Monday, 17 August 2020

Friday, 14 August 2020

BMC - FM Drum - build notes

BMC25. FM Drum
 F
 sTART WITH the lowest profile components ..
usually IC sockets , resistors , etc

These are personal build notes just to help me trouble shoot should I have any probs.

 As it turned out, this was a easy build.


cAPS next


the BOM calls for these:
0.002uf 1 Poly box type.  ... 2nf  or 2000pF
I'm using a 2.2nF cap


0.02uf 1 Poly box type ...20nF or 20000pF
I'm usinh a 22nF cap instead

.01uf 7 cheap ceramic disk....10nF (103)

 sWITCHES  next ... not sure how the panel and PCB link ??

i decided to install the jacks , switches first.. Then it became apparent the the panel is held to the PCB by the pots.


Solder the pots to the PCB.




 Time for the sole LED


Jacks:
IN - tip of the input jack
CV - tip of the CV jack
OUT - tip of the output jack and switch of the CV jack to allow self modulation



Modulation Waveform Selection switch:
MS - Top lug of switch
MC - Center lug of switch
MT - Bottom lug of switch



Output Waveform Selection Switch:
OS - Top lug of switch
OC - Center lug of switch
OT - Bottom lug of switch


For a ground connection, use the center wirepad of whichever power supply you're not using.

Nice !!!

Links
Manual BOM Build notes
http://www.bartonmusicalcircuits.com/fmd/

 

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For more Euro DIY builds click here:
http://djjondent.blogspot.com.au/2017/12/diy-index.html
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Repairing a Doepfer A-140 ADSR

I stupidly plugged in the module backwards.


Shit happens .
Remember, Red Stripe Down. !!!!

 If this happens to you , don't panic.
There are only a few sensitive components.
Start by swapping out the ICs.
Thankfully they are socketed.

Just 2 of them:
This is a TL084.
Its a op-amp

This is a CD4001 CMOS chip
They are sensitive to static electricity, and is the most likely culpruit.
It's a quad 2-in NOR gate

I swapped it with one of these and the module worked again


You can :-)

Links
+ CMOS
+ Integrated circuits - packaging 
+ Opamps - basic circuits
+ Synthesizer Logic Modules - The 7 gates

Basic 4 panel Buchla setup

A friend of mine is considering entering the Buchla world and asked for some ideas about where to start.
He is considering a basic 4 unit setup.

These are some of my suggestions.
Just personal ideas ... I'm no expert but have had some experience over the last few years.

Of course he could just buy an Easel, which is a great way to begin as it has all the basic modules.
But if you're keen to buy modules, then here goes.


Before Buchla started producing half modules, this was always my preferred basic system.
It has what I feel to be the essential Buchla modules:
1. a VCO ... 261e
2. a envelope generator (EG)...281e
3. a  LPG....292e
4. a SOU (source of uncertainity)..... 266e

The 261e VCO could be swapped for another VCO of your choice .... such as a 258, 259e,
or a 100 series such as the 158 or 144.

Basic system 2:


We have added two half modules the 291h & 292h.
These are the EG & LPG.
The SOU hasn't changed but I've added a preset manager module,
the 225e, which allows you to store presets and also adds MIDI to your system.

Basic system 3:

This is essentially system 2 but the 225e has been swapped for two half modules: the 202h (which is a adapter module) and the 225h which is a midi - CV interface.


Basic 4 is an evolution of the basic 3 configuration

We have swapped the 266e (SOU) for a 267e which adds a dual filter, but retains a basic uncertainity module.


Basic 5 drops the 202h (adapter module) and the 225h (midi-CV interface).
In its place we have the 225e midi-CV / preset manager.

If you come from the Euro world, you probably already have MIDI to CV converters
and might be tempted to drop any of the MIDI-CV modules.
But be aware that Buchla uses a different standard to Euro .. 1.2V/ Oct. and 10V gates generally.
Plus the CV and audio section are separated.
CV uses banana & Audio use Tiny jacks.

 Basic 6

If you have got this covered then swapping the 225e for a 206e would be a great choice.
You have added a mixer & retained the preset manager.

I hope these ideas help you make a good decision.
Cheers J

Saturday, 8 August 2020

Happy 808 Day

It's the 40th anniversary of the TR-808


This drum was introduced in 1980.
There were just 12,000 made and production was stopped in 1983 when some of it's parts (faulty transistors) became impossible to restock.

The TR stands for "transistor rhythm".

Unlike the Linn LM-1 Drum which used samples, this created sounds with analog circuits.
It's actually a synthesizer which focuses on making drum sounds
Thank you "Mr. Nakamura" for the analog voice circuits  and "Mr. Matsuoka" for the software.

You've heard the TR 808 on countless records and it's been "cloned" again and again.
.... the best form of flattery

Thursday, 6 August 2020

ARP 2500 - 1046 envelope generator & eloquencer

Some notes on the ARP 1046 envelope generator.


Triggering the ARP's envelopes is a bit tricky if you are using eurorack, as most modules put out only 5V gates & triggers. This is usually not enough.


I've just ordered FuzzBass TTSH gate booster PCB but while I'm waiting for it to arrive
I decided to test the Eloquencer sequencer by Winter Modular with a ARP 2500

 

The Eloquencer sends out 8V gates - good enough to trigger the 1046 EGs
You need to adjust the gate length from the Eloquencer.

Most of the old ARP gear seems to want +10V but will usually act on +8v.



yOU CAN trigger the EG from either the upper matrix or lower matrix

The upper matrix allows you to treat the 1046 as if it is 4 "basic" EGs

Use the lower matrix if you want to use the 1046 as two "combined" EGs
When the Trigger Mode switch is in the Multiple setting you need both gates & triggers to activate an envelope. In the single mode, only a gate is required (T not needed).

If you apply another trigger signal while the gate is still present the cycle
will restart. ..a good way for creating multi-peak envelopes.




The 1046 QUAD Exponential Envelope Generator is actually a ARP 1003 & 1033 in a single module.

The 1003 has the stages: Attack, Initial Decay, Sustain, Final Decay

The 1033 has the stages: Gate Delay, Attack, Initial Decay, Sustain, Final Decay

 The main difference between the two is the addition of a gate delay















A post shared by jono (@dj_jondent) on




As a side note, the ARP 2600's envelopes also can't be triggered with most eurorack gate/trigger modules. The ARP 2600 uses a gate range of 0-10v

The Gate & trigger output of the ARP 2600 keyboard is +10V

The FuzzBass TTSH gate booster is a useful module to have. In addition to the need for a 10V gate, the 2600's ADSR circuit has a retrigger function.

This requires a 10V trigger signal. This allows you to reset/restart the cycle when you press a second key (without disabling the gate signal).

I can also clock the eloquencer (slave) from the ARP 1027 sequencer's clock (master).
The 1027 clock sends triggers not gates.

The Greyscale Algorhythm also triggers the 1046 envelopes.
Use the gate inputs of the 1046

 



Links
+ More about the 2500's EGs


Eurorack modules that might work (I haven't tested this) with a 2500 or 2600 are:
+ MI Marbles - Output levels: -5V to +5V for CVs (largest setting), 0V to +8V for gates.
+ Make Noise -- maths, Rene & pressure points, 0-coast/0-control
+ ER - 101 - 9V
+ Doepfer A-149-2 .... +12V gates
+ TTSH gate booster (fuzzbass) .. converts voltages over 3V to about 10V 
+ The Arturia Keystep is also very useful.
    CV/GATE outputs: CV supports 1Volt per octave, Volt>Hz modes, 
    Gate output 5V or 12V for modern or vintage gear support
+ Arturia beatstep 
    CV/GATE outputs (1 volt per octave CV, 10 volt gates)
+ Arturia Microfreak
   Gate signals can also have different output ranges (S-Trig, V-Trig 5V, V-Trig 10V).
   CV: 1 Volt/octave (0-10V), Hertz per Volt, 1.2 Volt/octave (a Buchla specific standard)

MFOS Bi-polar Power supply

This is a excellent PSU


i'VE built an earlier one & it works well.



It uses LM78XX/LM79XX or LM78LXX/LM79LXX regulators
That is, it uses an AC output wall wart.
 DO NOT USE A DC OUTPUT WALL WART.




These are the parts needed:
1  LM7812 +12V Voltage Regulator  LM7812  U1  
1  LM7912 Voltage Regulator  LM7912  U2  
2  Resistor 1/4 Watt 5%  2.4K  R1, R2  
6  1N4004 General Purpose Rectifier  1N4004  CR1, CR2, CR3, CR6, CR4, CR5  
6  Capacitor Electrolytic  3300uF  C1, C2, C3, C6, C7, C8  
4  Tantalum Electro (35V)  1uF  C4, C5, C9, C10  
1  9 to 12 VAC Output Wall Wart  12VAC Output    
1  Optional SPST Switch  SPST    




Tantalum capacitors -- they are polarized.








Links:
http://musicfromouterspace.com/analogsynth_new/WALLWARTSUPPLY/WALLWARTSUPPLY.php

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For more Euro DIY builds click here:
http://djjondent.blogspot.com.au/2017/12/diy-index.html
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