

via AMSynths:

"This is replica of the VCO in the Roland Jupiter 4, their first polyphonic synthesizer introduced in 1978. The original VCO is a unique design based around a 555 timer and a CMOS divider chip, which was not seen in any other synthesizer. The Jupiter 4 is famous for its powerful sounds and efficient controls. The constraints of microprocessors in 1978 mean there were only 16 sliders that could be memorised, which limited the functionality of the VCO to 4 octave range and 3 waveforms.

This VCO is the sound of early Human League and Depeche Mode albums.

Detailed Description

The AMSynths circuit is very close to the original except for a new Tempco based matched transistor pair rather than the obsolete heated uA726 chip, as the exponential generator and variable slider controlled Pulse Width rather than a 4-way switch.

The waveform shapes are created from the 555 timer which generates square waves that are divided down for the lower ranges. These square waves are used for the square wave output and are perfect and stable 50/50%. They are also approximated into a sawtooth which has as many steps as the range (16′ has 16 steps, 2′ has just 2 steps). The sawtooth wave is therefore not perfect and is made up of steps, this creates a different sonic shape as you change octave. The pulse width wave is created from the sawtooth rather than the square wave, and therefore has some variability in width, rather than being totally stable. Adjusting pulse width is effectively quantised by the sawtooth steps and jumps from one setting to the next rather than being smooth.

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AM8075SE Athena VCF

AM8075SE Athena VCF Demo by AMSynths
via AMSynths
"Back in the 2004 I replicated the ARP 4075 VCF module using exactly the same design and sold a few PCB's to customers as the AM4075. I also licensed the design to Bananalogue, and you can still buy these modules on eBay all these years later. The licensing deal enabled me to buy a new PC and greatly speeded up my design work, which is all done in Eagle CAD. Whilst the filter sounded good, I wanted to improve and simplfy the design when I started up AMSynths. I also wanted to use slider potentiometers and introduce a HPF - the idea of a Special Edition version (SE) was born.

Athena The AM8075SE filter is the first module to be launched as part of a complete modular analog monosynth. VCO, VCA, ADSR etc will all follow. Athena is the greek god of inspiration.

The Special Edition At the end of 2011 I had a new prototype on the test bench, implemented with matched transistor pairs, reworked LM3900 power supply and cut out the rejection trimming circuit as this was no longer needed with matched transistors. Op Amp buffers before and after the filter core were added, as the one complaint from the original AM4075 was that it was rather quiet as it had no buffer circuits and worked best on 10V audio signals.

I added a 1-pole high pass filter based on the classic Roland OTA circuit rather than the awful design in the Odyssey. Slider potentiometers are used through out and after some adjustments to work on 12V power the VCF sounds fantastic! The matched arrays make a great improvement along with using high quality filter capacitors. The slider caps are the same as in the Odyssey Mark 1 and 2, and they will appear through out the Athena synthesizer (and yes I do have pink caps!).

The moudle went into production in July 2012 and the first batch sold out quickly. Further batches will be manufactured, as there are no rare parts to find.

AMSynths Panel The panel is professionally manufactured in 1.6mm thick alumnium in Germany with black lettering. The module is EuroRack sized and fully compatible with many other EuroRack modular synthesizer systems such as Doepfer."

AMSynths Update & AM108 Jupiter-8 / Jupiter-4 Filter

I just received the AMSynths newsletter. The latest news is that the AM8319 Ring Wraith will be in production in early January, and the AM8005 Filter Cube, AM8047 UAF and AM8027 VCO will follow. The newsletter also mentioned their current modules which you can find on their website.

The one module I realized I haven't posted yet is their AM108 Jupiter-8 and Jupiter-4 filter pictured here.

"This module is replication of the Low Pass Filter from the legendary Roland Jupiter 8 and 4. This is a 2 and 4 pole OTA design that Roland first used in the Jupiter 4 in 1980, replacing a discrete version of the filter which took up more PCB space.

This is a warm sounding filter with smooth frequency control and a resonance that gradually increases up to full self oscillation, a sound very reminiscent of the early 1980's.

The difference between 2 and 4-pole modes is not dramatic, with the 2-pole mode providing a more gradual cutoff slope and silky sound."

Other modules in development include:

AM8012 ARP2600P transistor VCF
AM8027 ARP2600P VCO
AM8044 Cascade LPF and HPF
AM8047 ARP2500 Universal Active Filter
AM8475 Odyssey VCF and HPF
AM8706 Titan Modulation Source
AM8280 CS80 Dual SVF
AM8104 Roland JP VCF + HPF"

AMSynths SUPERBOOTH Module News - April 2022

"Getting Ready for SuperBooth 22

We are hard at work developing new modules for launch at the best synth show of the year - Superbooth 22. We will be announcing the red faced AM8101 filter [posted here], a replica of the low pass filter in the Roland SH-101, as well as the AM8102 SH-2 style filter [below].

The AM8109 and AM8060 Jupiter filters are being relaunched - 10 years after they were introduced, with Special Edition and slim 10HP versions. AMSynths will also be announcing SH-101, Jupiter 6 and 8 VCO's to pair with these filters alongside the current Jupiter 4 VCO and VCF."

This module is faithful replica of the filter from the legendary Roland SH-2 that was released in 1979. The AM81012 is a fantastic sounding 4-pole low pass filter with that unmistakable Roland filter sound in a narrow skiff friendly, Eurorack module.

The module use an Alfa Rpar AS622 chips in the filter core (BA662 clones) and high quality polpropylene filter capacitors. The design includes buffering Op Amps to interface to Eurorack modular levels. The filter does not have Q compensation but the signal level does not decrease dramatically with higher Q settings. The resonance is smooth and controllable into self-oscillation, and the filter will oscillate from 20Hz to 20kHz.

There are slide potentiometers (with LED's) for adjusting the Frequency Cutoff, and the frequency modulation from Keyboard, LFO and Envelope CV signals, There are rotary potentiometers for adjusting the mix between two audio inputs and Resonance. There is a small slide switch to select whether the envelope CV input is Normal or Inverted.

The AM8102 is hand built with high quality components, including Wima polypropylene capacitors, Alpha potentiometers, and TR808 style control knobs.

There are six 3.5 mm jack sockets on the front panel:
2x audio inputs
3x frequency CV inputs
1x audio output
The module comes with a set of M3 mounting screws and washers, and a standard Doepfer power cable.

AMSynths Update: AM8060SE JP6 VCF & AM8044 VCF & VCA

AMSynths Newsletter July 2013

"Latest News: Over the last few weeks we have been busy building modules for customers, as well as completing the testing of the exciting new AM8060SE JP6 filter, and a new VCF, HPF & VCA module the AM8105. Stock levels in the web store will start increasing again, and we are building AM8109 JP8 VCF, AM8140 Dual ADSR, AM8044 and AM8328 VCF's over the next month. So if you are after one of these modules, they will be in stock.

We will launch a very limited run of AM8320 VCF modules that use the CEM3320 configured to replicate the sound of SCI Pro One in late July. Details are here. If you wish to reserve one just reply to this newsletter. And finally, during August we should get round to launching some VCO modules, you can see the E-mu Systems Simple VCO that we have redesigned and replicated as the AM2210 here. Next projects to complete in the summer are both a Roland JP8 VCO and the ARP dual Athena VCO.

Best Regards
AMSynths"

"AM8060SE JP6 VCF
This new module is being launched in July with a batch of 10x modules going out initially to customers who have reserved the module. This is a dual SVF filter with low, band and high pass modes controlled by original Roland JP6 switches. The module goes into self oscillation at high resonance setting and we have carefully trimmed the design to ensure this is controlled, as SVF's can produce a huge signal level when oscillating, The original AM8060 used hard to locate IR3109 chips but we are now using SSM2164's which means we can build all the modules that customers want. Sound demos will be up on the web site soon."

"AM8044 VCF & VCA
The AM8044 module has a 4-pole low pass filter, as used in the Korg Poly 6, followed be a precision VCA. Just connect a couple of VCO's and a Dual ADSR (lie the AM8140) and you have a complete synth! A nice warm filter coupled with a very useful VCA, buy one in the webstore today at 125 GBP. Here is the link."

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"

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 100M Module Update

video upload by AMSynths

"An update on the new AMSynths range of Eurorack modules that re-imagine the Roland 100M prototypes of 1978, and add exciting new modules and features. Seven modules are in development with release dates from May 2023. New powder coated panels with white silk screen lettering have been developed over the last few months, along with custom components."

AMSynths 2023 Module Plans

video upload by AMSynths

"AMSynths plan to release a new range of Eurorack modules in 2023 inspired by the Roland 100M. Thsi video provides an overiew of the first five modules that are in development. They are a combination of originals being reworked and expanded, prototypes replicated and many new ideas. These accurate designs, that use high quality components, will truely inspire new electronic music."

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.

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/

New AMSynths AM8109SE Low & High Pass Jupiter 8/4 Filters Eurorack Module

"This module is replication of the Low Pass and High Pass Filters from the legendary Roland Jupiter 8 and 4. This is a 2 and 4 pole OTA design that Roland first used in the Jupiter 4 in 1980, replacing a discrete version of the filter which took up more PCB space.

This is a warm sounding filter with smooth frequency control and a resonance that gradually increases up to full resonance, just before self oscillation, a sound very reminiscent of the early 1980's. The original Jupiter 8 filter did not self oscillate, and we have retained this configuration. However the customer can set the filter to self oscillate by adjusting a PCB trimmer on the rear of the module.

The difference between 2 and 4-pole modes is not dramatic, with the 2-pole mode providing a more gradual cutoff slope and silky sound. The high pass filter provides a gradual cutoff of low frequencies.

The AM8109SE is a new version of the 2010 AMSynths design, with slide potentiometers and a skiff friendly module depth of 35mm.

Eurorack Module: 14HP wide
User Manual: AM8109 Quick Start Manual

This module is an accurate reproduction of the Jupiter 8 low pass voltage controlled filter, using the AS3109 OTA chip in the filter core, as well as the high pass filter that uses an AS662 chip. The design has been updated to use modern components with high quality capacitors in the signal path. It delivers a very warm and smooth sound.

There are front panel sliders for adjusting the Cutoff Frequency and Resonance of the low pass filter, and level control of 3x control voltages (MOD, ENV and KYBD) and 2x audio signal inputs. The high pass cutoff frequency is adjusted using a rotary potentiometer with an original Boss coloured control knob.

There are five 3.5mm jack sockets at the base of the black anodised 2mm front panel;
2x audio inputs
3x control voltages
1x audio signal output
There is an audio output jack at the top right of the module. The slope of the filter can be switched between 2 and 4 poles using a small slide switch, and the envelope CV signal can be inverted using a second slide switch.

The module comes with a set of M3 mounting screws and washers, and a standard Doepfer power cable."

AMSynths AM8109 JP8 Low Pass VCF & June 2012 Newsletter

via AMSynths

"This module is replication of the Low Pass Filter from the legendary Roland Jupiter 8 and 4. This is a 2 and 4 pole OTA design that Roland first used in the Jupiter 4 in 1980, replacing a discrete version of the filter which took up more PCB space.

This is a warm sounding filter with smooth frequency control and a resonance that gradually increases up to full self oscillation, a sound very reminiscent of the early 1980's.

The difference between 2 and 4-pole modes is not dramatic, with the 2-pole mode providing a more gradual cutoff slope and silky sound.

EuroRack Module: 14HP wide
User Manual: Download PDF

Our Price: £125.00

Stock Status: New Stock in mid May
Availability: Reservations being taken now."



You might remember this one from this video back in September of 2010.

Via the June 2012 Newsletter:

"Latest News: We have had a busy few weeks shipping modules and completing the design of the AM8075SE Athena VCF and the AM8005 SH-5 VCF ready for launch in June. Stocks of the AM8705 Dual ADSR and AM8071 SnowFall VCF have run low, but we will have new stock in June. The AM8109 JP8 VCF consistently sells out but we have enough parts for another 20 to be shipped in 2012.Initial shipments of the AM8319 Diode Array VCF have started and a new iPad catalogue has been launched along with more SoundCloud demos. Work continues on completing the AM8027 VCO and AM8047 UAF, and a new online store will be launched later this month to enable customers to purchase straight from stock and with automatically calculated shipping."