Classic Audio Products of Illinois: VP26 preamp

As an owner of a 1976 API model 3232 console, Jeff Steiger has years of experience restoring, repairing, and modifying his desk. The modular build of those APIs is modification-friendly. Being a tech-nerd, he built, duplicated, or sourced many unique printed circuit boards and other components that are crucial to the 3232's sound. He founded Classic Audio Products of Illinois as a way to help other vintage console owners and to share his work with other audio electronics enthusiasts. Classic Audio Products offers two DIY preamp kits. The VP25 comes with an Ed Anderson EA 2503 output transformer and is more in line with a 312-style preamp. The VP26 uses an EA 2623-1 output transformer and is more aligned with the vintage console preamp sound. We tested the VP26. As I've mentioned in other DIY reviews, every project has a unique story when it comes to parts/component sourcing. The Classic Audio Products kits come complete except for a Discrete Operational Amplifier (DOA), which must be obtained separately. The project uses the standard 2520 footprint. And since the DOA attaches to the circuit board via Mill-Max sockets, swapping out DOAs is simple. If you don't have your own op-amp, Classic Audio Products has two options at their store. First is the gar2520, which is a nine-transistor DOA by Gary Barnett of Barnett Industries in Amherst, Ohio. Second is the SL-2520 Red Dot, a ten-transistor DOA hand-built and tested by Scott Liebers of Scott Liebers' Labs in Minneapolis, Minnesota. We used the SL-2520 because (a) it comes assembled, and (b) I had been reading about them for a while on Eddie Ciletti's site (www.tangible-technology.com). Neither op-amp is potted, meaning they are not encased in an enclosure filled with epoxy. Manufactures resort to such measures to prevent theft of their designs. Instead, they are exposed, which translates to greater heat dissipation, longer life, and ease of service should they require repair. As of this writing, I have yet to build and test the gar2520, but I will say patience, a steady hand, and experience are required to build one; there are a lot of parts in a very small space. Everyone's definition of "soldering experience" is different. This kit is designed for moderate to experienced builders. Perhaps I'm biased, but I believe most Tape Op readers are much more prepared for this kit than the average recording enthusiast. So, if you've made many microphone / instrument cables, built a few projects from PAiA or your own guitar effects, and know your way around a multi-meter, you're probably ready for this kit. That said, this was one of the quickest projects to build (again, I used the pre-assembled op-amp from SLL). The full-color directions are a solid "A" in terms of clarity and illustration. There is even a page that helps with resistor separation. Enough of the building, how does it sound? We did direct comparisons against our API 212 preamps, which live in our Sony MXP-3036 console. If you're not familiar with the 212 line, I would describe them as beefier than today's 512c and 3124 preamps, but slightly less colored than '70s era preamps from the 3232 console. Depending on how you set up the gain stage, the 212s can be reference-quality clean. In fact, we purchased our 212s from Sony Classical, who were using them for symphonic recordings. Our first impression was the VP26 is not just similar to the API 212, they're closely related. Specifically, on snare drum, it was difficult to tell the two apart, although it seemed that the VP26 had more headroom and broke up a hair later than the 212. On picked acoustic guitar the difference was more noticeable, with the VP26 having more clarity. The 212 seemed veiled in comparison. On strummed acoustic, the two were so similar I gave up trying to force a difference for the sake of the review. Likewise, electric guitar was the same story. These tests led me to conclude that on loud sources, the VP26 is virtually identical to our API 212s. But on softer sources, it's much more revealing than our 212s. Honestly, it was like comparing a Millennia Media against the 212; that's how much more clarity there was. Speaking of other brands, we decided to shoot the VP26 against some other makers. Singer/songwriter Ben Shannon was in for a vocal session and volunteered to be our test subject. Using a vintage Neumann U 87, we compared the VP26 against a Millennia Media TD-1, a Purple Biz (Tape Op #55), and a FiveFish SC-1 (#72). Ben has a voice that lives in the midrange but can wander in higher registers. I would say he's similar to Tom Petty from a frequency standpoint. All the preamps sounded good listening to them alone. When we added the backing tracks we started to form opinions. The FiveFish was too thick, leaving Ben's voice fighting with the acoustic guitar. In a similar sense, the Purple let the vocal sit lower in the midrange of the mix. Both the TD-1 and the VP26 tended to showcase the vocal, with the TD-1 being gentler on the low end and the VP26 being more forward in the mid and upper midrange. In the end, Ben and his engineer chose the TD-1, but it was a close call. This goes to show that our pre-conceptions about what certain brands "sound llike" aren't always how things play out in the real world. As always, it pays to do real tests with real performers and then make educated choices. In this case, we forgot how open and clear the API-family can be when not driven hard. Speaking of driving a preamp, one of our engineers noted that the VP26 was very easy to drive, providing that "aggressive rock" sound we often want. Hitting the input hard and pulling back on the output attenuator sounded completely different than minimal gain with the output wide open. For electric guitar, just grab an SM57 and experiment with the gain structure of the VP26. Most people will tend to drive the input, bringing out the harmonic color this preamp can provide, but the range of options is vast. As I finish this review, I'm just marveling at what a drum set would sound like through a full console of these bad boys. If you want a truly retro-sounding preamp, the VP26 nails it. Best of all, at low gain settings, it's open, detailed, and revealing in a way that is completely different from its driven sound. If you're handy with a soldering station, I urge you to order a pair of these for your collection. (Of course, fully assembled kits can be purchased at the Classic store.) The VP2x kits are GroupDIY 51X Compatible and require an appropriate 500-series lunchbox or chassis. I'm off to build other things. Stay tuned for more DIY reviews. (VP26 kit $199.37 direct, fully-assembled $535, SL-2520 $70; www.classicapi.com, www.scottliebers.com)