"Dalek's Handbag" (The synth in the 'Pictures!' thread) Soundclip

[frequencycentral]

Ok ladies - let's build some handbags.

I'm going to add the various bits of the schematic over the coming week, as I have to 'retrace my steps' on some of it!

Chapter One - Bipolar Power Supply

The Dalek's Handbag is powered from 12 volts DC. Here's the schematic for creating the 'Vref', which is 6 volts:



Chapter Two - LFO

The LFO is 'stolen' from the Roland System 100m 172 module. I changed the timing cap to make it run faster (the original is 0.22). The Roland original doesn't have a square wave output - I discovered where to tap off a square wave output.

Issues with this circuit: The square wave is a lot 'hotter' than the triangle wave. This is common with LFOs. I just went with it - but it would be nice if the triangle was brought up to the level of the square (as opposed to bringing the square down - that wouldn't be good!) - anyone know how to do this?



Chapter Three - Envelope Generator

My own design. I used the ARP Osyssey AR generator (transistor) and the Octave Cat AR generator (CMOS) as inspiration. All diodes are 1N4148. The 'Gate In' is 12 volts.

It occurs to me that it might work fine without the two 1N4148s and two 33K resistors to Vref - this would need to be verified. The two 1N4148 after the Attack/Release pots are essential though.

The 3.3uf cap is the timing cap. Smaller values will reduce the attack and release times. I think 3.3uf is just right though.

[frequencycentral]

Chapter Four - Noise Source

Jeez, I really can't remember what noise schematic I used - but noise is noise is noise is noise, so here's the one from the Maestro FSH, should work fine - maybe someone would like to breadboard it first? I guess the 0.047 filters the noise (?) - a few cap values could be tried. The base of the tranny is left with no connection.

I suggest one quad opamp is used for the Bipolar Power/LFO/Noise Source.



This is worth downloading and saving: http://eshop.engineering.uiowa.edu/NI/pdfs/00/79/DS007981.pdf

It's the datasheet for the LM13700, we'll be making the VCO, VCLFO and the VCA using this later. My VCA is a CA3080, now discontinued - so let's make one using half a LM13700.

[McGhie]

AWESOME! Thanks! Pictures are already on my harddisc.
This rests for sometime in the future though.. Maybe when you're done and have all your notes settled, you could make this explanatory walkthough in the layouts gallery? But that's quite a project in it self, I reckon.

[slacker]

This is worth downloading and saving: http://eshop.engineering.uiowa.edu/NI/pdfs/00/79/DS007981.pdf

Probably the best datasheet in the world  one day I'm going to build a synth using nothing but the stuff in there.

It's looking good so far Rick can't wait to see the rest of it.

About your LFO question, AFAIK there's anything you can do to the circuit to increase the size of the triangle output, it's just the nature of the beast with those sort of circuits. The square wave will swing between the supply rails or as close to them as the opamp can get and the triangle will swing between about 1/3 and 2/3 of the supply voltage, in this case about 4 to 8 volts.
You could use a voltage divider to drop the square wave to a similar level or boost the triangle to better match the square. You'd just need a single opamp to do this, feed the triangle out into the + input and connect a 100k resistor  between the out and - input and a 68k between the - input and vref, that will bring the triangle up a similar level to the square. You might need to tweak the resistor values a bit if you find the top and bottom are getting chopped off, maybe use a 100k trim in place of the 68k.

[Dragonfly]

I hate you.





















ok...not really...I love you.

GREAT work !

[frequencycentral]

AWESOME! Thanks! Pictures are already on my harddisc.
This rests for sometime in the future though.. Maybe when you're done and have all your notes settled, you could make this explanatory walkthough in the layouts gallery? But that's quite a project in it self, I reckon.

Ok, no problem! Maybe it will be even easier to make once Valoosj does a PCB.

This is worth downloading and saving: http://eshop.engineering.uiowa.edu/NI/pdfs/00/79/DS007981.pdf

Probably the best datasheet in the world  one day I'm going to build a synth using nothing but the stuff in there.

It's looking good so far Rick can't wait to see the rest of it.

About your LFO question, AFAIK there's anything you can do to the circuit to increase the size of the triangle output, it's just the nature of the beast with those sort of circuits. The square wave will swing between the supply rails or as close to them as the opamp can get and the triangle will swing between about 1/3 and 2/3 of the supply voltage, in this case about 4 to 8 volts.
You could use a voltage divider to drop the square wave to a similar level or boost the triangle to better match the square. You'd just need a single opamp to do this, feed the triangle out into the + input and connect a 100k resistor  between the out and - input and a 68k between the - input and vref, that will bring the triangle up a similar level to the square. You might need to tweak the resistor values a bit if you find the top and bottom are getting chopped off, maybe use a 100k trim in place of the 68k.

Thanks slacker, others who dare to build it should add your ideas. I doubt I will make another myself - too many synths here already - and too many other ideas to imagineer!

I didn't really want to drop to square wave level - it's great, and a big part of the sound - so boosting the triangle would be the way to go - hell, I should even make a little daughter board to incorporate your mod into my Handbag!

I hate you.

ok...not really...I love you.

GREAT work !

Hehehe - should we expect a 'swirl' Dalek's Handbag?

I really can't believe all these guitarist want to build a synth - what are they on drugs or something???

Still to come:

Chapter 5 - VCO

Chapter 6 - VCLFO

Chapter 7 - VCA

Chapter 8 - 4024 LFO Divider

Chapter 9 - Putting it all together!

[Valoosj]

I want to build it for the pianist/voilin-man/semi-singer/... in my band. We play postrock and this thing would be an amazing attribute to our sound.

BTW: about that CA3080, I can still get my hands on it. Any other takers that want some? I'm going to order a shitload of parts tonight...

[eleanor296]

I want to build it for the pianist/voilin-man/semi-singer/... in my band. We play postrock and this thing would be an amazing attribute to our sound.

BTW: about that CA3080, I can still get my hands on it. Any other takers that want some? I'm going to order a sh*tload of parts tonight...

me! me!
hehe... yeah, if you could spare one I'm in

[pud3000]

So really want to know all the "chapters" of that little Synth-Tutorial. who else?

[mth5044]

That was great. Where did you get the case for it at?

Now.. the challenge... do it all with TUBES!

[frequencycentral]

Ok, I'll post some more schematics soon....

The case was from Jessops, a camera shop in the UK.

As for doing it all with tubes - don't think I haven't already thought of it!

Tube VCAs are easy, the AR generator should work with tubes too. I can make tubes oscillate at low voltage, but I haven't yet worked on a voltage controlled tube oscillator. Hmm..! Maybe....

[sean k]

http://www.musicfromouterspace.com/analogsynth/rayspinknoise.html
I haven't built this yet but I found it because my Dad has a white and pink noise generator for his ears, that tinitus stuff, and the generator has a slider pot on it that goes between pink and white and when one shifts it back and forth is sounds really neat. I was going to use it to build a rhythm machine that feeds the outputs of the pink and white noise to two switches in a 4066 then have the controls operated from a 555 through two outs of a 4017... though a simple flip flop would work but I haven't worked those out yet.

As well the outputs from the 4066 will go into a transistor at unity with an inductor accross the collector resistor to build the salvo's of pink and white.

Anyways, if your using white why not add some pink? 

[gaddargaddar]

one word ... INCREDIBLE!!! ... Sound of the gear is amazing and at last somedy who loves squarewaves :D:D
Also I'd like to thank you for the schematics :D:D

[pud3000]

Schematics?

Where did you find them actually? Is there some kind of tutorial?
maybe i could put them all together by myself.


tino.

[frequencycentral]

I have a week off in a weeks time  - I'll finish putting the schematics together then. The VCO and VCLFO are based on the LM13700 data sheet, but with linear to exponential convertors added to the CV inputs. I promise to post the rest of the schematics by mid November!

[pud3000]

well....its a pitty....

[Valoosj]

Hey Rick, don't mind the noobss comment. We are all still patiently awaiting the schematics

[Jaicen_solo]

DOn't know about schems, I was looking for a G-707....

[JFX09]

and I'd like to reassess my complete admiration for this .

Don't rush on anything, I would'nt be able to build something like that for a few years 

ok ok , hurry up for those who can 

[frequencycentral]

Shame on me - I do feel so guilty about not getting this one together yet.

I have to partly reverse enginner the circuit, as I built it on the fly and didn't keep extensive notes. It's a bit of a 'mare really - I only ever planned to build one and didn't imagine there would be any interest. So, the full schemo........................t'll come....................one day.................soon...............