EXPIRED: FS: relist and price drop BARGAIN One Pair of very rare seriously powerful Musical Fidelity Supercharger 750k mono power amps- matching set with consectutive serial numbers

Eagleeyes · February 23, 2018

Item: BARGAIN One Pair of very rare seriously powerful Musical Fidelity Supercharger 750k mono power amps- matching set with consectutive serial numbers

Location: PERTH
Price: $5000 reduced by another 500 to $5k firm for the pair were $10,000.00 US new and are in perfect working order.
Item Condition: Very very good, very mildly scratched on tops of base plates and more on bottoms for complete transparency from sitting on floor only but not visible as underneath. Can be spiked as well.
Reason for selling: Remodelled listening room.Changing to rack mounted system due to lack of space. These are big and weigh 17.2 kilos each. and sit behind or next to speakers. 2009 Models from memory, have boxes and books to transport safely.
Payment Method: Pickup - Cash, Paypal, COD Only- Delivery or pack and send at buyers expense etc, have original boxes and manual etc. 2 nd owner bought from Simply HIFI in Perth
Extra Info: Stereophile Summing Up Sounding significantly less lean than both the kW and the 550K, the 750K Supercharger is, without a doubt, the best-sounding amplifier I have heard from Musical Fidelity.

While I still prefer the Mark Levinson No.33H for ultimate midrange sweetness, the Levinson is outclassed by the 750K in bass solidity, control, and overall dynamics. At $10,000 US/ a pair, it is undoubtedly expensive, but its immediate competition is more expensive or less powerful, or both (eg, Ayre's MX-R). Forget the Supercharger nomenclature—this is a power amplifier that can stand on its own feet.

Read more below or at https://www.stereophile.com/content/musical-fidelity-750k-supercharger-monoblock-power-amplifier-page-2#i6r6GAwqwpQxVePD.99

Happy to audition in Perth, super rare and exclusive and hardly ever for sale, if i could turn them horizontally and rackmountI would never sell but due to room reconfiguration they do not fit.

Musical Fidelity 750K Supercharger monoblock power amplifier x2.

Sidebar 1: Specifications

Description: Solid-state, monoblock power amplifier with balanced and unbalanced line-level inputs and 1 pair speaker-level inputs. Maximum power output: 750W into 8 ohms (28.75dBW), 1150W into 4 ohms (24.7dBW). Maximum output voltage: 78V RMS, 20Hz–20kHz; 222V peak–peak. Maximum current: 250 amps peak–peak. Frequency response: 20Hz–30kHz, +0/–0.2dB. THD+noise: <0.01%, 20Hz–20kHz. Damping factor: 220. Input impedance: 50k ohms (line), 50 ohms (speaker). Input sensitivity for full power out into 8 ohms: 2.5V (line), 35V (speaker). Signal/noise (no reference level quoted): >120dB (line), >115dB (speaker), both figures A-weighted.Dimensions: 22" (560mm) H (including feet) by 8.5" (215mm) W by 8.75" (220mm) D (including terminals). Weight: 37.75 lbs (17.2kg)..Price: $10,000/pair. Approximate number of dealers: 70. Warranty: 5 years parts & labor.Manufacturer: Musical Fidelity Ltd., 24-26 Fulton Road, Wembley, Middlesex HA9 0TF, England, UK. Tel: (44) (0)181-900-2866. Fax: (44) (0)181-900-2983. Web: www.musicalfidelity.com. US distributor: KEF America, Inc., 10 Timber Lane, Marlboro, NJ 07746. Tel: (732) 683-2356. Web: www.kefamerica.com.

Read more at https://www.stereophile.com/content/musical-fidelity-750k-supercharger-monoblock-power-amplifier-specifications#VQ5rr8YsdQZ4Cqdv.99

https://www.stereophile.com/solidpoweramps/1208mf/index.html

Musical Fidelity's "Supercharger" concept is simple, which is perhaps why no one had thought of it before: If you love the sound of your low-powered amplifier but your speakers are insensitive, or you just need more loudness, you insert the high-power Supercharger amplifier between your low-powered amp and speakers. The Supercharger loads the small amplifier with an easy-to-drive 50 ohms, and, in theory, has so little sonic signature itself that it passes on the sonic signature of the small amp unchanged, but louder.

image: https://www.stereophile.com/images/archivesart/1208mf.jpg

Michael Fremer reviewed Musical Fidelity's first Supercharger amplifier, the 550W 550K ($5000/pair), in September 2007. Using the 550K both as a traditional monoblock power amplifier and as a Supercharger to increase the dynamic range of his beloved Music Reference RM200 tube amp, a 1964-vintage Scott 299D integrated amplifier, and some solid-state designs, Mikey was impressed by what he heard. "Using a variety of very different-sounding amplifiers of various power outputs overwhelmingly demonstrated to me that the 550K Supercharger will retain the sonic attributes of your favorite low- or medium-powered amp (50–200Wpc), whether tubed or solid-state, while increasing its output by 10dB or more....The result will be dynamic realism and, in most cases, better overall performance. You can have your cake and make it rock, too."

In my own auditioning of the same pair of 550K Superchargers, used as conventional monoblock amplifiers, I was very impressed by their effortless dynamics and iron-fisted control of the loudspeakers' bass. However, I ultimately felt that the 550Ks did have some character, sounding lean compared with my reference Mark Levinson No.33H monoblocks, and with a less liquid midrange. Overall, the 550Ks sounded very similar to Musical Fidelity's flagship dual-mono kW behemoth, which Michael Fremer reviewed in January 2004, but perhaps with less delicacy (footnote 1).

Of Musical Fidelity's high-powered amplifiers, I much preferred the balance of the kW750 (750Wpc into 8 ohms, $10,000). I had first encountered this stereo design when I used it to drive Wilson Sophias 2s, playing some of my high-resolution recordings at a pair of musical evenings promoted by North Carolina dealer Audio Advice in December 2005. The kW750 combined the kW's extraordinary dynamic range and control of the woofers with a warmer lower midrange and sweeter-sounding high frequencies. Mikey found it too mellow compared with his kWs, though that is perhaps a matter of taste. After using it in my system for a while, I seriously considered buying a kW750, but a cooler financial head than mine prevailed. So when MF's Antony Michaelson told me that he was introducing a Supercharger based on the 750K's circuitry, I asked for a pair for review (footnote 2).

The 750K At first glance, the 750K Supercharger looks identical to the 550K: a black cylinder topped with an aluminum cap, made in Taiwan. It has the same music-sensing turn-on/off circuit and the same three LEDs at its base: red for standby, blue for operation, orange for thermal overload. However, while the new amplifier shares the 550K's 8.5" diameter, it is just over 6" taller, and its aluminum cap has a mesh-covered vent, through which two temperature-controlled fans exhaust hot air. (There are discreet inlet vents at the sides; the fans run briefly when the amplifier is first switched on, then remain off until the heatsink temperature rises above a preset threshold.) There is now a balanced XLR input jack on the rear panel in addition to the 550K's single-ended RCA. The maximum power is specified as 750W into 8 ohms or 1150W into 4 ohms, an increase of 1.75dB compared with the 550K, though the price is 6dB higher: $10,000/pair compared with $5000/pair.

Sound Psychoacousticians tell us that our aural memories are reliable only in the short term (though that doesn't tie in with the fact that we instantly recognize friends' voices on the phone despite the lack of fidelity). But from the instant I powered up the 750K Superchargers in my system, using them as conventional monoblocks from their balanced inputs, I was immediately reminded of the kW750. A warmish midrange, sweet-toned high frequencies, tight, deep low frequencies, and a voluminous, stable, well-defined soundstage—all were exactly what I remembered of the sound of the kW750 in my system, back in the day.

The images of the singers in Cantus's luminous performance of Eric Whitacre's Lux Aurumque, from While You Are Alive, the recording I made with them in summer 2007 (CD, Cantus CTS-1208), were precisely positioned in space; it was very easy to perceive when the tenors turned away from the microphones to add spaciousness to their sound. And the character of the voices was as natural-sounding and as unforced as I expected, with no added hardness in the climaxes of the suite, A Sound Like This, by Edie Hill also featured on the CD. (Male voices singing close harmonies at high levels provide the perfect test signal to reveal shortcomings in amplifiers and loudspeakers.)

The Musical Fidelity's enormous dynamic range and bass control got the best from Live at Merkin Hall, my recording of Stereophile reviewer Bob Reina's jazz group, Attention Screen (CD, Stereophile STPH018-2). I use as few mikes as possible when I record a drum kit: two cardioids overhead as an ORTF pair, a Shure cardioid clipped just above the snare drum's top skin, and an AKG dynamic mike in front of the kick drum's front skin. I time-align the outputs of the two spot mikes with the outputs of the cardioid pair, my goal being to capture both a natural image of the drums and their natural dynamic range. With an empathetic drummer capable of optimally tuning his kit—eg, Attention Screen's Mark Flynn—almost no equalization or compression is required in postproduction. And Mark hit the heck out of his Gretsch kit that February night in Merkin Hall. There are some snare-drum shots on "Blizzard Limbs"—the three beats at 3:40 that divide the rocking improvisation that begins the piece from the more contemplative second section, for example—that go from –60 to 0dBFS from one sample to the next. Amplifiers that can't swing as many volts as the 750K will clip those peaks, unless you play the music too quietly. With the Musical Fidelitys, I could play this track at live levels without waveform clipping.

It being the end of Zeptember as I write these words, I had to get the Led out, specifically How the West Was Won (DVD-Audio, Atlantic 83587-9), recorded live at two L.A. concerts in 1972 by Eddie Kramer. Yes, suck-and-blow compression is obvious at times, but this set features great recorded drum sound, with tangible space around and between the drums. Forget "Stairway to Heaven," "Immigrant Song," "Whole Lotta Love"—the highlight of this album is the blues "Since I've Been Loving You." Even at ear-bleed levels—is there any other way to listen to Led Zeppelin?—the Superchargers allowed me to hear into the layering of the soundstage, with Bonzo's drums behind Jimmy Page's guitar and "Percy" Plant's wailing.

Read more at https://www.stereophile.com/solidpoweramps/1208mf/index.html#V9ZajPhOcrMpjyHV.99

Musical Fidelity 750K Supercharger monoblock power amplifier Page 2

Looking back at what I've written, I seem to have concentrated on the 750K's abilities to play loudly and cleanly—which they indeed did. But for all their ability to kick loudspeaker butt, the Musical Fidelity could still do delicacy with aplomb. Robert Plant and Alison Krauss's Raising Sand (CD, Rounder 11661-9075-2) has been in heavy rotation chez Atkinson since I picked it up while killing time at a Starbucks a year ago. The double bass on this disc can be problematic with some amplifier-loudspeaker combinations, as its considerable midbass energy demands an amplifier capable of retaining control of the woofers if the sound is not to degenerate into mud, while at the same time allowing this recording's wealth of midrange detail to emerge unscathed. The bass in Gene Clark's "Polly Come Home" had the appropriate combination of weight and definition, without obscuring Plant and Krauss's mysterious-sounding harmonies as they soared over Marc Ribot's contemplative guitar figurings, all against a richly ambient backdrop.

Again looking back, I see I have avoided mentioning how the Musical Fidelitys coped with complex classical music. They did very well with naturally miked recordings. They allowed, for example, the sense of space Tony Faulkner had captured with Antony Michaelson's performance of the Mozart Clarinet Concerto, with conductor Robert Bailey and the Michaelangelo Chamber Orchestra (SACD, Musical Fidelity MFSACD017), to emerge from the speakers unscathed. And with a hi-rez, 24-bit/96kHz FLAC download of Britten's Simple Symphony, performed by the Trondheimsolistene (originally released on the SACD Divertimenti, 2L 2L50SABD), the joyous sound of the violins never became steely or hard, or too soft or mellow, while the double bass and cellos neither boomed nor sounded too lean.

Only once did the amplifiers' cooling fans turn on. I was playing organist Michael Murray's thunderous performance of Bach's Prelude and Fugue in D (Telarc CD-80088) and reveling in the Revel Salon2s' apparently limitless dynamic range when driven by the Musical Fidelitys. At the end of the track, after the blower noise from the organ on the disc had faded away, I could just hear the much quieter sound of the 750Ks' fans. They never came on at normal listening levels.

Comparisons While it shared many of the merits of Musical Fidelity's own 750K at half the price, the 550K Supercharger sounded lean in direct comparison with the 750K. Whereas the 750K worked well with every speaker I hooked it up to, the 550K needs to be matched with speakers balanced a little on the fuller-figured side. Significantly, after Cantus producer Erick Lichte had turned in his Follow-Up on the 550K, we spent a weekend together working on the mixes for the next Cantus CD, using the 750Ks to drive Revel Salon2s. "That," he said, pointing to a 750K, "is a very different amplifier from the 550K." Yes it is!

Against my long-term reference amplifier, the Mark Levinson No.33H(150W, $19,900/pair when last available), the Musical Fidelity surprised me by having better-defined, more extended low frequencies. The Levinson sounded somewhat "puddingy" in direct comparison—not at all what I had expected. The Levinson had slightly sweeter mids and highs, but it was a close-run thing. Next up was the Parasound Halo JC 1 (450W, $7000/pair), a long-term favorite of this magazine's review team and of mine. The Parasound had low-frequency slam and definition to match the Musical Fidelity's but was cooler-balanced overall, sounding similar to the 550K, though its highs were smoother.

My auditioning of the Musical Fidelity 750K was interrupted by two weeks spent with the Ayre KX-R preamplifier, reviewed last month by Wes Phillips, along with the Ayre MX-R monoblocks (300Wpc, $18,500/pair) he had used to prepare the review. In direct comparison, the Ayre matched the 750K's slam, bass definition, and soundstaging depth, and offered a slightly sweeter high end. I mean no disrespect to the 750K when I say that the MX-R could be my ultimate amplifier. But the price difference is significant, and I could happily live with the Musical Fidelitys.

Summing Up Sounding significantly less lean than both the kW and the 550K, the 750K Supercharger is, without a doubt, the best-sounding amplifier I have heard from Musical Fidelity. While I still prefer the Mark Levinson No.33H for ultimate midrange sweetness, the Levinson is outclassed by the 750K in bass solidity, control, and overall dynamics. At $10,000/pair, it is undoubtedly expensive, but its immediate competition is more expensive or less powerful, or both (eg, Ayre's MX-R). Forget the Supercharger nomenclature—this is a power amplifier that can stand on its own feet.