The name Cronus is past down to us from an ancient Greek myth. Krónos was the leader and youngest of the first generation of Titans. I did my usual on line peeking and sleuthing and found images of the Cronus, a very retro looking open frame amplifier. But while all of those pictures looked like the subject of this evaluation they were actually photos of an earlier version of the Magnum II amplifier. So these photos were taken before I ever got my hands on this review sample. This story is about the new extensively upgraded Cronus Magnum III. When I opened the box and peeled back the packing I lifted (grunt) an impressive 55 pound amplifier from its cardboard container.
Rogue Audio's Cronus is a very serious and convincingly constructed component; I didn't see any signs of money saving cost cutting construction anywhere. The Amplifier is shipped with five small triodes in place. That is three 12AU7 and two 12AX7 tubes. They are positioned halfway below the top of the chassis mounted on recessed tube sockets. There are four Pentode KT120 output tubes that are shipped in their original Soviet Tung-Sol boxes. They are numbered one to four corresponding to their individual designated tube sockets. All the tube types and locations are conveniently silk screen painted on the top of this black anodized amplifier. At the center of the amplifier chassis is a round D'Arsonval DC milliamp bias meter.
However the Remote Control is limited, it can only adjust the volume up or down or mute the amplifiers output. Looking at the back of the Cronus there is a small toggle switch to change the amplifiers output configuration from either Triode or to Ultralinear. The output can be changed while the amplifier is operating. Love that feature!
There are four pairs of gold plated unbalanced RCA inputs and an additional two pairs of RCA outputs labeled variable and fixed. The four inputs are labeled, left to right, Phono, CD, AUX 1, AUX 2. As you can expect, there are very high quality gold plated five-way loudspeaker binding posts for left and right channels made by Cardas. There's a 5 Ampere main fuse and detachable IEC connection for the power cord.
An Inside Look
1. With a Phillips screwdriver remove the 14 screws holding the top cover. At this time you would have removed the four KT120 output tubes. Insure the amplifier has been turned off for about 30 minutes and the amplifier power cord is connected a ground.
2. With a 0.5" wrench remove the outermost nut from the red positive binding post. Leave the black wire with heat shrink on the post.
3. Remove the 8 Ohm tap (Green wire marked 8) from the binding post. Careful to leave the black wire with heat shrink on the post.
4. Remove the polyurethane tubing from the yellow 4 Ohm wire and lug.
5. Place the polyurethane tubing on the 8 Ohm wire and lug.
6. Place the 4 Ohm wire onto the binding post, and then replace the outer nut. I did not have to make this change for my reference modified Rosewood 8 Ohm Aurum Cantus V30M loudspeakers.
A Deeper Bias
Chances are a committed audiophile would own a copy of Nils Lofgren's SACD Acoustic Live, and so let's spin it up. Immediately there is a dimensional expansion of the sound scape. The scale of stereo imaging within the performance space, including those in front of the stage, are clear to hear. There are great aural hints of 3D space. Space is what you should expect, and that's what would be a wonderful characteristic of this vacuum tube powered soundscape. Razor edged transient attack is what you might hear with a solid-state setup, yet Rogue Audio's Cronus Magnum III integrated tube amplifier with phono stage reveals something far more satisfying. The sound is full of natural resonant harmonic overtones both odd and even. More than that, those overtones decay into silence much more gradually. My favorite Harry Pearson phrase is "Continuousness", and here it fits nicely.
It's not at all like early digital delineation. That's when sound levels subside and they are eliminated as a least significant bit. What I have tried to convey is part of what some have called, "Tonal Body" but I would rather call this simply, the Gestalt! That's when every part blends together and forms a clear coherent concept. There is another significant tonal characteristic of the Magnum III. On a very good recording It puts spaces around and between parts of the performance. It's subtle, but it's like a renaissance masters painting in that the main subject/performer is made evident. The subject is highlighted and separate, in their own space and separate from the background.
First cut, is the always favorite sci-fi Star Wars opening theme. It was so rewarding for me in summoning such fond memories. Turn the volume up and the soundscape is huge, filling the space behind my speakers nicely. By comparison, my transistor reference Parasound P5 with a phono stage preamplifier and solid-state Sanders power amplifier could get the detail and width dimension spot on, but not the same sense of stage depth and height.
I saved the best for last. A comparison of the Magnum III onboard phono stage and my reference Tavish Design Adagio tube powered phono amplifier, which was reviewed by Enjoy the Music.com in February 2016. For continuity, let's replay John Williams a life in music and that Stare Wars theme again. It takes the entire Star Wars track and more! But it's basically a tradeoff between these two fine phono stages. The Cronus Magnum III projects a large and tonally rich panorama that I find satisfying involving and natural. Now this characteristic is easier to hear when the Cronus III amplifier is running in triode mode. On the other hand, my stand alone Tavish amplifier does not paint quite as expansive a stage; it seems to have a little better extension at the top end frequencies. As a result, there are small details buried within the soundscape that sound a bit clearer.
By a slight margin, that same characteristic detailing ability of the Adagio phono amplifier, as compared to the Rogue Audio Cronus Magnum III phono stage operating in either triode or ultralinear mode, makes the Tavish Adagio sound a touch more dynamic. So you get six measures of detail and a half dozen of tonality. The true question you need to ask yourself is what would you prefer.
Remember to enjoy the music and from me Semper Hi-Fi.