Monarchy Audio SE 100, KAB Souvenir TCA and Bryston Power Pac 120 power amps

      Date posted: June 11, 1998

Monarchy SE100's
Monarchy SE-100 Delux Class A Single-Ended Monoblock Amplifiers
Sugg. Retail: $1179 U.S. ea
Manufacturer: Monarchy International Inc.,
380 Swift Ave., Unit 21,
South San Francisco,
California 94080
(650) 873-3055 FAX 588-0335

KAB Souvenir
KAB Souvenir TCA Class A Single-Ended Stereo Amplifier
Sugg. Retail: $995 U.S. $1499 Can.
Manufacturer: KAB Electro-Acoustics,
P.O. Box 2922,
Plainfield, New Jersey 07062
(908) 754-1479

Canadian Rep: David Sims

Hear The Difference Audio Enterprises,
250-1857 West 4th Ave.,
Vancouver, B.C.
V6j 1M4
(604) 877-0675 FAX (604) 738-9050

Bryston Powerpac 120
Bryston Powerpac 120 Monaural Amplifier
Sugg. Retail: $890 (CAN)
Manufacturer: Bryston Limited,
P.O. Box 2170,
677 Neal Drive,
Peterborough, Ont.
K9J 7Y4
(705) 732-5325 FAX (705) 742-0882

(Reprinted from the Summer 98 AIG)

      Many single-ended amplifier fans don’t really want to know that the phrase “harmonic richness” is just a euphemism for harmonic distortion. And if you think that prejudices my thinking about the amplifiers here reviewed, read on. Too many reviewers confuse this over-articulated harmonic structure with increased detail, when, in fact, the truth lies in the opposite direction: the increased harmonics actually cover up real detail. This is especially true in the case of tube single-ended designs, which compound the harmonic distortion with soft-clipping artifacts because of their grossly inadequate power capability.

      And don’t start in on speaker efficiency, since even a Klipschorn needs 30 honest watts for real dynamics. Whoever said that tube amplifier watts are bigger than solid state watts simply doesn’t listen, especially for the kind of distortion products to which I am particularly sensitive. If single-ended designs have any real validity, they have it through solid state circuitry.

      And that brings us to the trio of amplifiers here, two of which are single-ended, and two of which are monoblocks, though not the same two in each case. The KAB Souvenir TCA is the stereo design, a minimalist design with a single gain stage and 20 watts of power at 8 ohms, and 18 at 4 ohms. The Souvenir is also said in the literature to have a “load responsive wide-band power supply,” with “power entry line filter” and shielded line cord. The toroid transformer in the power supply is also magnetically shielded.

      A lightweight at 14 pounds, the TCA (which stands for “True Class A”) is touted for such applications as a “Near Field Monitor”, with “Horn Loudspeakers”, and as a “Mid/Tweeter Amp”, the latter one peculiarly appropriate, as we shall see. Rather industrial in appearance, the amplifier has a painted black case with white lettering on the front panel, and quite sharp heat sinks at the sides. There are separate Left and Right volume controls on the front panel, too, allowing the amplifier to be used without a preamp in a simple CD-based system. KAB Graph

      I first used the Souvenir with the Klipsch KSP-300 speaker, and when driving it with other amplifiers had been impressed by its bass power through its own powered subwoofer. I therefore thought this modest little amp might be a good match. However, in the normal configuration, in which the KSP- 300’s bass amplifier is driven by the signal from the outboard amp, I noticed that much of the bass had disappeared. Puzzled, I re-connected the Bryston 3B ST, and back came the bass. Now perplexed, I did a pink noise sweep through our reference Energy Veritas v1.8 speakers using each amplifier to drive them. The mild rise in the bass through the 3B ST is due to the speaker placement near the room corner, and is not heard at the listening position, the rest of the range about as flat as you’ll find in a speaker, with some top end rolloff. The curve below that with the Bryston shows response through the little KAB amplifier, and it clearly exhibits a substantial rolloff in the bass region, down 4 dB at 100 Hz, 9 dB at 50, and about 12 dB at 30 Hz. Now, the Veritas is not an especially difficult load, though in the 4-ohm range, and is quite sensitive; the Klipsch was also quite a benign load, with no bass impedance variations to worry about, and mid-90s efficiency across the rest of the range. Therefore I think we can expect this amplifier to roll off the bass with all speakers.

      As I wrote to Canadian distributor David Sims, this is the first amplifier in my experience that needs a subwoofer, and is also eminently suited to be a “Mid/Tweeter Amp.”

      How did it sound? Pretty good, actually. The Souvenir had a slightly darker character than the Monarchies or the Brystons, with some extra harmonic energy giving it a warm, slightly veiled quality that was quite pleasant. Within its power limits, it was very musical and could appeal to listeners who don’t want it loud. Jazz and chamber music were well reproduced, with no harshness, and a generally correct sense of timbre. If the single-ended sound appeals, it could make you happy at a very modest price, though you may want to add a sub if you don’t already have one. With only 20 watts per channel, the Souvenir ran warm, but not excessively hot.

      The Monarchy SE-100 monoblocks are a more ambitious design, also built to a moderate price (the company’s slogan is “High End at Low Cost”), but offering 100 watts of Class A single-ended sound. Here there are two gain stages, the output one 8 matched power MOSFETS rated at 150 watts each, “for a total dissipating power of 1200 watts!”, according to the poop sheet. Given how warm, even hot, this amplifier runs, I don’t doubt that spec at all.

      On the rear panel the SE-100s have both balanced and RCA inputs, these paralleled without switching. There are separate fuses for all 8 MOSFETS, and large finned heatsinks at the sides, these sharp enough to dissuade anyone from trying to pick the 26- pound amplifier up by its sides. A slightly smaller and lighter Basic version offers 100/160 watts @8/4 ohms, while the Delux is rated for doubling of its 100-watt 8-ohm spec at 4 ohms, having greater current capability. With gold handles and trim, and excellent build quality (though one of the amps had a slightly crooked rack handle), the SE-100 Delux seems very impressive for the price.

      Sonically, they also impressed me, with a quality of sound that came close to the Bryston 3B ST, with a little more sparkle and harmonic content, but a good sense of depth and overall soundstage. They did lack that holographic quality I’m used to, and though the bass was powerful and full, it was less well defined harmonically. The Audio Research CA50 also surpassed the Monarchy pair in definition and refinement.

      But there was still a lot to like, a lively, engaging sound quality that gave music warmth and life, and was open and very dynamic. It was in dynamics that the SE-100 pair surpassed the Audio Research, with much more power available, and much more current to swing.

      My listening notes say, “warm and sweet, with lots of space, but a bit congealed”…”liquid, as opposed to lucid.” I found the 3B ST (and by implication, a pair of Powerpac 120s, since it is exactly the same amplifier) to have greater imaging precision, while the SE-100s had a more chromatic character: detail and depth were just ever so slightly swapped for harmonic richness. With some CD players this might be an advantage, to soften the CD edge, and provide warmth.

      Speaking of which, the Monarchies ran quite hot when pushed, all that dissipation heating the room (and when I think of that word, I’m always reminded of an old Playboy cartoon in which a doctor is completing a physical examination of a flabby, balding, middle-aged-looking man by saying, “Oh, there’s nothing much wrong with you; it’s just that you’re unusually dissipated for a man of 24.” Better heat dissipation than that kind).

      I’ve probably already said my piece about the Powerpac 120, which is a monoblock half-3B ST that can be used for subwoofers or can be attached to the rear of such professional monitors as the big PMCs that Bryston distributes in North America. It is rated at 120 (and typically delivers 150) and doubles its power into 4 ohms. It’s about the same price in pairs as a 3B the only difference being an extra power cord and a different chassis. I rank it with the ST version of the 3B as the most accurate and neutral amplifier I’ve yet heard. There may be more higher fidelity (in the true sense) amplifiers out there, and probably are, but I still prefer to live with the Bryston in my audio system because of its resolution across the whole bandwidth. However, I have been hearing some pretty interesting things about the Celeste Moon amplifiers.

      All that said, both of these single-ended designs are well executed, and can sound very good in the right circumstances, in the case of the KAB Souvenir TCA with efficient speakers with full bass response or a subwoofer. The Monarchy Audio SE-100 Delux amplifiers will fit into almost any situation where you want punchy, powerful, and warm sound, keeping in mind that the louder you play them, the warmer your room will become.

Andrew Marshall

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