So everyone on here is a troll, got it!
-- Hellseeker
No, not really. But if you're going to post a build, and it's got clear and apparent issues, you're going to hear about it. And this one fits right in there...
For one thing, there is an excess of audio modules here. I see several possible audio chains...except for the fact that you've only got five VCAs for this entire build, and you need VCAs for both the audio AND modulation. Five won't cut it. Then there's the envelope generators...as in, there aren't any. Sure, you can use the Maths for that, but doing so is sort of like using your Ferrari Dino to pop around to the Circle-K for some jerky and a Monster tallboy. Also, I see no submixing possibilities (and I refuse to count the Erica Mix/Splits here...mixing implies control over incoming levels, not "jam everything in with no control") at all aside of the three inputs on the Fusion VCF.
Then there's all the tubes. Tubes draw more current than solid-state devices, and tend to require beefier power supplies to deliver it. So, at present this build has a "calculated" draw of 2.4A. Then, to avoid inrush (and tubes do current inrush like nothin' else!) issues affecting the power supply, you would need a supply to deliver 3.2A on the +12V rail alone. And that's going to COST...
But what's here costs already...and unnecessarily so, as well. ARE the tube modules necessary? Are they present from the idea that "tubes = loads of noise" (not really true)? Couldn't you do better (and cheaper [and with less current draw]) with some regular-ish VCOs, a PROPER submixer, and a wavefolder to deal with the distortive waveshaping? Do you have to have these large modules eating up your valuable panel space? Panel space that NEEDS to be filled with all of the various utility and modulation modules that are necessary...but not present here for the most part?
There's a term around here for the problem this build has: "Sexy Module Syndrome". This happens when someone gets all hot-n-bothered about slapping "feature" modules in, mesmerized by the blinkenlichts und tvistenknobs to the point that they neglect the fact that those "sexy" modules REQUIRE a proper complement of the "boring" ones so that they can be used to their fullest. That's what utilities DO. It's VERY easy to build a build like this...but all you get in the end is a very expensive noisemaker, and not a proper synthesizer.
I'd strongly suggest looking at the builds on here that are done by experienced synthesists. There's plenty of them here. Note how they deal with this primary issue. Then, if that's not sufficiently convincing, get a copy of VCV Rack and try putting together a mockup of the above (as best as possible in VCV...although, you can get pretty close). See what it does and doesn't do. Then apply whatever knowledge you can glean from those example builds to the VCV mockup...and you'll notice that, all of a sudden, that VCV build is really acting like a synthesizer.