JonDent - Exploring Electronic Music

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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#emssynthi #ems #synthie #synthi-e #synthesizer

A post shared by jono (@dj_jondent) on Oct 21, 2020 at 2:32am PDT.....

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.

Allinaire - youtube channel

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

+ The Synthi AKS Envelope Generator

Elk Elektroniks - Elektron Monomachine repair

URL of post

https://www.facebook.com/elkelektronik/posts/2724728094439906

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.elkelektronik.com.au/

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'!