Today, we are completing the Mullard saga by putting the legendary 12AU7 family to the test. I decided to “tube roll” three distinct, “king of the hill” variants: the Short Plates, the Box Plates, and the Long Plates. Each brings a unique flavor to the table, and the results were nothing short of captivating.

The Mullard 12AU7 Short Plate is a well known gem in the vintage market. Frequently found for as little as $8–10 on eBay, its value-to-performance ratio is staggering. This tube delivers the classic “Mullard signature”—characterized by incredibly sweet mid-ranges and a relaxed, liquid presentation. There isn’t a hint of digital iciness here; it is a tube designed for pure, fatigue-free musical enjoyment.

Moving up the ladder, the Mullard CV4003 Box Plate commands a steeper price of around $50. Is it worth five times the cost of the Short Plate? If you value technical precision, the answer is likely yes. This variant produces an expansive soundstage and a level of detail that is truly phenomenal. The way it handles the nuances of female vocals is almost peerless—at least until you step up to the flagship.

Finally, we have the Mullard 12AU7 Long Plate. At roughly $90 for a New Old Stock (NOS) specimen, this is a premium investment. It manages to outpace even the Box Plate in terms of micro-detail and harmonic undertones. However, it is notably “darker” in its tonal shift. For listeners spinning vinyl (LPs), this richness is essential. Conversely, if your primary source is a computer or a digital DAC, the Long Plate might lean a bit too far into the shadows.

Final Verdict: Whether you are looking for the budget-friendly warmth of the Short Plates, the holographic detail of the CV4003 Box Plates, or the deep, dark sophistication of the Long Plates, Mullard offers a world-class experience for every palate.