If a tube fails, Adaptive AutoBias will instantly put the amplifier into protection mode so no parts can get damaged. A red LED will light up in front of the tube that needs replacing. Simply plug in another tube, and listen. No guesswork. No smoking amp. No getting out the soldering iron.
Power transformers generate two types of noise, magnetic and acoustic. Compared to standard transformers, toroids radiate about 1/10 the magnetic field that pollutes music and obscures detail. Additionally, the absence of an air gap typically means toroids have an 8:1 reduction of acoustic noise. All PrimaLuna products use massive, potted toroidal transformers. PrimaLuna transformers are enclosed in a metal housing and then potted in a non-microphonic resin to further reduce noise and to protect the windings from moisture and deterioration forever.
Output transformers are the most important part of any tube amp. They determine how low the bass will reach and how high the top end goes. 250 watts of power will have no top and bottom extension if the output transformers don't have the bandwidth. We use lower power to extend tube life, and bandwidth to give you slam. PrimaLuna output transformers are custom-designed, wound in-house, and massive. "The flat tops and bottoms of these squarewaves correlate with the amplifier's extended low-frequency response.
What most companies call Auto Bias is actually "Cathode Bias"- It reduces the available power of the amp and runs the tubes hard, meaning shorter tube life and failures via "shorts".
PrimaLuna's Adaptive AutoBias is a true, smart technology employing an array of sensors to monitor tubes and make adjustments seamlessly in real time. More important, it is the ONLY circuit of its kind that is truly "adaptive" by addressing "tube pinch off" at higher volumes, therefore reducing distortion by over 50% and greatly extending tube life. Adaptive AutoBias is completely passive and NOT in the signal path. The result is low to no maintenance, long tube life, and the lowest possible distortion for amazing sound.
Adaptive AutoBias also provides unparalleled flexibility by allowing use of almost any tube on the market today. It even has a fine-tuning switch for EL-34 and KT88/KT120/KT150 tube types.
PrimaLuna employs Point to Point Wiring on all products. The entire signal path, including resistors and capacitors, is painstakingly hand wired with heavy-gauge cable by craftsman.
The only way to extend tube life is to run them as close to zero as you possible can, making sure it is not so low you go into crossover distortion. The life of a tube will depend on two things: Plate and screen voltage.
If the plate and screen voltage is high, you are more likely to get tube shorts when you turn the amp on and you get cathode stripping which greatly effects the cathodes ability to spit out electrons. Our tubes run at just about 417 volts for the plates and screens.
PrimaLuna runs their output tubes at a minimum dissipation without going into crossover distortion. When you look at our amps, they provide less power from each tube. With KT-120’s as an example, a PrimaLuna will give you only 21 watts per tube. So running a pair of them you get 42 watts. That’s a lot of power, but the demands per tube are a fraction of some manufacturers that give you 100 watts from a pair of KT-120’s. To get more power the right way is expensive. It requires bigger transformers, sockets, wiring, resistors, capacitors, and the tubes to do it.
Ask any seasoned tube-head what the most musical output tube is and they will most certainly declare it the EL34. Other amp manufacturers would love to use it. Only PrimaLuna, through our proprietary output transformer designs, can give you EL34 midrange beauty with top-end air that goes on forever. And, bass extension with so much slam, our amps are used to power subwoofers.
However, every system is different. What if you bought a speaker with bass that overloads the room? Or, that is too dark? Or, too bright? What if you just want to have fun trying the different colors of sound from a vast pallet of tubes? With other manufacturers' products, you're stuck. They're a one-trick pony. With PrimaLuna, you get to choose. Go for it. 6L6G, 6L6GC, 7581A, EL34, EL37, 6550, KT66, KT77, KT88, KT90, even the KT120 (the EVO 100 is not KT150 compatible). A future-proof design, PrimaLuna is compatible with NEW tube types not even thought of today!