Wiardgroup

I added a picture from the Pacific SDIY get together of some cool looking modules.

They look like Mini-Wave PROM expanders, but I don't know.

Fetafarm - Nice work on the faceplates, care to share the details with us?

--- In wiardgroup@yahoogroups.com, "grantrichter2001" <grichter@a...>
wrote:
>
> I added a picture from the Pacific SDIY get together of some cool
looking modules.
> 
> They look like Mini-Wave PROM expanders, but I don't know.
> 
> Fetafarm - Nice work on the faceplates, care to share the details
with us?
>

I sold Kevin at Fetafarms a Expander PCB last spring.

Dave

Hey!  Glad people liked the panels : )  I've been too busy trying to build my synth to stop 
and take pictures of everything, so the SDIY meeting was a great opportunity to show 
some of that stuff.

Laying on its side on the left of the photo was my v2 MiniWave panel - standard features, 
except for the inverted out jack coming from Dave's MiniWave Expander.  I liked it quite a 
lot, but I was always irked by the binary bank/wave indicators.  They're fine for reading 
static values, but once once you modulate them, they just turn into blinky lights.  Since 
one of the most powerful features of the MiniWave is creative modulation of waves and 
banks (and PROMs, if you're so endowed), I wanted to get these indicators displaying in a 
format that was instantly recognizable to my brain - decimal 1-16.

A friend quickly pointed me to the 4514 family - a chip that can take 4 binary inputs (like 
we have one the MiniWave), and output the corresponding decimal values.  I used a pair of 
these to handle the job, and the results are beautiful and immediately informative.

Now I must say at this point that I know nothing about electronics beyond an intro course 
in college and some general notions of logic.  I'm an adept assembler, but can't engineer 
the simplest of circuits on my own.  Therefore I have no way to troubleshoot the problems 
that have arisen from implementing this mod; others will surely find them trivial, and I 
thank you in advance for your insight ; }

I removed the transistors at the LED outputs on the MiniWave PCB, and grabbed the signals 
directly from vias nearby the MiniWave's ADCs.  Those feed to the respective inputs of the 
4514s, which are currently living on +5V similarly tapped from a PCB point (via by the 
lower-left corner of U11).  Each 4514 output runs through a 1K resistor to an LED.  The 
LEDs are two concentric circles with the ground pins of each bent 90 degrees to form a 
bus ring that leads to a single ground point on the MiniWave PCB.

Now for the problems:

I have a lot of noise on the output of the MiniWave.  It's been suggested that using a 
separate +5V supply for the mod might alleviate this.

There are faint "misfires" on LEDs at times.  I think this might be an amplification of the 
(unavoidable?) error present in the original circuit, where a value that sits right between 
two stages (often 7-8 if I remember my experience correctly) will cause a flickering 
between the two stages.  This is purely speculation.

Clocking the MiniWave frequency into the mid-audio range causes a weird LED 
phenomenon.  If you imagine that the stages are swept with a sawtooth, so that in my ring 
configuration you see a single dot traversing a circular path, increasing the frequency will 
eventually produce a ring, where all LEDs are essentially lit at all times.  The strange part is 
that continuing to increase the frequency causes the ring to "break open" at a single point, 
receding symetrically until only a single LED remains lit.  The phenomenon makes me 
imagine a phase-cancellation analogy.  I'm told that the 4514s should be able to handle 
speeds well beyond the audio range.

Anyhow, all that remains to the design is the manual PROM-select switch which lies inside 
the bank/wave indicator rings.  Oh, and Grant, I duplicated the Wiard logo script by 
digitizing a photo of my Boogie's panel, and hand-tracing the paths in Illustrator.  I 
assumed that you wouldn't mind, since I'm not going around selling bootleg Wiard gear ; 
>

Cheers to everyone out there - the Synth-DIY meeting reminded me that there are still a 
lot of creative people around.  Always a refreshing sight in these times : P

Kevin



--- In wiardgroup@yahoogroups.com, "grantrichter2001" <grichter@a...> wrote:

>
> I added a picture from the Pacific SDIY get together of some cool looking modules.
> 
> They look like Mini-Wave PROM expanders, but I don't know.
> 
> Fetafarm - Nice work on the faceplates, care to share the details with us?
>