Wednesday, 28 October 2020

Testing out a MFOS Sound Lab Mini Banana Synth - Elk Electronics

 Thanks to Ed for testing out one of my old Banana Synths.
 
It's a MFOS Sound Labs Mini Synth.
I've had this for a decade at least and it still sounds great. 
 
Some pics 



This test is preparation for a future synth lecture & workshop teaching basic Modular Synthesizer concepts 
The class will be held on the 21st November at Elk Electronics (Crown St, Wollongong. NSW, AUSTRALIA)
 
We will also be using many other synths in the demo including Eurorack. 
 
This will be great for you if you are new to synths and would like to find out how the various components fit together. For more experienced synth users, it would be great to have you share your experience - maybe you have a synth you would like to bring along.
 
You are very welcome to bring along a synthesizer that you would be happy to have on display or demonstrate during the Session. We just ask that you please let us know what you are bringing so that we can coordinate these things.

 

Sunday, 25 October 2020

EMS Synthi E - VCO sequenced with a Korg SQ-1

 The Synthi E is quite a rare synth.
I think there are only about 200 of them around.
I understand, the year of production was 1975. Designed by Tim Orr 
(Tim also designed the EMS Vocoder 5000, worked for AKAI & designed the Powertran Trancedent 2000)

The Synthi-E was produced as an educational tool and appears very simple at first glance.
Just one filter, EG, Oscillator, LFO, noise, inverter, VCA and mixer.
 

Apparently, "a complete teaching course has been built round it allowing teachers and students to learn the techniques and background of electronic music and its production". 
When I first bought this I didn't have a keyboard and the ribbon controllers were not functioning very well.
I'm sure there was a manual however it alludes me (as do the schematics).
 
 
Patching doesn't use a matrix. Just very simple cables. 
I only had a limited supply of the original cables, but discovered that 2mm banana cables also worked just fine. They have the added advantage that they are stackable.
 
 
From  what I can decipher from the internet, the general signal level at the patch nodes is  3V P-P.
This however, seems to vary quite a bit depending on which module you are talking about.
It should be safe however to patch 2Vp-p voltages. (I don't have any definitive data regarding this so do so at your own risk).
The Korg SQ-1 is ideal for this.
You can limit the voltage range to 1V, 2V and 5V/oct.
I found the 2V setting provides a good range of pitches 
 
 
Remember to also set the SQ1 to Negative (S-trig) gate.

You will need to ground the sequencer with the synthi. The scope output is prefect for this.
The sleeve is ground.



Here are the specs of the VCO:
Total frequency coverage: 1 Hz to 10KHz.
 
There are 3 waveforms available: Sine,Tri, Rectangle.
All three waveforms are accessible simultaneously and can also be
used as modulation sources.
Sine wave distortion: 5% THD (TYP)
Triangle symmetry (rise and fall): 3% at 1 KHz.
Rectangular wave mark space ratio voltage control range: 0 to 100%.
Two CV inputs: Width & Frequency
Interestingly, the frequency CV input has two flavors .. 1/2 and 2.
There is a trimmer to fine tune the V/Oct scaling.

Deviation of voltage control of frequency from ideal exponential law
Over musical range 100Hz—2KHz: .8% (B.S.L.)
Over audio range 10Hz — 10KHz: 1.7% (B.S.L.) 
General short term stability. Drift at 1 KHz: 2% per hour.
 

I really like the sound of the filter... squelchy ... almost acid like.



Instagram post


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If there are any mistakes, errors or omissions, do let me know.

Cheers J

Sunday, 18 October 2020

Erica Synths Syntrx and an original Synthi AKS.

 Part One of the shootout between the Erica Synths Syntrx and an original Synthi AKS.

Simple patches are compared highlighting a single Oscillator, FM, RingMod, Filter, Reverb & Noise.

This video simply compares Sound and Timbre, not the functionality, extras or differences in the Matrix implementation.
It's important to remember that no two original Synthi' are the same. I have a Putney & AKS and I can
never get exactly the same sounds from each even when the patch is identical.
The mechanical pins used in the matrix have different resistances .. and just these can alter the sound. 
 
The Erica Matrix of course doesn't have these "limitations" ..... though I like to see the inconsistency of the old fashioned EMS matrix as part of its charm.
 (Part Two will look at a Putney VCS3 and some more complex patches).

Thanks to Allinaire for the use of his new Syntrx.

Saturday, 17 October 2020

EMS Synthi-E - Trapezoidal Envelope Generator

 Playing around with the Synthi-E's envelope shaper.


It's an unusual beast.
 

We are all used to a 4 stage ADSR style of envelope.
EMS however used the Trapezoidal Envelope.
This also has 4 stages. They are Attack, ON, Decay, Off.
 
The Synthi AKS uses knobs to adjust the 4 stages, and can be set to
"manual" or "free run" triggering.
The Synthi E is much simplier. 
Attack (rise) & decay (fall) are set using the rise & fall sliders.
On /off are determined by the gate length.
 
The 3 variants of the envelope are available simultaneously. 
Variation 1 : attack & decay are adjustable using the sliders.
Variation 2 : attack is variable, but decay is fixed (fast)
Variation 3 : attack is fixed (fast) and decal is variable.

Connecting a gate to the second black input form the bottom  (bipolar "?") will make it behave as if it were an LFO. 
The envelope starts on both the rise & fall of the gate ... I think this is the equivalent "free run mode".

The gate itself is interesting ... it's a short to ground.
Touching a cable with your bare fingers will produce the required gate.
This is essentially an S-trig. 
Manufacturers like (vintage) Korg & Moog use S-trigs.


 
About the patch:
I'm using a square wave to trigger the EG.... which is opening /closing the VCA.
The filter is in self oscillation mode.
 
If you still want to trigger the Synthi' gate with eurorack, you will probably need a V-trig to S-trig converter. I haven't tested this myself. These synthi's are rare and expensive so be careful if you plan to try this.
BTW, I don't recommend plugging anything into your synthi which is not from EMS.
 
The Synthi E's envelopes seem to have a 1.7Vpp range.
 
 

Analogue Systems still produce a Eurorack version of the Trapezoidal Generator.
(Thanks to James from Synthwerks for the info) .
"AS make both it (RS-510e) and the EMS filter module (RS-500e) both 
now with universal mounting hole and power connector for both AS and 
Doepfer systems".
Erica Synths also has a Euro format envelope generator module... It looks like
two EMS Synthi functionality inspired looping envelope generators with simultaneous unipolar (0V - 10V) and bipolar (-5V - +5V), VCA, Noise generator and Sample & Hold.  ...... That's nice :-)

 
I wonder if it's inspired by the Synthi 100, who's envelope shapers also have dual trapezoidal outputs.
The Synthi 100's envelopes however differ in that they have 5 triggering modes (Signal threshold, Hold, Single Shot, Free run & Gated free run) & the 4 stages are Delay, Attack, On, Decay.


The addition of a second output for each of the synthi 100's trapezoidal generators is pretty neat.
The second output lags behind the first by one quarter of a complete trapezoidal cycle.

 Links

Elk Elektroniks - Elektron Monomachine repair

 URL of post


Elektron rhythm machines are super fun! They are built solid and have a logical interface. This one needed some repairs...

Posted by Elk Elektronik on Tuesday, September 15, 2020


Contact Ed for further details.


https://www.facebook.com/elkelektronik/ 

Friday, 16 October 2020

Allinaire - Hacking into Max for Live Video Device

Allinaire latest track. He told me the video was produced using a 'hacked' or modified existing Max for live video device (details to follow). Learning by experimenting with existing Max devices is a valid way of learning. Whereas other prefer to start from scratch Allinaire dives right in and stands on the shoulders of experienced programers. He calls it 'Circuit bending existing code'!

 

;;;;; 

Allinaire - youtube channel


Saturday, 10 October 2020

Elk Electronics DIY Workshop - Elmyra Synth

Some pics from yesterdays DIY electronics workshop.
 
We started with a beginners synth build  : The Elmyra by Neutral Labs.
 

The workshop was held in Wollongong , NSW, Australia.
 

 
Youtube : full kit build
 



 

 
  The Elmyra uses a Teensy microcontroller.
 

Thanks to everyone who attended.
Such a satisfying day.
We all left with a fully functioning synth that we built ourselves.
 

..

The next Electronic Music workshop will be held in November in Wollongong ... 
Sat Nov 21st.
Address: Shop 266 Crown St, Wollongong NSW 2500
It will probably cover modular synthesizers .. focusing on Eurorack

Thanks for organising this workshop Ed.
We all had a great time.