Thanks, just did it …
I expect that my USB charger might be the culprit … not adquate stability of level of power … but let’s see, what the expert says.
Did you buy your preen prebuilt or did you assemble it yourself? I bought mine from Van Daal prebuilt, and I’ve never experienced anything like that. using USB, sometimes with an USB battery pack and sometimes with an iPad charger here
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I got my synth pre-built from Van Daal too. The hardware looks built pretty professional and I don’t think it’s the hardware.
Xavier Hosxe answered to my post on the preenfm2 forum and suggested to try OS version 2.03_A. He said, using OS 2.03, as I did, could have an issue concerning the new OLED and a display driver. I checked on my preen and found out that 2.03_A was already on the drive, but the 2.03 was loaded as firmware instead. Such things happen 
Well, so yesterday I burnt 2.03_A. I have to give it some stress now … maybe the issues are gone
ok then, let us know how it goes! hope you’ll sort it out
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I really want one of these PreenFM2, but I am just about at the limit of my gear already 
Has anything improved on the PreenFM2 as far as the synthesis architecture being able to accurately mimic a DX7?
I was so incredibly stoked to get this thing, it really is powerful…but not being able to load and recreate REAL DX7 patches made me sell it last year–I totally thought I had a “live friendly” portable DX7… 
I think the culprit was the lack of FEEDBACK implemented in the algorithms, which is essential to classic DX7 patches like HARP, one of my most favorite patches.
Has this functionality been implemented yet?
PreenFM is very different from DX7.
The later is based on Phase Modulation synthesis while PreenFM is doing real Frequency Modulation.
DX7 waves are only sine, PreenFM can do any waveform.
Feedback is usually a way to introduce noise, so it is not really necessary on PreenFM.
If you want the glass FM of the DX7 you’d better go with a Volca FM.
Only downside is that you have only 3 notes polyphony…
But it loads DX7 patches.
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Thanks Dalai!!
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I bought one of these from a user on this forum, it was prebuilt and is the SMD version so has a single stereo output jack, as opposed to the original pair of outs.
I mention this because I find that sounds seem to distort fairly easily. It seems worse when using a single voice on an instrument, sometimes increasing the number of voices will decrease the distortion. But, the overall volume level also increases distortion. I keep the volume dial about 12oclock.
Any suggestions for how I can test if it is happening due to a fault at the audio output stage, rather than being a dac related issue that Xavier mentions in a couple of threads on his forum? If it was dac related, would the final volume output level make a difference to the distortion I’m hearing? Maybe it’s both.
Sorry, I have no suggestion for you, but I want to say “thank you” to bring this little synth into my “view” again.
27 algorithms with up to 6 operators and the ability to use custom (user) waveforms for the operators makes it an extremely powerful little machine (especially for its price / ~300 Euros assembled … and there exists also a Eurorack version with CV inputs).
The “normal assembled version” is actually out of stock, but gets available again in a few weeks.
The firmware is still in active development and it is open source, so I can customize it however I like.
Hmm, Mmm…
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As is, it’s a really powerful synth.
My only problem with it was the amount of menu diving to reach synthesis parameters
You may want to have a dedicated controller for this. But that’s such a huge number of parameters, more than 200 for each instrument! For instance, you have 8 envelope parameters per operator (ADSR with parameters for time + level on each point).
Possibilities are insane, and programming way better than DX7. But you have to have a clever surface if you want to avoid too many menu diving!
Yep, that’s also my line of thoughts. There is at least an editor available (VST and standalone / Mac and Win).
What I really would like (and haven’t seen yet if it is implemented) is an Octatrack like CC values request (in the case of the PreenFM2 for subsets I guess). Or better: a config page to setup which CC values should be automatically sent when a new instrument gets loaded. This way it would play quite nicely with a faderfox controller with encoders. I guess I could implement something like this by myself.
More “Hmm, Mmmmm” … 
Indeed! I had totally forgotten that it was open source / open hardware!
I updated the latest firmware 2.10 overclocked and the sound does seem better. I’m not even sure it was meant to address the issue but the distortion I was hearing seems less now. Maybe placebo but still!
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Ha! Of course the day after I upgrade to 2.10, 2.11 is released!
Most notable addition here is the extensive choice of filters- although working out what they all actually are might not be straightforward!
EDIT_ Actually, the full list is here: https://github.com/pvig/preenfm2
(text below is from Xavier on the update page: https://github.com/Ixox/preenfm2/releases
Filters
I merged the great work of Toltekradiation (Patrice Vigouroux).
http://ixox.fr/forum/index.php?topic=69544.0
All filters are in the source code, so that i can easily merge his future work if any.
The midi value for each filter is also the same, so preset should be compatible with his firmware.
I just made the choice to reorder and not to show some of the filter in the preenfm2 UI.
The new (impressive) list of filter is :
1 Mix
2 LP
3 HP
4 Bass
5 BP
6 Crsh
7 Oryx
8 Orx2
9 Orx3
10 h3o+
11 Svh3
12 Pann
13 LP2
14 HP2
15 Lp3
16 Hp3
17 Bp3
18 Peak
19 Notc
20 Bell
21 LowS
22 HigS,
23 LpHp
24 BpDs
25 LPws
26 Tilt
27 Sat
28 Sigm
29 Fold
30 Wrap
31 LpSn
32 HpSn
33 Not4
34 Ap4
35 Ap4b
36 Ap4D
37 18db
38 La+d
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About the “request all CC values” topic:
I did some digging around in the sourcecode and the docs about how the editor is communicating with the device and it is quite simple:
The preenfm2 will flush all its parameters with NRPN midi messages if it recevies a NRPN with ParamLSB = 127 and ParamMSB = 127.
So a controller able to sync its NRPN controls to incoming NRPN (like the Faderfox EC4) will work already out of the box. That’s really great.
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Let’s say I wanted to try and install something like this on my PreenFm2 but know nothing of coding and the software side of things: http://ixox.fr/forum/index.php?topic=69607.0 (code here: https://github.com/pvig/preenfm2/commit/fa29cf8748360fbe0865c30cb072e355fef81082)
Can someone point me to an ‘idiot’s guide’ of what I need to understand and do to get these matrix options on to my preen? I’m not asking you to give me a walkthrough, but if you can point me to an existing tutorial/resource that will help me do this without having to become a coding master myself
Just ordered a kit for one of these…
Due to my predilection for chiptune I was thinking about getting one of Kasser Synths DAFM’s with the Megadrive chip, but for not-too-much-extra-cash this one just seemed to to do so much stuff and things keep getting added to the firmware…
That list of filters is a little bit scary though, how do you even choose from that many
edit: oh wow, formant filters in there too.
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Will be interesting to hear your experience with it, I’m going to order a DAFM soon just because I prefer an FM sound that uses feedback. Using chipsynth MD right now and it’s pretty good, I just realized I prefer hardware.
I am thinking the Preen might sounds a bit clean… but I felt like I’d probably miss things like unison and portamento/glide (although the DAFM creator did say he was planning to implement portamento soon when I spoke to him about it). Plus, I have a load of SID chips for lo-fi grunge, so hopefully it’ll be a nice contrast