Krell Power Consumption


I'm a bit new to ultra high end. I'm considering a Krell Evolution 402. One thing that jumps out at me is the power consumption in standby. The manual says it draws over 300 watts in stand by and recommends that you leave it on all the time. 300 watts 24/7. Good grief. Is this bogus or just the price you pay for a serious amplifier?

thanks for any advise.
Wrf, I just checked the Evo 402 specs and you are reading it correctly; 370 watts in STANDBY! I've owned several Krell amps (KSA and FPB series). They operate in Class-A and therefore draw an incredible amount of current and give off a lot of heat. A 20-amp dedicated line is a minimum requirement. Heat can be an issue if you live in warmer climates and have your listening space upstairs. Good air conditioning is also essential.
I run the Evo 403 and yep, it probably eats more than that! It is always at least warm to the touch and after serious listening can be frankly hot.

It sounds really good though!
The new Evo amps draws way too much in standby mode.... I own the FPB-740MCX monos which are class a and they only draw 45W each. The replacement Evo-900 monos draws 450W each in standby mode and they are class A/B. I wonder why Krell has gone this route when things are supposed to be GREENER???

Other than radiated heat into the room, why would you care? If you can afford a Krell amp, you should be able to afford the extra 1.00 per day for power.
If the greenies make you feel guilty, I would suggest to sit back and enjoy the music and green out somewhere else in your life.

That is so besides the point in what you had said.
FYI, I dont care the extra money needed to be spent in keeping the amps on standby. My point is why can't Krell make the new Evo amps consume the same amount as the older models.

Before you go into another one.... I just bought a pair of their reference mono's. :)

The evolution amps are not class A anymore and they contain twice as many parts that are off the shelf garden variety sourced. Only the EVO amps are Class A. The Evolution amps are dry and lacking in color...Duh, no Class A, that's why...I owned the 402 and sold it quickly!
Dave b...

Seems like you never tried the 402 with their newer evolution pre amps hence you found them dry sounding. You are spot on regarding only the Evo-1 being class A... go back and read what I said. Duhhhhh.
I owned the 202, 402 and 505. My previous FPB series amps and pre-amps had more tonal color and were more liquid.
Dave b,

You are correct that the FPB are tonally more liquid but when compared to the newer evo series especially the 202 pre to KCT, it is more correct and made the kct sounded very slow and dull.

Correctness is in the ear of the beholder. Having owned most of Krell's offerings over the years in various systems listening to exceptional recordings I witnessed the slow decline of a great company.
hi can some one tell me between krell kav250 and marklevinson no27 with one is better thankyou
Dave_b, No comment, but isn't this a quote from your review of Evo 402/202?

"What these evolutionary components deliver is a complete musical picture with no exaggeration or flaws...just pure unhyped musical reproduction. Low level detail..yes! Resolution..yup! Frequency extension and wide dynamic bet! Tonal accuracy and micro dynamic shading..uh huh! Turn off the lights and set the volume for concert hall level images coalesce into a mosaic of musicians..natural and oh so believable."

I like the Krell Evo gear a great deal, but it's expensive.
New buyers enthusiasm? I did like alot about the Evo stuff but eventually heard the dryness set in and the slight lack of color which the previous designs delivered. It does take time to tell if your gonna like something for the long haul:O)
and now you've moved on to the cheap integrated...
I subsequently went to ARC stuff and sold that as well. Decided to drop out of the super high end club for awhile after the recent dissapointments, although I must say that the so called cheapo integrated has been one of my most beloved components (400xi not the S300i). The integrated does for me what the Sophias deliver compared to the Wilson lineup...purity, tonal accuracy and balance:O) My cheapo system has actually been my most satisfying in recent years. Maybe Wilson Watt/puppy's coming out soon and I haven't tried Pass Labs or Ayre yet?
Dave_b, I hear ya! Sometimes I enjoy my interim systems the best, even though I know they are not as technically good. I chalk that up to the scenario that since it didn't cost me an arm and a leg (so to speak) that my critical listening expectations are not quite at the same level and I just relax and enjoy the MUSIC. Like you I have gone from mid-fi's quest for the best to some pretty high Q gear, then to SET, to moderate levels and working back up again.

Performance wise, my favorite has been when I had the DCS stack, Calypso pre, Krell FPB 300C and Watt/Puppies 5.1. I had few complaints about that system and could bury myself in the music that enveloped me. Something the SET system could never do as it seemed to bore me over time (YMMV).

As to the OP, I just got off the Krell site and had the same concerns as you about the draw of the amp in standby. My power bill is about $700 in the winter and was just thinking what it would be with the 402? Not very green either in my pocket or for the environment.

I'd still like to hear comparisons from people that went from the FPB Series to the new amps - honest opinions not new buyer euphoria (which we can all be guilty of). Sometimes it is best to hear about equipment that from somebody that has already sold it off.
I am amazed!
Owned FPB 600c and KPS 25sc, sold teh combo and bought 700cx + KCT and KPS 28c. I liked the 700cx and KCT, not KPS 28c (sadly) though. Still, i have not heard EVO line in my home system, but i thought it was more musical than cx series. Weird EVOlution i must say!
I would like to hear 700cx + KCT with ARC CD8.
Good info guys.
Also would like to hear the latest top of the line Jeff Rowland power + pre.
300 WATTS at standby - is that the same as 3- 100W light bulbs being left on? Can't see where that would cost too much?
Maybe $0.15 per kW/hr is typical rate, which is 4.5 cents per hour, or $1.08 per day, which works out to about $33 / month and $400 / year.

Not everyone will be comfortable with that, but of course if you can afford the big Krells, you probably won't bat an eye.
Do the math.

.37kw X $.16/kwh X 24hr/day X 365 day/year = $518/year

In ten years that's $5180 at today prices, more as electricity costs go up.

Here in Southern California our power is very expensive.
While my first 280kwh or so is at about 0.15$/kwh, once I'm above that point, my rates go in 2 tiers. The highest marginal rate is about 0.20$kwh and I expect that to go UP since we now have rat-fink electronic meters that can be programmed for different rates at different times of day.

At 7.2kwh/ day, the Krell is wacky expensive to run. My current usage is about 450kwh/month to which the krell would add about 50%. That's even MORE than the 20 year old 'fridge I just junked out in favor of a unit rated at about 450kwh/year.

I use slightly different numbers to get to agreement with Ken.
Krells run hot and use lots of power . Levinson also did but they fixed that a few generations ago .
Dan D'Augostino (spl?) is expelled from Krell and part quality go down and so the sound...

Mark Levinson was sold to Harmon Group... The same group which in 1970's bought famed names like Infinity and converted it into mass production junk.

The co-founder of Infinity, John Ulrick started then "Spectron Audio" and went to development of new class D amplifier mostly for pro-audio (and introduced first hi-fidelity one in..1974).

I always was "toobeman" and never tolerated Krell/Mark Levinson for brutish sound but now with my B&W 802 Diamond I needed very power amp and I drive them by Spectron monoblocks. Paired with flagship Joule-Electra full tube preamp its the best system I owned or auditioned.

You are talking about cost of electricity, heat (and weight) and.... cannot get out of "brand names" class A behemoths !!!!.

Did any of you tried high quality class D amps like Spectron, Jeff Rowland(312), Weiss etc [ I do not mean cheap junky class D with noisy switching power supplies ] ?

However, if you still insist on class A begemoths then there is new generation of such amplifiers, much more musical and involvong then Krell/ML. These are BAT600SE, Plinius Reference & Pass Lab XA200.5 - none better then my Spectrons but classical class "A"....
Into which camp do you place the ASP modules from B&O?
I've lost track of all the players using these modules....from Bel Canto on down.
My PSAudio is a fine piece of goods but has the dread SMPS.

I believe Jeff Rowland did fine job with ASP modules but his main achievment was development of very high quality of switching power supplies with Power factor Correction, PFC - making this power supplies highly regulated. It was done in his "312" amp. Interestingly, Spectron uses switching power supplies with PFC in their pro audio amps but in their hi-fi amp, Musiican III they use traditional transformer based power supplies

The rest just (IMO) grabbed ASP, placed into their chassis, put their label (the best added their midor mods) and sold.

Bel Canto Ref 100 MkII has added battery of electrolitic capacitors improving power supply.
H2O uses (like Spectron) traditional power supply with B&O which improve sound.

However, my post was specific for this thread dedicated to the titans of 1980's - Krell and Mark Levinson - now 30 years later new geberation of class A and class D (and others) amplifier are available. not cheaper, as a rule, but...better in sound.
The Krell 402 and 402e both draw "only" 260 watts in standby. The initial manual stated 370, but it was a typo. They changed the manual when I pointed it out to them.

The 402e has a low power standby that only draws a few watts, but does not keep the amp warmed up.
Even the lower consumption is 4x what my refrigerator draws.
The new number is about 6.5 kwh/day.

Does anyone have a kill-a-watt meter to actually measure this?
Now, the ASP modules COME with an on-board SMPS. There will need to be some modifications made for these additional power supply components. Bel Canto adds a board in the top monos.
B&O warranty considerations will apply, but as long as the modifier covers it, I'm ok.

I'm just curious what the supposed effect of PFC is on your amp or sound? Making your power supply look more like a resistor to the power company? I don't get it.
Also, what is the measured PF of any amp? Does anyone have any data? I may measure my amp using test tones to get some idea.
Magfan .. Monster has a power stablizer that meters and displays power consumption . I no longer have mine but it was very interesting to observe .
" what the supposed effect of PFC is on your amp or sound?"

If done right - enourmous !!!

It suppose to make your power supplies fully regulated i.e. to remove ripple and other terrible artifacts power supply do create - usually resulting in addional ear-piercing odd-order distortions.

I don;t know if Jeff Rowland audiophile or Spectron Audio pro audio amplifiers power supplies with PFC are fully regulated.....
As far as I know, regulation and PF should be unrelated.
PF is a measure of the reactance of a load, be that inductive or capacitive.
A (perfect) resistor has a PF of 1.0 while at a PF of 0, no work is done.

I'd be curious to know how PF and regulation relate.

Thin Ice alert:
Isn't regulation simply how well the PS maintains voltage under load? Aren't their either formula answers or 'rule of thumb' answers to how much capacitance a PS needs given voltage and proposed power output? Doesn't that kick out a %ripple number....lower generally being better?
PF is a measure of the reactance of the load.
your monster will display what? Watts or VA? maybe Amps and Volts?

I doubt it displays PF.

Just an example. My 40 watt fluorescent lamp next to my workstation measures about .34 amps. at 117.5v that is about 40va. But, since the lamp has a PF of about .8, it is only about 32 watts.
My electric company (yours, too) bills for WATTS but you use VA. The electric utility company will bill you a surcharge for Low PF. Some factories even have huge PFC correction circuitry in order to avoid this surcharge.

If you want to just monitor power consumption and get an idea what the PF of various devices is, get the 'Kill-A-Watt' meter.....they are very inexpensive and functional.
"I'd be curious to know how PF and regulation relate. "

Hello Magfan: It is that PF correction, as I wrote above, remove ripples and other "terrible" artifacts which produce odd-order ear-piearcing harmonic distortions. Please see below from Jeff Rowland web site:

"External JRDG PC1 is active Power Factor Correction (PFC) units. These devices preconvert the AC from the mains to a steady 384V DC current fed into the monos through a banck of intermediate charge capacitors and make the "501" much less sensitive to AC noise and fluctuations. They also keep the 501s internal caps optimilly charged avoiding AC induced ripples. PC1s should yield even larger authority to the "501"s and will give them a lot more subtlety and nuance"

mote "avoiding AC induced ripples ".

Effects of ripples and other things on distortions are desribed in Simon Thacher of Spectron paper:

All The Best
I guess we're talking about 2 different things.
Power Factor is simply the phase relationship between voltage and current in an AC it the power coming in or the audio to your speakers.

The JRDG approach is a complete power supply and IMO, the PF is tossed in as an advert blurb. This does NOT mean the power supply does not work as advertised. Just that PFC doesn't have much to do with it.

The article you linked is far as it goes. In the discussion of REAL speaker loads, NO mention is made of phase angle. At a phase angle of 45 degrees....not uncommon, the delivered power will drop by about 30%. This represents an additional load to the amp. Now, I realize the numbers were used for illustration purposes only, but that is the real effect of phase on deliverable power.
The same is true of the power supply as it plugs into the wall. I'm no expert at this, but if your power supply has a 100va transformer and a PF of say.....0.8, you won't be able to get the full power out of the'll saturate.

Does the JRDG amp deliver? You bet. Does PF have much to do with the rest of the claims? I'm a little leery.
FYI, I did go from the FPB Cx amps to the Evo stuff....drumroll........keep the FPB stuff if you have it! Krell is now obsolete. Moment of silence please:O(
Interesting topic gents,

I have used and listen to Krell stuff over the years and while powerful tanks, i was never really fond of the
sonic's. Recently i was presented with the opportunity via a good friend to play around with a Krell he had and one thing lead to another and we ended up servicing and modding this unit (KSA200)and would like to pass on my most recent experience and address a few concerns mentioned here.

Firstly due to the high class-A bias most Krell products operate at there idle current will always be excessive and of course nothing like CLass-D stuff...

1. There is no necessity to leave any high bias Krell product running 24/7, 1 hr before listening is sufficient IMO, there high quiescent current is sufficient for the amplifier to reach operating temps and a stable Bias.

2. Regardless of what the guys in print will say, leaving any amplifier that runs at such a high Bias/temperature running 24/7 will shorten the life of the components and lead to sound degradation over the years. Amps that are only 7 yrs old can have issues and of course this IMO lead's to that hard, cold , dry sound most associate krell's with, especially used Krell's.

The Krell in Mention KSA200..

The KSA200 was an amp in long service by my friend and over the years it has made 2 trips back to Krell ( enormous expense) for repairs. Of course this beast idled at 15 amps, YES 15amps and ran as hot as a stove.

On it's second trip back to Krell 2-3 years a go my friend decided to try Bel Canto mono bloc's and was immediately impressed and voiced to me that he will not want the Krell back in his system and upon it's return he would put it up for sale. His decision was later reinforced on the amps return as it's sound was promptly condemned after a thorough listening session comparing the 2, to make matter's worst the Krell failed again a few months later..

The decision was then made, for us to take a look at the amplifier and see what could be done. On examination we found that Krell was only replacing the broken parts and never attempted to fix the problems which by now were bad leaky caps all over the amplifier main boards. Long story short, we went through the whole amp , replaced all caps
(upgrade) except the PSU ( perfect when measured ).

We had reduced the Bias on start up as a safety precaution with the intent of re-biasing the amplifier back to class-a as to Krell specs and after the usual precautionary checks all seemed well, good power,sine wave /et al.
The suggestion was then made to try the amplifier at the lower a/ab bias ( since it speced well ) before going to full class-a Bias.

THE DIFFERENCE WAS ASTOUNDING .. much faster and dynamic than we had ever remembered this amplifier, the sound was so much better, the Bel cantos now did not stand a chance.

During the listening session a few thought the top end was better in full class-a , but all agreed that
1. Bass
2. Sound stage
3. Attack and Speed

was vastly improved with better tonality than before.

Anyway we took this behemoth back to the bench and adjusted it back to it's full class-a spec, plugged it in and ........ Yes.... a disaster!

The difference was staggering , dynamics lost, bass pulled back, dead , dead sound ..

Now my friend has a cool running KSA200 barely warm after hrs of listening,fantastic sound and many new Krell friends :) leaving many anti-Krell individuals ( myself included) blown away at the transition and how really good this amplifier sounds.

I have always felt when listening to high bias class-a amplifiers that they did not exhibit the rhythm and or pace of a good a/ab amplifier, always dead sounding to me by comparison, refined sound, Yes , but no music..

I would like to believe this is what most hear when switching to Class-D, but to my ears class-d is a bit Harsh sounding, yes definitely fast sounding and alive , but there is some crudeness there where a good a/ab amplifier does not exhibit that IMO.

Currently looking into modding and comparing a few other Krell models ( FPB series up next) to see if the mods were specific to this one model or will other Krell models benefit from cap upgrades and reduction of it's quiescent bias.

Stay tuned ..