Another PreenFM2 born today

[Rob]

Completed my PreenFM2 today, built from an R4 PCB purchased last year.  It worked perfect right from the start and I was astonished by how good it sounds.  I am near Vancouver, BC Canada.  It might be the only one around here for all I know.

I don't have a case for mine yet, so that will be next.

Rob

[Xavier]

Hi and congrats for your build.

The current svg files have some problems. I have to convert them to proper eps files.
And I'll publish the new ones in a couple of days, still have a little work to do on them.

To help you choosing the right case, i need to know which display do you use ?
OLED and LCD have different bezel size.

Xavier

[Rob]

I have the ERM2004SBS-1  display which is (I thnk) LCD.

Thanks for your help Xavier!

Rob

[Xavier]

I just uploaded the only one i have which is compatible with the LCD displays in eps format.
http://ixox.fr/preenfm2/download/

See the first case line : "Case that fits regular LCD".

If you know how to use a vector apps, you'll be able to use other ones and adapt the display hole size.

Xavier

[Rob]

I ordered a case today.  I did the whole thing in 3mm thick dark grey tinted acrylic to save on cost.  It looks like it fits OK in the smallest sized piece of material; P1 - 181mm x 181mm.  Including shipping it came to just under US$27.00

My first Ponoko experience.  Hopefully there will be no surprises.

[Xavier]

....It looks like it fits OK in the smallest sized piece of material; P1 - 181mm x 181mm....

  The 6 pieces fits in a P1 material ? I'm afraid there's a scale problem..... 
It should not fit in the smallest piece.

[Xavier]

Top surface alone is around 160 x 100 mm.

[Rob]

As predicted, I got an email from Ponoko to tell me that the P1 material is too small for the design.  They offered to fix the order by changing it to the P2 sized material.  It added US$11 to the total cost. Well, I expected it to be an adventure.

Edit: the total cost was $38 including shipping.  I will scrounge locally for hardware to assemble the case so no guess on that cost.

[Rob]

While I wait for the case to arrive, I keep the circuit board hooked up in my studio so I can play with it for 1/2 hour each day.  I already have a Shruthi and some other pre-made synths but none of them suits me as well as the PreenFM2.  No disrespect to the Shruthi, it makes amazing sounds but I just don't play in a way that makes a mono synth that useful to me on a day to day basis.

The quality and variety of the sounds on tap in the PreenFM2 really impress me and the ability to play chord runs or melody over bass really compliments my playing style.  I am more of an organ player than a pianist so the polyphony lets me do my thing synth style.  Props again to Xavier for designing and sharing it with us.  I worked for years as a computer programmer but I don't think I could ever write a piece a software as cool as this!

[Xavier]

Thanks a lot Rob for the nice words... 
I'm really glad your preenfm2 fits your style.

Xavier

[Rob]

I received the laser cut material from Ponoko today and it looks pretty much as expected except for one small thing.  I had assumed that the label engraving under the switches and controls was done as part of the Ponoko laser process but, like most assumptions, that turned out to be wrong.  There is no labels or logo or anything.  How was that done on the cases shipped with the kits?

One other question...  What is the small extra hole for between the large holes for the MIDI connectors?

[Rob]

Ok, I think I drew my assumptions too quickly.  The material came with one side covered in brown paper showing scorch marks from the laser.  I assumed that this is the side the laser work is done from.  I think I have now figured out that the cutting is done from the other side and then a sheet of white sticky paper is applied to keep all the parts together for shipping.

The white paper side was covering the engraving for the labels and logo etc.  The only remaining mystery is the extra hole between the MIDI ports.

[Xavier]

The extra hole should be aligned with the LCD contrast variable resistor. You should be able to adjust it with a small screwdriver without opening your case.

Don't forget to post a picture of your finished preenfm2 

Xavier

[Rob]

Finally finished!  I ran into a long delay in sourcing an MC33202.  The early version of the BOM had a link to an alternative surface mount OPA2340 at Mouser.  I didn't realize that and didn't have a DIP adapter.  I improvised with the spidered chip on a socket thing you can see to the left of the second photo, while I waited for a surface mount MC33202 to arrive (it takes forever for things to get to Canada) along with a matching SMT to DIP adapter.  Both solutions worked, but I wasn't comfortable with leaving the spider thingy in my case so I waited for about 5 weeks for the parts needed.

The case went together perfectly.  I had put a Shruthi kit Ponoko case together before, so I knew what to expect. This one went together very nicely and I am happy with the look of the finished results.  The only surprise was that the Ponoko website had information suggesting that "Grey Tinted" acrylic would be semi-transparent.  It isn't, so I don't get to look through the back of the case to admire my assembly handiwork.

Thanks again for all the help!

[Xavier]

Congrats, it's always nice to see a new preenfm2. 
Specially when the builder spent much time on it 

Yes, the MC33202 through hole is not built anymore.

But there are several other  DIP8 alternatives :
The one in the Kit :
http://www.mouser.fr/ProductDetail/Texas-Instruments/TLV2472CP/?qs=sGAEpiMZZMtCHixnSjNA6Dh9CQmOfcFceratuKPWvDw=
Another one :
http://www.mouser.fr/ProductDetail/Texas-Instruments/OPA2340PA/?qs=sGAEpiMZZMtCHixnSjNA6Mrdwin7F8A2ufI6Oo3Mpig%3d
Or even the cheap MCP6002 (used in the meeblip) :
http://www.mouser.fr/ProductDetail/Microchip-Technology/MCP6002-I-P/?qs=sGAEpiMZZMsUzhEcHltCuXqlSkK5TY8x

Xavier