Frequently Asked Questions
Q: Is it a requirement to use a micro-SD card for operation?
A: Not at the moment but in future there will appear channels that do not work without it, as they need more temp space or use samples from SD (downloaded or previously recorded material).
Q: Which micro-SD card size, speed, brands are recommended?
A: Branded Class 10 cards work great, I've tested a few 8-32GB but no reason why larger would not work. Non-branded Class 6 that was previously used in a camera worked reasonably well too, apart from an occasional glitch (perhaps as a block of sectors needs to be erased here and there and it takes longer than expected). An older 1GB Class 4 card proved to be too slow.
Q: It seems it's not included?
A: No it isn't.
Q: What kind of Li-Po should I install?
A: Any 3.7V will do, ideally 1000-1200mAh. Even 800mAh is enough, Gecho's power consumption varies between 70-110mA, that should give you 6-7 hours of play. Just make sure the cell has built-in protective circuit as shown at the end of this article, and follow precautions in the assembly guides.
Q: Where can I get such battery?
A: I got mine from eBay but cannot recommend any particular seller as the consistency / quality of what is arriving varies - and these things are a potential fire hazard. You should have no problem finding a suitable one in Sparkfun, Adafruit, Conrad... Or a R/C model shop if you have one nearby.
Q: How many 14500 batteries does it need?
A: Just one.
Q: My unit has a holder for a single 1.5V AA battery...
A: Yes the 14500 lithium battery looks exactly the same as AA, but works at 3.7-4.2V. The 14500 refers to dimension (14 x 50mm), there are also larger and smaller form factors of the 3.7V li-ion cells (e.g. 18650 or 10440).
Q: The cover panel mentions that protection circuitry needs to be in place if a rechargeable battery is used. Can I be sure that this is in place? Is there anything I need to do? I don’t want to blow up this beautiful unit! :-)
A: The protection circuit is already installed, if you peek sideways from the slot you can see the wires going up and then later down to the board, the circuit is at the other side of the bottom panel. So it will be safe with any battery whether it does or doesn't have its own protection. The stored energy in such cell is minimal in compare to some other common rechargeable devices and the enclosure is made of flame-retardant material but just in case, don't leave it charging unattended e.g. while you're away from home (that's a good rule to follow for every electronics device anyway).
A: Shipping is 12 to 20 Euros absolutely anywhere - our post office is cool (but it does not mean it ships everywhere - see the next question). You can check estimated delivery times for some countries. So far Gechos found their new home in: Argentina, Australia, Austria, Belarus, Belgium, Brazil, Bulgaria, Canada, Canary Islands, Chile, China, Colombia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Guadeloupe, Hong Kong, Hungary, Iceland, Ireland, Israel, Italy, Japan, Korea (South), Latvia, Luxembourg, Malaysia, Mexico, Montenegro, Netherlands, New Zealand, Norway, Philippines, Poland, Portugal, Romania, Russia, Singapore, Slovakia, Slovenia, Spain, Sweden, Switzerland, Taiwan, Thailand, Ukraine, United Arab Emirates, United Kingdom and United States. Hoping to add new destinations to the list! :)
A: As long as it is not blacklisted, yes. It's illegal to ship Gechos into some countries as the CPU is powerful enough to drive an ICBM. No kidding.
A: They arrive from Ireland, and Europe is no problem - no customs, and very quick.
A: Our website only accepts payments in Euros (enabling other currencies brings a whole lot of technical issues). The exchange will be carried out by your credit/debit card issuer, please look up today's rates to get the idea. There might be a processing fee on top of that. If you wish to use bank transfer, we can agree on amount in your currency via e-mail up front.
Customs and taxes:
A: Sorry I don't know (neither for any other country). Please check with your local authorities. Parcels are shipped via post office, no couriers - sometimes the customs do not intercept. But nothing can be guaranteed.
Q: Is it possible to mark the package value under 35 EUR so I don't have to pay so much tax on it?
Q: Can you send it marked as a gift?
A: No. You are asking me to engage in an illegal activity just so you can save a few bucks? I would be risking having the goods seized or even getting banned from shipping to your country again. Please let me know if you prefer to cancel your order.
A: No plans right now. It's the same amount of work for me to ship to them as to you directly. Although I am looking at working with a distributor in USA, it might make things easier for you there (payments in USD, no customs and getting it quicker).
Please note the information below is concerning v1 Gecho (made in 2018 and earlier), however most of it still applies.
Inputs and outputs:
A: Yes, the outputs are capable of driving low and high impedance loads - from 16-64 Ohm headphones to 10k Ohm line-level inputs.
A: Great idea! Never tried it, but if it works with guitar perhaps it will work with violin. The input takes quite a broad range of voltages - from piezoceramic or electromagnetic pickups to line-level sources. Input gain can be controlled digitally.
A: Input is stereo, with LMV324 pre-amp and it is using MCU's internal ADCs which are 12-bit only (that's why I call it a "lo-fi in, hi-fi out" machine). Op-amp's gain is controlled by two 1M trimmers, and out of the factory set to the middle of the range. Not sure about how to express this in dB to be honest, haven't done necessary calculations yet. The DAC is CS43L22, same as on STM32F4 Discovery boards, but I am thinking of replacing it with TLV320AIC3104 in the upgraded version, so we can have 16-bit inputs and proper line-in (already tested it on some of the prototypes and it works very well). More info about architecture and also the schematic is here. The DAC is running at 22.050kHz in most channels (a trade-off between sampling rate and polyphony), but can go up to 96kHz. New DAC will have the same range. You can find details about the frequency response in linked datasheets.
DIY and MIDI:
A: It requires assembling some 0603 SMD components and an IC. They are at the edge of the board, so not many things around to damage, but using a practice board first is a good idea. If you want to get into DIY electronics, this might be a motivating challenge. Otherwise it's better to wait for the next production run that will have MIDI assembled, and probably a 3.5mm connector for break-out cable.
A: Current version - yes, the guide is here.
A: Cool! That's why I am not giving up supplying DIY kits, although they don't make too much sense economically (it takes almost the same time to pack them as to mount, and often they are even harder to program and test).
A: Recently these kits were packed with absolutely everything necessary, but not updating website just yet in case there won't be time to do this in future. The remaining components are only required in very small quantities and you should have no problem finding them in a universal SMD kit from eBay. It's a good thing to have at hand anyway.
A: Sorry, none at the moment. Master kit can take days to weeks to complete, plus there are various ways how to solder it (not only for passive components but those finer IC packages too). I am in no way expert to teach you the best practices, there is plenty of great videos on Youtube.
A: Next batch will definitely have MIDI assembled straight out of the factory (no way I am soldering one more damn opto-coupler :) The no-box option will be available too. Currently it isn't as equal number of boxes and boards were made, but in future we can plan this according to actual demand.
A: As long as "adept" kits last, MIDI bits can be added in the order form (SMD elements and a pair of DIN5 connectors, hope you can source the wires for cables easily, also decide what kind of "break-out" connectors works best for you).
A: Yes it is great to take it outdoors, it works best in not too loud areas (unless you plug a good noise cancelling headphones). Forest with birds is probably most interesting. Plugging into a loudspeaker will cause feedback loop, but after some experimenting owners were able to set it up to their satisfaction.
A: Great! There might be another Kickstarter, or pre-orders on the website. Working on it! :)
A: Software versions - adding bits and pieces all the time, updates are released at random but usually every 2-3 months. Hardware is evolving too, I have some prototypes under construction - but more on that later ;)
A: There is no difference. It's actually the same wood, just finish or paint is different.
A: Not right now, only the good wavelengths are allowed in Gecho ;) One of the prototypes uses ESP32 which has BT and WiFi peripheral; however, FCC / CE certification of such device is a lot more expensive than if it is just an "unintentional radiator". We could build such synth and leave those features unimplemented, so you can hack it and make it work the way you want. I felt that wireless is not really useful here, but might be cool for a DIY project.
A: Unfortunately I can't promise anything right now because I am not familiar the platform - it is one of the very few things that is not in my power to do in the scope of this project, so it needs to be outsourced. If the user base grows and there is funds for it, then by all means - support for other platforms (Mac and Linux) will happen. For now, Mac users have been successfully updating the firmware using Gecho app in Windows running in a virtual machine, also there is a way how to do it with a Python script. Hope this works for you.
A: I'm a lizard-person.
A: You should become a hardware engineer. But only if you can grow up quickly. Machines will obsoletize us soon. But we need to build them first. That could be your job.
A: I'm sure it can put you into an alpha state or such. Prolonged use also causes auditory hallucinations, significant loss of time and elevated mood for no apparent reason. Quite like a dream.
A: All the time! :)
A: Working on it! As for emailing, will do on regular basis. However, Internet overlords haven't yet acknowledged this website for a legitimate source of emails - if you don't receive anything in a while, maybe peek into the "spam" folder.
A: Yay! This one turned out very well. But every time I add a new channel, it feels like it's more fun than all existing ones.
A: MFG IS A GO. HDSHK. WE TX. U RX. LOADZ FUN. KTHXBYE!
A: Totally! We are all Cylons after all...
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