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Classe CT-2300 Stereo Power Amplifier Review

by September 16, 2012
  • Product Name: CT-2300 Two-Channel Amplifier
  • Manufacturer: Classe
  • Performance Rating: StarStarStarStarStar
  • Value Rating: StarStarStarhalf-star
  • Review Date: September 16, 2012 20:00
  • MSRP: $ 6,500
  • # of amplifier channels: 2
  • Frequency response: 1Hz – 80kHz, -3dB
  • Output power: 300W rms into 8Ω (24.8 dBW); 600W rms into 4Ω (24.8 dBW)
    Both channels driven Harmonic Distortion <0.002% at 1 kHz balanced
    <0.004% at 1 kHz single ended Peak Output Voltage 150V peak to peak, 53V rms no load
    136V peak to peak, 48V rms into 8Ω
  • Input Impedance: 50kΩ balanced / single ended
  • Voltage gain: 29dB balanced / single ended Input level at clipping 1.88V rms balanced / single ended
    Intermodulation Distortion >90dB below fundamental into 8Ω balanced / single ended
    >90dB below fundamental into 4Ω balanced / single ended
  • Signal to Noise Ratio: -116dB at peak output into 8Ω
    Measurement Bandwidth: 22kHz Output impedance 0.015Ω @ 1kHz
  • Rated power consumption: 420W @ 1/8th power into 8Ω
  • Dimensions: Width (including faceplate) 19” (483mm) Width (excluding faceplate) 17” (432mm) Depth (excluding connectors) 18.625” (473mm) Height 6.97” (177mm)
  • Gross weight: 109lbs (49.5kg)
  • Net weight: 89lbs (40.5kg)
  • Mains voltage: Specified on rear panel

Pros

  • Pristine fidelity
  • Oddles of reserve power to drive virtually any speaker load
  • Benchmark performance
  • Runs cool

Cons

  • Expensive
  • Ho hum feet
  • Front faceplate protrudes in rack mount installations

 

Classe CT-2300 Introduction

CT-2300_A_LG.jpgYou know within the first few bites at a new, but really good restaurant that you’ve found an exquisite place to dine at. The flavors, the texture, the quality of ingredients; it ALL makes a difference. What applies in food also applies in virtually all other areas of life. Audio is no exception. Classe has been one of Canada’s premier electronics manufacturers since 1980. When I took delivery of the new $50k/pair Status Acoustics Titus 8T Speaker system, I wanted to collect a few exceptional amplifiers to test them with. I’ve always heard the Classe name thrown around but never had the chance to formally sit down with any of their gear…. Until now. I requested a CT-2300 two-channel amplifier for review. The CT-2300 is a relatively compact, yet powerful amplifier rated at 300wpc into 8 ohms and 600 wpc into 4 ohms. With amp in hand, it was time to sit down and get a taste to see if we were dealing with a gourmet or fast food offering.

In this review, I will take you on a tour of the inner workings of the Classe CT-2300 two-channel power amplifier. We discuss Classe's proprietary and unique ICTunnel system that helps to keep this Class AB amplifier running cool at all power levels.  We examine how this baby ticks and also do a full barrage of power and distortion tests to see if its performance justifies the  $6,500 price tag.  How does the CT-2300 amplifier sound?  Well, your gonna have to keep reading to find out.

Classe CT-2300 Two-Channel Amplifier Design Overview

Classe electronics are designed and engineered in Canada and built at a state of the art facility in China. They offer two versions of this amplifier, the rack mountable CT-2300 (MSRP: $6,500) and the stand alone CA-2300 (MSRP: $7,000) Delta series. Both amps share identical internal components only the Delta version offers spruced up cosmetics since it’s meant to be out in the open as a showpiece instead of rack mounted and out of sight like the CT series. The $500 difference in cost between the two units reflects Classe’s extra manufacturing cost for the fancier housing. The CT-2300 was sent to me because it’s more readily available, but had I been on the market to buy this amp, I’d have opted for the CA-2300. In my opinion, it’s well worth it if you’re thinking about showcasing this amp out in the open. It just looks awesome.

CT-Tunnel_C_LG.jpg     CA2300-InsideShot-RGB.jpg

 Classe CT-2300 (left pic); CA-2300 (right pic)

The Classe design goal for their Delta/CT series was to produce an amplifier module that would be as simple and compact as possible. Signal paths were kept as short as possible to preserve fidelity. Their 6 layer PCB board ensures this, and Classe claims these are their finest sounding and performing amplifiers they’ve built to date.

The CT-2300 employs a class AB amplifier topology with 18 bipolar devices per channel and 67,200 uF of capacitance (12 x 5,600uF) per channel. Ganging up multiple smaller caps is a great way of not only saving space but also lowering ESR (Effective Series Resistance) since each capacitor in parallel halves resistance while doubling in capacitance value assuming the same values are used throughout. The power capacitors are rated at 100V / 85 deg C. The voltage rating is plenty big to meet the 300 watt continuous rating (and 87.5V DC rail voltage), but I was a bit surprised Classe didn’t employ 105 deg C parts. 85 deg C is pretty much industry standard, but some companies go that extra mile and use higher temperature parts for increased longevity. As an EE myself that loves to overdesign stuff, I appreciate those little details. The amplifier topology is differential through the entire circuit path all the way to the final current stage. The power transformer is a torodial type rated at 2356VA which is nice and meaty. I have no doubt based on the sum of the parts thus far that this amplifier has a pair of cojones.

Classe talks about the CT-2300 requiring a break in period of up to 300 hours for the capacitors to fully form to provide the best audio quality. While there is some merit to this, I often feel manufacturers exaggerate the break in periods as a talking point for salespeople to convince their unwary customers debating on returning the product that performance will get even better over time. Take it with a grain of salt. Break in is real for bass drivers and to some extent capacitors. If someone tells you speaker cables break in too, suggest to them a healthy dose of Audioholics rehab and send them to our Cable University section of the site. Thermal equilibrium is however a different matter and Classe recommends a warm up period of 10-15 minutes before conducting critical listening. I do this with pretty much all amplifiers I listen to and also let them run 30 minutes loaded at 1 watt prior to engaging bench tests.

Classe has designed the CT-2300 amplifier to be safe from various fault conditions such as output overload, DC offset and the AC mains operating out of their nominal range (for 120V models that +15% to +10%). I find it commendable that the fine folks at Classe put forth so much effort to engineer proper protection into this amplifier. I was a bit surprised that the CT-2300 wasn’t switchable between 120/220V operation. I’ve reviewed much less expensive amplifiers that not only were switchable, but were also auto-detectable switchable.

A unique feature of this amp is how Classe chose to keep it running cool. Their proprietary method is what they refer to as ICTunnel. Their ICTunnel system is said to operate like the human hypothalamus which regulates body temperature. The ICTunnel utilizes an aluminum bonded-fin heatsink. It exploits the principle of low thermal mass, so it heats quickly but can also be cooled quickly. Inside its relatively small sized chassis are heatsink fins providing nearly 31 square feet of surface area. The fins are closely spaced to each other to maximize the surface area inside the tunnel, but not so close as to heat each other up. In conjunction with the critical spacing of the fins, a low noise fan along with pressure and temperature sensors maintain the amplifier's target temperature.

ICTunnel allows the amplifier to reach thermal stability within 15 minutes from power up. Once thermal stability has been reached, the heat sensors and the fan will keep the operating temperature stable regardless of how long the amp will be used (hours, weeks, months). The amp will also run cooler than a conventional amplifier using heat sinks which is a very important factor for both sound quality and long term reliability. The front face plate protruding nature is a result of the shape of the air intake that has been designed to allow air to circulate freely in the IC Tunnel while keeping turbulences and the resulting noise low. I even measured the idle power consumption when plugging this amp into my ACP S20 power conditioner and it was well under 100 watts. This is a lot of cool (no pun intended) tech for an amplifier and it works per my testing.

The CT-2300 includes adjustable rack rails to accommodate racks of different depth. I didn’t use them in my Middle Atlantic Rack since I already had a shelf in place. But, for those wishing to install the amp into their racks with the included rails, simply loosen the screws, extend the rails to the desired depth, fix to the front and back of the rack, and then re-tighten the screws. The user manual gives clear instructions and illustrations on how to do this and most consumers purchasing this amp will likely have a professional installer (recommended) do it for them anyways.

CA2300-BackPanel-RGB.jpg

Classe CT-2300 / CA-2300 Back View

A good portion of back panel real estate of the CT-2300 is dedicated to fan exhaust for the ICTunnel system. The CT-2300 has quite a lot of connection points for a two-channel amplifier. That’s because it sports CAN-Bus controls to interface to other Classe products, USB & RS232 for firmware updates and to interface with Crestron/AMX devices, 3.5mm +5V trigger inputs/outputs, two sets of WBT 5-way speaker binding posts for bi-wiring, balanced and unbalanced input line level connections and a 3 prong power receptacle with a supplied 2 meter 14awg 3 prong power cord. The balanced input pin assignments are in compliance with AES14-1992 where pin 1 is Signal ground, pin 2 is Signal+(non-inverting) and pin 3 is Signal- (inverting). Make sure to check the polarity of your mating preamp when making your connections. I have found some gear flips pins 2/3 which would essentially flip the phase of the signal between the preamp and power amp.

CAN-Bus will allow a Delta or CT series Preamp/Processor touchscreen to:

  • Display status information for every connected unit, including amplifiers which do not have a touchscreen display.

  • Create a “PlayLink” that allows an SSP or Preamp to automatically switch to the correct input when a Delta series source component starts playback.

  • Adjust the global system brightness.

  • Configure the entire system to go in and out of standby at the touch of a button and also bring individual components in and out of standby.

  • Mute any connected unit


CT-2300_B_LG.jpg      CLASSE_CA_2300.jpg

Classe CT-2300 (left pic) & CA-2300 (right pic) Front Panel View

The Classe CT-2300 won’t win any beauty prizes but the CA-2300 probably could. Both units are exceptionally crafted as expected for products of this price class. The only front panel user interface is the front panel illuminated button which serves as a status indicator and on/off switch.

  • On (dim red) = standby

  • Flashing blue (on power-up) = initialization

  • On(blue) = operating normally

  • Flashing (after power-up) = AC mains voltage out of range

  • Flashing (alternating red/blue) = the air intake filter needs to be cleaned

  • Slow flashing (red) = protection circuit(s) engaged

Set-Up

ShowcaseUnboxing the CT-2300 was a bit unusual. The entire box literally collapses as you open it to take the amp out. The thick cardboard and ample framed foam inserts demonstrates that Classe has put a lot of effort in ensuring this amp shows up at the customer’s home damage free. The 90lbs CT-2300 was as brute to haul up the flight of steps for testing in the Audioholics Showcase Theater room. I connected the CT-2300 to my Denon AVP-A1HDCI A/V processor via Bluejeans Cable balanced interconnects and Kimber 8PR speaker cables with compression WBT banana plugs to the new Status Acoustics 8T speaker system I currently have under review. The source devices included the Oppo BDP-95 and Yamaha MXC-2000 MusicCAST system. The listening space is a 6,000 ft ft^3 room that is moderately acoustically treated, courtesy of Auralex Acoustics.

I spent most of the time evaluating the CT-2300 using two-channel music sources but I also tortured it by running my reference speakers as Large with all of the LFE/Sub info directed to them when engaging multi-channel sources. This is something I NEVER recommend unless: your speakers are up to the task (most aren’t) and your amplifier has enough power reserves to handle the strain. We did some brief comparative listening tests between my reference Denon POA-A1HDCI amplifier, an Axiom Class D amplifier, and a Pass Labs X350.5 that I currently have in for review.

The CT-2300 front panel power switch blinks blue for a few seconds while the fan kicks on and a series of internal clicks can be heard with a very slight pop sound from the speakers once the amp circuits are engaged. The fan then powers down never to be heard again in most circumstances unless you’re sitting right on top of the amp in a separate room from your speakers. Seriously, I’m not a big fan (no pun intended) of using forced air cooling in amplifiers. But, the Classe ICTunnel system is so well executed that it rarely turned on unless I was beating the snot out of the amp. At those listening levels, it was impossible for me to hear fan noise. Don’t sweat the fan, it’s a good thing that keeps the amp running cool and allowed Classe to reduce the product weight by not having to build in more heat sink area to cool the beast.

Classe CT-2300 Two-Channel Amplifier Listening Tests

CD: Anne Bisson – Blue MindCD-Anne.jpg

I had never heard of this singer before but it was handed to me by a close friend that said I should check it out as a reference quality recording to really hear a loudspeakers vocal prowess and ability to properly place all of the instruments within the front soundstage. Track #3 “Hoping Love Will Last” started out with a nice piano melody along with the angelic voice of Anne Bisson. Her voice emanated front and center tricking even the most experienced listeners like myself into thinking the center channel was playing. The tonal characteristics of this track sounded similarly good on my reference Denon POA-A1HDCI amplifier and the Classe CT-2300. Initially I wondered what all the fuss was about the Classe. Well that wondering quickly ceased about 1 minute into this song. Patient listeners are rewarded with deep extended bass you frankly don’t expect from this recording. On my reference Denon amplifier, the bass got compressed and lacked definition as the volume level was turned up proving it just couldn’t fully handle the 2.6 ohm dips that the Status 8T speakers exhibit in the lower bass regions. Even the high powered A1400-8 class D amplifier I had on hand simply didn’t provide satisfactory bass control and overall clarity, perhaps even less so than the lower powered Denon. Only the Classe CT-2300 and Pass Labs X350.5 amplifiers could properly drive my speakers here. The CT-2300 produced tight deep undistorted bass in a very similar fashion to the Pass Labs amp. Tonally we did here a slight difference between the amps. The Pass Lab’s seemed to be a bit more forward in the upper registers making the high frequencies pop out at you while the Classe seemed a bit more laid back persuading you to listen while not drawing attention to itself. Neither myself nor the other two listeners present in this comparison could definitively say which sounded better as we all felt they both sounded stellar. The very fact that the Classe amp was hanging with a much more expensive esoteric amplifier spoke volumes for how good Canto-SACD.jpgthis amplifier was proving itself to be.

SACD: Andre Geraissati - Canto das Aquas

My wife picked up this little gem for me at a CES show nearly 7 years ago and until recently it remained shelved. I was quite flabbergasted by the quality of the recording and the content when I finally dusted it off to take a listen. This music is classified as Brazilian Instrumental and I really took a liking to it. Each instrument was individually mic’d with top of the line microphones and two additional mics were used to record room ambience. Reference level electronics and recording equipment was used all of which was listed in the recording insert. According to the label, this SACD was recorded at the most sophisticated recording studio in Latin America. Based on the pristine sound quality I was hearing, I have no reason to doubt that claim. I chose this recording to get an understanding of the CT-2300’s ability to finesse. Track #1 “Agreste” demonstrated the CT-2300’s resolve at extracting all of the details in this recording. The acoustical guitar was anchored to the left speaker while the triangles panned the front soundstage. The noise floor was dead silent and you could clearly hear the finger sliding up and down the strings before they were even strummed. The reverb from the guitars in track #2 “Frazenda” was hypnotic. I’m pretty certain that the guitarist employed the Lexicon Reverberator that the insert mentions for this recording on this track. There was so much body to the recording that it sounded like I was planted at the live studio recording. Track #8 “Entre Duas Palavras” opens with some nice background cords on a synthesizer with the acoustic guitar front and center soundstage. This song seemed to have a Pat Metheny mood to it which I was really digging. The deep bass notes displayed excellent transients and had me almost begging for more. I really cranked up track #9 “Benguela” simply because it just seemed to me the CT-2300 wanted me to do it. The nylon string gSACD_Barber.jpguitars sounded pristine with no hint of edginess at any listening level. Again this felt like a live performance to me.

SACD: Patricia Barber – Modern Cool

I’ve written about this album many times in past reviews and for good reason. It separates the men from the boys, so to speak, with home audio systems. On a system without compromise, you are showered in a holographic front soundstage and plummeted with deep extended bass that rivals even the best live amplified performances. Track #1 “Touch of Trash” doesn’t waste any time exercising the woofers in your speakers and testing your amplifiers ability to drive them. The CT-2300 was right at home perfectly controlling the speakers. Track #7 “Company” is the absolute best song on this album in my opinion. You know you’re in for a serious listening experience right from the first snare drum hit. The stand up bass simply pounds your chest while you experience the drum kit as if you’re sitting right in front of it. The trumpets extended beyond the vertical plane of the speakers and Patricia’s vocals remained anchored and crystal clear despite all of the complex instrumentation paining the soundstage.

Blu-ray: Jienat - Mira (this is a recommend purchase)

You’re probably wondering why I am using a muli-channel Blu-ray as a source for reviewing a twBD_Jienat.jpgo-channel amp. Remember when I said I am running my new reference speakers fullrange with the subwoofer/lfe channel routed to them? Well this is one helluva torture test for a speaker system and the amplifier that powers it. Jienat is by far the highest quality 96KHa/24 bit multi-channel Blu-ray disc I’ve ever experienced. This disc was recorded in Norway employing a five microphone array surrounding the panel of singers speaking a dialect only used by 500 or so people in the world. An additional mic for LFE info was utilized in a close-miking configuration. There was absolutely no compression or electronic manipulation used for this recording. This disc is a nightmare for wimpy speakers or amplifiers. The Classe CT-2300 loved strutting its stuff here. Track #4 “Dancehall” surrounds you in the middle of the room with singers all around you. The percussion was full of life and vibrancy that you rarely ever hear in a recording. Most playback systems are incapable of reproducing the dynamic range of this recording but the CT-2300 did a fabulous job delivering the power necessary for the Status 8T speaker system to accomplish this goal with pure ease. Towards the end of the recording, the electric bass kicked in which literally blew my friends and myself away while we were belted with sustained tactile bass that was not only heard but rattled the core of our bones. It wasn’t until I cranked the volume up past the point of insanity that I heard the CT-2300 gracefully run out of gas and hit its rails. This made me thirst for the CT-M600 monoblock version of this amplifier which basically bridges the two channels into one massively powerful single channel amplifier with over 2X the power of the CT-2300. Perhaps I will have to revisit this track if I review the CT-M600 at a later date. However, for 95% of installs the CT-2300 should be more than enough power.

Classe CT-2300 Two-Channel Amplifier Measurements and Analysis

All measurements were conducted using our Audio Precision APx585 8 Channel HDMI Audio Analyzer following our rigid Amplifier Measurement Test Protocol.

I did some quick spot-checking on the CT-2300 amplifier gain structure to ensure it could be properly driven with a wide assortment of preamps or receivers. My personal criteria for amplifier gain structure is that it should be able to hit full power when driven with 2Vrms which the CT-2300 met just fine clipping at about 1.9Vrms. I measured 29dB gain with an 8 ohm load attached which is what Classe specs this amp to be.

Signal to Noise Ratio

CT2300-SNRa-1watt.jpg

Classe CT-2300 SNR @ 1 watt (A-weighted)

The CT-2300 exhibited a very good low noise floor. At 1 watt I measured 94dB (A-weighted) and 92dB with only a 20kHz filter engaged. The small improvement with A-wt filtering engaged indicated this amp exhibited a very low out of band residual noise. At rated power, I measured 117dB which is slightly better than Classe specs the CT-2300 at.

Frequency Response

 CT2300-Freq-fullpwr.jpg

Classe CT-2300 Frequency Response @ Full Rated Power

The Classe CT-2300 exhibited ruler flat bandwidth from 10Hz to 30kHz with a gradual roll-off of about -1dB at 50kHz and about -3dB at 80kHz which is what Classe specs this amp at. Frequency response linearity between both channels at 1 watt and full power was +-0.1dB for the entire audio band which was excellent. This indicates very tight tolerances in parts selection and excellent overall engineering.

Power Measurements

Using our Audio Precision APx585 8-channel HDMI analyzer, I conducted a full barrage of multi-channel amplifier tests on the Classe CT-2300. We tested power using three methods all of which were taken at < 0.1% THD + N:

  • Continuous Full Power Bandwidth (CFP-BW) from 20Hz to 20Khz into 8 and 4-ohm loads (up to two-channels)

  • 1kHz Power Sweep vs Distortion (1kHz PSweep) - popularized by the print magazines, this is an instantaneous power vs distortion test at 1kHz. The problem with this test is it often masks slew related and or frequency response problems some amplifiers exhibit at the frequency extremes, and thus inflates the measured power results. It does provide an instant gratification # for consumers to argue over on the forums so we are now incorporating this test to please the masses.

  • Dynamic PWR - 1kHz CEA-2006 Burst Method testing. This is a dynamic power measurement adopted from the car industry similar to IHF method only a bit more difficult for an amplifier and more representative of real musical content.

Keep in mind most review publications don't do continuous power measurements and they usually publish power measurements into clipping at 1% THD + N. Our measurements are very conservative as we use a dedicated 20A line with no Variac to regulate line voltage. We constantly monitor the line to ensure it never drops more than 2Vrms from nominal which in our case was 120Vrms.

For more info on amplifier measurements, see: The All Channels Driven (ACD) Test

CT2300-1ksweep-8ohm.jpg 

CT2300-1ksweep-4ohm.jpg 

Classe CT-2300 1kHz Power Test
Top Pic: 2CH driven, 8 ohms; Bottom Pic: 2CH driven, 4 ohms

CT2300-dynamicPWR-8ohm.jpg

CT2300-dynamicPWR-4ohm.jpg

Classe CT-2300 Dynamic Power Test (1kHz)
Top Pic: 2CH driven, 8 ohms; Bottom Pic: 2CH driven, 4 ohms

 

# of CH Test Type Power Load THD + N
1 CFP-BW 360 watts 8 ohms 0.1%
2 CFP-BW 340 watts 8 ohms 0.1%
1 CFP-BW 670 watts 4 ohms 0.1%
1 CFP-BW 700 watts 4 ohms 1%
2 CFP-BW 590 watts 4 ohms 0.1%
2 CFP-BW 610 watts 4 ohms 1%
2 1kHz Psweep 344 watts 8 ohms 0.1%
2 1kHz Psweep 357 watts 8 ohms 1%
2 1kHz Psweep 590 watts 4 ohms 0.1%
2 1kHz Psweep 610 watts 4 ohms 1%
2 Dynamic PWR 394 watts 8 ohms 1%
2 Dynamic PWR 767 watts 4 ohms 1%

                   Classe CT-2300 Power Measurement Table

Classe rates the CT-2300 as follows:

  • 300 watts x 2 continuous @ 8-ohm

  • 600 watts x 2 continuous @ 4-ohm

Classe doesn't specify at what frequency they rate their power output, but I assume they mean 1kHz which is how most manufacturers specify all channels driven power claims. They also don’t specify the power level or test conditions the specified distortion of 0.002% was conducted at.

The amp protection circuits shut down the CT-2300 when sweeping at full power (2CH driven) starting at 10Hz, but was fine when I raised the start frequency to 20Hz. This is something that would never happen in real world usage. It’s a smart idea to build in protection like this to increase longevity and reduce failures when reviewers (like myself) attempt to break products during our bench testing.

My measurements revealed that the CT-2300 is a true powerhouse and lives up to the published power figures Classe specified for this amplifier. Since we don’t use a Variac to hold line condition constant, it’s very difficult to get accurate distortion measurements at full rated power. Although the amp was showing 1% distortion driven at full power into 4 ohms, the analog waveform was still very smooth and unclipped.

The CT-2300 produced virtually identical full power bandwidth and 1kHz power sweep tests indicating that the power supply and output devices were robust enough to deliver full rated power at any audio frequency, not just a sweet spot. This is just one of many hallmarks indicating the CT-2300 is a seriously great amplifier. The dynamic power results were likely limited by the wall current of my test setup. I suspect under ideal test conditions, the CT-2300 would have more available dynamic power. At these power levels, who cares? The CT-2300 could drive virtually any speaker load. I didn’t need these test results to be convinced after just a few short listening sessions powering my new Status Acoustics 8T reference speakers.

FFT Distortion Analysis

CT2300-FFT-1watt.jpg

CT2300-FFT-Fullpwr.jpg

Classe CT-2300 FFT Distortion Analysis
(Top pic: @ 1 watt ; Bottom pic: @ full power)

I ran FFT distortion plots at 1 watt (top pic) and full rated power (bottom pic) to determine how clean this amplifier really is. At 1 watt, the spectral distortion was below the noise floor of my measurement equipment which is another way of saying “awesome”!

At 316 watt, I observed the 3rd harmonic (34.032 + 51.67)dBV being 85.7dB down from the fundamental or 100*alog^-1(-74.1/20) = .0052% The odd order harmonics start dominating as the amp starts hitting the rails and becoming slew rate limited at very high frequencies. This is really a great result and shows how over designed this amplifier really is. When I lowered the power level to 300 watts (rated power) the 3rd harmonic dropped and the FFT looked excellent; perhaps one of the best results we’ve seen from any amplifier to grace our test bench.

Crosstalk

The sweep tests I ran on the CT-2300 produced excellent results, but I am sad to say the file got corrupted so I cannot post an image here. Luckily I wrote down the data at various frequency points as follows:

20Hz to 1kHz: > 100dB

20kHz: > 90dB

I consider anything less than -40dB @ 10kHz acceptable and anything less than -80dB to be superb so the CT-2300 met that minimum requirement with over 10dB to spare and at 20kHz no less. I reran these results at 100 watts and near full rated power and achieved similarly excellent figures. Classe did their homework with respect to board layout and component isolation to ensure minimal crosstalk which also assures excellent stereo separation.

Recommendations

Classe InstallBecause of the large power capacitance reserve bank, powering up the CT-2300 produces a large inrush current transient that may cause your lights to momentarily dim if you’re not running it on a dedicated line. I recommend connecting the CT-2300 to a dedicated 15A or 20A line so you can take full advantage of the power this amplifier offers. I’d also recommend plugging this amplifier directly into the wall as most power conditioners could potentially rob this amplifier of power and also needlessly strain during turn on cycles. If you plan on installing this amplifier into an equipment rack, the supplied rack rails could be useful but I’d advise the installer to see what works best for the particular installation. Always follow the manufacturer’s installation instructions carefully when placing this amplifier into a rack to prevent damage or personal injury. Although you can stack these amps, I’d still recommend giving a few inches of ventilation at the top with plenty of back air flow so the ICTunnel can function properly.

It is important to note that with the faceplate installed, the CT-2300 won’t flush mount to your rack like other component gear often does. While there is nothing wrong with that, it may look a bit odd like it does in my case having one of your components in your rack protrude while the others do not. It also makes it easier for an envious audiophile friend to pull a heist on you when you’re not looking so watch out.

If you’re planning on installing this amplifier on a shelf or floor mounting it, I’d suggest considering spending the extra $500 for the CA-2300 version. An amp that performs this good deserves to flaunt its stuff in fancy clothing.

Classe CT-2300 Two-Channel Amplifier Conclusion

2300-frontMy time with the Classe CT-2300 two-channel amplifier has been a pure delight. Its pristine sonic virtues, ability to drive even the most challenging of speaker loads beyond reference levels, and its stellar bench tests results all equate to a trifecta amplifier few at any price could surpass. The fact that it runs cool even when driven hard makes it an installers delight that they can rackmount a few of these virtually right on top of each other without worrying about heat dissipation issues.

About the only thing I can diss the CT-2300 on is its rather generic rubber feet. OK I’ll admit, I have a foot fetish and expect my audio components to have nice feet, especially at this price. However, Classe does offer an optional foot upgrade for those not as concerned with taking up a bit more valuable vertical rack space or wanting to place this amplifier as a stand alone piece on a shelf or the floor. With the CT-2300 powering your speakers, you will soon forget about the ho-hum rubber feet while entering a sonic landscape not achievable with lesser designed amplifiers. The only thing I urge potential buyers on before considering the Classe CT-2300 for your next amplifier purchase is to make sure your speakers are up to the task. Your system is only as good as the weakest link and I can assure you the CT-2300 will not be the kink in the chain. After two months of dining on the CT-2300, I can say with total confidence that my appetite is fully satisfied. Highly recommended!

Classe Electronics
5070 François Cusson
Lachine, Québec
H8T 1B3, Canada
Phone: 1-514-636-6384
FAX: 1-514- 636-1428

CT-2300 Review
MSRP: $6,500

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

  • StarStarStarStarStar — Excellent
  • StarStarStarStar — Very Good
  • StarStarStar — Good
  • StarStar — Fair
  • Star — Poor
MetricRating
Frequency Response LinearityStarStarStarStarStar
SNRStarStarStarStarStar
Measured Power (8-ohms)StarStarStarStarStar
Measured Power (4-ohms)StarStarStarStarStar
Multi-channel Audio PerformanceStarStarStarStarStar
Two-channel Audio PerformanceStarStarStarStarStar
Build QualityStarStarStarStarStar
Ergonomics & UsabilityStarStarStarStarStar
FeaturesStarStarStarStar
PerformanceStarStarStarStarStar
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Gene manages this organization, establishes relations with manufacturers and keeps Audioholics a well oiled machine. His goal is to educate about home theater and develop more standards in the industry to eliminate consumer confusion clouded by industry snake oil.

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