Crown K-2 Amplifiers

K-2

2500 watts, 4000 damping factor, very efficient

User Reviews (9)

Showing 1-9 of 9  
clemmtec   Audio Enthusiast [Oct 11, 2013]

I bought this amp to try it out on my bi speakers I was using mark lev ml 23 to drive them
when I connected the crown k2 to the woofers, and the mark lev for the mid range and the tweeters,
You can not askd for a better bass, unless you are looking for noice like you find in some cars
Yes the crown k2 do not sound good in the mids but stand back when it comes to good clean
bsaa.
I give the amp 5 stars.

OVERALL
RATING
5
VALUE
RATING
5
tyrebyter   Audio Enthusiast [Nov 08, 2007]
Strength:

'silent, powerful, light, efficient, versatile, smart, compact (2U) and pleasing to the eye'

Weakness:

Failed three times.

Amazing... when it works. I bought this as a factory refurbished unit from Musician's Friend to use as a bass guitar amp with a Tech21 preamp and Rane crossover driving Eminence sub, mid-bass and compression driver on CD horn. I also couldn't resist lighting-up the stereo with it driving a pair of AR LST-2s. There is no sound of its own. It is silent, powerful, light, efficient, versatile, smart, compact (2U) and pleasing to the eye. And if it matters (it does to me), was made by God fearing Americans in Indiana. Not cheap but not obscenely expensive. Now here's the rub: It failed once since it is a factory refurb. It failed when I put it in service (channels cutting out randomly). It took three weeks to get it fixed and now it is failing again (same symptoms). I'm a patient man and will not condem this product for its transgressions especially since I don't know how it was treated by its previous owner, but Crown keeps certifying this amp as 'good-to-go' and clearly, it is not. I will stick with it and send it back one more time. What else can I do anyway; I can't sell it like this. When they get it sorted out, it will be my favorite.

Customer Service

OK. Could be faster. Three time loser in this case.

Similar Products Used: Crown PS400, GAS SOA
OVERALL
RATING
4
VALUE
RATING
5
Chesteta   AudioPhile [Jun 25, 2006]
Strength:

Crown rates their amplifiers to a "Minimum Guaranteed Output". You will get everything and then some that has been advertised.

Highs are excellent (on the K1, K2 also but its used for sub) for a switching amplifier. After some research I have found that the K Series amps are similar to "Class D" (Pulse Width Modulated) amplifiers however they run at 250khz switching/pulse frequency (greater than 10x the frequency we can hear) therefore they can accurately reproduce the audible spectrum with excellent clarity.

Bass is simply tight. Use short THICK cable runs to keep the Damping Factor up. Damping Factor is the (Speakers Impedance + Wire Resistance)/Output Impedance
The output impedance of the K Series from my calculations is 0.0027 Ohms. My sub has a TOTAL DF of 166: I have heard that above 50 the difference is inaudible... Use the Calculator at BCAE.com for more stats.

Temperature: Even with the Z1 mod the amp is 'warm' to the touch, approx 105 deg F across where the transistors heat sink to the chassis; if you look at the amp, there are the screws around the OUTSIDE on the TOP, then there are two rows of four screws each. On the lines formed by these four screws is where the transistors are. In the middle of the chassis (the coolest part) it is approx 100 deg F. This was tested when playing music at a low volume (Note: I can hardly notice a temp difference from different volume levels). Without the mod, with no signal the amp is downright cold after a while since it shuts off the output stages.

Weakness:

There is the Z1 circuit to bypass but if you can solder you should be fine. It is one wire across two points on a circuit board, you can do it! **Not sure how this affects warranty now that Crown no longer tells people how to do it**

All I can say is WOW. I purchased the K2 (sub) along with a K1 (highs) off eBay and have been using them for a good 5 months now. This is in a home stereo setup. Wow, currently driving a JL 13w7 sub and Klipsch synergy SB-1's (planning to upgrade the speakers...) the sound has perfect clarity; I have yet to cause distortion with this amplifier. The bass is indeed very tight due to the damping factor; I can feel my clothing pulse against my body from the shockwave the subwoofer produces! (I am a young audiophile :) and like my bass...) the sub is actually 6.5 CF and with (2) 18" passive radiators should be hitting -3 db at 14.5 Hz (computer simulated statistic, see WinISD Pro).

I keep the gains all the way up and have to put my ear within two feet of the tweeter to hear any noise (in a dead silent room). I am planning on owning these amps for LONG to come.

In a home audio situation, I have found it necessary to use the Z1 circuit mod:**I am not to be held responsible for any damage YOU cause to YOUR amplifier: this is only meant to help people figure out what took me a very long time to find**

The Z1 circuit is labeled "Sig. Det Disable". Look (with the front of the amp facing you, upside down; you need to take off the BOTTOM of the amplifier) at the circuit board in the upper left circuit board. This should be the circuit board the XLR and 1/4" plugs are on. The Z1 circuit should be on the lower right corner of this circuit board (with the amp upside down and the front facing you). Use a small piece of wire Crown no longer will tell anyone how to do this (I found the mod described on one of the reviews on this site). I found issues with my subwoofer clicking in a tenth of a second from when it should have been playing. Please note, there is also a modification that involves replacing a resistor with one of a higher value to change the timing threshold on the circuit (makes it take longer for the amp to turn off the output stages). I have never done this (it should be simple though) and there is more information available on this mod so you should look elsewhere for that info. Sorry…

Customer Service

Friendly, when calling about Z1 they tried to help me as much as they could but weren’t allowed to help because the Engineering Department had 'banned' them from telling customers about how to perform the mod; I believe it was ‘banned’ sometime in 2003 (if memory serves me correctly)… Overall they have been very helpful with my questions about Crown equipment.

Crown Audio has quickly (after comparing the amplifier specs and technology of several pro grade amplifiers) become my favorite brand. This company seems to be the straightest forward about their amplifiers in ‘advertising’ (looking at the pages on their website) under, not over the specs and telling you what they are truly capable of. I have just purchased a CTs8200 (it’s in shipment now!) for a surround sound system. I stand by this company 100% and hope to someday change over every amplifier in my possession to a Crown. I am not affiliated with Crown audio in any way besides being a very satisfied customer.

Similar Products Used: Crown K1 (little brother), the Z1 circuit is also on this amplifier in the same location. They appear to be very similar on the inside.

Soon a CTs8200!
OVERALL
RATING
5
VALUE
RATING
5
Henri   Audio Enthusiast [Aug 20, 2004]
Strength:

This amplifier is silent, does not run hot, has seemingless endless amount of power. The musical attacks are awesome.

Weakness:

None. I have not encountered the problems cited elsewhere with energy saving shut off. Perhaps my unit does not have this feature?

The Crown K-2 is used in my home audio system and not for professional work. This amplifier has transformed my stero system from ordinary to extraordinary! My 30 year old ADS L810 speakers never sounded so spectacular.

Similar Products Used: I have had experience with Antique Sound tube amps which cannot be compared to the Crown equipment.
OVERALL
RATING
5
VALUE
RATING
5
rgvivace   AudioPhile [Jun 07, 2004]

Several reviewers have noted that the K2's "quiescent circuit" -- which puts the amp in standby or "sleep" mode in the absence of a signal -- causes problems when the amp is used for home audio. So I wrote Crown tech support and here is their reply, which seems to answer all of ***my*** questions. Rob Gold ~~~~~~~~~~~~~~~~~~~ Mr. Gold, To disable the sleep circuit, on the input board in the upper left hand corner area you will see printed on the board a "Z1" location that is labeled "Sig. Det Disable". Place and jumper in this location and the sleep circuit will be disabled. The amplifier will run at idle about 200W current draw so it will be warm to the touch but it should be fine. No this will not void the warranty and it can be easily done by you. Thanks, Kip Whitehead Crown Technical Support Crown International, Inc. Ph# 800-342-6939 ext.8013 Fax# 574-294-8301 -----Original Message----- From: Rgvivace@aol.com Subject: Defeating Crown K2 Quiescent Standby Circuit? I am building a DIY two channel home audio speaker project and am considering the Crown K2 amp to drive the woofers. I have read that the "TLC" quiescent circuit -- which places the amp in standby mode in the absence of a signal -- can be quite obtrusive in such applications, but that there is a way this can be defeated. 1) Could you please give an overview of the process to implement this change? 2) Is this a factory-only modification, or can it be implemented by a user in the field? 3) What, if any, are the implications for thermal control and other protective functions? 4) If implemented, does this change affect the amp's warranty?

OVERALL
RATING
5
VALUE
RATING
5
Dave Campbell   Audio Enthusiast [Mar 08, 2000]
Strength:

Seeming unlimited power

Weakness:

Price

I bought this for my 2 Shiva subwoofers. Pro audio in general seems to have more bang for the buck and the K2 was no exception. I liked its cutting edge design and power. It has many features that proves usefull for sub use. It has balanced or unbalanced inputs that can accept one input to feed both outputs. The input has sensitivity switches and the outputs have individual level controls they can be safely bridged. The power is awesome and it can drive 2ohm loads easily. The energy consumption is very low despite the prodigious output. It also runs cool enough so it does not have a fan and associated noise.

OVERALL
RATING
5
VALUE
RATING
5
steve brown   Audio Enthusiast [May 19, 2000]
Strength:

powerful & clean

Weakness:

power saver or sleep mode

a friend of mine purchsed three k1 amplifiers for use in
his tri-amped home theater system; the amplifiers sound great, but they tend to go into power saver or sleep mode when there is a lack of signal, or if the signal is of a small amount; there is a way of modifying the sleep mode timig to allow the amp to remain in the active state longer, but the current supported modifications will only go up to
a little more than 1 minute; when the amp goes into sleep mode, when a strong signal comes along, the amp doesn't wake up quick enough to realize the full impact of te audio signal; in addition, the amps assigned to the lower level signals - such as the tweeters, due to the magnitude of the signal being sent to the amp, the amp will go to sleep at times, while the mids and lows are running just fine.

It becomes apparent when you go from a quiet scene in a movie that lasts more than 1 minute to an instance where there is a sudden or loud signal - such as a car crash, or explosion - the amp dedicated to the highs will not respond as quickly.

There is a way to bypass the sleep or powersaver mode permanantly, as explained by one of the authorized crown dealers, but it is not supported.

All in all, they are great amps, but more thought should have gone into the possiblility of bypassing the power saver mode altogether in case the amps are being used for multiway home theater applications - this way, you as the user would have control on whether you want to use this feature or not.

A great feature of this amp is high power with no fans. If it weren't for the sleep mode, this amp would be worthy of 5 stars.

Similar Products Used: k1
OVERALL
RATING
4
VALUE
RATING
4
Hurricane Johnson   an Audio Enthusiast [Oct 03, 1999]

I purchased this amp to replace a defective Mackie 1400 amplifier that had anintermittent problem in one of the channels. I bought the Mackie because it was
about 1/2 the price of the K2. I was kidding myself
When you need a Pro-level amplifier, don't sell yourself short. I'm running the K2 as both high and low of a mono 2-way biamped set up. The K2 drives 4 15" speakers on the lows at 2 ohms - and the bass is powerful, punchy, and smooth. The highs - JBL SR series - are nice and controlled. We get compliments on the
mix many times.
This amplifier runs hot - but it is nearly indestrutable. Worth every penny. I'll only buy Crown for Pro Sound applications.
I've never listened to this amplifier attached to high quality stereo speakers. I'd be curious.

OVERALL
RATING
5
VALUE
RATING
Jeffrey Flaws   Audiophile [Jan 22, 2002]
Strength:

Low power consumption, light weight, small form factor (2ru), gratuitous output power, high damping factor, convection cooling, reasonable heat production.

Weakness:

(see review)

I purchased a pair of Crown K2 amplifiers specifically for subwoofer drive. Each amplifier is operating in bridged mono mode, and each is driven into a parallel pair of Electro-Voice Sb180 Manifold subwoofer cabinets. In this four-ohm stereo configuration, each of the four eighteen-inch EVX-180B drivers has available drive power of 1250 watts RMS. Each amplifier is physically located near it's respective speaker stack, with about five feet of quad 10-gauge stranded copper cable for connection.
Crossover frequency is typically about 130 hertz, adjusted for environment and physical placement.


The Crown K2 amplifiers in this very low impedance configuration can provide an effective damping factor in excess of 10,000 (this is charted in Crown's documentation) and over years of use, have consistently delivered the "Chest-slamming" low frequency response and speaker control that Crown promises. Output headroom has never been an issue; I have yet to discover any reasonable limitation on the available output power. Noise is inaudible.

The K2 is an example of "you get what you pay for." By no means inexpensive, it completely delivers the specified performance. And the K2 is completely accurate and musical - it adds no colour to the sound, and produces incredible amounts of power. I shopped pretty extensively and auditioned many before choosing these, and have been completely satisfied.

I have only found two problems. First, there is a muting circuit that will quiesce the amplifier with no or very low level signals. Unmodified, this is not the amplifier to chose for a quiet living-room background sound system. Note that Crown can provide modifications to alter the characteristic of this feature, or remove it. This done, the fan-free K2 would be an excellent home amplifier. Second, I wish I owned more of these fine amplifiers. Which I plan to address the next time my system grows.

Similar Products Used: AB International 9420, Carver M1.5t, Electro-Voice 2.0kW
OVERALL
RATING
5
VALUE
RATING
5
Showing 1-9 of 9  

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