Classic Audio Products VP26 Mic Preamp

One of my recent projects on the bench is a pair of mic preamps by Classic Audio Products of Illinois.  I can’t say enough good things about this company. They are providing parts, circuit bards, and instruction that make top-quality builds of classic audio circuits available to people who are passionate about sound.

I had started with their 2520 discrete opamp kit, described in a previous post. These mic preamps are the end use of those opamps. I’ve put off building these for awhile to save up the cash, but finally bit the bullet and bought most of the parts to complete a pair. They aren’t finished yet… I still have a few more parts to buy, and I’m deciding whether to fabricate my own faceplates or use theirs. But I’ve competed enough of the build to give at least a preliminary report.

A pair of VP26 mic preamps at my bench. Still have transformers, pots, and switches to add.

For me, building one of these is not a casual proposition. I’m not a component-level engineer, and the risk that I could somehow screw this up is very real. But if there’s one thing that defines this company, it’s quality. Everything they supply is top-grade.

For example, let’s start with the documentation. The VP26 assembly manual can be downloaded here, and it’s clear that Jeff spent a lot of time to make this as clear as possible. With a project like this, clarity is important… there are plenty of opportunities to botch any electronics circuit (even more so when I’m holding the soldering iron), and the extra photos, instructions, and advice help to ensure that you aren’t likely to end up with a non-functioning preamp.

The circuit is an all-discrete update of a classic mic preamp circuit that has been optimized for contemporary parts. I’ve often studied old circuitry, only to find that they use obsolete and unobtainable parts, and I lack the ability to re-design for modern components. Jeff Steiger, who owns a 1976 API 3232 console, founded Classic Audio Products after years of experience maintaining and tinkering with his own console.

The components used in this circuit are the other side of the quality coin. There are no shortcuts in this design. The circuit boards have nickel-plated holes… this means the they take up solder for better connections with less exposure to heat for the part. Pots are all Clariostat sealed conductive plastic, and a glance through any Mouser or DigiKey catalog will show you that these things ain’t cheap. They should last for decades. The design uses Nichicon electrolytics, which are widely regarded among the DIY community. And the transformers are custom-wound by Ed Anderson to be as close as possible to the original equipment used by API.

This company should be appreciated by everyone in the professional audio field. In this day and age, it’s all too common to find gear that’s cheaply made by overseas copycat suppliers, and this is the antithesis of the “cheap is good” mindset. These things AREN’T cheap… each kit comes out at a hair under $200. But if I went out and bough all the components from individual suppliers, it would likely cost more. Their profit margins must be pretty slim indeed, and I believe that a big part of their business plan is a passion for quality audio. I want to support that whenever I can, and the best way to support them is to buy their stuff.

I’m very much looking forward to completing these units, even though I won’t be using them much for live production. What I need to do now is beg and plead the folks at Classic Audio Products to design an EQ or compressor circuit board and/or kit that uses the 2520 op amp, so I can build some more!

2 responses to “Classic Audio Products VP26 Mic Preamp

  1. Great review, and you couldn’t be giving publicity to a better company. Just curious–how are you planning on racking them up?

    The only DIY comp or eq I know of that uses the 2500 DOA footprint is Peter Cornell’s 5003 EQ.

  2. For racking, I’ll probably have to bite the bullet and buy an API Lunchbox. I’m still undecided about the faceplate… I’ve fabricated my own aluminum plates, but I want different graphics. I’d like to develop a method of printing them without the cost of a silkscreen, like an inkjet print on photo paper that’s then laminated, but so far my results haven’t been good enough. The hunt continues…

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