preenfm Forum

PreenFM => preenfm2 and preenfm3 => Topic started by: synthboy on July 05, 2014, 01:19:07 AM

Title: Newly build PreenFM2 with custom case.
Post by: synthboy on July 05, 2014, 01:19:07 AM

Quite happy with this one and I'm impressed of the software and sound. Great work Xavier!
I added a headphone amplifier (3.5mm) and a rechargable mobile battery. There's is also a [battery pwr - off - USB pwr] switch below the USB connector.
Now I can play with it outside in the summer :)

Title: Re: Newly build PreenFM2 with custom case.
Post by: Xavier on July 05, 2014, 01:14:54 PM

Awesome job !!  :D
I really like the look of your preenfm2.
Even it looks great like this, you should add some knobs on the encoders... Even small ones make it so easier to control.

Is the battery behind the PCB or do you use an external one.

What is the reference of your round black button ? They seem tall, that's interesting.

Xavier

Title: Re: Newly build PreenFM2 with custom case.
Post by: Xavier on July 05, 2014, 01:16:19 PM

Also, any aditional information on your headphone amplifier would be greatly apreciated  ;)

Title: Re: Newly build PreenFM2 with custom case.
Post by: synthboy on July 08, 2014, 01:25:10 PM

Thanks Xavier for your kind words :)
I'm also quite satisfied over the result. I kept the design as minimalistic as possible, mostly to save time.
Done the drilling, cutting and so on in about a hour at my work during a break.

Many questions.. well:

The front is 3mm gray tinted perspex ordered from ebay UK. I also tried a much darker one with great results in a dark room. You only see the display text and it looks really cool. Unfortunately it was to dim in day light and now I also want to have the synth outside in the sun so that was no good solution.
The bottom is alu.

The buttons is "Tactile Push Button Switch 12mm x 12mm x 18mm" and costs almost nothing on ebay (there is also 20mm height). I think they have a great feel too and the best part is that its easier to drill round holes then square ones..
http://www.ebay.com/itm/PB40-20Pcs-12-x-12-x-18-Tact-Tactile-Push-Button-Switch-12mm-x-12mm-x-18mm-/140735792263?ssPageName=ADME:L:OC:GB:3160 (http://www.ebay.com/itm/PB40-20Pcs-12-x-12-x-18-Tact-Tactile-Push-Button-Switch-12mm-x-12mm-x-18mm-/140735792263?ssPageName=ADME:L:OC:GB:3160)

I'm still looking for some really small, long knobs (without any position marker) for the encoders but haven't found anything that I liked..

The headphoneamplifier is a LM4808 Dual 105 Mw and built on a small general use pcb. Its good value and sounds ok but unfortunately the reference design (look in its datasheet) gives an output that is always at maximum. Have to solve it with another gain setting.. maybe you have any suggestions?

The battery is a small mobile battery on the bottom below the PCB together with a cheap 5V step up circuit but not yet in use. Waiting for a small USB charge regulator before I finish that part :)

Battery + Headphone jack + a small MIDI keyboard makes this setup great during lazy summer days somewhere outside :)

Title: Re: Newly build PreenFM2 with custom case.
Post by: dimifrag on September 08, 2014, 10:03:06 AM

This is the most beautiful knobs for the preen fm http://rogan.rogancorp.com/viewitems/pt-series-collet-control-knobs-2/pt-series-collet-control-knobs "I WANT THIS"

Title: Re: Newly build PreenFM2 with custom case.
Post by: toneburst on September 08, 2014, 12:09:24 PM

You'll be VERY lucky to get any of those in quantities of less than several 1000s, though, I imagine.
Shame, because they are really nice, as you say…

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