To follow a different drummer is to fall in line behind the likes of Ralph Karsten. It is he who provides a stepping stone to the present. The Atma-Sphere Ultraviolet preamplifier as reviewed here is a great example of Ralph's design genius. Yet first we need to fire up Mr. Peabody's Wayback Machine to take a look at the device that ties this narrative together. Zap! We find ourselves back in the year 1950. We are sitting at a desk in a patent office shuffling through a large stack of new patent applications. Buried in amongst them is a connecting thread, it's the Circlotron Amplifier application. This patent application is for an innovative circuit design for a triode push pull type of electronic amplifier. As you may see from the diagram below, in its simplest form this amplifier stage can function without any type of feedback or an output transformer and without coupling capacitors.
Simple Circlotron Output Stage
From the man to his machine, the Ultraviolet Preamplifier: As suggested by the designer Ralph Karsten, let us now refer to the preamplifier as the UV-1. The back story is that the UV-1 circuit design was something that had been kicked around and refined over a period of forty years. My attempt to pry some specific circuit details out of the guys that build the UV-1 got me absolutely nowhere. However I do have a strong impression that the design is just as innovative as the OTL amplifier. But as I recall specifications were not all that emphasized even back in July of 1998. The UV-1 preamplifier under evaluation is one of three configurations available. The UV-1 is available as a basic $1,900 line stage without a Phono Cartridge amplifier. Or you could purchase a full function preamp for $2400 with the addition of a high output moving magnet (MM) cartridge amplifier. My review sample is the most expensive at $2800. It has all of the line functions and with the inclusion of a pair of Jensen step up transformers it then becomes a full function Moving Coil cartridge preamplifier. At this time most of the production will be the line stage version.
Atma-Sphere’s Ultraviolet Preamplifier
The things that do the amplifying are on the top of the chassis and in plain sight. Fixed to the top of the chassis are two power supply capacitors and their individual clamps. Next and side by side are two 12AT7 Phono Stage mini twin triode tubes. In the center there are two JAN 6SN7GT Line amplification dual triodes and at the far right a power supply transformer. At the rear panel there are six pairs of hi quality RCA line input jacks. When I say hi quality that means the RCA connectors are fixed and wired to the rear panel and are not just poking through holes in the sheet metal.
Again moving from left to right there is an IEC power cord socket followed by a 1 Ampere fuse holder. Near the rear middle are two pairs of RCA jacks, the first is the main preamplifier output, next a secondary preamplifier out. At the right side we see the line level input connections AUX, 1, 2, and 3 plus the last pair is the Phono amplifier input and finally a chassis grounding lug.
Fire In The Whole
Lucky me, for a gift of music from the Ms. It is Carole King and James Taylor, Live At The Troubadour [Syzygy CD-88072 32053]. Listening to this CD we enter a night club surrounded by adoring fans. The sound of this performance is remarkably clear and articulate. The Ultra Violet conveys not just the music but the atmosphere surrounding the performance. It is intimate and layered through the audience with a very real ability to draw you upfront and into the audience. On track 13 You've Got A Friend, both James Taylor and Carole King sing an emotional duet imbued with the warmth of an enduring mutual friendship. After long hours conditioning the UV-1 using my Sangean HDT-1 digital tuner and many CD's. Transitioning to vinyl is like waking up with a strong cup of coffee. Your senses are more alive and now full of small details buried in the soundscape. At this time the most notable characteristic of the UV-1 is the ability to easily amplify the volume of my low output 0.20 Uv (Micro Volt) Denon 103 moving coil cartridge. There is gain to spare and running the Denon cartridge is no challenge. I doubt very much that there is any very low output moving coil cartridge that the UV-1 could not amplify with ease.
First up, a black disk Flea Market find: Huey
Lewis and the News [Chrysalis Records CHS 12 2798]. This record had a
nasty gouge through the first track on the A side. But this was a four dollar 45
RPM album that I could not pass up. Although this better buy it when you see it
album is a little more compressed than I would like. Still it does what tubes do
best, it has three dimensional. Width, Height and most important on my list,
Depth. It does expand the space in my room by pushing back the rear wall and It
allows me to join the space they perform in. The dynamic tempo and the in your
lap presentation can not fail to get your emotions involved. I must mention one
other go to black disk, another flea market acquisition. It is Sting, The Dream of the Blue Turtles [A&M SP-3750]. This album
is by far the least compressed slab of vinyl I own and so it has become one of
my references. The very first cut, If you
love someone set them free.
From the very first uttered phrase there are loads of dynamic energy, some reviewers call this the "jump factor". From somewhere deep in the center stage the back up voices chant, "Free, Free set them free" this chant reverberates off the rear wall. The air is charged with dynamic bass energy. once again the UV-1unravels the performance separates and expands the venue into my room. The overall performance has a subtle and yet familiar quality that you think you might have heard somewhere before. But then you realize the recording is amazingly clean and clear with a quality very much like listening to a reel to reel tape.
Review System Components
Amplification: Sanders ESL power amplifier.
Speakers: Rocket Strata Mini 3.5-way and Aurum Cantus
Leisure 2 SE two way monitors on 24" stands.
Speaker Cables: Kimber Kable 12tc 9’ length
Interconnect Cables: Monster Reference Four pairs 2.5 meter, 1
meter and 1.5 meters, and Nordost Red Dawn 1 meter.
AC Power: Wire World 10 gauge IEC line cord, Homemade 3 pairs,
12 gauge IEC
Islatrol Industrial 20 Ampere AC line conditioner, Richard
Gray 20 Ampere Sub Station
Alpha Core Balanced Transformer Power Supply and Audio Power
PE-1 power enhancer.
Triad 2-Ampere isolation transformer
And a comfortable chair.
Dimensions: 15.318" x 7.5" x 5" (WxDxH)
Voice: (651) 690-2246