I'm plugging away at smart.fm sentences, and I've run into an unfamiliar conjugation of ない - なく。

For example:
「昨今では農家は家畜ではなく近代的な機械を用いている。」
or:
「…その他には、声もなく。」

Kind of like looke like て form but w/o the て... What grammar is this, I can't figure it out

I couldnt figure it out either. I just go with it.

I'd like to hear some explainations as well.

Isn't that the... adjectival form? Something like that. I think this is covered and Tae Kim somewhere?

Yes, but ない isn't an i-adjective, so I can't see how it could be used as an adverb (where you have like 早い being used like 早く食べる)

The original sentence ...ではなく近代的な... and the て version ...ではなくて近代的な... mean pretty much the same thing. You'll come across the former pattern more often in written text and formal speech while the latter is more common in everyday conversation. Also, you might want to see them as a conjugated version of a set phrase "ではない" rather than the ない -> なくconjugation because 〜ではなく and 〜ではなくて are almost always interchangeable while 〜なく and 〜なくて are usually not, i.e., ない has various grammatical functions and meanings, but when it follows では, the little word て most likely doesn't change anything aside from the slight difference in nuance.

For example, なにも言わなくていいよ。(You don't have to say anything.) is ok, but なにも言わなくいいよ。sounds unnatural. So the function/meaning of ない here is different from that in your example.

The ないs in the first and second sentences in your post may be the same. But I can't say anything for sure without context.

FooSoft Wrote:Yes, but ない isn't an i-adjective, so I can't see how it could be used as an adverb (where you have like 早い being used like 早く食べる)

Where did you get that idea? It most certainly is an i-adj..

大辞林 Wrote:な·い [1] 【無い·亡い】 (形)[文]ク な·し

Formal writing often leaves out the て of て form. It is not the adverbial form.

@magamo:
Thanks for the explanation - it makes a lot of sense now. I was kind of suspecting it something was along those lines, but didn't want to learn it incorrectly.

@jarvik7:
Ah, did not know that. I thought it was only a negative conjugation of ある. Good thing to know.

ある doesn't have a plain negative form in modern use. A different word is just used instead (ない).

Negative conjugations of ある:
polite: ありません
literary/formal: あらず
(obsolete) plain form: あらない