Saturday, 17 January 2015

Bently Rhythm Ace test video

This is a test video of the Bentley Rhythm Ace sync Mod.
Here is my previous post with the mod details:
djjondent.blogspot.com.au/2015/01/bentley-rhythm-ace-fr-8l-roland-tr77.html


The Bentley is almost identical to the Roland TR 77 however its sync input
appears in a different place.



We are testing the drum using a combination of modules: lots of Buchla
for the background sounds but the actual drum is triggered from a Eurorack format Flame Arpeggiator sending +5V clock pulses


Seems to work perfectly. More mods coming soon.



Korg PS 3100 - Demo 2

We are putting together some audio for a movie soundtrack.
So Paul and I are experimenting with the Korg PS 3100 today.


What's not to love about this lumbering beast of a machine.

There are 48 keys and each one has its own oscillator, filter and envelope generator.
The resonator (3 band pass filters) still astonishes me with its richness.
I really should play this more often.

The PS 3100 came out in 1977 and was one of the original polyphonic synths. Moog had the  Polymoog, Yamaha had the CS80, and Oberheim had their SEM-based  two voice, four voice and eight-voice machines.


The PS 3100 has only one VCO per voice.This sounds on paper to be a bit weak, but when you can play 48 VCOs at once this isn't really a problem in my opinion. In addition, Korg added the "Ensemble" setting which is like a chorus. This really thickens up the sound.


This is a old video of mine:



 Apart from the resonators and ensemble another really special quirk are the envelope generators.
We have the usual ADS (attack,decay,sustain) knobs, but instead of a knob for R (release) we have some switches.

We have Damped (very short), Half (0.5 sec) & Release (R = the decay knob setting).....These are envelope presets....... You don't see these very often & I kinda like these (esp the Damped... very short one).




Friday, 16 January 2015

Bentley Rhythm Ace - FR-8L - Roland TR77 - Mods - Adding clock sync

We (Cobramatic & I) purchased some Bentley Rhythm Ace  & TR-77 drums the other day.
Some we got to mod and some to just preserve in their vintage glory.

The TR77 and the Bentley Rhythm Ace are Roland's very first drums so we feel that they have
a special place in the history of electronic music.
They are both beautiful & warm sounding analog (1972) machines with discrete components.
Thus they are perfect candidates for modding.
One of their drawbacks however, is the lack of a way to sync them to our modular gear.
I guess Roland never envisioned that someone 50 years into the future would want to sync them with a modular synthesizer.

BurnKit 2600 has a mod for the Roland version of the Bentley
http://www.burnkit2600.com/tr-77/
that shows where to add external clock sync.
However, after opening the Bentleys we discovered that their PCBs are slightly different to that of the Roland TR 77.

After a bit of probing we located the revised sync input for the Bentley.


 Here is a closer pic:

A +5V clock pulse will do the trick.


If you are game to open your Bentley PLEASE BE CAREFUL.

The Power Supply section to the right is exposed and will KILL YOU if you aren't careful.
If you are not sure leave the mods to a qualified technician.

 The power supply - be very careful !!


The brown PCB on the left is the voice board.... ripe for individual triggers. (a future mod)
The TR -77 uses a very basic circuit to produce the sounds. The circuit consists of just 3 main components : A resistor, a capacitor & a inductor. Called a RLC circuit or "tuned resonant circuit"
The circuit forms a harmonic oscillator for current and will resonate.

Further reading that you may find useful re resonant circuits:  
Inductor-capacitor "tank" circuit
and
Simple parallel (tank circuit) resonance
and
https://www.youtube.com/watch?v=8vu9WDjBAho


The Voice board apparently needs -5 to -12v spikes to trigger the sounds.
CircuitBenders UK has very informative site re this:
http://www.circuitbenders.co.uk/newsarchive/BRA.html

Another great site with TR 77 mods is here:
http://www.adambaby.com/studiotech_TR-77.html

Bently Rhythm Ace test video
The Roland Drum Machine History

Wednesday, 14 January 2015

Fenix 1 & 3 - sequence two


Synton Fenix 1 & 3.
All sounds are from the Fenix 1.
The F3 is purely a sequencer (on steroids).




Kumbhalgarh Fort - Rajasthan - India

Kumbhalgarh Fort is located 64 kms from Udaipur in Rajasmand district.
This is the approach by road. I was struck with its beauty. Reminds me of some of the castles I've seen in Bavaria & Spain.


The Fort was built by Maharana Rana Kumbha in the 15th century (1443 A.D completion).
The fortifications of the fort extend 36 kilometers making it the the second longest wall in the world, the first being ''the Great Wall of China''.

It's one of the few forts in history that was never conquered by direct assault and fell only once, due to a shortage of drinking water. This helped the combined armies of the Mughal Emperor Akbar of  Delhi,, Raja Man Singh of Amber, the Sultan of Gujarat, and Raja Udai Singh of Mewar to breach its defences.



This is the main entrance - called the Ram Pol.



A view of the castle from the ramparts. I would have loved to walk the entire 36kms, but that would have taken 2 days. One day I'll return for this.

The walls are broad enough to ride eight horses side by side.... 15 feet thick in some places. And there are 360 temples inside the fort complex.


The wall stretches across the Aravali Mountains.


Views from the summit of the fortress.
Badal Mahal (the Palace of Clouds)

Some of the temples inside the fortress complex date from the 3rd century BC:
300 are Jain Temples. The rest are Hindu.

Jain Temple Complex
Ganesh Temple, Kumbhalgarh Fort

Neelkanth Mahadev (Shiva) temple
I was struck by how much this looks like a Greek Temple. Alexander the Great never conquered India but his armies did reach the borders of Rajasthan in 327BC.

Quote from Wikipedia :
According to Plutarch, at the time of Alexander's Battle of the Hydaspes River, the size of the Magadha's (he was a Indian King) army further east numbered 200,000 infantry, 80,000 cavalry, 8,000 chariots, and 6,000 war elephants, which was discouraging for Alexander's men and stayed their further progress into India:
--Plutarch, Parallel Lives, "Life of Alexander"

Exhausted and frightened by the prospect of facing another giant Indian army at the Ganges River, his army mutinied at the Hyphasis (modern Beas), refusing to march further East. Alexander, after the meeting with his officer Coenus, was convinced that it was better to return.


Je Suis Charlie


Tuesday, 13 January 2015

EML Electrocomp 400 & 401

A few videos of the old EML electrocomp 400/401

Great synth / sequencer combo.

I'll be getting this out of storage soon.

...

Monday, 12 January 2015

Synton Fenix 1 - VCOs, EGs & VCAs

I though I'd upload some pics & a brief description of the VCOs, envelope
generators & VCAs of the Synton Fenix 1.

First the oscillators:


There are three VCOs. The first is the most complex with no fewer than 7 CV ins.
CV 1 is fixed to 1v/oct. We also have a CV2, PWM , sync source  & sync level input.
There is also a CV in for FM, and a CV to control the phase of the sub-oscillators.
The sub oscillators are both square an octave & 2 octs down..... great for some deep bass.




 There are 5 audio outs. - sine, square, ramp (reverse) and I've mentioned the square subs already.
The bottom dial is a phase shifter. - allows you to un-sync the phase of the sub-oscillators for added vibrato or to thicken up the sounds if mixed with other waveforms.

VCOs 2 & 3 are simplier. They have square and sawtooth waveforms with individual outs & four CV inputs
------------------------------------------

The VCAs are pretty standard:
Each have an audio  & CV input, and one out.


 The envelope generators are very different to your standard fare. EG 1 is described as a APDSR.



What's the P stand for?
P = Peak Hold.... this is a time control where the envelope is held between the attack and decay phases. (In EG2 the Peak Time is only active if the decay-release switch is set to the decay position)
In EG1 & EG2 the top pot sets the length of Peak Time.


From what I can decipher, EG1 can actually be used as TWO separate envelopes:
Top: A(P)DR.
Bottom:  a simple AD

EG 2 is like nothing I have seen before.
Firstly it has three outputs & there is no sustain control.
It has a switch which allows you to select between a APD envelope or APR envelope. We have pots for the attack time and peak hold time, plus a knob and a CV input for the Decay/Release time.

So it looks like the EG2 can be broken up into 3 separate envelopes:
EG2(a) = 1 which is the APR or APD (depends on the switch setting)
EG2(b) = 1 + 2 {a combination of EG2(a) + EG2(c)}
EG2(c) = 2 which is a APD envelope.

Goodness gracious me !!! :-)

EG3 is also very unusual.
Again, there are 3 outputs.
The upper one is your envelope.
The lower two are outs for gates (positive & Neg).

The envelope itself  has only decay & delay settings.
It behaves like a simple AD envelope with a sharp attack (immediate)

The Delay knob is a time delay. It delays the start of the envelope.
The delay will also delay the gate outputs relative to the gate inputs.

Fenix 1 & 3 - Sequence 1

The first pairing up of these two beasts.






Here is the full unedited version of the video