Most of the assembly on the first VC528 is done
Description from Jeff Steiger of Classic API:
The overall goal of the VC528 is to achieve the complete and lovely sound of a vintage API console channel without the cost of the rest of the console. It is definitely a little something different for the 500/51x format. Basically, it is a two stage console channel with the vintage circuitry of my API board.
I finished my second VP26 preamp this week. It’s ready for testing and then studio work. The first one was done a month or so ago, but I didn’t have time to write a post since I took it straight into a week-long remote recording session. The VP26 sounds excellent on snare drum – I dialed in just a taste of input stage crunch and controlled the output level with the attenuator. With an SM57 on the top of the snare and a blackface UA 1176 compressor afterwards, it sounds just like a snare should sound.
Finished VP26 preamp #2
Next, I’m building two Classic API VC528s, and then two JLM BA 500s.
I’m well underway with my first VP26 preamp. So far, everything has been smooth sailing. The instructions from Classic API are very thorough, and parts are well labeled and packaged. As someone who is used to building things from a schematic that I made myself, it’s been a pleasure to build from a kit.
The only puzzle I’ve had to solve was the gain switch. When I ordered the VP26 kit, I selected the option for Stepped Gain. This allows gain matching of two VP26 preamps, so I can get a true stereo image when recording things like an X-Y room mic pair.
The gainswitch board, stuffed with resistors
The instructions mention a special mounting procedure for the Bourns 25K gain pot, which I couldn’t find anywhere in the kit. I did find a bag marked “VP26″ with two small PCBs, some resistors and two Grayhill rotary switches. It took me a while to figure out that these were the stepped gain switches, and that I didn’t have the Bourns pot because it was replaced by this assembly. I found an email that Jeff Steiger at Classic API had sent me with thorough documentation on assembling the gain switch. That got me up and running again.
Here’s a shot of the main board for the VP26. Note the large cutouts for the input and output transistors, and how simple this circuit board is. There really aren’t that many parts to the API console pres, but as the kit instructions say, “High quality, sometimes custom component selection is crucial to achieve this sound.”
Main board of the VP26, a vintage API console-style preamp
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While I move forward with testing and implementing new ideas for the Spectrum, my digital preset switcher for analog pedals, I’m also doing some kit building. I’ve got four kits for 500 series microphone preamps, including kits for discrete op-amps, and two kits for console-style faders. In case you’re unfamiliar with the API 500 series format, it’s a DIY builder’s dream. The idea is to centralize the power supply and routing for studio effects units, which saves me time and money. I can use a standard API Lunchbox, which comes assembled with the power supply, routing and enclosure, and add preamp kits as I build them. The effects are modular and mounted to a faceplate with a standard card edge connector that plugs right into the power supply / routing unit. This makes assembling a custom setup easy. The modular idea works a lot like the Colorbox, and I immediately found it attractive from the user perspective.
My first kit is the VP26, from Classic API. It’s designed to replicate the sound of preamps from API consoles of the mid-70s, which are largely responsible for what people call the “LA sound” on drum recordings. They’re supposed to be aggressive and gritty in the midrange, perfect for snare and toms. Sounds good to me!
The first step of building the VP26 kit is assembling the discrete op-amps. These are parts which can be subbed out for integrated circuits, but most people agree that the discrete versions sound better. I keep making this discovery in audio electronics: when circuits are built from the best possible parts, and kept as simple as possible, they sound better. In this case, the more advanced technology of ICs, though it may reduce the parts count and keep the cost low, is not as desirable in terms of tone.
Here’s a photo of my first gar2520, the opamp I chose to build for my VP26s. I’ll post more as I go along.
gar2520 discrete op-amp
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Well, I’m back in the land of the work week and weekend. SXSW was an amazing experience, to say the least, and it taught me a thing or two about my ideas. I met lots of people, played 11 shows in 10 days, and saw some incredible performances.
I’ve already got a list of improvements to make to my prototype. Here are a few of the big ones:
- Standardize the enclosures. Making boxes for pedals to fit in is hard to do right. They have to fit like a glove, take lots of abuse, work right, and look good doing it. I’ve been working on this problem for a while, and I have approached it from a few different angles. My plan is to find a partner in crime who can build me some awesome enclosures, to the specs I need. More on this to come.
- Fix switching behaviors. I figured out that the switch which determines whether the pedal is operating in manual or program mode is hooked up backwards. It all still works, but that just means that when the Spectrum is disconnected from the Colorbox, the Colorbox can’t work on its own. That’s a major part of the design – the idea that the Colorbox can work like a simple multi-effects pedal – so I have to get this part working right. Fortunately, that should be an easy fix. Also, I learned that vintage Fender reverb circuits are switched opposite from the tremolo circuit. This means that the reverb is engaged when it’s not grounded, rather than being engaged when grounded. Another easy fix, but important.
- Build, test, rebuild, retest. I had a lot of positive feedback on my ideas, and I hope to release my product for sale soon. However, it’s going to take a while to get this ship ready to sail. Add a week or two for me to get set up with my workbench again (I just moved to Oakland), and it’ll be a bit. Rest assured that when I do hit the market, my products will be shipshape.
Until next time, here’s a photo from the last show of the tour, at the White Barn in St. Helena, CA. Enjoy!
Playing through Sonic Wizard prototypes with Buckeye Knoll
More photos of the prototypes I’m making:
I’ve been heading to the workshop to build enclosures (electronics-speak for boxes) that my prototypes will live in. Here are some photos of my progress.