Triode and Ultra Linear Tube Power Amplifier
Remote Control Triode/Ultralinear Switching
Do you have some classic rock albums you used to love so much that have now ended up left on the shelf, un-played for years? How about jazz or classical recordings from the 60’s? Every audiophile has albums that they used to play, but stopped because they are harsh, brittle, or bright. There is a solution.
Triode and Single Ended Triode (SET) amps are popular for their warmer, fuller, and easy to settle into sound. But triode amps have limitations! Ultra-linear has more extension on the top and bottom, not to mention greater power. They have greater “pop” with a bigger difference between light and dark, and loud and soft. Having triode only is VERY limiting.
The best option is to have both triode and ultra-linear. PrimaLuna engineers in Holland designed an ingenious circuit that lets you change from triode to ultra-linear with a push of a button on the supplied remote control. No need to get up and stop the music. Make an instant comparison while you listen and choose what you like best for that song or album.
Bad Tube Indication
PrimaLuna engineers wanted to make owning a tube amp so simple you would have no excuse not to have your tube dreams come true.
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 or dropping your amp off at UPS.
Custom Wide Bandwidth Output Transformers
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. Transformers are the most expensive components in an amplifier, so manufacturers save money by using ‘off the shelf’ units available on the market. PrimaLuna output transformers are custom-designed, wound in-house, and massive. One reason why no other brand sounds like a PrimaLuna. "The flat tops and bottoms of these squarewaves correlate with the amplifier's extended low-frequency response; PrimaLuna's output transformers are of excellent quality." -John Atkinson, Stereophile Magazine
More Power, Less Hassle
All PrimaLuna's have incredible slam because of bandwidth. Power is secondary, and can in fact be bad news for unwary customers. To learn more about power, read Less Power, More Bass. But for customers with speakers that are 86dB efficient or lower, that have larger rooms and play at higher volumes, they may need more power.
The cheap way to get more power from a tube amp is to raise the tube's plate and screen voltage, and bias them harder. It costs nothing to do so as a manufacturer, but we refuse to follow the pack. You will see claims of as high as 100 watts from a pair of KT120's. Initially, the customer is happy. But talk to the same customer in a year when his tubes are worn out. PrimaLuna amps are famous for long tube life, running cool, and being absolutely the easiest amplifier to own.
The best way to add power and keep running cool is an bigger build. We increased the size of the power transformer, added all the supporting circuitry including tube sockets, Swiss silver-plated OFC wiring, Takman resistors, SCR Tinfoil caps and a second Adaptive AutoBias board. And of course, four more EL34's for unrelenting power. And if you want the ultimate, add a second EVO 400 later and flip the switches to mono. Incredible!
What most companies call Auto Bias is actually "Cathode Bias"- A commonly used method that is cheap to make, and often found in guitar amps, but also $20,000 high end audio amps. 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.
Point to Point Wiring - Swiss Made Wire
You spend a lot of money on interconnects. So why have the signal go right from the RCA jacks or speaker terminals into circuit boards with copper traces so thin you can hardly see them? What’s high-end about that?
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.
EVO 300 and EVO 400 models use Swiss-made, silver-plated, oxygen-free continuous crystal (OCC) copper with a Teflon dielectric in the critical signal path for superior signal speed and increased clarity.