Speed and damping, mid-range performance.

Sibilance and harshness at higher frequencies. Unacceptable in bridged or bi-amp use.

I have used the 150a to drive Sonus faber speakers (Concerto Grand Piano first, later replaced by Cremona) for nearly five years, after switching from Graaf tubed separates. The 150a is fed by a KAV-250p through the balanced connections.

My early impressions of the 150a were that they were much faster on transients and exerted much stronger control over the speakers. Bass performance is tight and well damped, in comparison with the Graaf, which tended to produce slightly bloated bass notes on lower frequency extremes. Paired with the 250p, the soundstage is wide but not as deep as with the Graaf separates. Individual instruments are well defined but slightly lack the air and bloom of tubes. Mid-range perfomance is very good -- the sound of close-miked vocals through this amp is attention-grabbing.

Where the 150a falls short is in the higher frequencies. There is noticeably more sibilance in the highs which can induce listener fatigue. There is a sense of harshness in violin and piano reproduction, which masquerades as transparency or resolution but after extended listening, it becomes clear that this is an inherent character of the amp. The effect is exaggerated at higher listening volumes.

Bridging a pair of 150a's made matters much worse. Imaging was utterly destroyed and the amps performed poorly throughout the frequency range in mono operation. Switching from bridged mono to bi-amping (on the Sf Concerto GPs only - the Cremonas are not bi-wireable) improved matters slightly but not adequately. I promptly returned the loaner 150a and reverted to stereo operation.

In fairness, the 150a does improve after warming up, sounding more fluid as the hours pass. While the bass remains impeccable throughout, the mid-range and high frequencies seem to balance out the longer the amp is in use. However, the exaggerated top-end emphasis can still be perceived and the amp never quite achieves the neutrality and even tonal balance one expects.

In summary, the 150a is a very good solid-state stereo amp with fine low and mid frequency performance. The slightly harsh top end could possibly be tuned out by component matching, though in this sense, it is still short of excellent.

Similar Products Used:

Graaf 5050 power amp, Marantz PM4200 integrated, Cyrus 3 integrated.

Krell KAV150A is smooth, truly tight with the bass, a natural voice producer with Martin Logans speakers.

While it bring the singer to a 3 dimensional and real image of the singer but still could not quite match the Threshold class "A" amps....which is not made anymore.

Am an audio fanatic, Melodically as well as electronically since i was 4 years old. The first song i listen to was petty page's Kentucky waltz and Dinah Shore's Button and bows. In 1957 Dad upgraded the system and bought Bogen amps, RCA amps with Jensen Horn SPeakers while uncle bought the classic marantz AMps. My other uncle introduced me to Grundig T_46 Taperecoder and i fell in love with music and started to listen to all sorts of music and reel to reel tapes....Then dissaster hit Indonesia and communists took over and we could not buy US equipment, so we just listen to the Beatles and Rolling Stones underground, under the pillow with short wave radio and stereo was dead until 1967 when the commies was gone and japanese gear started to move in. By then i fled the country and studied in Germany and went back to my old hobby of recording and listening to music using Tandberg taperecorder, Grundig, Ampex, and several Uher and Revox gears. SOme day i record 3 days and nights without sleeping or eating much. GOing to disco's on saturdays just to listen to a real band to compare my stereo set up. IN 1970s after serving the US MArines i went back to college and started to design and sold my own speaker systems using Electro VOice components to practice the audio engineering i learned at school. IN the 1980's i finally realized i could not beat the transparency of the ribbon elelctro static speakers and so i started using Mr Graebners speakers and designing the woofer myself. Tested equipments such as SAE, SONY, uxman,Denon,Soundcraftsman, COnrad Johnson,Threshold, Aragon, Phase Linear etc etc..... Tons of money spent ......in the 1990s I moved to australia to continue work and designing and selling speakers to the OZs. 1993 I consulted recording studios in Jakarta on Hometheater and stereo demos. And In 1996 I again moved to Europe (london and italy) to further my research in audio quality (but this time in the wireless world of mobile phones). In 2000 I finally started to go back to my roots of HiFi Stereo toys......Well after all those years and countries and gears, this is my personal opinion and not in anyway a judgment or recommendation or rejection of any brand under the sun, for a non millionaire with and limited budget,this is what I would do: 1. Never confuse home theater and Stereo HiFi. Hifi pinpoint you to a singer on stage and instruments on the side while Hometheather system emerged you in the jungle and no point of reference, they are diametrically opposed in principle. If you want a good stereo you would not get a good home theater system. Each HT speaker must then have the same Sound Pressure Level (SPL) made from the same factory of the same model otherwise the other will sound different and be out of phase with the rest etc etc..... 2. If you want a good affordable Hifi, use only USA equipment. (Long story). 3. Always buy a separate system (Amp AND PreAMP), never buy an integrated system. 4. For transparency and realness in my case I in my case i Use MArtin Logan Request (6 foot tall), below that model it is too dull and above that too expensive. For the budget, is THE BEST, nnobody beat ribbon speakers. For AMPS, well Threshold SA3 ( Class A) 50 watts each , is to date still the best when it comes to bring the 3 dimensional person in front of your nose....bar none. Unfortunately, it is outdated, It is having problems with smoothing todays CD metallic sound and Threshold has shut it doors down. After stuying it for the last 5 years I bought afordable Krell KAV150. Sounded sooo good that i bought another one. I retire my CJ Motif8 Pre AMp and replaced with Jeff Rowland SynergyIIi. All balanced systems. The result is awesome..The little Krells drive my woofer and ribbons like no other amps I had. Transparent...no heat..I may sell one of them since I may not need it. Paid around $1900.

Similar Products Used:

Threshold SA3, Luxman, Phase lInear, SAE, DUAL, many others.

Bass and the Midrange. Very good imaging though not as good as tubes i.e Cary Amps

Absolutely, Positvely, and Authoratively, None at this Price Range.

Okay here it is again. If you scroll down you will see that I posted the first review on this Amp and after 2 years, I thought I would post again. My system has changed completely since my first post. As follows: Krell Kav 150A Amp Krell Kav 250P Pre Amp Cary 303/200 CD Player Audio Quest Viper XLR Cables throughout Vienna Accoustic Bachs Adcom Ace 515 Line Enhancer All things being said, I'll change the "other" equipment BEFORE I replace this Amp. If I was to replace this Amp, I would climb the Krell ladder first or go to tubes. As far as Solid State is concerned, there simply is no competion out there at this price range! Should you find a 150A used on E-Bay, buy it!!!!

Dynamic punch and huge soundstage.Stays quite cool.

19" width is tough for some racks.

This "little" Krell is an absolute gem.I''m currently using it for front channel duty from an EAD Ovation Plus to Aerial 6Bs.The soundstage and bottom end authority is clean and articulate.I had used at one time both the Sony TA-E900ES and a Citation 5.0 prior to going with the EAD.The Sony was somewhat constricted,the Citation sounded so clear it scared me.But after awhile,the Citation just had a sound that wasn''t what I was loking for.The EAD is it for me.Just so much warmer.Now,the bass from the Krell is tighter and more dynamic.I think I''ve found a perfect match.In fact,I''m going to look for another used KAV-150A for the rears.It''s amazing how well this "little" amp performs.It weighs a ton for it''s size.I just love it.

Truly Everything!

Absolutely Nothing!

Here is my spin on the Krell 150A Amp. I just recently bought this unit off of E-Bay for $1,300.00. This Amp. is no longer made by Krell but when it was in production, it went for around $2,200.00. This unit has been called the “baby” of the Krell Line where their Reference Series Amps go for $120,000.00! However, there is nothing child like about this amp.

After owning this amp for a few weeks, I think I can now write an informed opinion on its performance. First let me say that I am in the process of completely re-doing my system and this amp was but the first step. My listening environment includes the following.

Krell 150A Amp
Bose 601 II Speakers (15 years old and sound and look like the first day I bought them)
Adcom 515 Line Enhancer
Denon DCM 260 5 Disk Player
Basic 12 Gauge Copper wire with gold connectors

I will mention that the Krell has replaced a fine Denon PMA 720 integrated amp.

As you will see above, I’m not using a Pre-Amp; rather I’m just using the Gain on the CD player to control the volume. With this amp you don’t need bass or treble controls; the sound is that good!

Realizing that the Denon CD player is not that great, the Krell is able to transform the signal into an incredible sound stage. The bass is very controlled, yet when appropriate can really kick . . . sharply. The midrange is absolutely incredible; vocals almost seem to be on top of the instruments. The high end is also very sharp and defined making up for the shortfalls of my Bose. The stereo separation, depth, and clarity are just absolutely phenomenal. Finally, it’s just easy to listen to! It doesn’t “beat you up”.

Since this is only going to be a two channel set up, I’ve struggled with the idea as to whether to buy a pre-amp. However, with the above described sound; why bother??? I will tell you that I am very interested to see how a SACD will sound through this amp as this will be my next purchase.

For a solid state amp, you just can’t go wrong with a Krell, especially this one. Dollar for dollar @ $2,200.00 you just can’t go wrong! This particular amp is the best introduction to “True” Hi-Fi equipment around.