Sontec MEP-250EX by Slug1
Sontec represents the holy grail of analog parametric EQ. Designed by Burgess Macneal and George Massenburg, these EQ's represent the foundation of parametric EQ. Sontecs are known for the amazing neutrality and transparency attributed largely to the HS1000 and HS2000 opamps designed by Sontec/ITI. There is the 400 series (430, 432, 482) which are at the top of the food chain of analog parametric EQs and are in many of the large major mastering studios. These are all stepped EQs of the highest order. And it comes at a premium where you typically can't find one under $15,000!! And then there is the little brother 250 MEP-EX, which is being reviewed here. These go for roughly $3,000 new and tend to retain their value.
The 250EX uses the HS2000 (some say the HS2320) opamps, while the big brother uses the HS1000. The HS1000 is supposed to sound slightly different but its believed the HS2000 is more reliable. All in all these EQs are super transparent both from the stand point of all bands off, and when making EQ moves. The brochure for this EQ states that its because of the low noise opamps, which let you make big eq moves and not increase noise. These eqs are great for both boosting and cutting and do so in a really neutral way. Aside from the first cousin GML created by George Massenburg, you'll be hard pressed to find an eq that just sounds so natural when you put it in the sound path. My favorite use is adding low end and adding hi mids. I also like it for cutting mids.
To be honest, if you are mastering, you can find things that seem to have more precision. The 250 is all pots, with the gain pot having a center detent. It has a full +/- 12dB, which is great for mixing and maybe mix buss, but for mastering +/- 6db would probably be better. There are some shops out there that will do the mod to +/- 6db. I've been planning to do it for a while but would not want to lose it for some period of time. I do need to do it though because it will likely improve its precision. It also has wide frequency range and broad bandwidth/Q range for broad or narrow cuts/boosts. I would probably make those types of moves with a good digital EQ, but when these were first built, analog choices were probably the only good choice people had and Sontecs and GMLs were among the best to do narrow cuts/boosts with limited phase issues. But there are other options with more precision. But hard to find something that sounds as good.
Ease of Use
Again, the issue is that this is not a stepped devise so precision is limited. But most vintage (this is a newer build but still a bit vintage) EQs were not stepped except for the uber expensive versions. But when you put it in the path and hear how it sounds, and then start turning knobs, you'll actually find it relatively easy to use and to get a good sound out of.
Overall, this is definitely an amazing EQ for the mix buss, and for some people who don't obsess over recall it can be used in a mastering context. I do because I'm okay knowing generally where I am and if I have to come back to something I can get close enough but will likely approach a revision a bit differently so perfect recall isn't as important to me. Also, I do like the ability to "hear" myself around the continuous pots from the frequency and Q standpoint to find what sounds good and not be locked into specific frequencies. This especially when I want to make a cut. I can use a frequency meter like Span to see and hear a resonant, and I can sweep through with this EQ to find specifically where I may want to cut or boost. Again, some knock it for not being precision enough, but one man's trash is another man's treasure.
I love this EQ and it would be hard to see myself without it. But of course if I get into a place where I'm ready to drop $8K on a Buzz, $12k for a GML 9500, or $15k for a Sontec 432, my opinion might change.