Electric Druid VCLFO 'Modulation Druid' [2nd Run]

[frequencycentral]

I snagged a couple of these chips a while back and am working through building them into a couple of modules and creating a PCB layout.

http://www.electricdruid.net/forums.html?page=projects.taplfo

Here's a base schematic for the modular version:

http://www.electricdruid.net/images/lfo/TapCircuitV1.gif

I've designed two PCBs:

Main PCB:

Tempo, Multiply, Waveform, and Distort knobs
Ext sync input
Clock output
LFO output
Tempo LED
Output LED
Provision of 10 pin header
Built in 78L05 5v source
Additional pad for expansion (see below)
Provision for 3 pin power header to CV PCB

Pretty much straight off the data sheet, except I've set the Level to maximum (though I've left a pad for external control) and set up a Distort knob. Although I see the benefit of having VCA control or at least CV control of the level, I've got enough DC coupled VCAs elsewhere.......

So, the main PCB can be used as a stand alone LFO which will fit behind a 4hp or 6hp Euro panel. Here's the clincher: I've laid out the main PCB in such a way that it's really easy to hook it put the the second PCB via an 8 way ribbon cable. The four pots on the main board can have their lug 2's connected to the second PCB, and there is a jumper to select either 5v to lug 3's for the stand alone LFO version, or 15v to lug 3's for the 'Modulation Orgy work-a-like' version.

The second (CV) PCB includes:

Pads for connections to Main PCB
Tempo CV input and amount pot
Multipy CV input and amount pot
Waveform CV input and amount ppot
Distort CV input and amount pot
Provision for 3 pin power header to Main PCB

It's based on the VCLFO datasheet page 6 for 1v/oct CV inputs (x4).

Using both PCBs together will give pretty much all the features of a Modulation Orgy and would squeeze everything onto a 12hp Euro panel if you have dainty little finger like me (!).

Both PCBs are the same size, dimensions are 71mm x 54mm. Pots are mounted along the 71mm edge. Pot lugs 2 are 18mm apart. I'm using 16mm Alpha pots.

I've just etched a pair of PCBs so I'll be verifying them over the next few days, then I'll post the layouts. I'll be offering sets to anyone who wants any. It also occured to me that it might be worth worth me splashing out on a tube of 30 x TAPLFO2 chips (the minimum order from Electric Druid)if there's enough interest, so I could put together some little kits which would include:

Main PCB
CV PCB
TAPLFO2 chip
20 MHz crystal
4 x 50k 6mm top adjust trimmers (to set the CVs for 1v/oct)

I'd need at least 10 interested parties before I could consider buying in the chips. Any interest?

BTW, examples of my PCB work can be seen here: http://electro-music.com/forum/post-350314.html#350314

[dark000arena]

thanks for all of these superlative contributions freqy. please do stick with the diy friendly big pad / fat trace layout style. these are the easiest to etch / solder boards on the forum

[frequencycentral]

^^^ thanks!

Yup, in my opinion fat traces and big pads are essential for making stuff accessible for folks who want to etch at home. I've just embarked on a new modular synth build after years away in the (fx pedal) wilderness. There will be plenty more layouts to come from me, plus a few original projects too.

[frequencycentral]

[Tim Servo]

One note: I carry the Electric Druid chips at Magic Smoke and can sell one or more for $8 each + shipping. Drop me a note at magsmoke@gmail.com for a quote or more info.

Another note: I love the ED chips. Easy to use, and they work great. Really dig all the waveforms available on the LFO chips. Highly recommended, even if you don't get them from me.


Tim (Chip off the old block) Servo

[diablojoy]

[frequencycentral]

I didn't realise you still stocked them Tim - I looked on your site last week and didn't find them. I'll order a few of the VCADSR chips if you have them too.

So......looks like there's enough interest to justify me doing some PCB + chip sets. I'll get the boards verified and order 30 x chip / crystals etc. Should be ready to take orders in a few weeks.

[Tim Servo]

Yeah, I keep them on hand. Drop me an email and I'll shoot you the latest price list. I've also been fairly lucky and have 566, 2206, 3080 and 8038 chips in stock (I try to keep enough on hand to go with the boards I carry - if you need a large quantity I may not be able to help you).

Looking forward to seeing how your project looks!

Tim (a Druid orgy?) Servo

[dark000arena]

Freq, have you seen the video entitled namm: ssl modulation orgy? this looks to be the ultimate LFO. if your druid vclfo can match this beast you will become an instant synth diy superstar indeed.

[frequencycentral]

[frequencycentral]

Woot! Just got the main PCB verified:



I'm gonna make some small changes to the PCB to make more space around the crystal, as I'd under estimated it's size.

This is a freakin' awesome LFO just in the basic form - I haven't added the voltage control PCB yet. Great set of waveforms, and the wave distort feature is just awesome and really expands the modulation possibilities.

I'm going to build this one into a module then start working on the full version - I want to ensure that it's a solid build both as a basic LFO and as a full blown VCLFO.

More to come.......

[frequencycentral]

Ok, this project is now fully verified! I've spoken to Tom (Elecric Druid) and agreed a royalty, though I think it might just be easier for me to buy a tube of 30 programmed PICs from him. I'll get the build documents tidied up and post here forthwith. So, I'm ready to take orders! How many you want? The cost is £30 GBP per kit, which includes shipping to anywhere. Each kit contains the following parts:

Main PCB
CV PCB
TAPLFO2 chip
20 MHz crystal
4 x 50k 6mm top adjust trimmers (to set the CVs for 1v/oct)

Payments by Paypal gift to:

rickholt22 AT hotmail DOT com

Please include your forum name and your full shipping address.

Here's my finished module of the full featured version:




And here's the two PCBs before assembly:



On the left is the Main PCB, the 8 way multicoloured ribbon runs to the CV PCB which is on the right.

[wmonk]

Does it come with a place for a MOTM style power header?

[frequencycentral]

[wmonk]

[chvad]

PM'd

[frequencycentral]

[Paradigm X]

Hey rick just paid for a kit!

I forgot to add sorry, can i get the MOTM power connector version rather than the reuo. Sorry. Cheers

BTW are you the same guy who invented all the phasers (gemini, causality) for guitars? If so any chance of modding some for modular use!

Cheers, Ben

[frequencycentral]

[Paradigm X]

Cool

Check your PMs as well before posting please!

Sorry, did this in a rush last night, would also like 2 of the Roland ADSR PCBs please.

Many thanks

Ben

[Tim Servo]

Hey FC,

Do you have overvoltage protection on your CV inputs? Might be worth adding a couple of schottky diodes to +5 and GND if you don't have something in there already.

Tim (preventing the zapping) Servo

[frequencycentral]

[isak]

Hi Freq..

i was wondering if you can make a video clip of how the VCLFO sounds like?
and on the way also for the VCADSR please.

i read about thous digital modules and its very interesting, i want to see and hear how they behave.
is video clip is an option?
i will be very grateful if it is.
i'm very interested in them.

cheers,
Isak E.

p.s please email me at - isak.mgm@gmail.com

[tazer]

hi wondering if there is any of these left up for grabs? i'm interested, please let me know.

thanks

[frequencycentral]

First run is now sold. The next run will be pro fabbed, soldermasked and silkscreened, probably around Easter. If you're interested, PM me with how many you want, I keep a spreadsheet.

I don't really have video facilities here (hmmm maybe my Android?), but I'll be at the MW Coventry meet in April, where there should be video.