Building a new bass / melody / lead synth

ashleym · Joined: Aug 20, 2009 Posts: 181 Location: uk

Dave,
What a good idea..........

The Wasp filter has plus and minus CV inputs. The CGS matrix mixer has plus one way and minus the other controls too. So it is sort of covered. With my design I keep the attenuators separate from the modules so I can mix the CV levels with mixers or use simple passive attenuator and stack some bananas. This is in the spirit of Moog modulars.

You say you possibly send the ADSRs into the VCO. Have you thought of using a couple of these, one for each VCO?

http://www.muffwiggler.com/forum/topic-64769.html

Giving +/- options to modulation. If you think they would be useful drop me a PM

Skrog Productions · Posted: Fri Sep 13, 2013 7:52 am Post subject:

Hi Ash , i've got +/- adsr on my ASM-2 synth i built a while ago , im going for what i've got so far , thanks for the link tho , cheers.

Here we have the final Panel layout , going to mull over it this weekend to see if i've missed anything Smile

Dave.

mfos synthSept 2013 longer 600mm panel v3.JPG

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Skrog Productions · Posted: Tue Sep 17, 2013 11:21 am Post subject:

Hi.....

Fixed a few alignment mistakes and i have double checked that the jack socket & switch retaining washers & nuts do not foul any text .
A few things i've squeezed in at the last min.

Two level pots for the input to the lockhart wavefolder.

A switch to cut the gate in to the filter ADSR's 1&2 so they can be triggered seperate from the VCA- ADSR's 3&4.

I think i've ironed out all the little errors now , the final final panel before vinyl printing Cool

Final design X1.JPG

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Skrog Productions · Posted: Tue Sep 17, 2013 11:51 am Post subject:

Some of the smaller stripboard circuits , CGS burst generator and Roman Sowa frequency dividers, now wired and ready to test , all the main modules are coming from the modular.

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Skrog Productions · Posted: Wed Sep 18, 2013 1:57 pm Post subject:

Hi

After doing some tests with the light purple vinyl and the black text i decided on the orange colour for better contrast of the text & dials.

After getting home from the printers shop with 2 prints of the panel (it was quicker to do the drill template the same colour) , the good finishing print is lying in wait for the drilling to start over the weekend Smile

A quick pic of the drill sticker'd aluminium sheet sitting in the wooden case.

Dave.

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Skrog Productions · Posted: Thu Sep 19, 2013 1:20 pm Post subject:

Progress.....

Got back from work and went straight to the shed Smile

First job, use a center punch & hammer and center dent all the crosshairs.
then gave the front a spray with drill cutting oil and drill the 230 odd holes with the stand drill at 3mm , that does the fixing holes top & bottom and a pilot hole for all the others.
Then 6mm bit for the toggle switches and pilot for pots n sockets.
8mm bit for the pots.
10mm for the rotary switches.
11mm for the sockets.

Peeled off the oily smeared template sticker then
sanded with fine grade P1000 wet'n'dry on the front and a rough sanding on the back.
Quick spray of automotive carb cleaner and wiped all the dust & grit away,
Then i washed the panel with warm water and washing up liquid and applied the good sticker , you can use a can of adhesive de-activator or a little soapy water to allow adjustment of the lineing up.

Next job , take a craft knife blade and slice out the holes and leave the panel for a couple of days to let the few air bubbles contract.

Dave.

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Skrog Productions · Posted: Sun Sep 22, 2013 1:16 am Post subject:

Out of bed early this morning to start fitting the toggle switches , starting to take shape now Smile

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Skrog Productions · Posted: Sun Oct 06, 2013 4:58 am Post subject:

Hi , slowly coming together, been chipping away after work , built the noise circuit from the mfos ultimate on stripboard, some buffers to distribute cv's & gates to different areas of the synth , and ive stripped down 2 vco's / 2 vcf's & 2 ADSR's from the main modular , need to lengthen the wires going to the new panel.
Also sorted out my wedge case power supply.

The panel so far ....

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Skrog Productions · Posted: Sun Oct 06, 2013 5:27 am Post subject:

The power supply.
I have totalled up the current needed on +12v line and -12v line and i need 550mA / 420mA respectively , i built a mfos adjustable power supply with just the regulators & volt adjust area of circuit , i have a large diy Raw DC power supply that powers the whole modular system , the rectified and smoothed DC from the main power station distributes to multiple regulator busbars which usually have 8 to 10 modules per busbar inside my main blue system.

All of this orange new synth is +/- 12V , keeps things simple Smile

here is a pic of each of the main 12V 1.5A regulators on 150mm long alum "L" bar and a smaller "L" bar for the 9V 1A regulator which supplies the Behringer FX600 & RAT distortion.
The green sockets are 3pin (+12 / 0v / -12) and the stripey long lead is +9V.

The switch at the side is a double pole rocker , power switch to break the incoming +/- Raw DC.

Dave.

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Skrog Productions · Posted: Tue Oct 15, 2013 11:50 am Post subject:

Hi
Wiring has started , first job, the 2 mfos vco's transplanted from the blue modular to this synth , then the dual frequency dividers (Roman Sowa) for vco 1 & 2 sub osc's , Ken Stone simple wave folder for vco 1 , 5Pulser (Ian Fritz) for vco2 , mixers for vcf1 & vcf2 (mfos simple mixers) and a couple of buffers to send the sum of mixer1 to vcf2 and vice-versa (that gives the option of 2 vco's to either vcf).

Also have the mfos 24dB filter & 12dB svvcf wired in with a toggle switch to route vcf1 cutoff control to vcf2 cutoff for twin sweeps with the one dial.

Just bolted on the filter ADSR's which i need to lengthen a couple of leads.

pcb's & veroboards made already but still to hook up...
dual vca.
vca ADSR's.
6-lfo's.
noise circuit.
S & H.
Burst generator.
FX600 multi-FX.
RAT distortion.

a few pix of what's been soldered so far.

Dave.

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ashleym · Joined: Aug 20, 2009 Posts: 181 Location: uk

Part of me likes the front of your synth and the other part likes the jumble of wires and boards on the back!! I think that says more about me than you.

Good build. Keep up the flow of pictures please.

Paradigm X · Posted: Thu Oct 17, 2013 5:05 am Post subject:

yeah, cool stuff skrog, amazing how quick you work

Skrog Productions · Posted: Thu Oct 17, 2013 1:11 pm Post subject:

Thanks Ash ,
how is your filter module coming along ?

Skrog Productions · Posted: Thu Oct 17, 2013 1:16 pm Post subject:

ashleym · Joined: Aug 20, 2009 Posts: 181 Location: uk

Skrog Productions · Posted: Sat Oct 19, 2013 5:31 pm Post subject:

, yes , if i have no luck with cricklewood electronics London for any chips that rapid or farnel don't have , i too order from HongKong , only takes a couple of weeks to come, bit like royal mail Very Happy

Wires wires wires , just enough room to fit boards 18 / 19 & 20 on the white "L" bracket (2"x 2" Electrical containment pvc trunking sawed to length & bolted to panel) .

Couple of silly faults found only on my veroboard circuits .... 2 surplus isolator holes , bridged now and a resistor leg in the wrong hole, fixed now , and a red faced moment when the 6 lfo's were pulsing crazily and randomly , yes, i had not connected the 0V ground tail wire for all the pots to 0V at the supply , deary me , heh , nevermind .
Here is another pic at the latest stage , getting busy round the back of the panel now.

Dave.

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blue hell · Posted: Sat Oct 19, 2013 6:27 pm Post subject:

Nice space ship Laughing

and a great picture that too Exclamation

Skrog Productions · Posted: Wed Oct 23, 2013 10:38 am Post subject:

thanks Jan Smile

Skrog Productions · Posted: Wed Oct 23, 2013 11:10 am Post subject:

2 more boards fixed in , a Ken Stone burst generator , hooked it up to the scope after no-chip test & "is the chip/chip's getting hot" test , passed both Smile

and it seems to be bursting with trigger pulses quite good , and the other board is the level converters for the stompbox fx circuits.
Next job , de-box & dismantle a Behringer FX600 pedal & transplant into the synth , this and the Rat distortion have to be patched on the panel , i thought about hard wiring them but there was room for sockets Smile

another pic of round the back

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Cynosure · Posted: Wed Oct 23, 2013 11:49 am Post subject:

How are the boards supported? It looks like it might be a lot of weight on the larger boards if they are only supported at the front.

Skrog Productions · Posted: Wed Oct 23, 2013 12:21 pm Post subject:

Hi Jake , the boards don't flex when it sits in the box ( i've peeked inside with a torch Very Happy

, i was curious last week ) , each has 2 fixings per board to the bar , there is not a huge weight in a populated board and the wiring acts as soft brace , it will never go on the road because it's power supply comes from the blue monster's substation Very Happy

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Skrog Productions · Posted: Sat Oct 26, 2013 3:40 am Post subject:

FX dismantle & wiring this weekend Smile

.
I have taken the pcb out of the stompbox case and it looked quite difficult to take the pots off the manufactured pcb without damaging tracks so, i decided just to snip the pot legs with cutters , leave the pots in place but not connected and run wires from the snipped legs sticking up from the pot thru holes and sleeve them with heatshrink , this allows me to re-assemble the stompbox if i ever need to , unlikely Smile

.

All the pots are 47K , easy job , but the fx type selection is operated by a pot , im going to change this to a rotary switch with resistors between the poles to emulate the fx select pot action.

the last board , hurrah ! Smile

Dave.

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PHOBoS · Posted: Sat Oct 26, 2013 4:26 am Post subject:

Skrog Productions · Posted: Sat Oct 26, 2013 5:51 am Post subject:

Heh , do you think the fx chip would catch fire if i changed between fx at audio rates Wink

Skrog Productions · Posted: Mon Oct 28, 2013 11:44 am Post subject:

Hullo

I connected all the power connections and hooked up to the modular supply's Raw DC output yesterday , No magic smoke , hurrah Smile

, had 5 trips from studio to soldering workbench to fix several little errors on my part , only 1 of my veroboard circuits playing up , the mfos micro-sample n hold , i robbed an LF444 from my soundlab++ to try it out , great triggers coming from it , but a rather lame cv with no stepping , i'll take a look at all my tracks with a magnifying glass , likely a sliver of copper somewhere , or something else silly.
Left the synth running for 3 hours yesterday and i do need some air flow around the 12v heatsinks , trip to the local DIY store for a couple of 50mm round, push in air vents & try to find the 50mm holesaw in the work van.

Final pix to come and sounds after the weekend.

Dave.