First of all, this ModularGrid module builder is great! thank you, i wish i saw it a month ago haha.

Right now, technical people would call my style 'industrial hip hop', sort of like technoanimal i guess but better. Maybe some days more Funk than others. Anything near experimental or ambient tends to be dub reggae like King Tubby or Lee Scratch. If i feel like turning up the BPM, it's jungle-ish with maybe a Gangstarr sample. Heavy Drums, Heavy Bass, add in a catchy melody with some accents, samples, etc, that's my style since the 90s.

I own the following external devices for reference:
-NI Maschine....a bunch of Volcas.......a bunch of Pocket Operators....a Drumbrute Impact.....a Microgranny, Thyme, Kastle, 60 Knobs, and Trinity LXR Drum Machine.....miscellaneous digital rackmount effects....a Monologue......four turn tables and a microphone.....and a BEATSTEP PRO.

What i'm trying to do is expand my sound repertoire for more Industrial Hip Hop. I prefer to call it Digital Hard Hop but whatever. Any modular rack system is incorporated to my toolkit above, i'm looking for sounds the others don't offer.

Here's the modules i have already purchased(most purchased in kit form still need assembly):
RACK............108 HP ghetto rack
DRUMS.......Qty 3 Synthrotek DS-M drum modules (bassdrum, snare, hihats)
VCO.............Atari Punk Console (square wave, it was cheap)
VCO.............Rat King Modular - TONE - (triangle, saw, pulse, AS3340 chip)
VCO/LFO....Bastl Tromso (triangle, LFO, sample and hold, distortion)
ADSR...........Blue Lantern ADSR (linear and exponential, loop mode)
FUNC GEN...Joranalogue Contour 1 (env generator, LFO, VCO, everyone else has Maths)
FOLDER.......Bastl Timber(wavefolder, VCA, feedback, overdrive)
FILTER.........Bastl Cinnamon (hp,bp,lp, can be used as oscillator)
FILTER.........Synthrotek 308 Distortion
FILTER.........Synthrotek Dirt Filter (sounded cool, supposed to be effects filter, low pass)
SEQUENCER... Division 6 Business Card Sequencer (may use BEATSTEP PRO instead)

Last thing i think i need is VCAs. Was looking to buy the following:
VCA .............Doepfer A-135-2 (Quad VCA and MIXER but not exponential(!))
VCA.............Bastl SKIS II (VCA, Env generator, but also linear)

Is there FUNCTIONAL aspect of SYNTHESIS that i am MISSING here?
Do i really need exponential VCA's? If i buy the two listed above, i have 10HP left.

Any recommendations?

Thanks guys! hate to be anther NOOB haha.

Exponential VCAs don't have to be entirely new VCAs. The Intellijel Quad VCAs can be tuned to respond linearly or exponentially. It's a matter of preferences. If you want your VCAs to respond exponentially to your linear signals... then sure. But it's up to you if you need them.

Your rack could use some utilities like attenuators or attenuverters. You have a quad mixer/VCA unit. That's fine. But I see at least five sound sources. You don't necessarily need more mixer channels. But it's something that I noticed. Another small mixer for mixing CV (or audio) would be great in here. It doesn't need to be special, just handle audio and be DC coupled for CV.

Do you have a noise source? Pink and white? Noise mixed at low level can add some grit and character to a sound, even if you're filtering off the high end.

I'm assuming that your sequencer and time based effects (reverb, delay, etc.) are all handled outside of the box.

Thanks so much for your answer Ronin!
Actually i have 6 VCO sound sources haha.
I was looking at the Intellijel Quad today, it looks perfect but i dont have much space left. I can always remove some of the elementary synthrotek stuff. Any VCA function inside the rack would be strictly for voltage control and logic functions, i have an extra 6 channel desk mixer to use for output.

REgarding white noise, the DS-M drum modules have 3 color types on a toggle switch. The MIX pot blends the built in VCO with the built in noise VCO. However, you are correct, if i am using all three modules for drums already, i have no noise source. My 'studio' area also has an old short wave radio that i built years ago, i was thinking of using that as a noise/sample source at times.

Regarding the attenuators, inverters, adders, shifters, polarizers.....thank you for the heads up. I cant really fathom what i would use an inverter for or an adder for, i need to see it on an oscilloscope and hear it with my ears first. However, my goal here is to be able to modulate and create logic functions wherever possible, i'm an automation guru at my day job, that's my cup of tea.

Would a single quad passive attenuator be sufficient? (hopefully one with add/subtract also)
Maybe i throw in a Doepfer A-183-2 Offset/Polarizer for good measure?

An side question also, If i plan to bring in external audio into the rack, is line level going to work well? Do i need one of these LineLevel Utility modules if I plan to bring in a sample to mangle?

Thanks guys! Just me writing this out helps a lot anyway haha, thanks again Ronin for the input.

I'll take whatever recommendation that are out there.

" I cant really fathom what i would use an inverter for or an adder for, i need to see it on an oscilloscope and hear it with my ears first."

The inversion won't make a huge difference to audio rate signals but will make a major difference in much slower CV.

Well, let's take an attenuverter module as an example. I own a Befaco dual attenuverter.

Each channel has two knobs. One controls attenuation the other controls offset. Full clockwise passes your original signal, full counter-clockwise passes your original signal 180 degrees out of phase. 12 o'clock mutes your signal. The positive range simple attenuates the signal, the negative range ALSO attenuates the signal but inverts the phase. The offset moves where your signal centers.

So let's take a simple LFO and plug it into the Befaco. Its range is -5 to +5v. If I start at full clockwise and turn the knob down I can diminish the range to something else... let's say -2 to +2V. If I'm in the counter clockwise range I can possible have my LFO running at +2 to -2V. Again, for slower modulation, this will make a difference.

Now let's get to the offset. We'll pick up at the +2 to -2V we just dialed in. By turning the offset knob I can keep the range of the signal... which is now 4V peak to peak versus 10V where we started... and offset it to something else. How about +5 to +1V, or -1 to -5V?

In the modular environment, it's all about the voltages. So being able to manipulate them in this way is going to give you much more fine control over how you modulate a CV input. Some modules do have built-in controls over the CV inputs; others do not. Some have controls for some functions but others are just a straight input (think of a filter with a built in attenuator for filter cut-off, but only a simple jack for resonance).

Precision adders. They simply sum a signal. But they do so with... precision. For something like summing two sources of modulation to control a filter cut-off... it's probably overkill. But where it counts is if you're taking two CVs that are controlling something like an oscillator's pitch and trying to sum them into a third pitch, you want something that's going to be exacting as inaccurate summing when you're trying to control pitch will lead to notes that are out of tune... even more so if you're covering a greater range of notes.

I'm sure there are details I'm leaving out and more accurate ways to describe the above... but in practical terms, this is why that these types of modules are very helpful in a modular environment.

Examples of using both:

Inverter: Let's say you have a pair of mono phase shifters, and you'd like to use these to create a signal that pans its phasing. To do this, you would mult your audio to both phase shifter inputs so that each one has the same signal to process. But when feeding the phase shifters with a single LFO for modulation, you'd first split these as well, but then one LFO split goes through an inverter before the phase shifter, while the other goes in to modulate the other phase shifter as normal. The result will be that when the first phase shifter is at the top of its sweep, the other is 180 degrees opposed and is at the bottom of its sweep. Also, in audio inverters can have a very neat use with effects; you can use a mono reverb to put a typical reverb effect on an audio signal, but before the reverb you'd mult the audio. One mult goes on to the reverb, and the other to an inverter, and both signals come back together in a mono mixer. In this usage, the inverted audio will cancel the "dry" part of the reverbed signal...but will also partially cancel similar waveforms in the reverb's output. As opposed to cranking the reverb to 100% wet, this method creates more of a "ghosted" signal, with the cancellation of the similar waveforms in the resulting mixer output becoming less and less as the reverb processes the zero degree signal with a certain degree of imprecision.

Adder: These are the reliable method for adding offset voltages to CVs. Let's say you have several VCOs fed from the same CV. This goes through an adder before splitting. Then, you have a sequencer, and you want to transpose all of these VCOs identically with it. The messy way would be to feed the VCOs directly. But the right method would be to use a precision adder to combine the incoming CV with the sequencer CV, then split the adder's output, as this gives you a lot more control, a simpler signal path, and as long as your sequencer CV out has quantizing, you can transpose the VCOs in exact steps to anything you prefer while at the same time maintaining proper CV control from your own local controller, MIDI, etc. Simple, straightforward. That example is one of what's probably countless uses for these.

Lastly, line level audio in Eurorack. Yes, you need a preamp. Audio signals within the modular environment are several times higher than typical line level signals, plus the impedence difference between your external source and the modular can also be a detriment that a good input module can correct. Another reason for having an input module is that many of these also have envelope followers, which allow you to take the dynamic information in an incoming signal and extract that to a CV, and these prove invaluable when using the modular as an external signal processor...such as in using the incoming dynamics to sweep a VCF in tandem with the external signal's peaks. Plus, a good preamp with isolation helps keep ground loops out of the synth; conversely, this is also why you should have output isolation, in addition to stepping the synth levels back down to line level.

input is appreciated guys THANK YOU!

i did some studying up on attenuverters this weekend, and i saw the utility in all the utility modules and realized they are probably was more important and versatile then the latest coolest filter. Inverting a signal to create panning with VCAs is pretty darn awesome.

i guess now i need an attenuverter, quantizer, and precision adder haha. what else ha?
tons of mults? i picked up some 3.5mm female jacks and blank panels to make my own passives. Also got some toggle switches to make passive mutes.
I picked up another VCA (Intellijel Quad) so i'll have 1 linear and 1 linear/exp.
Not sure which attenuverter to pickup, i'll figure it out.
My old soldering iron didn't have enough wattage so i just got a new Hakko.
I still have to put most of these together.

Now i have to lookup adding voltages, i'm sure it's much deeper than doubling an octave.

I think the plan now is to get that attenuverter, then put all these kits together and actually make some noise to figure out what else i need going forward. Looks easy in this game to make the wrong decisions as a noob and have a $2000 rack that does nothing! ha!

Thanks for your help guys! Going to research utilities til the holidays and work with what i've got so far.

If you enjoy putting together your own modules, Befaco almost always has kits available for some nice finger burning sessions. :)