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Product Review
 

Monarchy Audio SE-250 Hybrid (Tube/Solid State) Monoblock Power Amplifier

June, 2005

Jason Victor Serinus

 

Specifications:

 

● Output: 250 Watts RMS into 8 Ohms, 500 Watts
    RMS into 4 Ohms

● Input Sensitivity: 2.5 Volt RMS for Full Output
● Input Impedance: 100 kOhms, Direct Coupled

● MFR: 20 Hz to 20 kHz ± 0.25 dB at Full Power
● Slew Rate: 80V/
µsec
● Bias: Input Stage is Single-Ended Pure Class A;
    Output Stage is Class A to 50 Watts
● Dimension: 5" H x 12.5” W x 16” D
● Weight: 46 Pounds/Ea
● MSRP: $5000/Pair USA

Monarchy Audio

 

www.monarchyaudio.com

Introduction

Let’s cut to the chase. I really like the sound of these amplifiers. But, before we get into what is so good about the SE-250 monoblocks, let’s begin to address design specifics. I say “begin” because my experiments with choice of tubes (reported below) have inspired C.C. Poon to change the circuitry. This will be explained in full as the review proceeds.

Designed by C.C. Poon, the SE-250 is a hybrid amp with, to quote the website, “one Dual Triode used in an SRPP configuration, and 12 pieces of complimentary MOSFET in the output stage.”

The website touts that the current-output stage is totally transparent; C.C. attributes any observable sonic signature to the sound of the input tube. While the amp comes equipped with a single 6DJ8 Military Grade tube, other dual triodes with the same pin-out and filament voltage may be substituted according to personal taste. Monarchy, in fact, encourages experimentation with a variety of 6922s, ECC88/12AU7s, or 6N1Ps.

The tube supplied with the SE-250, a NOS (new old stock) Siemens E88CC from the ‘80s, is the European version of the 6DJ8. C.C. explained by phone that he chose this tube because it is reliable, readily available, and long lasting, not because it is the best sounding tube he has heard in the amp. Among other tubes he has sampled is a Russian 6N3OP, which draws more filament current and is, in his words, “a tad more dynamic.”

The SE-250 has single-ended (RCA) inputs. Speaker terminals are gold plated solid brass and easily accessible. The aluminum chassis features Thermalloy high-heat dissipating fins. The power cable is removable to accommodate after-market power cables.

In a phone conversation, C.C. emphasized that the SE-250 employs zero feedback; it uses neither global nor local feedback. He attributes what he terms the amp’s “unbridled dynamic range and expressiveness” to the absence of feedback.

“Feedback brings dynamic degradation,” he claims. “While feedback has been used in the past to boost frequency response, a design that doesn’t employ feedback allows the music to blossom.”

It is important to note that C.C.’s claim about zero feedback is countered by assertions that every circuit responds differently to feedback, and that in some circuits, feedback is not only necessary but also sonically beneficial.

Because the Monarchys deliver 250 watts RMS each, you might expect them to act like sonic powerhouses. This is not the case; the four times as expensive 100 watt Jadis DA-7 Luxe stereo amp sounds more powerful (with more substantial bass and greater dynamic contrast) and requires less preamp gain to play music at the same listening level. This is in part attributable to a difference in input sensitivity. Input sensitivity, which is determined by the number of stages in an amplifier and the amount of gain per stage, is lower in the Monarchy than the Jadis.

For the upgraders amongst us, I questioned C.C. about the quality of resistors and capacitors used between the tube input stage and the MOFSET output stage. Capacitors are from WIMA in Germany, and resistors are carbon-coated or metal film from Dale in the USA. The small amount of hook-up wire in the amplifier is silver-coated.

What is not known is the extent to which higher quality parts might fundamentally change the sound of these amps. When I received my Jadis DA-7, I was warned that upgrading resistors and capacitors would change the nature of the Jadis sound. Audiophiles wishing to experiment would be wise to save the original parts just in case.

Listening - Round 1

Using the stock tubes – note – using the stock tubes - I first auditioned a variety of single music tracks. Playing the first two tracks of Warsaw Village Band’s intentionally cacophonous "Uprooting" (World Village) produced music bright, driving, and jarring. Drums were softer and a bit slower than with the Jadis; highs neither as grating nor as extended. While there was a nice amount of air, the Jadis seemed to have more.

Beyond these limitations, however, the sound of the SE-250s was natural and eminently satisfying. Timbre was neutral and true, neither overly bright nor sweet. If I had not heard the same tracks on far more expensive amplification, I would have been quite content to live with the sound of the Monarchy monoblocks.

The next selection was mezzo-soprano Anne Sophie Von Otter singing several selections from her new Music for A While recital (DG). The voice was absolutely lovely, albeit lacking the clear leading treble edge heard with the Jadis. Guitar, theorbo, and harpsichord also lacked a fully developed treble edge. This I especially confirmed when listening to one of the solo harpsichord tracks. It was as though I had moved farther back in the hall, where treble diminishes in vibrancy. Regardless, the voice was so beautiful, the mezzo’s winning smile on the Frescobaldi track so truthfully conveyed, and accompaniment so satisfying that I focused far more on what was present than what was absent. Besides, if one has to choose between a reticent top and one that is unduly bright and harsh, I choose the former.

Further listening proved consistent with my earlier observations. Rachmaninoff’s Symphonic Dances (Reference Recordings) was less weighty and three-dimensional than through far more costly amplification, but the Monarchys’ excellent midrange and overall musical rightness provided adequate compensation.

Patricia Barber’s “Touch of Trash” from the Mobile Fidelity SACD version of Modern Cool revealed a leaner sound and looser bass than I’m accustomed to. Lacking a defining treble edge, horns sounded rounder and less in my face. While satisfying, the presentation was a little softer, slower, and less hard-hitting than one might wish.

The All-Important Tube Change

As I continued to listen, I reminded myself that, since acquiring my Jadis, I have not spent more than 1/2 hour listening to it using the Electro-Harmonix input and output tubes supplied by the manufacturer. Instead, I’ve opted for vastly improved sound by quickly changing to the NOS tubes recommended by distributor Pierre Gabriel.

It was time to give the Monarchys the same advantage.

Rather than continue listening to individual tracks, I picked a sonic and interpretive whopper of a recording: the two-SACD set of Mahler’s monumental four movement Symphony No. 9 from Michael Tilson Thomas and the San Francisco Symphony (SFS Media). Having sat in prime orchestra seats while the music was being recorded, I am intimately familiar with how the orchestra should sound.

While I immediately noted a nice air and depth from the Monarchys, I had to admit that the first movement sounded a little flat. The weight of a huge Mahler orchestra was lacking; the sounds of massed strings, horns, and percussion seemed produced by much smaller forces. All the lines of music were audible, but it was as though they were being produced by a large-scale chamber ensemble.

Then I made a major tube change. I replaced the NOS Siemens with the same NOS Jan Philips 5814A (ECC 82) that I use in my Jadis.

Listening - Round 2

What a major difference!!!! Once I increased the gain of my Theta Gen. VIII preamplifier to reach the volume level delivered by the stock Siemens tube – I used a Radio Shack DSP meter to insure accuracy - the presentation became notably richer and more complex. While highs still lacked ultimate extension, the sound was especially full in the lower midrange. In fact, it was delicious!

It was as though the orchestra had increased in size. Cellos, double basses, clarinets, oboes – all forces seemed bigger, more detailed and closer to the sound of the real thing. The dynamic range was still not overwhelming, nor the depth of soundstage as great as with the Jadis. Regardless, what I heard was close enough to the sound of the actual orchestra in Davies Symphony Hall as to make for most satisfying listening.

While I did not have enough tubes available to experiment further, my experience totally validated C.C.’s claim that the SE-250’s sonic signature is to a large part determined by choice of tube. You can get a lot more out of these amps by simply changing a single tube.

More on Tube Swapping and Forthcoming Update

After I conducted my modest experiment in tube swapping, my audio guru friend David Tonelli raised an interesting question. While the 12AU7/ECC 82 tube I liked best in the amp - the Jan Philips 5814A - uses 12.6 volts between pins 4 and 5, the amps are designed for a stock 6DJ8 which only uses 6.3 volts. David wondered why, if there's only half the amount of voltage necessary to run the 12AU7, it still sounded better than the 6DJ8.

C.C. sent the following reply:

“I have checked the pin-out and spec on the 5841A. It is indeed a substitute for the 12AU7.

“In our SE-250 power amp at Pins 4 and 5 there are only 6.1 volts (regulated) on the PCB. We deliberately used a few percent less than the 6.3 volt standard to give the tube a longer life, as many of our customers insist in keeping the amps ON 24/7.

“So the 5841A receives only half its required voltage at the filament (6.1 volts instead of 12.6 volts) when used in our SE-250.

“I put two used 5814As in our SE-250 amps and measured about 120 watts on 8 ohms instead of the rated power of 250 watts. But in a listening test, this lower power version still sounds wonderful.

“The bottom line is that if the user can settle for less output power, 12 volt varieties of the 6DJ8/ECC88 can be used in the SE-250 amps with the advantage of a much extended life span on the tubes.

“I think that if we can feed the 12AU7 with its full voltage requirement, it should sound exquisite. If our customers want a 12.6 volt configuration, we want to give them that upgrade option.”

C.C. is about to send me pairs of 6.3 volt 6H30Ps (which may be a 6N30P – there’s a question about translation of Russian characters) and 6CG7 tubes that he believes will sound quite good in the SE-250. At the same time, he is about to convert two SE-250 monoblocks to accommodate 12.6 volt tubes, and send them to me in a month or so. With both 6.1 volt and 12.6 volt versions of the monoblocks on hand, I’ll compare models and tubes and report my experiences in a future update to this review.

No one, least of all C.C., knows if this new, never tested version of the SE-250 equipped with a Jan Philips 5814A or other 12.6 volt tube will take the SE-250 to another level. Please check back in October, 2005 for the update.

Conclusions

The Monarchy SE-250 hybrid monoblocks represent outstanding value. Their enviably neutral presentation, by no means a given when it comes to amplification, is both musical and satisfying. With careful attention to choice of tube, the Monarchys provide a wonderful taste of the real thing.



- Jason Victor Serinus -

Reference Equipment Used For This Review:

Digital Front End
Sony 707ES transport modified by Alexander Peychev of APL Hi-Fi
Theta Gen VIII DAC/Preamp
Theta Carmen II transport (on loan from Theta)

Amplification
Jadis DA-7 Luxe

Loudspeakers
Talon Khorus X speakers MK. II (with latest modifications and Bybee filters on woofers and tweeters)
Rocket UFW-10 subwoofer

Cabling
Nordost Valhalla single-ended and balanced interconnects
Nordost Valhalla balanced digital interconnects
Nordost Valhalla bi-wired speaker cable
Nordost Silver Shadow digital interconnect for DVD-V
Nordost Valhalla Power Cables
Elrod EPS-2 Signature

Also on hand and sometimes used:
Interconnects: WireWorld Gold Eclipse 5 and Gold Starlight 5 digital, Harmonic Tech Magic One, Acoustic Zen Silver Reference II balanced, and Nirvana BNC-terminated digital.
Power cables: Elrod EPS Signature 2 and 3 plus EPS 1, 2, and 3; WireWorld Silver Electra 5, PS Audio X-treme Statement, Harmonic Tech, and AudioPrism SuperNatural S2.

Accessories
PS Audio P600 Power Plant power synthesizer with MultiWave II
ExactPower EP15A (for amplification)
PS Audio Ultimate Outlet; PS Audio Power Ports
Ganymede ball bearing supports under all components and speakers
Michael Green Deluxe Ultrarack, Basic Racks and Corner Tunes
Shakti stones on amp, Theta, and transport
Stillpoints ERS EMI/RFI sheets on most components
Bedini Dual Beam Ultraclarifier, Audioprism CD Stoplight,
Marigo Signature Mat for use atop CDs, Ayre demagnetizing CD and the original Sheffield/XLO demagnetizing and break-in CD.

Room Size

25.5’ deep, 37’ wide opposite the speakers, 21.5’ wide in the listening area. Ceilings are 9’2” high with heavy wooden cross-beams. Floors hardwood and carpet. Walls are a combination of plaster and wood. There is a large archway opening next to the right speaker.

 

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