The ProLogue Premium preamp is almost an exact DNA match with its big brother. It would take a real expert to tell them apart; either from reading the schematics and build sheet or from the incredible performance.
There has not been a new design in tube preamps for decades. There have been improvements in some areas, but they are all built in the following ways: Preamps with one or two tubes are either hybrid (cheap to make) or use a lot of feedback. If they have four or more tubes, they use one of several designs, many of which have been around since the 1940's.
The top-tier, most expensive preamps selling for $10,000 or more will have tube rectification so they are "pure tube." Many of these "flagship" preamps will also be dual-mono, so they don’t share parts between channels, yielding better separation. They will have point to point wiring instead of thin printed circuit boards to carry the signal (though even some flagship preamps still use circuit boards). Then, they will use a high-quality analogue potentiometer volume control instead of a $2.50 volume “chip”.
PrimaLuna uses TWO 5AR4 rectifier tubes, one for each channel in a true dual-mono circuit that is all point-to-point wired using the highest quality parts including the awesome Alps Blue Velvet volume control. All things included in this incredible preamp weighing in at an amazing 37.5 pounds.
PrimaLuna buyers are typically well-seasoned tube-heads, and they know all this stuff. If you are new to tube preamps, you can help yourself by doing two simple things: Take the name and model of the product you are considering, and put it into Google. Then, get the weight and click on “Images” so you can see exactly what you are getting inside. Funny, we do that type of investigation in most everything we buy, but only in high-end audio do we get influenced by fairy dust.
PrimaLuna doesn’t offer fairy dust. They offer world-class European engineering, the finest name-brand parts, and workmanship that’s been declared over and over by experts to be untouchable.
Dual Toroidal Power Transformers
Why? For the lowest noise. The #1 reason for having an outboard power supply on a preamp is to isolate sensitive small signals from EMI and hum radiated from the typical EI transformers used by many companies. The best cure for this problem is to use toroidal transformers, as they don't radiate EMI outside the core. Transformers are the single most expensive part in audio equipment, and that usually means cutting corners. Toroidal transformers cost much much more than typical EI core, because they take a long time to wind. Instead of a machine making many at the same time, the best quality ones like they use at PrimaLuna are made one at a time in-house. They are massive, resulting in a preamp weighing a substantial 37.5 pounds.
Tube rectified, dual mono design
In the world of preamps, experts agree that tube rectification offers the most natural, textured, vibrant presentation. That's why you find it in the best, top of the line models. Finding a preamp using one rectifier tube is sweet. But PrimaLuna uses two 5AR4 rectifier tubes in their dual-mono design.
Look at the interior photos and you will see that all PrimaLuna preamps are actually two preamps in one chassis. The result is obvious. Better imaging...like no other. That's where the weight comes from.
SuperQuiet Line Inputs
Input selector switches mounted on the front panel requires long wires to run from the switch in the front to the rear RCA jacks, and they invite stray noise like RF and EMI.
PrimaLuna has a better way. Instead of a switch, input selection is done using premium quality sealed relays mounted in the rear where you plug in your components. When an input is selected, that relay closes giving you the best connection possible. All the other relays are left open, so noise and signals from other sources can’t leak in. The signal path is now almost non-existent, so there are no wires to pick up noise.
New Front-End Circuitry
PrimaLuna chose 12AU7 tubes because there are more factories around the world making great ones today than any other tube, so you can try them and see if you prefer their "color." In addition, because 12AU7's have always been a popular tube, there are tens of thousands of vintage new-old-stock 12AU7's available everywhere from the greatest factories like Telefunken, Mullard, Amperex, Cifte, Siemens, and more. Tons of them. If you haven't "Tube Rolled," it's a gas, and how you get that last 10% of PERFECT tonal balance to YOUR tastes.
Point to Point Wiring
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.
A preamplifier is typically not required to add any gain to your system when you are using it. It is usually lowering gain from the source you are listening to. The number one complaint from audiophiles about preamp performance is noise. So why is it that so many manufacturers design preamps with 20 to 27dB of gain? And you wonder why there is "hiss", and why tubes go noisy or microphonic? PrimaLuna preamps use SmartGain. With a gain specification of only 12dB, you will find your PrimaLuna preamp is as quiet as a church mouse. If tubes are less than perfect, you may never know it because they are not amplifying as "loud". High efficiency speaker owner's rejoice!
RCA Input Impedance
Each input has a circuit designed to present a perfect 100K ohm input impedance to the components you are plugging in, assuring you that every piece of gear you listen to will sound its best.