EVO 400 TUBE POWER AMPLIFIER

BAD TUBE INDICATOR

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. 

STEREO OR MONOBLOCK OPERATION

It's as simple as flipping a switch, and PrimaLuna EVO Poweramps instantly switch from stereo to monoblock operation! Buy one, and as your budget grows your system can grow too. The benefit of monoblock operation is the amp now has dual output transformers for the best coupling with your speakers, and the addition of a 2-ohm speaker tap added to the 4 and 8-ohm taps. While all PrimaLuna amps are made for ribbons like Magnaplanars and electrostatics like Martin-Logan, you haven't heard anything until you have heard a PrimaLuna monoblock!

CUSTOM TOROIDAL POWER TRANSFORMERS

Power transformers generate two types of noise, magnetic and acoustic. That's why toroidal power transformers are used in the very best audio products. 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. As transformers are the most expensive components in any audio product, manufacturers will even house cheaper C-core and EI-core transformers in an outboard power supply box with an umbilical cable rather than upgrade to an expensive toroid. The increased cost is significant, but PrimaLuna doesn’t cut corners. 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.

CUSTOM SUPER-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

ADAPTIVE AUTOBIAS

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.

POINT TO POINT WIRING W/ 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.

SMARTWATTS - EXTENDED TUBE LIFE

Tube life is simply a matter of how hard you run the tubes. That’s it. 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. Manufacturers that run the hell out of tubes to pump up their power ratings will never tell you what voltages they use. They’ll say it’s “proprietary” as if it’s some secret sauce. There is no such thing. But if they told you that they used 575, 600, or even 625 volts you probably wouldn’t buy. We proudly tell you 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. It’s a cheap way to get big power, and it’s cheap. In fact, free. To get more power the right way is expensive. It requires bigger transformers, sockets, wiring, resistors, capacitors, and the tubes to do it.