Monday, 18 August 2014

TTSH (ARP 2600 clone) build notes - Mixer & Reverb (DIY)

This is part 13 of my TTSH (Two thousand six hundred) build which is an ARP 2600 clone synth.

You can see my full build thread HERE

There are two awesome TTSH threads in Muffs.
2600 clone - Two Thousand Six Hundred (TTSH)
and
Two Thousand Six Hundred (TTSH) Project General Build Thread

The DSL-Man site has a very good TTSH thread

And of course the official build thread is here
--------------------------------------------------------------------------------------------------------
  The Mixer section before components.



A little on how it works
The mixer circuit looks like it uses a standard Op-amp inverting config.
Signals enter the mixer through sliders R200(100K log) & R201 (100K log).. then through R202(100k) & 203(100K). They enter the first LM301 op-amp via pin 2.(in the schematic it's identified as A25).

The signal leaving A25 goes to the pan slider & reverb.

At the pan slider the signal again splits into left & right channels.
The right channel passes through R256(100k) into pin 2 (inverting input) of A27 (LM301 op-amp).
The left channel passes through R255(100k) into pin 2 of A26 (LM301).
-----------------------------
So basically op-amp A25 inverts the initial input signal.
Then op-amps A26 & A27 re-invert, buffer & amplify it for output to the left & right channels.

TTSH (ARP 2600 clone) build notes - Envelope Follower (DIY)

The ARP 2600 envelope follower is a really cool module.
The pre-amp is internally wired (normaled) to the envelope follower.
It converts amplitude to voltages.The louder the input signal, the greater the output voltage.
It's a great way of introducing external sounds (like drums) into your TTSH to modulate the filter cutoff for example.

--------------------------------------------------------------------------------------------------

This is part 12 of my TTSH (Two thousand six hundred) build which is an ARP 2600 clone synth.
You can see my full build thread HERE

There are two awesome TTSH threads in Muffs.
2600 clone - Two Thousand Six Hundred (TTSH)
and
Two Thousand Six Hundred (TTSH) Project General Build Thread

The DSL-Man site has a very good TTSH thread

And of course the official build thread is here

-----------------------------------------------------------------------------------------------------


A bit on how this works.
The Envelope Follower is basically a full wave rectifier.
It generates a +ve DC voltage output directly proportional to its input. (a 2V peak to peak = 5V DC).
The rectifier basically consists of A1 & A2 (both LM301s) and two diodes.
The +ve input leaves pin 6 of A1 & passes through CR2(diode),then enters A2 via pin3(non inverting input)
The -ve input passes through the diode CR1, and enters A2 via pin 2 (inverting input)
The rectified signal leaves A2 via pin 6.
The resistors R12,13,14,15 & caps C7,8,9,10 filter the signal.
Finally A3 amplifies the signal.


Pre soldering of components.

Resistors, Diodes, Caps

The LM 301s are in. 

Test then on to the mixer.


Sunday, 17 August 2014

MUSEO FRIDA KAHLO

The Frida Kahlo Museum (in Spanish it's called the Museo Frida Kahlo) is one of the must sees when you visit Mexico city. It is also known as the Blue House (La Casa Azul) after its cobalt-blue walls. You can find it in the Colonia del Carmen neighborhood of Coyoacán in Mexico City.


 It's a moving tribute to Freda. She was born (1907) & died here.The home is today a museum dedicated her art (& tragic) life. She spent the last 13 years of her life there.

The house is built around a central courtyard with garden space in a French-style.
It gives a good glimpse of how wealthy Mexican bohemian artists and intellectuals lived during the first half of the 20th century.


Freda spent much of her childhood here and this is where she developed her sense of social consciousness. Her connections to the communist party are well documented. During the Mexican Revolution, her mother would open the windows of this house in order to donate supplies to the Zapata army. 

In 1918 she was struck with polio. This left her with one leg shorter than the other. And when she was 18 a tram accident almost killed her. She spent over 2 years in hospital and never totally recovered. This was a very painful period in her life, full of casts and orthopedic devices. It was however a blessing in disguise as in order to pass the time & communicate her anguish & pain she began to paint.




The museum is decorated with lots of Mexican folk art, Kahlo’s own personal art collection, pre-Hispanic art, photographs, postcards and letters.There are also works by José María Velasco, Paul Klee and Diego Rivera (her husband).




This wing was added on by Diego Rivera (volcanic stone and shells).

For more travel postcards click here:

Saturday, 16 August 2014

Friday, 15 August 2014

Elektron Rytm & Buchla (Test 1) - Cobramatic & JonDent

Just trialing out the new Elektron Rytm drum machine with some Buchla.

The Rytm is sending midi clock to the Buchla/Euro modulars.
Perfect Swedish precision.


Here are some links to unlisted videos from the night:
Video 1
Video 2
video 3
video 4



Thursday, 14 August 2014

TTSH (ARP 2600 clone) build notes - Pre Amp (DIY)

The Microphone PreAmplifer build of the TTSH synthesizer. 

This is part 11 of my TTSH (Two thousand six hundred) build which is an ARP 2600 clone synth.
You can see my full build thread HERE

There are two awesome TTSH threads in Muffs.
2600 clone - Two Thousand Six Hundred (TTSH)
and
Two Thousand Six Hundred (TTSH) Project General Build Thread

The DSL-Man site has a very good TTSH thread

And of course the official build thread is here

-------------------------------------------------------------------------------

 The front section of the PCB

The back of the PreAmp PCB

There is no submodule for the Pre-amp.
The schematics of the 2600 indicate the use of a Teledyne 1339 Op Amp (A4). This has been replaced with the LM301 Op Amp in the TTSH.


A little on how it works:
The signal enters via R23 (100k resistor) the gain control and is coupled through C24 (a 0.1uf cap for the ARP 2600 & a 100n cap in the TTSH) to the non inverting input of A4 (133901 teledyne).(pin 3)

The range switch (S1) selects the feedback path for A4.
through either
1. R20 (X10),
2. R20(100k) & R 26(10k) (X100),
3. R20(100k) ,R25(1k), & R 28(100k) to ground (X1000)


The amplified signal then passes through pin 6 of A4 and through R27 (1k) to the output.


------------------------------------------------------

TTSH parts list.
Resistors
  • 100 x 1 (R28)
  • 1k x 2 (R25,27)
  • 10k x 2 (R19,26)
  • 100k x 2 (R24,20)
Capacitors
  • 5p x 1 (C15) --- slightly different from the ARP schemo
  • 50p x 2 (C15,C17)
  • 100n x 1 (C24) ---slightly different from the ARP schemo
  • 10µ x 2 (C13,C14)
Semiconductors and Integrated Circuits
  • LM301 x 1 (A4)
Other
  • 3,5mm jacks x 2
  • 100k audio Potentiometer x 1 (R23)
  • DP3T slide switch x 1 (s1)
  • 11mm M3 standoffs x 5

RESISTORS & Caps.

Install the jacks & 100k pot.

Install the five M3 standoffs
The BOM specifies 11mm. These are 10mm. They seem Ok.

 First test of the fit of the faceplate.
Looks good. Make sure the sliders, pots, jacks are in the right places.

Sit that slider in the correct position. This is a 10mm gap.

Before soldering check that the slider's pins just poke through.:-)


the switch& op-amp are in.

Wow ... it looks great !!!! Everything fits in place like it should. :-)

Tuesday, 12 August 2014

TTSH (ARP 2600 clone) build notes - Ring Modulator (DIY)

The Ring Modulator build of the TTSH synthesizer. 

This is part 10 of my TTSH (Two thousand six hundred) build which is an ARP 2600 clone synth.
You can see my full build thread HERE

There are two awesome TTSH threads in Muffs.
2600 clone - Two Thousand Six Hundred (TTSH)
and
Two Thousand Six Hundred (TTSH) Project General Build Thread

The DSL-Man site has a very good TTSH thread

And of course the official build thread is here

---------------------------------------------------------------------------------------------------


 There are actually 3 circuits here: the Ring Mod, a envelope follower & a pre-amp.

The TTSH ring modulator uses the ARP 4014 submodule circuitry.
The 4014 was used in both the ARP 2500 & 2600.
The schematics from ARPtech are here

The large white square corresponds to the 4014.


 4014 closeup consisting of two LM301 op-amps and four matched transistor pairs.

The original ARP 2500 & 2600 used matched TZ-581 & TZ-81 trannies.
The TTSH uses their modern counterparts, the 2N3904 & 2N3906
(see the link to the schematic above)

It's sometimes tricky to match transistors. Oakley sound has a Euro clone of the 4014 that use THAT 320P PNP arrays & THAT 300P NPN arrays. It's a neat way to avoid the problem of getting those perfectly matched transistors.



The lower section of the ring modulator. This is the section outside the 4014 sub-module.
There is a mistake in the Cap orientation. The schematic indicates that the top left 10uf capacitor
needs to be rotated so its negative terminal is connected to the cathode of its 10uf pair.

R32 (18K resistor) connects to the anode of c21 (10uF cap)
C20 & C21 should connect via their cathodes
if the original schematics are correct

The inputs of the ARP 2600 & TTSH ring modulator are normalised to VCO 1 & VCO2.
.
Front plate of the TTSH synth
                                                                                 

       This is the corresponding PCB front side.
                                                                                                                                                                                                  
 Resistors,Diodes, Capacitors.

These 2 resistors on the extreme right connect directly to the 4014 module. They are your audio input points when you come to test the ring mod.

Install the trim-pots. (This is a pre-soldering pic. I use blutack to hold the pots in place).

Transistors & ICs are in. Ready to test.


An original 2600.

Monday, 11 August 2014

TTSH (ARP 2600 clone) build notes - VCA (DIY)

The VCA build of the TTSH synthesizer. 

This is part 9 of my TTSH (Two thousand six hundred) build which is an ARP 2600 clone synth.
You can see my full build thread HERE

There are two awesome TTSH threads in Muffs.
2600 clone - Two Thousand Six Hundred (TTSH)
and
Two Thousand Six Hundred (TTSH) Project General Build Thread

The DSL-Man site has a very good TTSH thread

And of course the official build thread is here



The ARP 2600 used 4010 & 4019 sub-modules in the VCA section.
There were matched transistors (TZ-581 & TZ-81)  and a Op Amp (LM 301) at the output stage.

The TTSH uses the TZ-581 & TZ-81 modern equivalents (2N3904 & 2N3906)
The LM301 is unchanged. :-)
----------------------------------------------------------------------------------

 Front PCB (pre population)

Back face of PCB

 Resistors, Diodes then Caps.

Unmatched transistors.

Matched transistors & the LM301 op-amp