Bumblebee Bb-D2 Discrete Op-Amp Direct Box - DIY Kit

Bumblebee Bb-D2 is a state-of-the-art direct box for recording studios and stage. Its main features are the discrete op-amp topology and a premium grade LSK389 Dual Jfet input stage. Moreover, the kit includes our own custom designed toroidal output transformer to balance the output. The DI circuitry incorporates the electronic ground lift for breaking the ground loops on long cable runs. You can have the Bb-D2 Discrete Op-Amp Direct Box either as a full DIY kit or an assembled unit.

Improve Your Sound with a Premium DI

A proper direct box is a very important pro-audio device that can sometimes make a day-and-night difference in reproduction quality. Typically DIs are used for electric basses and guitars, but also for piezzo pickups, passive Rhodes and various other keyboards.

The Bumblebee Bb-D2 Direct Box circuitry in particular was designed for getting the best out of your instruments. We’ve fine-tuned it for precise reproduction of sound, right as it comes from your fingertips. No buttons or switches, just plug in the instrument and turn the phantom power on. The Bb-D2 DI will do the rest – exactly what is was made to excel at.

The Most Notable Features of Bumblebee Bb-D2 Direct Box

Discrete Op-Amp Topology

The discrete op-amp based topology is usually found in expensive top-level recording gear. With Bumblebee Bb-D2 we are bringing the discrete op-amp philosophy to the world of direct boxes. As you might be aware, the most critical part of nearly any audio circuitry is the input stage. It determines the quality of sound to the greatest extent. Therefor, with Bb-D2 DI you can have a Hi-Z instrument input equivalent in quality to Hi-End studio equipment that is usually outside the budget for most recording enthusiasts.

LSK389 Dual Jfet

Hi-End Dual Jfet Input Stage

The input stage of the discrete op-amp in Bumblebee Bb-D2 uses the ultimate quality LSK389 dual Jfet. It is an electronic component that consists of two perfectly matched Jfets in a single metal can with six classy gold-plates leads. The properties of an op-amp differential input strongly depend on the precision of input amplifier matching. As a result, the nearly ideal consistency of a Jfet pair in a single can guarantees the great performance of the whole op-amp.

Custom-Designed Toroidal Output Transformer

In order to avoid the huge costs of branded transformers that would double the price of the kit, we’ve designed our own. It is a toroidal design with outstanding sonic properties and very low DC resistance. So, every Bumblebee Bb-D2 Direct Box comes with output transformer included by default, so you don’t have to pay extra to get one. Moreover, by designing the transformer ourselves, we were able to match it perfectly with the circuitry.

PCB-Mounted Neutrik Input and Output Connectors

In our previous designs we’ve used the standard panel-mounted jack sockets. However, the practice had shown that jack socket wiring sometimes caused confusion among DIY builders. Moreover, those sockets often lacked reliability. So, the Bumblebee Bb-D2 uses Neutrik PCB-mounted jack sockets. There is nearly no wiring in the kit, as the only wire you will use is the one that grounds the top of the enclosure.

Aluminium Enclosure for Low Weight

Good news for those who are often on the road with their recording equipment. We’ve replaced the mild steel with Aluminium for the enclosure. It reduced the weight of the Bumblebee Bb-D2 Direct Box nearly twice. Therefor, the assembled DI only weights 300 grams (10 ounces) now!

Beginner-Friendly Assembly Manual with Photographs of Every Step

The Kit is Easy Enough for a Novice DIYer

There is a detailed assembly manual for Bumblebee Bb-D2 DIY kit with photographs of every step. Therefor, even if you are a beginner, there should be no problem assembling the DI if you follow the instructions.

As a general policy, we supply full kits, e.g. you will have every single part needed to make the DI. The kit includes all the electronic components, connectors, screws, output transformer and our branded powder-coated Aluminium.

You can find the kit assembly manual here: Bb-D2 DIY Kit Assembly Manual
And remember, if you are still not confident about your ability to DIY after reading it, you can always order the Bb-D2 Direct Box pre-assembled and ready to use.

You can read more about the functionality and applications of Direct Boxes in my article: What is a Direct Box and How It Works

User Review & Test Videos

Review, test and comparison by professor Dan Boner, the director of Bluegrass, Old Time and Country Music Studies in East Tennessee State University.

Review, test and comparison with a built-in DI of an audio interface by Paul Brewer, the owner and operator of Genius Move Audio in Tullamore, Ireland.

We Deliver Worldwide with Expedited Services

Very Low Shipping Fees for Any Destination Around the Globe

We deliver with UPS/Fedex/TNT to any place worldwide. The delivery fees are fixed and do not depend on weight and volume of your order.

The shipping fees are as follows:

  • EU (plus Norway and Switzerland), economy: 9.95 EUR (5 – 7 workdays)
  • EU (plus Norway and Switzerland), express: 14.95 EUR (1 – 2 workdays)
  • US & Canada: 14.95 EUR (4 – 7 workdays)
  • All the Other Countries: 19.95 EUR (5 – 10 workdays)

The tracking number is provided for every package.

The Bumblebee Bb-D2 Discrete Op-Amp Direct Box Kits are always in stock and dispatch in 1 – 3 workdays after the order is placed.

Still Have Questions?

If you still have any questions regarding the Bumblebee Bb-D2 Direct Box Kit, don’t hesitate to write me. I normally reply within few hours and I am always happy to chat with fellow DIY auido enthusiasts.

Yours, Artur Fisher,
The Owner of Bumblebee Pro

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