Messages

1036

preenfm2 and preenfm3 / Re: PreenFM2 SMD version

« on: November 17, 2017, 12:03:29 AM »

The target are hobbyists who want a PreenFM2. After I proof the design someone else or a small company can manufacture the PCB with all the SMD components soldered and sell that as a kit. The end user will only have to solder the encoders, LCD, switches and sockets. With a stencil and a soldering oven and even a manual component place these PCBs can be manufactured very fast and cheap. Small companies who have automated pick and place machines can churn these boards in tens per hour.

The strength of this project is the firmware and the hundreds of man-hours you guys put in to develop it. So any derivative design should be able to reuse this firmware without too many modifications.

Keep in mind that a new Korg Volca FM can be bought for 150$. It can also load DX7 patches, has a case, MIDI and a sequencer. It doesn't have the same flexibility as the PreenFM2 though. The out of stock PreenFM2 kit and a metal case is 212E + 70E (approximately 330$) and this is one reason the Volca FM is selling so well.

I will build these SMD versions PreenFM2 mostly for myself and I'll solder them by hand. I do have a powerful stereo microscope and a steady hand so the only drawback is that it will probably take me an hour per board.

So I think you can use my build to proof a cheaper design, add a few new developments if you want and make the PreenFM2 more accessible and popular.

I was hopping you were not going to write that.
I really like the preenfm2 like it is today.  I would like it to remain a DIY project.

If like you say a small company manufacture the PCB, i would really feel robed.

1037

preenfm2 and preenfm3 / Re: Subtle distortion on one channel

« on: November 15, 2017, 11:01:05 PM »

Each channel is the sum of 2 Dac outputs (12 bits + 6 bits).
The resistors pair 115K and 1.8K have a ratio of 63.88 (6 bits = 64) which is what is used in the sum.

You can verify with a multimetter that you mesure the same value on the 2 115K and the same on the 2 1.8K.
You'll get a lower value for the 115 because of the other components in the circuit.

(You can verify the same thing for all the paired resistors around the op amp, they are all part of the output audio.)

1038

preenfm2 and preenfm3 / Re: PreenFM2 SMD version

« on: November 15, 2017, 10:41:35 PM »

Xavier, do you think the design I'm doing will be of any interest?

This is a great project. But i'm not sure who the target is...

1039

preenfm2 and preenfm3 / Re: Vishay OLED brightness

« on: November 13, 2017, 09:34:06 AM »

Thanks a lot for the screenshots. 
That's very usefull and interesting.

All people who were annoyed by the high frequency peak reported it's not audible anymore after the shield + OLED resistor modification.
If you haven't done it before, look at the spectrum while trying to find the best place for your shield. 5mm can make a difference.
Also, verify what you hear is not directly the display (put the preenfm2 far away from you) and not a peak in the audio. (That happened to someone);.

I've just ordered a white and a green OLED display (Raystar). I'll report what result i got from them.

1040

preenfm2 and preenfm3 / Re: November 5th 2017 -> 2.08

« on: November 10, 2017, 08:38:44 PM »

I think i remember there's 60Ko of RAM free on the preenfm2.
That's 30Ko per channel (stereo).
Each float takes 4 bytes to store so that's 7500 samples, at 40.000Hz your delay can be 0.18 second long... Could be a chorus maybe.

I don't know to much how a reverb algo works, but i assume the CPU usage will be big.

1041

preenfm2 and preenfm3 / Re: November 5th 2017 -> 2.08

« on: November 08, 2017, 02:08:53 PM »

but how high can the ui go? do i loose resolution if i choose higher frequency range? or can the ui display values above 99.9? can the preset save values to 600.0?

The display maybe a bit weird after 100.0, but everything should work.
The UI also uses the same define.

The only thing is that your midi clock synchronised value will be after the last available frequency. it means that if you save presets with "MC" (or MC/2 or MC*2 etc....) frequency, they won't be "MC" anymore after the change.

1042

preenfm2 and preenfm3 / Re: November 5th 2017 -> 2.08

« on: November 08, 2017, 09:20:08 AM »

just curious, where did the extra cpu come from that we can now have such fast lfos?

That does not use more CPU.
What ever the LFO frequency is, LFOs are updated every 32 samples : ~1200 times per seconds.

In theory with 1200 update per seconds, you should be able to go up to 600Hz.
If semeone wants to experience, it's now a simple constant to modify in the code :
https://github.com/Ixox/preenfm2/blob/master/src/synth/Common.h#L158

1043

preenfm2 and preenfm3 / Re: Midi CC Bug?

« on: November 07, 2017, 11:25:23 PM »

I forgot to "publish" the release, it should be visible now in the link above.

1044

preenfm2 and preenfm3 / Re: Midi CC Bug?

« on: November 07, 2017, 10:54:17 PM »

Firmware 2.08a will make your octatrack happy
https://github.com/Ixox/preenfm2/releases

1045

preenfm2 and preenfm3 / Re: Windows & macOS editor 2.08.2 : standalone & VST

« on: November 07, 2017, 10:07:03 PM »

I've checked in the 2 Makefile i used under Linux.
I think it's the best way to be sure binaries are linked correctly against the libs of your distro.

I have 2 linux distros, I could not have it compiling under the older one. It compiles fines under ubuntu Mate 16.04.

Go in Host/Builds/Linux and type make to build the standalone version.
The standalone version works fine.

Go in Plugin/Builds/Linux and type make to build the VST version.

I never tried VST plugin under linux before. I quickly downloaded the free Tracktion 6 for linux, but it complained not being able to inialiaze the VST.
What host do you use ?

1046

preenfm2 and preenfm3 / Re: Midi CC Bug?

« on: November 07, 2017, 08:59:55 PM »

That's definitely a bug, value should not go above 1.00.
I'll fix that.

To bring back sound, just press INST+MENU.

1047

preenfm2 and preenfm3 / Re: Windows & macOS editor 2.08.2 : standalone & VST

« on: November 06, 2017, 09:35:49 PM »

thanks for the updates , ive just been playing with the editor and latest firmware.... very usable and got some nice results quite easily.

thanks again...

Thanks for the feedback.
Do you use the mac or windows version ? if mac what macOS version ?
Thanks

1048

preenfm2 and preenfm3 / Re: cc question

« on: November 06, 2017, 09:34:08 PM »

Hi,

CC 73 seems the way to go.
Don't forget it's digital mixing, so lowering the volume of instruments will decrease the bit resolution (sound quality).

Xavier

1049

preenfm2 and preenfm3 / Windows & macOS editor 2.08.2 : standalone & VST

« on: November 05, 2017, 11:00:25 PM »

New major version 2.08.2 despite the small number increase.
See first message of this thread.

1050

preenfm2 and preenfm3 / Re: November 5th 2017 -> 2.08

« on: November 05, 2017, 08:57:23 PM »

Just uploaded the final 2.08 firmware.
Only a NRPN / Stepsequencer bug fix since 2.08b4.