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Doug Schroeder describes a progeny of OTL amplification: The $6,495 Moscode 402Au stereo power amplifier

Reviewer: Doug Schroeder

I recall being in a discussion years ago with a long time audio manufacturer who mentioned a person nicknamed “Gizmo”. I blanked, “Uh…,” while trying to cover my profound ignorance. Harvey “Gizmo” Rosenberg, the colorful owner of New York Audio Labs, made his mark as a manufacturer of Output Transformerless (OTL) audiophile amps. It was only after researching his name that I heard of his antics including delivering amps from NYAL to customers along with diapers! I do recall from long term memory having perused an audio magazine and seeing a picture of an enigmatic character wearing a kilt and tube headdress. At the time I had dismissed Harvey’s colorful antics as the actions of an audio show weirdo. That wasn’t the most astute conclusion to draw in regards to the man who helped Julius Futterman preserve the OTL design. I’m working hard hereto make up for it.

It is a good thing that personalities in audio are tied to recordings and equipment, so that those who discover new gear may also absorb some of the culture and history of audiophilia. Such it was that I was led to a greater appreciation of the electrical and “theatrical” aspects of amplifier design when I arranged for a review of the Moscode 402Au amplifier. In truth, it was not the journalistically opportunistic antics of “Dr. Gizmo”, the history of OTLs or the tenure of Moscode’s amp production that I held foremost in my mind as I emerged from a particular demonstration at CES 2009 - it was the sound of the amplifier. The Moscode 402Au struck me as one of the better sounding amps at the show, and thus became the impetus for this article.

The commemorative amplifier dedicated to Harvey Rosenberg was the 401HR. It’s rare that an amp memorializes an individual, but George Kaye has made sure via the 401HR that Harvey Rosenberg will not be forgotten. It seems Harvey pulled Futterman’s disheveled notes and ever changing models of amps together to preserve his work on the OTL. The amps had been made literally one at a time by Julius, never realizing a final form for production. Harvey, acquiring the rights to the OTL circuit, brought that to the equation after Julius’ death.

Harvey was keen on taking the OTL design one step further, by using MOSFETS in the output stage. A MOSFET, short for “metal oxide semiconductor field effect transistor”, is used to amplify or switch signals. George Kaye originated the Moscode’s tube+MOSFET concept, and he took it to Harvey of NYAL and took on the title as the NYAL chief engineer while further developing the concept. In other words, George and Gizmo took what were the strengths of the OTL and mated them to the strengths of a solid-state design. Thus born Moscode, a design utilizing triode tubes in coscode arrangement to control the signal being utilized by the MOSFET, resulting in a hybrid (“MOS” + “code”).

Ok, so it’s a hybrid amp – so what? One must remember that this was pretty radical thinking nearly 25 years ago in 1984! We don’t even look twice at hybrid cars, as they have become so common. A hybrid amp was anything but ordinary back then; it’s had incredible longevity and sonic merit to be implemented a quarter century later!

George is adamant about the fact that the Moscode 402Au is not just a tube gain stage slapped onto a solid-state power amplifier; rather, it is a tube amplifier with a MOSFET output stage. It’s obvious from the depth of the discussion in the Owner’s Manual that he wants people to appreciate the thoroughness of the design of the amp, not just its sound. For the three pages which comprise the discussion of the circuit the manual uses technical nomenclature, extolling the amp’s topology. Discussed is the fact that the tube driver stage and the MOSFET output stage are complimentary as both are high impedance devices. Further, the use of MOSFETs eliminate the need for Output Transformers, which George insists add unnecessary inductance and capacitance, “…and that,” states George, “interferes with the transfer function of the output transformer at high frequencies. They exhibit phase shift within the limits of the audio band.” This hinders them from revealing the maximum musical detail. MOSFETs, while not perfect, have power-related (harmonic distortion) as opposed to frequency response errors. George uses feedback to control for THD. His design rule, his “Rule of Ten”, is to, “Make the circuit work well to 10 times the highest or lowest frequencies it will handle…” A little overkill is a good thing!

Case in point, the “Au” in the name stands the use of gold plated, three-ounce circuit boards. These improve the musicality of the amplifier supposedly. The redesigned circuit layout offers advantages over the HR version (for Harvey Rosenberg) in the areas of lower noise pickup, clearer highs, tighter bass and better low-level detail.

All this extra attention to build quality reminds me of the garage on my first house, the ridge beam of which was bowed to the point of cracking. I was disgusted at the flimsy 1”x8” which had been used. Over forty years it couldn’t take the weight of winter snowfalls. My solution was to overkill on the repair, so that it would never budge again. It was recommended that a 2”x8” be used. I said, “Put a 2”x12” in there,” and they did. When the contractor was finished he smiled, “You could put a VW on top of that roof!” Good! Ten years later, whenever I drive by the old house I look at that garage roof line – it’s still straight as an arrow! I think George feels the same way about building amps which will last.

George continues his tutorial in the manual on the topic of developing a robustpower supply. The goal is to simulate infinite power reserves. As a junkie of high-output amplifier, that sounds very good to me! The amps are to act as if normal power line fluctuations do not exist, accomplished by way of voltage regulation. According to the manual, “Voltage regulation eliminates interaction between the driver and power output stages.” Neither stage can influence the other unduly in terms of demand. Consequently, there is no need for power conditioning when using the 402Au.George intones, “A well designed power supply doesn’t need any help.” The amp stores 88,000mF of capacitance per channel, as well as sporting dual-mono supplies for each of the output stages. I like the fact that the heavy-duty power transformers are specified for 50Hz rather than 60Hz, “…to get more iron into the power supply.” Sounds like a discussion of a Harley Davidson; bigger, beefier is often a good thing – in cycles and amps.

WASHINGTON, Aug. 19 /PRNewswire-USNewswire/ — The U.S. Consumer Product Safety Commission, in cooperation with the firm named below, today announced a voluntary recall of the following products. Consumers should stop using recalled products immediately unless otherwise instructed.

Name of Product: Amplifiers

Units: About 2,300

Distributor: Krell Industries LLC, of Orange, Conn.

Hazard: The amplifiers were designed to operate at a temperature warm to the touch. However, a component input device can fail and cause the amplifiers to overheat, posing burn and fire hazards to consumers.

Incidents/Injuries: Krell has received 50 reports of the amplifiers overheating including reports of smoke and electrical fire. No injuries have been reported.

Description: This recall involves Krell power amplifiers with model numbers KAV-250a, KAV-250a/3, KAV-500i and KAV-1500. The amplifiers are used to provide power to a loudspeaker in a home audio playback system. The Krell logo is printed on the front of the amplifier.

Sold by: Authorized dealers and distributors of audio equipment nationwide from January 1997 through February 2001 for between $3,000 and $8,000.

Manufactured in: USA

Remedy: Consumers should immediately stop using the amplifiers, and contact Krell to schedule the free installation of replacement fuses.

Customer Contact: For additional information contact Krell at (888) 436-6055 between 9 a.m. and 4:30 p.m. ET Monday through Friday, or visit the firm’s Web site at www.krellonline.com. Consumers can also email the firm at service@krellonline.com.

CPSC is still interested in receiving incident or injury reports that are either directly related to this product recall or involve a different hazard with the same product. Please tell us about it by visiting https://www.cpsc.gov/cgibin/incident.aspx

The U.S. Consumer Product Safety Commission is charged with protecting the public from unreasonable risks of serious injury or death from thousands of types of consumer products under the agency’s jurisdiction. The CPSC is committed to protecting consumers and families from products that pose a fire, electrical, chemical, or mechanical hazard. The CPSC’s work to ensure the safety of consumer products - such as toys, cribs, power tools, cigarette lighters, and household chemicals - contributed significantly to the decline in the rate of deaths and injuries associated with consumer products over the past 30 years.

To report a dangerous product or a product-related injury, call CPSC’s Hotline at (800) 638-2772 or CPSC’s teletypewriter at (800) 638-8270. To join a CPSC e-mail subscription list, please go to https://www.cpsc.gov/cpsclist.aspx. Consumers can obtain recall and general safety information by logging on to CPSC’s Web site at www.cpsc.gov.

Firm’s Recall Hotline: (888) 436-6055
CPSC Recall Hotline: (800) 638-2772

source:  U.S. Consumer Product Safety Commission
via: audioREVIEW forums

It is the holiday season and I am going to give you a present. This is the culmination of a long and winding and interesting and frustrating and expensive journey from that first audio component to hearing one that had me saying, “That’s the one!” It is the story of developing specific ideas about good sound reproduction, validating or replacing those concepts, and finding that some of these tenets no longer applied. Some of these tenets include:

* Only low powered amplifiers, preferably single ended tube amplifiers, can sound really good.
* High powered amplifiers can reproduce the full dynamic range of music.
* Only tubes can produce the full harmonic envelope of acoustic music.
* High bias, Class A operation is necessary for solid-state amplifiers to sound good.
* Tube amplifiers are best at creating the illusion of a real acoustic sound stage.

Each of the above has been true at certain times in the past and with certain associated components and loudspeakers. We can generally agree that most early solid-state gear was not an advance in sound quality over the tube-based components that they attempted to replace. It was a case of “one step forward and two steps back”. We gained features and possibly reliability, but the trade-off was too great: those early transistor products often sounded like fingernails on a blackboard. Having mostly lived with tube amplifiers for about 20 years and, over the last year, performed a listening survey of some of the better solid-state amplifiers, I can state with some certainty that each technology has sonic advantages. The quest is, and has always been, to find the perfect marriage of the best sonic characteristics of the different technologies.

Tube sound is typically more dynamic – both large scale (macro) and small scale (micro). It is harmonically richer, revealing far more of the fine and delicate structure of every voice and sound, without any sense of grain or harshness. Solid-state sound is usually described as having deep and tight bass and extended high frequencies, with sound that is often marred by a somewhat flat soundstage and usually rendered painfully with grainy and harmonically thin higher frequencies. The better solid-state amplifiers have a wonderful sense of focus that renders an instrument in a very specific point in space and keeps that image intact. The better tube amplifiers have far superior harmonic development and warmth in the upper frequencies. Over the last few years, the better amplifiers of each technology have begun to sound more and more alike. My preference has been to have the much more satisfying realistic harmonic resolution of tubes and simply accept their maintenance costs and relative sonic deficiency in the bass, however small.

Marantz MA-9S2 Power AmplifierThe list above has one tenet that I continue to hold true: high powered amplifiers are necessary to reproduce the full dynamic range of music with most speakers. This became apparent when I changed from the 100 Watt per channel Bella Extreme 100 to the 250 Watt Manley Neo-Classic 250s. Both models are monophonic tube amps. While the “Bellas” are sonically excellent, early in the audition of the Manleys it was apparent that the latter’s extra power was indeed sonically significant. Most of my listening is in the 10-30 Watt range with speakers of average efficiency. When you realize that a 10 dB peak pushes that power requirement from 30 Watts to 300 Watts, the need for lots of amplifier headroom becomes obvious. My personal “must have” list for the perfect amplifier includes deep, powerful and high resolution bass, an enormous and accurate spatial environment, richly detailed midrange, and high frequencies that are smooth and absolutely grain-free while preserving the life-like micro detail of such instruments as cymbals, flutes and piccolos, bells, and soprano voices. Add in high power, low maintenance requirements and also, in these “green” times, low heat output. This is where the Marantz MA-9S2, a 300 watt monophonic golden beauty, weighing 82 pounds with a list price of $7499.99 each, entered the listening room and life of this writer.

# power output:

* 300 watts into 8 ohms (20-20,000 Hz) at 0.01% THD
* 600 watts into 4 ohms (20-20,000 Hz) at 0.01% THD

# frequency response 3-150,000 Hz (-3dB)
# signal-to-noise ratio (IHF-A): 123dB
# front-panel level meter indicates output power
# preamp-level RCA and balanced 3-pin XLR inputs
# rear-panel attenuation dial (0, -3, -6, -9, -12, -∞ dB)
# full current feedback amplifier stage
# fully balanced amplifier design
# double-shielded, low-noise toroidal transformer
# all copper-plated chassis and double layered bottom plate
# WBT® speaker terminals
# 2 sets of speaker terminals for biwiring
# detachable AC power cord
# champagne finish
# weight: 82.4 lbs
# 18-1/16″W x 7-13/16″H x 18-11/16″D
# two MA-9S2 amplifiers are required for stereo operation

www.marantz.com

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New C 245BEE Amp Provides Numerous System Building Options, Power to Spare, Optional Bi-Amplification and Multizone Compatibility

SHARON, MA, Oct. 14, 2009 — NAD Electronics, the highly regarded manufacturer of high-performance audio/video components, introduces the C 245BEE Four-Channel Power Amplifier, an uncommonly talented installer-friendly amplifier. Upload

The exceptionally versatile C 245BEE features a 4-channel architecture that provides installers with several system building options. When used with NAD’s C 165BEE Preamplifier, it delivers more than enough power to drive virtually any loudspeaker, as well as the option to bi-amplify. Connected to the Zone Output of an NAD AV Receiver, the C 245BEE can also send different music programs to remote speakers.

The C 245BEE was designed, like many earlier generations of award-winning NAD amplifiers, by NAD Engineer Emeritus, Bjorn Erik Edvardsen. Harnessing multiple discrete high-power output devices, it easily provides the instantaneous peak current required for good bass response.

The C 245BEE is rated at 35 Watts/per channel, Minimum Continuous Power, into 4 or 8 ohms, with all channels driven simultaneously, for 20Hz – 20kHz, with 0.03 percent THD (NAD Full Disclosure Power). It can also handle 55W, 85W and 100W Dynamic Power into 8, 4 and 2 ohms, respectively; and 2 x 90W Minimum Continuous Power into 8 Ohms in bridge mode.

read more on eCoustics.com…

source: eCoustics

nadelectronics.com

Rotel has a reputation for high quality products by consumers and installers alike, and offer a high amount of quality at generally affordable prices. After requests from their dealers though, they set out with a new goal in mind for the RMB-1512. Lighter and cooler than past models by far, according to Rotel, the 1512 can put out no less than 100 watts at 9 ohms across 12 channels. At a 4 ohm load, that number doubles.

read more at avrev.com…

source: avrev.com

MSRP: $ 4000.00 Description: Gain: 30 db Frequency response: -0 dB at DC, -3 dB at 100 kHz Power Output: 150 W maximum @ 1% THD, 1kHz into 8 Ohms (300 W into 4 Ohms) Maximum Output Voltage: +_ 50V Maximum Output Current: +_ 20A Input impedance: 22 kohms balanced Slew Rate: +_ 50V/uS Output Noise: 300 uV unweighted 20-20 kHz Random Noise Floor: approx. 2uV Dynamic Range: 145 db (random noise floor to peak output) 16 Reviews 0 Quick Ratings 4.88 of 5 More Amplifiers from Pass Labs >> Search AudioReview forums for the Pass Labs X 150 >> www.passlabs.com

Reviewed by:Jbreezy5 (AudioPhile)
Review Date September 7, 2009
Overall Rating 5 of 5
Value Rating 5 of 5
Used product for 1 to 3 months

This is a consumer review of the Pass X150 stereo amplifier, compared and contrasted w/Parasound Halo A21 and Krell KAV-400xi (integrated).

Review System:

Preamp: Arcam A75+
Amp: Pass Labs X150
Universal Player: Denon DVD-2910
Cables/Interconnects: Blue Jeans Cable 10 ga. speaker cables w/locking bananas; Interconnects
Speakers: Dynaudio Audience 82’s (frequency response rated 25hz-25khz)

My ridiculously small room: 10′ x 10′ [I know I have broken all audiophile rules w/my choice of speaker]

I recently purchased the Pass X150 and had a 30-day, in-home trial. It is a 150 wpc amplifier that reportedly runs in pure class A up to 50 watts/channel. This is quite remarkable since most listeners never reach this level of power continuously. After the first 50 watts, it switches to class A/B operation. It runs pretty warm but I can touch the (large) heat sinks and not get burned. It seems even the fascia of the amp serves as a heat sink since it is sometimes warm as well. The front of the amp is very thick aluminum (?) on top of aluminum in a silver-gray finish. It is very utilitarian/masculine looking. Other amps may not want to pick a fight w/it based on appearance alone. The blue LED’s indicating power/standby are a little annoying, if watching a movie, but can easily be covered (this is the original version w/o current meter). It’s pretty hefty at about 60-70 lbs, for being the entry-level amp in the series. However, there is nothing entry-level about the sound.

THE BIG PICTURE

I tried to start this review discussing particular characteristics from bass to treble. But that just wouldn’t be right; it is contrary to the nature of the amp. This is the defining characteristic of the X150; it has an overall sound of organic delivery and focuses on the whole of music. It doesn’t favor any particular frequency range; in this way it doesn’t seem to highlight any particular hi-fi characteristic. The presentation is of the music and that is this amp’s concern. You may get better delineated bass from a Krell, which is brutal in the mids/highs (IMO). You may find more seductive midrange from tubed gear, which often rolls off the bass and highs. But consistency top-to-bottom, neutrality if-you-will, is this amps trademark. It will reveal the “character” of components upstream/downstream; this includes the recordings themselves.

Some may think this amp does hi-fi imaging/soundstaging. If by that they mean, it has a convincingly large soundstage and pinpoint imaging, they’re right. However, if the recording isn’t well sorted, that’s how it comes through the X150, while preserving the musical enjoyment. On good recordings all of the placement cues are there, w/solid life-sized images and a walk-in-and-around 3-dimensionality. The stage is not forward (in front of the plane of the speakers), nor recessed (behind the plane of the speakers). It seems, once again, neutral; starting at the plane of the speakers and extending to the sides and back. It’s stage is both wide and deep.

The X150 does have superior soundstage depth compared to other amps I’ve had in my system. More recently I reviewed the Parasound A21 in my system (all other components/accessories the same). I like the A21; it is an overall good performer, but I had reservations about transparency (compared to my 50 wpc Arcam integrated). Having installed the Pass amp my observations seem to be confirmed in this regard. Because of the Pass amps transparency there seems to be more of an invitation to walk through the soundstage and around the performers. I wouldn’t say its like holography, per se, since the images are focused; however, the images don’t seem “fat”, for lack of a better word, as they did w/the Parasound. This may be the result of perceived added warmth w/the Parasound. On the other hand, the Pass doesn’t give the impression of bleached/pale images as I feel Krell does.

Which brings us to tonality. If Krell is winter and Parasound Halo is summer, then Pass Labs is spring and fall. That’s my kind of weather! It neither jolts you to tears of pain when listening to violins, nor makes females sound somewhat “fat”. It is simply a refined and smooth sounding amp, that portrays tonal colors and shadings accurately w/o going to extremes. By smooth I mean, there’s not a gritty/grainy characteristic to the sound. That happened sometimes w/my Arcam on its own at louder levels, probably due to clipping. The Parasound also is smooth like the Pass Labs, but w/the added warmth.

It seems like I’ve been beating up on Krell. So I just want to say I haven’t heard better bass from another amp than the Krell. The detail and power in the bass from this thing was outright astonishing from the diminutive-sized amp. It does have the edge over the Pass in this regard. The Pass and the Parasound I thought were pretty comparable in the bass.

CONCLUSION

The Pass Labs X150 is a coherent, neutral, powerful, smooth, 3-dimensional, musically satisfying solid-state amp. This is the best I have heard in my system. I would specifically recommend it for those who want their systems to present music as a whole and be as neutral as possible (as opposed to those who like to dissect, or those who want an amp with added character). It does all of the hi-fi things one would expect from a dedicated amp, but in a civilized and even-handed way. I would recommend the Parasound A21 for someone who has a leaner sounding system. The Krell sound I think goes best w/a system that is a little warmer/juicier in nature.

These are all good amplifiers; but the Pass worked best in my system.

Also want to thank Mark at Reno Hifi, who sold me the amp; excellent customer service and included 3 free SACDs (to my surprise when I opened the package) w/the purchase and delivery was on-time; included 1 yr warranty.

I don’t know the exact product model year; I believe these began production around year 2000.

-JBreezy5-\

Popular Amplifiers 1. ROTEL RB 1070 2. Phase Linear 400 3. Audiolab 8000A 4. Hafler DH-200 5. ROTEL RB-985 THX more…

Top Ranked Products from Pass Labs. X 600 Rated: X 350 Rated: Aleph 4 Rated:

www.passlabs.com

AudioREVIEW works best with your help. Write a review for others.  It might be a highlight!

Neuhaus Laboratories introduces the new T-2 Integrated Vacuum Tube Amplifier designed for todays digital music files. Give life to flat digital audio. Designed for true plug and play with PC’s and Mac’s.

Just attach the USB to your computer and the T-2 amp and music is automatically  played through the vacuum tube amplifier. Two digital inputs USB and Optical (SPDIF/Toslink) and 3 analog inputs. Play all your ITunes files with exceptional clarity and depth.

source: George Golik

from www.neuhauslabs.com

The Neuhaus Laboratories T-2 Amplifier is built to last. Typically, most big name audio components are mass-produced, primarily of plastic components and are often large in size and difficult to set up and operate. Have you noticed how many buttons and switches they have. The rear connector panel has so many inputs even Einstein would be intimidated. The T-2 Amplifier has an elegant retro look and is built to last with a sturdy steel and stainless steel body, not plastic. Even the knobs are of high quality produced in Japan. It is engineered to provide a long life, and is simple to set up and to operate.

• The T-2 Amplifier has a beautiful black high gloss piano finish on the front steel panel and the transformer covers. The body is a mirror finish stainless steel. The tube cover is flat black with clear polycarbonate side panels.
• Gold plated input jacks (3) and speaker connectors.
• Slow Start Power On Switch-This feature extends the life of the components and the tubes by powering up slowly (about 15 Seconds) every time you turn it on.

Specifications

• T-2 Amplifier is a true Push Pull Vacuum Tube Amplifier (not solid state)
• Output- 20W x 2
• Frequency Response-10-30KHZ
• Output Impedance-4ohm-8ohm
• Harmonic Distortion-1.5%(1KHZ)
• Input Sensitivity-1000mv
• Input Impedance-50Kohm
• Signal to Noise ratio-85db
• Power Consumption 100W
• Weight-19.8lbs 9kg
• Dimensions-11.5 (W) inches x 11.5 (D) inches x 6 (H) inches
• Tubes 4-6N7 2-6N1 2-6N3
• Homemade out put transformer is made with two special designed EI steels and the OFC wire by our technicians. It has high frequency range with low distortion.
• Stainless Steel Case
• Japanese ALPS Motor potentiometer
• Steel Black Piano Black Glossy Finish Front Panel
• Mirror Stainless Steel Body
• Removable Flat Black Steel Tube Cover/Clear Polycarbonate Side Panels
• Volume Remote Control
• Slow Start Power On
• USB and Optical/Toslink/SPDIF Input
• 3 Rear Gold Plated RCA style input jacks
• Gold Plated speaker connectors

MSRP: $795.00

www.neuhauslabs.com

Onkyo has released a SACD/Amp Combo aimed at audiophiles. The player will not only do SACD but CD, MP3s CDs, CDR, CD-RW and will also play WMA files on CDs.  The amp put out 40 W per channel and allows for bi-wiring. The cost for the A-5VL and C-5VL combo is around £350.

read some more details at CNET…

source: CNET

Popular Amplifiers 1. ROTEL RB 1070 2. Phase Linear 400 3. Audiolab 8000A 4. Hafler DH-200 5. ROTEL RB-985 THX more…

Popular CD Players 1. Cambridge Audio Azur 640C 2. NAD C542 3. Rega Apollo 4. Marantz CD-5001 5. NAD C521BEE more…

Trends Audio launches TA-10.2P Class-T Power Amplifier, bringing audiophiles the outstanding Hi-Fi gears in affordable prices !

Hong Kong, June 5, 2009 - ITOK Media Limited’s innovative Hi-Fi brand “Trends Audio” (www.TrendsAudio.com) launched their new innovative Hi-Fi product - Trends TA-10.2P Class-T Power Amplifier. This is a revolution technology among these several eras of the audio techniques. Though the product is only in a palm size, the sound quality is audiophile grade. Yet, the price is only one fifth to one tenth of the same quality power amplifiers. It totally has broken the tale story that ¡§the larger, the heavier, the more power consumption,the hotter, the best sound amplifier¡¨. Trends TA-10.2P Class-T Power Amplifier lets more audiophiles, music lovers or even PC users can enjoy the high fidelity music in an affordable price.

read more on the TA-10.2P amp on eCoustics…

source: eCoustics

I love music. I love not just listening to music, but the whole music experience because there are so many levels and “components” involved in the whole subject. From music composition, to playing instruments, to recording and production, and finally to playing music on component audio systems, the subject is vast, creative, and personal. There is some area for each and every person in which to participate. Regardless of any creative or technical ability, every person can find some music-related activity where their particular talents or yearnings will find an outlet. The fact that there are so many successful endeavors in every area of the musical universe is both a testament to the creativity of our species and absolute proof that every style, every characteristic, every quality of every area of music will find a welcome audience.

I offer the preceding observation to introduce the Nuforce Reference 9 Version 2 Special Edition power amplifiers to you and to prepare you for a set of observations that will likely find resonance with other music lovers, if not the majority.

The main comparison amplifiers are the outstanding Marantz Reference MA-9S2 amplifiers, which are 300 Watt mono blocks. Their linearity, resolution, dynamic abilities, and long term enjoyment have earned them true reference status. To compare the $5,000 Nuforces to $15,000 reference amplifiers might seem unfair, but this is the playing field today at 10 Audio. The rest of the review system consisted of a SOTA Cosmos IV turntable, TriPlanar VII u2 tonearm, Miyajima Shilabe and Air Tight PC-1 moving coil phono cartridges, Manley Steelhead phono preamplifier, a Prism Orpheus studio AD/DA converter used with a Bob’s Devices step up transformer and Pure Vinyl software RIAA used as another phono stage, Cary 306 Professional and Marantz SA-7S1 CD players, and Marantz SC-7S2 and Sonic Frontiers Line 2 SE+ preamplifiers. Cables included Mogami interconnects, Audience Au24 E and Element Apollo speaker cables, Audience, Element and DIY power cords. A PS Audio Powerplant Premier provides the AC for all of the front end gear. Loudspeakers included my reference Dali Euphonia RS3 monitors, Dali Mentor 5s from the home theater system, JL Audio f112 and Velodyne Optimum 12 subwoofers, and little Solid Team speakers from my computer just to cross-check some of the findings below.

Nuforce Reference 9 V2 SE Specs and info from Nuforce:

The Ref 9 V2SE adds refinement and delicacy to the already excellent-sounding Ref 9 V2. The When used in less than the most revealing systems, the SE’s advantages may not be fully realized. As excellent as the Ref 9 V2 is, the Ref 9 V2 SE takes its strengths to an even higher level. These include:

• Sweeter highs, without any compromise in frequency extension.
• A smoother and more palpable midrange, while preserving the natural harmonic structure for which the Ref 9 V2 is famous. The Ref 9 V2 SE is one of the few amplifiers in the world that does not impart a signature on the music.  This results in a more natural and relaxed presentation.
• The bass remains the amp’s a huge strength.  The Ref 9 V2 SE has same tightness and texture of the standard  Ref 9 V2, but with a little more weight.
• The stage is more coherent and deeper.

In summary, the SE’s sound is more neutral and liquid, with a more relaxed yet powerful soundstage presentation.

NuForce Reference 9 Rated: 5 of 5 Read the Reviews

NuForce Reference 8b Rated: 5 of 5 Read the Reviews

NuForce IA-7 V2 Rated: 5 of 5 Read the Reviews

NuForce P-8 Rated: 4 of 5 Read the Reviews

NuForce AVP-17 Rated: 3 of 5 Read the Reviews

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