First, you need to explain what you mean by "phonetic", "phonological" and "analysis". You also need to explain what you mean by "before". To simplify matters, I reduce "phonetics" to acoustics, because that provides the necessary and sufficient basis for any statement about sound systems of spoken languages (and I also restrict the discussion to spoken languages).
In order to analyze a language at any level, you need data, which comes in the form of acoustic waveforms. The first piece of analysis that you perform is a segmentation, where you approximately divide the waveform into sub-pieces that correspond to "segments". Now you (Teusz) need to explain what you mean by "phonological" versus "phonetic". Presumably, you agree that anything that deals with numeric measurements of the waveform, such as the duration of a sub-part defined by certain properties, or anything having to do with frequencies or amplitude, these things are all "phonetic". Questions about rule-ordering, underlying forms, cyclicity and so on, are questions about phonology. It is completely unclear where to slot questions such as "is that a cluster [th] or an aspirated stop [tʰ]?"; "is that [d] or [t]?"; "is that sequence [tua] or [twa]?", along the phonetic-phonology divide.
The basis of all analysis is a phonetic object, the acoustic waveform, but the very first analytic product is a crude phonological categorization into segments. It is obviously premature to be thinking in terms of contrastiveness at this point: the initial goal is to develop an adequate system for reducing the massively variable acoustic waveform to vastly fewer discrete symbols. Is this a phonological analysis or a phonetic analysis? The input of analysis is a phonetic thing, but the output, a discrete segment symbol, is a phonological thing. So it depends on what you mean by "phonetic analysis" versus "phonological analysis".
Suppose the first word you hear is nivaka "knife". The objective fact is that there is about 30 msc VOT after the release of the stop, though you are not yet doing an acoustic analysis. There is no phonetic basis for deciding whether to record this as [nivakʰa] versus [nivaka]. It's not until you encounter ehalakha "basket" with 70 msc of VOT that you understand that nivaka and ehalakha contrast in terms of the phonetic property of VOT duration (a.k.a. aspiration). The thing that you have to attend to in the data is a phonetic property, namely VOT, and the product of your observations is a phonological fact, namely a contrast.
Discovering this contrast allows, indeed forces you to review your data to discover that you had previously encountered [kʰ] in solokho "mung bean", which you believed to be soloko. Since you happened to be recording everything, you determined that the speaker produced a somewhat atypical token with 50 msc VOT. There is no absolute minimum or maximum VOT value that defines phonetic aspiration, as shown by the fact that the aspirated stops of Thai have a shorter VOT than the unaspirated stops of Navaho (both languages have an aspiration contrast). One consequence of the fact that phonetic values of segments are not absolute is that in lieu of a contrast, you will have a hard time justifying a transcriptional choice. In very many languages, the highest back vowel sounds somewhere between Jones-defined [u] and Jones-defined [o]. IPA letters like [u], [ʊ], [o] represent ranges of formant values, and any attempt to numerically define the range presupposes a phonological categorization -- it would be invalid to include the values of the contrastive phoneme /ʊ/ from a language having the contrast /u, ʊ/ in a data-pool of formant values of [u]. It would be equally invalid to exclude languages which have no such contrast and where the highest back vowel sounds more like the Norwegian high back round vowel in the word "2".
The problem with the word "before" is that it may falsely lead you to believe that you must create a repository of phonetic conclusions which you can subsequently further analyze into phonological conclusions. There is no strict separation of levels of analysis: creation of some phonological conclusions is a prerequisite for creating phonetic conclusions, which can be used to justify further phonological conclusions. The basis of analysis in sound systems is a phonetic object, the acoustic waveform, but the kind of analytic object that results from doing the analysis may be phonetic or phonological, depending on the methods that you use.