H-Pi Flash Synth - World's smallest MIDI Synth

Sure will! Hope I have some time to do a little vid or something in December, but I’ll at least let you know what I think.

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:+1: have a good time exploring!

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want one of this.
must try get on the next round ordering.

looking forward to hear how anyone goes with this and digitakt
(and digitone too!)

First manual version is up, my initial impressions/comments:

  • output is described as ‘quiet’, which is expected and I imagine most people will have a gain stage to run this through, but what will really matter is the noise floor and no dynamic range figure is given.

  • MIDI - responds on ALL 16 CHANNELS. This is so that all 16 voices can have separate pitch-bend. But that means that CC and note on any channel will trigger the module, which I suspect will be … sub-optimal for a lot of setups, so hopefully that can be changed in FW at some point.

  • patches - you can save 128, changed with MIDI PC (again, on any channel). 34 are pre-programmed.

  • Controls - There are 19 CC controls, including mod wheel if you’re not concerned about the micro-tuning. So 2 MIDI Channels on the OT can control all parameters.

  • Algorithms - There are the 2 described in the video, standard FM and waveshaping. No subtractive/filter algo. Use of the arpeggiator reduces polyphony to 1. Algos can be mono or ‘stereo’ but no description of what kind of ‘stereo’ control is available is given in the document that I can see.

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Thanks fot you’re comments!

Mmm this is indead sub-optimal…

Got it over the Xmas break and had a chance to jam around with it sunday. Haven’t plugged it into the main setup because I didn’t want to deal with the MIDI channel headache, but I plugged it into the vortex 2 keytar and it was happy to share battery power - made for a nice little jam setup with just headphones plugged in! Sounds good, the output level is low as expected, but the noise floor is quite low also. I have a slight suspicion it does some power regulation tricks like switching the DACs off, but in any case any digital noise isn’t noticeable when playing. There is some digital noise that comes through when adjusting parameters over MIDI. This isn’t surprising, but is noticeable. It might be made worse by the fact that I’m running the Alesis on under-voltaged rechargeable batteries. TBD. Happy with it overall provided there is an eventual solution for the MIDI channel thing - either an update or it gets open sourced and I can fix it myself. I’ll do a more thorough eval at some point.

Thanks for this review

From the manual (https://www.ploytec.com/pl2/manual.pdf)

“At a Glance - New Features with Firmware V2.0
Now you can choose the MIDI channel and even the Omni mode (receive on all 16 channels) is available”

@johnl Different synth. It looks like maybe you can select a single channel in the ‘Universal Tuning Editor’ software we are supposed to get, but that is speculation. I haven’t gotten my license for the software yet and the demo version from the site doesn’t list the flash synth yet.

Sorry about that :slight_smile:
Did you get the channel selection working?

Any more opinions on this? I was curious about this one, but never followed up to see if anyone liked this. I just got an email about them being available again…

Oh, yeah, it’s cool. The channel selection works now, so it works pretty much like a ‘set and forget’ vst plugin on the octatrack. I have 2 MIDI channels devoted to the flash synth so all the parameters just come from the MIDI automation on those channels. I don’t think there is a way to store presets without hooking up the UART base, but it isn’t necessary, there are few enough params that 10 from each OT track covers everything.

One thing is that I have to be careful with the digital gain parameter - it is very easy to clip, and it clips unpleasantly. I usually have the gain down around 8 or so, and then I have it running through a MS50G pedal with a noise filter and compressor to keep the level even and provide a little more FX and tone shaping.

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Using it with OT was my plan as well:). Thanks for following up.

They keep mentioning that there’s an alternative firmware coming, with subtractive synthesis.

I just got mine today (it took a full month to get to South Florida from Germany) and I can’t get it working with the DT. As soon as it’s plugged in there is a strange rhythmic thumping sound and no synth sound. It works on the BS2 and the M:C so I don’t think there’s anything wrong with the unit. Has anyone used one with a DT?

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Update: It works exactly as expected on the MIDI out of the Keystep with the DT going into the MIDI in on the Keystep. DT is sending note data and program changes just fine through the Keystep, but I can’t get it to work plugged directly into the back of the DT. Maybe the DT doesn’t put out the right voltage to power it?

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Update: I put a Midi Solutions Quadra Thru (passive thru box) between the DT and the Flash Synth and I’m in business. I wonder if the DT puts out 5V on the power pin instead of the 3.3V the Flash Synth is expecting, as the Quadra Thru calls itself a “multi-voltage” box that works with both.

It sounds great and it’s awesome to add a poly FM synth to my setup without taking any space.

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It’s totally amazing to me that the H-Pi is able to run a microprocessor doing all that calculation, a D to A, and an audio amp all from the stray wattage that leaks through via the MIDI data itself.

We have done so much, for so long, with so little, we are now qualified to do anything with nothing. — Konstantin Jireček

This new algorithm did come out:
https://hpi.zentral.zone/blog?p=236

The tiny size gave me the idea of using this as a “3rd oscillator” on a monosynth, by setting it to listen on the same MIDI channel, and bringing it through the input and the filter.

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Currently available: Hπ Instruments | FLASH

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