• entries
  • comments
  • views

About this blog

Musings and construction

Entries in this blog


Modular mania

Finally mounted all the PCBs on one of the 2 more or less identical modulars we're building over at the labs. I made some 2cm (0.787 inches if you prefer mongoloid units of measurement) thick strips of brass. Those were perforated with a 10mm hole so that they can sit between the pots and the front panel, then I added a small hole for the M3 screw that fixes it all in place. 2 strips per card ends up in too much metal shop for my liking but the end result is surprisingly sturdy.

We opted for using lots of internal (in-panel) wiring as there are enough wires flying to and from the panel as is. The method of mounting the PCBs for all the modules near their panel space made for short cable runs.

Now we ended up with one modular with an almost finished pre-wired front panel, one where all the synth PCBs sit where they should. Add the cabinet holding the PSU, add the MB-SEQ PCBs in the top panel of the cabinet, debug beyond the basic short/continuity tests done and we should get some tunage. Grr, it's a long trip but I see the train headlights emerging at the end of the tunnel!

Basically, the mechanical (BORING!) aspects of it all takes up nearly the same time as the electronics. Le sigh... But, it will make weird sounds soon whistle.png


Lately I've been working on the proper control surface of the 6582 having run the mighty 6582 in a somewhat completed state with a perfboard control surface just for lulz. I followed Hawkeye's excellent tutorial on the CS construction but mixed and matched with the older methods from Wilba's construction hints where applicable just to be non-conformist fat rebel. :bug:

Now I'm at teh "waiting for the glue to cure" stage. :sleep: I wish one could just use superglue or Goop and be done with it. But oh noes, clamping and waiting seems to be the soup du jour... Guess I should detent the encoders or make up a nicer cable to my LCD meanwhile.

Meanwhile, this got me thinking about that elusive external filterbox with VCAs (ze famous EEFV, of which there are only whispers of a handful, being rare as hen's teeth). Wonder which filter to use:

Transistor ladder a la Moog, diode ladder a.k.a ARP stylee, CEM3372 in the Oberheim fashion, Wonky ladder 303 stylee, or IR3109 in the Jupiter 8 fashion. Mebbe I should just stick to LPF using SSM2044's there or CEM3379 and call it a day? Anyone got any suggestions? Gimped late/early MS-20 perchance? SVF based on a SSM2164 quad VCA like the Shruthi is doing it? Decisions, decisions... :frantics:

I smell experiments and a sudden uncotrollable urge to slap something together. It also needs pre/post filter distortion if I can get away with it :sorcerer:


This morning saw the panel components fitted to the paper copy of the panel in order to check the clearance around the knobs, switches and jacks. It looked promising and photos reside in a Canon somewhere. I hope to put those up later, plus a quick how-to for people using Front Panel Designer - there are some interesting tricks to discover.

Then came the time to fit the paper to the rack just below the MB-SEQ. Interesting! Somehow I figured the SEQ was 4U high, but it's only 3U! Guess the 4U came from the idea of SEQ plus outputs from the A-OUT being 4U. It doesn't exactly help that we had already placed the AOUT jacks on the rack panel for the modular... :whistle: So, there's now a full HE more to fill up with interesting gear. A clock module plus clock dividers will round out panel one nicely.

This means that rack 2 now has tons of space to spare for the future modules. Plus that I should get back to finishing the MB-6582 I started on earlier this fall. There's a front panel in there too :frantics:


Been at it for some time now. I'm building a mystery. :whistle:

I figured that it would be nice to combine the awesomeness in a cute little box that is the MB SEQ with my ongoing modular. I snatched a couple of sequencer front panels from Julian F and finished two sequencers, one for me, one for my partner in crime - mr F.

After assembling a whole host of modules, both of our own design and PCBs sourced from various people on the electro-music forum it all came together thanks to the Aout_NG module and TK's awesome work. No more external MIDI-CV converters! In fact this modular has 4GB of flash, ethernet and other non-standard goodies.

The rest is transistors and chips, some SSM, some CEM, some OTAs and even a light sprinkle of discrete transistors where we could get away with it. At the moment we are filling up the 8U/HE panel that is to host the Aout CV outputs, the gates and some bread-and-butter modules interfacing the system with the real world plus the usual VCO/VCF/ENV/VCA chain in order to make it a complete synth in one rack. All this will sit in a light-weight Adam Hall 12U tabletop racks.

The VCO is a Thomas Henry XR-VCO using a XR2206 oscillator with skewed waveforms, the VCF is our own take on the CEM3379 VCF/VCA/PAN that is dual and in full stereo. On top of this we have a noise source from the Thomas Henry Super-Controller that uses the good old SN76477 IC to great effect. This also gives us an LFO and S&H/lag processor. Add a couple of SSM2056-based ADSR modules (we have a ton of these plus we are lazy - sue us!) and some mix/split channels and were good to go. So far it's all panel 1.

The preliminary design is printed on paper so that we can make sure that fingers fit between the knobs, there are guard lines around the holes to make sure we don't place any components inside others on the backside.

Off to Shaeffer/FPE soon. Not time for POIDH just yet, unless you enjoy nekkid PCBs or similar perversions :geek:

Panel 2 and panel 3@12HE must be the targets in line...