One of the most popular destinations for musicians looking for help with any number of technical issues is Sound On Sound magazine, a veritable treasure trove of information just waiting to be unearthed, and on a recent visit I came across a really useful guide to buying modular synthesizer gear.

Don't be put off by the fact that it was published in 2009 because the modules described aren't going anywhere soon. A VCO is a VCO and VCF is a VCF regardless of when it was manufactured, the only difference between the classic modules and modern ones is the addition of digital circuitry and more efficient components.

Check it out here.

Update: There's a more recent article here.