A good question but with a rather complex answer. The early modern period saw a huge rise in army size and growth, as well as a disproportionate increase in the proportion of infantry with an army. How soldiers were equipped in western Europe was often similar, but who supplied the arms was dependent on where the unit was raised, and who raised it. Let us take the British Civil Wars for instance ( and place a timeframe at 1639-1651), partly because I know more about it, and partly because taking place as it did in a nation which had been largely peaceful while Europe was waging multiple wars, it gives an example of different methods.

First its important to note that the lords did not levee or conscript their own regiments in these wars, the colonels of regiments were indeed often lords (at least initially) and during the outbreak of the English Civil Wars, many of these new colonels sourced volunteers from their own social networks - junior officers from their friends and their families, and private soldiers recruited by beat of drum from areas where they held influence. (But the view that Lords forced their tenants into service is not accurate, although it still hangs around in the popular imagination). Finding volunteers for officer roles was not that hard though as the pay was good for them, and the role carried a certain status, as well as returning officers from overseas service providing experience and training in modern techniques finding senior roles in the new regiments. However, apart from a brief period of 1641-1643, the majority of infantry in the field armies recruited in England were raised by impressment, at the parish level from the poorest and meanest in parish society. Their clothing and equipment was supplied by the army administration, sometimes at the regimental level, sometimes at the local army level, and deducted from their wages. This is simply because the men raised in such a manner did not have the private funds necessary for equipping themselves in the latest military technology. If they had that much money, they would have been able to avoid impressment by several different reasons (such as by serving in the militia which was by long custom and expectation immune to impressment).

Now militiamen of the period in England, by the nature of the seventeenth century militia had to source and equip themselves on their own money, and to keep their equipment in good condition if called to duty. For the Bishops' Wars of 1639/1640 the English king attempted to recruit/press some of these militiamen into service as regular infantry and thereby bypass the costs of equipping them, however widespread use of the substitution clause, and a desire not the lose their expensive equipment, meant that many of the "militia" so recruited were in fact poorly equipped substitutes. For the initial wave of volunteers in 1641 against the Irish rebellion, and in 1642-43 at the outbreak of the English Civil Wars, some of the signing bounties were increased if a man brought some or all of his own equipment (this would normally be a militiaman joining the field army of his own free will).

Initially most of the equipment was drawn from military stores in the Tower of London, however these were rather rundown in equipping troops in 1640 and 1641 so when the English Civil Wars broke out, a lot of the equipment from the various forces came from three main sources: Seized county armouries where many militia arms were stored, foreign imports, and private collections. Bear in mind that some of these private collections could be quite large, comprising not just a wealthy individuals own weapons, but also the weapons he was expected to equip and maintain his proportion of "trained men" as part of his militia duties. Likewise, personal armouries had been built up through the preceding years from a variety of sources and for a variety of other reasons. As the wars progressed so too did the weapons manufacturing industry expand dramatically everywhere across the country, mostly in major towns like London, Oxford, Bristol, Shrewsbury, Manchester, etc. Gunsmiths and other weapon makers would be paid for supplying their produce to the regiments, often initially on credit, and subsequently reimbursed when cash was ready. Again, soldiers had their pay docked (in theory) to pay for this.

I am not sure how much more detail to go into, so if you have any further questions I can try answering those if you want to dig down into the detail.