Frequency Central Product Euro Kit. Thank Goodness It Worked the First Time

To change things up, this week I decided to build a Euro synth kit. A first.

Happy to say audio DIY kits are now everywhere, after a two or three decade lull it seems, and I'm sure at least some of you already buy from Internet shops the likes of Thonk and SynthCube.

Their FCP artwork, shamelessly lifted from their website.

Kits haven't been a part of my AudioDIwhY thing for a very long time--since the PAIA (1970s), CGS (2000),  and EFM (2004) days. What got me buying this kit was this vid (only 1K hits? For something called Frequency Central "Device"?) The dudes at my synth geek meetup said FC's "Product" is like what's in the vid, but better, FCP sounds frigging GREAT!!! Fat VCO--fat VCF--snappy VCA. Yeh baby yeh!!!!

Let's get building! Based on their advice I went to Thonk and slapped down USD. Three weeks later the FCP kit showed up, sat for a while as I got some 3340 VCOs going, but finally i got around to unwrapping it and checking out the build docs and found--wait for it:

****************THE BUILD DOCS CONTAIN NO SCHEMATICS************

Now I know I'm not Tom, Don or Bob, or whatever, but still, if I have a schematic in hand, I feel I can fix and mod (to my liking hopefully?) most anything. So I was really taken aback that the kit didn't have a schemo I could find anywhere.

How the hell can I build a complex electronics kit without a schematic?  For instance, to help me figure out why the damn thing is smoking?

The VCA/VCF PCB. The kit had 5 PCBs and one whole buttload of a lot of through hole dookie.

I emailed the support link on the FC site as I was starting the build--can you please please please send me the schematic--I promise not to post it or steal anything or even look at it unless I need to! And got--again, wait for it--nothing. Emailed them again--nothing.


UPDATE: 2-11-20 I understand the support email address on EC's site is wrong. For another DIYer I correspond with, Thonk gave out a different address which FC responded to. Hopefully FC fixes this?

I emailed them twice more about minor issues w the build--like a PCB silk part value contradicting the BOM--and a hf trim Roland doc they mention but don't provide a link--nothing.

OK now I'm worried. Big money for the full kit--hours spent building it--no schematic--no email support--this got my OCD knickers in a knot.

I told my psychiatrist girlfriend I was pretty upset, feeling like I was doing a trapeze act without a net, and that if I spent a lot of time on this kit, and it didn't work, I'd start (in my usual OCD way) digging into everything I could dig into to fix it, perhaps endlessly, and perhaps to the point of madness.

Trace all five PCBs out by hand? It'd take days, but, sure I could do that. Compare the FC PCB layouts to the Roland and Moog designs FC seems to based their FCP on, then redesign the entire thing using my own schemo and PCBs? Sure. Why not. It could happen. Who needs a day job?  Who needs personal hygiene?

My FCP module, ready for testing--what if the SOB smokes?

You know the drill: Is it safe?  Yes, very safe. Is it safe? No, not safe at all.

I told her for my sanity maybe I need to drop the whole DIY thing and chuck all of it, everything in my shop, everything on my bench, everything in my racks, before I go nuts. She took me very seriously and was, really, in her own very kind way, quite alarmed.

OK fast forward a few nights.  I didn't end up pitching anything. The build doc said what it needed to say; the PCB layouts from FC are fantastic, works of art really, and when I was all done, I fired it up. No smoke. No shorts. No red hot TL072s.  All the trims worked. All the jacks worked. The v/oct VCO scaling worked first time and was actually pretty easy to cal.

Even the stupid little 3mm LED worked.

Thank goodness--the FCP kit came out--great.

FCP in the rack.  Damn! Sounds good!

I got lucky.

To bench test the FCP, I also built a power breakout board for Euro power.  I already had a like breakout for Frac power, and now I have one for Eurorack as well.

The breakout was all from scratch, using perf, 22 gauge solid wire, and some cut up banana cables I had lying around. The schematic only exists in my head. That's better than squat.

OK, the perf breakout build part was rel fun.The rest of it? Um, nope.