Prologue Premium Integrated Amplifier Review
THE HIGH NOTES
- All Tubes Under $3k
- Super High-End Parts
- Auto Bias Means No Tube Worries
Company & Product Overview
PrimaLuna has a very interesting company history and design philosophy. Around 15 years ago Herman Van Den Dungen, a Dutch gentleman, decided to form PrimaLuna. Herman had been importing high-performance products into the Netherlands for 20 years, but he wanted to create a line of affordable tube products. Specifically, he wanted them to be made the way the legendary Marantz and McIntosh amps were made in the 1960’s. These used all point-to-point wiring, had massive output transformers and had very long tube life.
Herman hired Marcel Croese, who had been the chief engineer at Goldmund for many years, to design these amps. Marcel developed PrimaLuna’s Adaptive Auto Bias circuit and the brand was born.
Today, we are testing the PrimaLuna Prologue Premium Integrated Amplifier. This is an all tube integrated amplifier.
Audio Advice was actually started soon after our founder, Leon Shaw, heard his first all tube system. It blew him away and set him on a journey that continues nearly four decades later.
Tubes have a sound that musicians have always loved because it is warmer and richer than solid-state designs. In the 70s and 80s, there wasn’t a big difference in price between tube and solid-state designs. As time passed, a gap started to occur, which made it harder to get into a good tube design for your audio system.
The Prologue Premium Integrated Amp resets this as it represents a fantastic value for an all tube product.
Design & Build Quality
When you first have a look at the PrimaLuna Prologue, the first thing that will jump out at you is its retro styling.
The Prologue is available in your choice of brushed black or brushed aluminum finish. The tubes are protected by a cage of horizontal bars, arcing toward the back of the unit. The front panel is stark and simple, with an input selector switch and volume knob. The power switch is located on the side and the inputs and speaker terminals are on the back.
Don’t let the reasonable price tag fool you -- the PrimaLuna Prologue is built like a tank. It weighs in at 50lbs! All of the internal wiring utilizes the point-to-point method -- a much better but also expensive and time-consuming way to manufacture these units compared to just putting it all on the circuit board. Doing it this way also allows them to use heavy gauge wire instead of those thin circuit board traces.
All of the knobs and connections feel really solid. Even the little remote that comes with the unit feels well-made! Based on the build-quality alone, we would have guessed the Prologue would be priced in the $5,000-$10,000 range. To find a tube amplifier with this much attention to detail for under $2,400 is astounding.
To keep costs down, PrimaLuna uses a manufacturing facility in China that is known for making military-grade parts for the aerospace industry. They’ve been using them since the beginning, and we can see why. Each and every product goes through an intensive testing procedure. A robotic arm moves through six different tests, sending signals through the unit and comparing the results to a reference.
Features & Technology
The Prologue Premium has 4 sets of analog RCA inputs. Many of our customers are interested in both home theater as well as great sounding two-channel audio. Marrying those two for best sound can be a challenge because you need a home theater receiver or surround sound processor for home theater, yet a great and simple two-channel rig for the best pure audio. The Prologue (and all their units from this one up) have what is called a “home theater bypass” input.
So, how does this work and what is the advantage? Just about any decent home theater receiver is going to have preamp outputs for the front channels. Instead of connecting your main left and right speakers to your home theater receiver, you connect them up to the PrimaLuna integrated amp. You then run a set of analog audio cables from the front preamp outs of your receiver to the home theater bypass on your PrimaLuna.
When you want to play your home theater system, simply select the home theater bypass input on the PrimaLuna and the surround sound effects from your home theater receiver pass straight thru, with volume control occurring through your home theater receiver. The cool part is, when you want to play just some vinyl or two-channel digital, you won’t even turn on your home theater receiver because your main speakers will be connected pure and simple to your great tube amp.
You’ll notice the speaker connections on the back have a negative terminal and two sets of positive terminals: one for 4 ohms and another for 8 ohms. This allows you to perfectly match your speakers to the amplifier. The output transformers used by PrimaLuna are one of their main secrets to their great sound. In a tube amp, the output transformer is one of, if not the most important parts. Even if you had a 100-watt rated tube amp, with bad output transformers you would be settling for bad sound. Instead of buying off-the-shelf units, PrimaLuna manufactures all of their output transformers in-house -- and they are massive! Their great design allows them to run the tubes in the amp at a much lower level, thus increasing tube life.
Speaking of transformers, all amps have a power transformer. All high-performance designers know a toroidal power transformer is far better than a standard one. But again, they cost a lot more. As you might have guessed, all PrimaLuna products use a toroidal power transformer. It’s even potted and enclosed to further reduce transformer noise.
PrimaLuna’s adaptive auto bias circuit is another one of their hallmarks. Every tube amplifier has what is called a bias circuit that controls how the tube outputs eventually become sound. Every tube has an optimum bias point, but as tubes age you have to readjust the bias. This is done manually in some amps, while in other amps they’re simply forced to change without much real feedback. PrimaLuna invented a circuit that monitors the tubes and makes adjustments in real time. Better yet, it is not even in the signal path. The result is tremendously extended tube life and better sound!
Finally, one worry some people have about getting into the world of tubes is the fact that you do have to replace the tubes over time. They are somewhat akin to tires on a car...eventually they wear out. PrimaLuna designs their products to have extremely long tube life, but what about when you get a “flat tire”?
With most tube amps, a failed tube can be catastrophic, sending the whole amp into a bit of a tailspin. PrimaLuna has a fail-safe system that instantly shuts the whole amp down any time a tub fails. All you have to do is pop in a new tub and their auto bias system sets things back to normal. There is even a light next to the tube that shows when you have a bad one.
If you’ve never had the experience of listening to a great tube amp, there is something really special about it. Tubes draw you into the music. There is a natural sound to the voices that you just don’t get with other types of systems. It just feels more real.
Don’t let the low power rating fool you. Even though the standard EL34 tubes are rated at 35 Watts per channel, the Prologue Premium was able to drive a large set of $10,000 MartinLogan speakers that have challenged some 200-Watt solid-state amps!
The frequency extremes of some tube amps have been criticized over the years for not having the bass slam or ultimate top-end extension of a great solid-state amp. Yes, a $8,000+ Mark Levinson solid-state amp has far better bass and somewhat better top-end extension, but the $8,000 is for just the power amp! The PrimaLuna amps have the best bottom-end we have heard in their price ranges, no matter if it’s tube or solid-state. And the highs are sweet and silky!
Honestly, we can’t remember the last time we had so much positive feedback about a product from people who have brought them home. Our customers are just amazed by the sound.
This product is not for everyone. It is for the person who cares about audio and is especially well-suited to someone who loves vinyl and it’s signature warm, rich sound. If this speaks to you, you really owe it to yourself to take a listen to the PrimaLuna Prologue Premium.
HIGH NOTES UNPACKED
All Tubes Under $3k
It is truly amazing to get an all tube integrated amp of this quality for under $3000. This allows more music lovers to experience the allure of all tube sound that will take you to a new level of listening.
Super High-End Parts
PrimaLuna products have part levels you would expect to find in units costing 3-10 times as much, which is just amazing.
Autio Bias Means No Tube Worries
What if your car adjusted the way it drove as your tires aged? Imagine that! Their Auto Bias circuit assures you of awesome performance at all times.