September 2012

Copland CTA 506 Vacuum Tube Power Amplifier
Combining classic design with the latest developments in vacuum tubes.
Review By Phil Gold

  Copland's website reads "Copland has a more than 30-year legacy of producing a select line of exclusive audio components, aimed at the serious audiophile. We invest years of research and development in each individual Copland product, deploying high-grade components and exquisite materials, offered in an extraordinary industrial design and built quality." That sounds like a pretty fair claim, and I have admired the looks and sound of Copland gear on many occasions. But this is the first time I've had one of their components at home for an extended audition. I'm pleased to say I have come away impressed. Copland has given us a fairly priced ($6500) power amp that performs its job as advertised in a most unobtrusive manner.

Unlike most manufacturers of tube components, Copland normally wraps its electronics in a conventional sealed box with typical Scandinavian elegance hiding the componentry within. On this occasion however, they've given just a glimpse of the innards through slits in the front panel, because they are so impressed with the looks of the new KT120 tube with its long plate structure and huge grid cooling. This tube is a development of the classic 6550 / KT88 tube so popular in this industry. This variant produces 30% more power so that in a push pull configuration a pair can deliver nearly 200 watts of audio power, or in a more modest power range as we see here (90 wpc) it can provide massive headroom without compression. The CTA 506 is one of the first amps to take advantage of this new tube, along with the similarly priced Audio Research VS 115.

Copland employs buffer circuitry, using low distortion current amplifiers to partition the the load from the amplifying tubes and to provide low impedance DC-coupling between the driver and power tubes. The output stage is an Ultralinear design with dual KT120 tubes. By using a dedicated power supply for the amp's input stages, the massive central reservoir capacitors can be dedicated to feeding the output tubes. Copland applies active tube regulation via two 6550 tubes, one for the driver stage and the other for the amplifying stages. This isolates voltage fluctuations from the output stages from affecting the power to the input stage and driver stages. Copland specifies polypropylene film capacitors, gold plated high current WBT binding posts and other high quality componentry in this flagship product while fit and finish are to Copland usual excellent standards. It's a bit of a beast to move around, but that's par for the course for most good power amps and it looks very good alongside my EMM Labs Pre2-SE preamplifier and matching XDS1 CD player.

There is a single control on the front panel – a rotating on/off switch. At rear you have a choice of inputs (unbalanced or balanced) and output taps (4 Ohms / 8 Ohms), plus a power input and a toggle switch to control amplifier lighting. The chassis sits on four massive brushed aluminum feet with rubber contacts. The slats that let you see the tubes run full width across the front plate while part of the top plate and sides are perforated for ventilation. The amp runs moderately hot and you should of course allow ample airflow around it, and give it 20 minutes or so to hit working temperature for best results.

I used three sets of speakers with the Copland – ASW Genius 310 floorstanders ($3,200), Totem Ember bookshelf monitors ($4200 + stands) and the floorstanding YGCarmels ($18,000). The ASW was happy only on the 8 Ohm tap, while the Ember sounded good on either tap but preferred the 8 Ohm and the YG sounded more comfortable on the 4 Ohm tap. I linked all the components up with Nordost Valhalla wire, choosing the balanced inputs throughout. I detected a very faint hum in one channel but his was completely inaudible at the listening position. In my system, no tube amplifier seems to completely avoid hum, while it is almost never an issue with the silicon components that pass through. I also noted the Copland has considerably less gain than my ModWright KWA 150SE. Using the YG Carmel as a reference, through the 4 Ohm tap the Copland required an increase in the preamp volume of 11.5 dB to match levels, while the 8 Ohm tap required an 8 dB increase. This was never an issue in practice since there was plenty of headroom for high volume listening with all the speakers tested, but there may be some combinations of inefficient speaker and limited output preamp where peak listening levels might be curtailed.

The Sound
The Copland amp operated faultlessly throughout and thrived on everything I could throw at it. Its sound is transparent and not noticeably tubey. It exerts a firm control over all the speakers I tried at a variety of listening levels. The little Totems showed rich color and threw a huge image while stopping and starting on a pin. Complex soundscapes were easily resolved and the image was quite forward with strong presence. The larger ASW speakers resolved a little less detail but maintained rich color, low distortion and splendid imaging. The YG speakers seemed to have a direct connection to the musical source with a wider dynamic range greater and exceptional resolving power. Only in direct comparison with the considerably more expensive ModWright KWA 150 SE could I detect a slight difference of emphasis. The Copland shows its richest color, resolution and dynamics in the all important midrange, with a slight softening in the deep bass and extreme treble. The ModWright maintains its speed, accuracy and resolution all across the board, which is what makes it so successful across every musical genre. The Copland may be said to favor jazz and classical music, chamber music in particular, but be less ideally suited for heavy metal or the organ.

Let us dive into a direct comparison using the enormously demanding new recording of Shostakovich's Tenth Symphony [Naxos 8.572461] played through the YG Carmel. The Copland offers superb definition in the strings, excellent imaging and a deep bass which is both softer and rounder than the ModWright. The orchestral color is simply wonderful and rich. The winds are fabulous. It's a fully convincing sound. You could not ask for more. But the ModWright does give you more. The dynamics are explosive, the transient attack faster and the level of detail even stronger. Jennifer Warnes has a magnificent voice, wonderfully captured on the SACD release of The Well [Cisco SCD2034]. The Copland does this disc full justice. My notes say ravishing. On track four, which progresses Bolero fashion to introduce more accompaniment at each repeat, the Copland allows each separate layer to maintain full clarity and focus, even the gentle pipes and drums, while the total image is huge and precise. The ModWright performs in a very similar fashion, with an edge in terms of openness and definition in the low bass line.

The Copland CTA 506 amp revels in the modern classic Afrocubism [Nonesuch 2-525993]. The Totem Ember shows clarity, control and image focus while maintaining enormous dynamic range. Color is rich, pacing fast, every line easy to follow. The YG tops this with a greater ease and longer sustain of harmonic information. There is simply nothing to criticize here. An older classic, the Rolling Stones' Let it Bleed [ABKCO 90042] proclaims "THIS RECORD SHOULD BE PLAYED LOUD". No problem! "Love in Vain" shows off Ry Cooder's excellent mandolin ands some fine multi-tracked guitar licks from Keith Richards. The deep bass is tuneful, albeit at a fairly low level in the mix. Jagger is at center stage with everything laid out clearly in front of you. A great understated beats emerges from Charlie Watts' drum kit. You get the whole picture as well as all the details. That's with the Carmel but the description fits perfectly well for the Totem too. When you switch to the ModWright there's more to choose between the two sets of speakers, with the Carmel showing the greater dynamics and speed, the guitar so crystal clear and colors so well differentiated.

As good as Let It Bleed sounds, it's no match for the recording quality on The Beatles Love album [Capitol 0946 3 79810 2 3]. The Copland audition finds superb close harmonies, bird sounds, guitars and vocal leads. There is no hint of sibilance. The cello tone on "While my Guitar gently Weeps" is rich and the guitar has a strong sustain. In short it is magical, and as the song progresses, tension subtly ratchets up. "Blackbird" has that distinctive foot tapping, a colorful guitar and Paul's sweet voice at the centre, continuing into "Yesterday" with strings left and right surrounding the voice. Again each instrument is easy to hear on its own and yet the whole is coherent. A fine performance. The ModWright brings a little more texture to the strings but in all other ways is remarkably similar through the Totems and again brings bigger improvements with the Carmel.

Conclusion
The current Copland lineup extends to five components. To partner the CTA 506 there is the attractive CDA 825 top loading CD Player with apodizing filter and the CTA 305 Class-A tubed preamplifier with phono stage. They also offer the CVA 306 six channel preamp and an integrated stereo amplifier, the CTA 405. I can offer a very confident recommendation to Copland's power amp. The Copland CTA 506 combines classic design with the latest developments in vacuum tubes to create an impressive and attractively priced power amp that seems equally at home across musical genres. It stands up well against the other power amps - tube and silicon based - that have been through my listening room. It doesn't pretend to be the last word in power amps, but it sits at a sweet spot in the market where you'll need to pay a lot more to eke out small performance gains in most systems. It's a looker, and it's a keeper too!

Specifications
Type: Stereo vacuum tube amplifier
Frequency Response: 5 Hz to 100 kHz (-3dB)
Tube Complement: Four KT1220, two 6550, four 12BH7 and two ECC81
Power Output: 90 wpc continuous from 20 Hz to 20 kHz
Distortion: < 1% at all levels|
Signal To Noise: > 100 dB 
Overall Feedback: 17 dB
Sensitivity: 1.5 V
Input Impedance: 100 kOhms
Output Taps: 4 Ohms / 8 Ohms 
Binding Posts: Gold plated WBT 200 Ampere
Power Transformer: Shielded toroidal
Inputs: XLR, RCA
Dimensions: 17" x 15.4" x 7.5" (WxDxH)
Weight: 57.3 lbs
Warranty: One year parts & labor, 5 year parts replacement
Tube warranty: 30 days
Manufactured: Denmark
Price: $6500

Company Information
Copland
Ryesgade 25 D
2200 Kobenhavn
Denmark

Website: www.Copland.dk

North American Distributor
Divergent Technologies
E-mail: divergent@divertech.com
Website: www.Divertech.com