Showing posts with label DIY. Show all posts
Showing posts with label DIY. Show all posts

Monday, 5 June 2017

Cluster Matrix Mixer - NLC build notes.

These are my build notes for the NonLinearCircuit Cluster Matrix mixer module.
It's 42Hp Eurorack format. The mixer has 8 ins & 4 outs.
 
Lots and lots of SMD here so be warned. This could take a while to put together :-)

Andrew's build notes are here.
http://www.sdiy.org/pinky/data/CLUSTER%20guide%20&%20%20BOM.pdf

The NLC blog has some pics that might be useful.
http://nonlinearcircuits.blogspot.com.au/2015/03/cv-controlled-matrix-mixer.html

Some NLC words of wisdom.

A post shared by jono (@dj_jondent) on

Back to the build.
My PCB is version 2.
So only two mods need to be made. Check out Andrew's build notes for more details.
A trace needs to be cut where the yellow line is.
I've also circled it in the image below.

There are 32 VCAs

It uses 16 of these  NJM13700M s:
Mouser cart 

The NJM13700M is a Transconductance Amplifier or an OTA (Operational
Transconductance Amplifiers)
It has 3 input pins (V+ & V- like in standard Op amps plus a 3rd input)
 In the above example the pins are respectively, 3, 4, & 1.

The output of an OTA is not a voltage like in a standard opamp. It's a current.
(Now I understand the Tesla vs Edison quote. It's a reference to the AC Vs DC battle). 
The gain of the OTA is controlled by this 3rd input pin.
 It seems that Andrew has used these 16 Dual OTAs to build the 32 VCAs.

If I'm reading this circuit correctly The TL074 acts as the current to voltage converter.
The output of the OTA feeds into the regular Op-amp which has its feedback loop.
This effectively has infinite input impedance.
Since the original input of the OTA is inverting, the final output of the TL074 is non inverted.

 I like to get all the IC's on first.

 Then the rest of the passive components.


 These are the mods needed for rev2 PCBs.

Pots first. These are all B100k.

Jacks next.

The first mod wire broke and removed some of the PCB trace.
So I reattached it further down.


Initally there was a slight hum on the top channel .... channel A.
Andrew suggested checking the channel A 470R resistors are soldered properly to ground, same or any opamp pins that should be going to ground.

I touched up Pins 3 & 4 of the 13700m VCAs. This fixed the hum.

Nice one Andrew.

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You can find more NLC builds here.
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Wednesday, 24 May 2017

1050 Mixer sequencer - Build notes

This is a Eurorack module inspired by the ARP 2500 mix sequencer.

There are lots of SMD components so it's probably not a good one for beginners.


Here are Andrew's build notes:
http://www.sdiy.org/pinky/data/mixseq1050BuildBOM%20vers1.pdf

Muffs notes:
https://www.muffwiggler.com/forum/viewtopic.php?t=154469

Some pics of the virgin PCB & Panel

Some NLC words of wisdom

This is great SMD soldering practice.
I like to get those ICs on first. These are SOIC.
The sequencer section uses one CD 4017 (decade counter) , three CD4071s (quad 2-input OR gate) and  one CD 4081 (CMOS Quad 2-input AND gate).


The 4017 decade counter is central to this sequencer.
Sending a pulse to the clock input (pin 14) sends a pulse out from each of the outputs in sequence.

A bit about gates.

CD4071 (quad 2-input OR gate)
 
 Truth table of the OR gate:

 CD 4081 (CMOS Quad 2-input AND gate).
This is the truth table for the AND gate
I'm using a DG 212.
Here are the mouser details.

You can also use a DG 442. Just make sure it can handle +/-12V.
My DG 212 can handle +/-15V so should be OK.
It's an analogue switch. 4x SPST.

Some earlier versions of the DG442 require a voltage offset on pin12, the spaces for these resistors are on the PCB marked 100k* and 120k*.
New versions do not require these resistors, so check the datasheet for your  IC, if pin 12 is marked ‘NC’ you do not have to install these resistors.

My DG 212 has pin 12 marked as VL. so I will install the resistors.
Data sheet.

Next install the rest of the SMDs.... lots of resistors & caps. These are 0805s
Parts marked "c" are 100K .

Then the through hole stuff.


Install jacks, switches first. Line up with panel.
Then pots. I used B100K.

Don't forget the ground wires for the jacks. I use left overs from caps & resistors.

The PCB looks like this:

Finally the LEDs

LED orientation : The long lead (anode) , (+) goes into the square hole on PCB.


Yah it works. Nice one Andrew.
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You can find more NLC builds here.
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Friday, 19 May 2017

Switches - Toggle mainly

All about switches

Firstly,
Poles Vs Throws.
Poles: A switch pole refers to the number of separate circuits that the switch controls.
Throws: This indicates how many outputs each switch can connect its input to. 

MTS stands for Minature Toggle switch.
The Switch bushing  has a 6mm diameter.

There are a few variations on these switches.
1. Momentary switch remains in its “on” state only as long as it is being compressed. Once the user removes the compression of the switch the device is no longer on. ...
2. Latching switch needs to be pressed once for ON and again for OFF, for example a light switch.
3. Non-Latching - When pressed it is on. The reverse action is off 

There are also various codes:

MTS 101 On - Off. SPST
Terminals : 2P











-----------------------------------------------------------
MTS 102 on - on   SPDT
Terminals : 3P





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MTS 103 on - off - on. SPDT
Terminals : 3P





----------------------------------------------------------------
MTS 112 on -(on)
SPDT
Terminals : 3P









--------------------------------------------------------------
MTS 113 on-off-(on)
SPDT
Terminals : 3P

-------------------------------------------------------------------
MTS123  
mom-off-mom    (on) off (on) 
SPDT
Terminals : 3P


 


---------------------------------------------------------------------------------
MTS 1033 On-On-On
SPDT
Terminals : 3P

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MTS 201
on-off
DPST
Terminals : 4P













------------------------------------------------------------------------------------
MTS 202
on - on  DPDT
Terminals : 6P









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MTS 203  On - off - on.
Terminals : 6P
DPDT










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MTS 212 on-(on)
Terminals : 6P
DPDT
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MTS 223  (On) - off - (on).
Mom - off - Mom
Terminals : 6P
DPDT





----------------------------------------------------------------
MTS 2003
on-on-on

2 pole, 3 throw. (2P3T)















This slide switch is another version of a 2P3T switch

 
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 MTS 301
on-off
3PST
Terminals:6P

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MTS 302
on-on
3PDT
Terminals 9P




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MTS 303
on-off-on
3PDT
Terminals 9P




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MTS 401
on-off
4PST
Terminals:8P
-------------------------------------
MTS 402
on-on
4PDT
Terminals:12P



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MTS 403
on-off-on
4PDT
Terminals:12P




Links
+ Restoring Vintage Toggle Switches
+ Massuse Switch