cooling my Krell monoblocks

You might end up drawing dust in.

In reality.... if your amps are in open area... not crammed into cabinet. The manufacturer design does not need any additional cooling. They were made by top quality engineers who took the heat issue into consideration when they were designed.

Good Luck

Thank you for the replies - both make sense. One of the mono's "clicks" as it heats up and cools down but when I aim a fan at it the clicking stops - Krell says it is nothing to worry about but the the clicking is annoying and I find my ears "tuning in" to the clicks rather than the music or movie. BTW, the monos are out on the floor in open space, not in cabinets.

They had problems with the contraction/expansion of the metal casework...worth living with though. Keep em hot and they will make less noise and always leave them on standby.

Yeah my Evo600s click all the time from the thermal expansion, bloody annoying. Why don't they just make the case a fraction bigger?

I'd like to keep them on standby but it is expensive to do so. I agree with Davidbigeye - it definitely is bloody annoying but so is the fan that I have been blowing on them!! I thought that perhaps some small silent PC fans might create just enough cooling effect to stop the clicks.

First, be careful aiming a fan at Any piece of gear. IF you are somehow interfering with the natural convection (hot air rising) currents that the heating of the piece causes, you could actually make it run hotter, or too hot.

Premium (read as HEAVY) power amps like the Krell should be able to take any power demands in stride. Especially when used in an open installation. The Krell 300 or 400 integrated is a possible exception. My brief exposure to one (the 400) showed it to run bigtime hot. For my confined rackspace, that was a deal breaker. The Stereophile test confirmed my impression when they remarked on the heat of the amp after the pre-conditioning period before bench measurements, Worse Case Scenario, to be sure.

How much are you asking of these amps? I don't see how you should be able to put a dent in 'em....... If they have not gone into thermal protection then there is probably nothing to worry about.

I believe there was a thread somewhere that some folks loosened the fin bolts a smidgeon and that fixed the clicking sound. I havn't tried it as I just live with it. My FPB300cx clicks only a tad bit and only on occasion so I just leave it alone.
-John

My 400Xi runs hot...even toasty in standby, but that is why is sits at the top of the rack, nothing hinders it.

I have had mono blocks that have run much hotter, but they like that tropical heat level, that's the way they were designed.

Besides...where am I going to put my cat?

All electronic lifetimes is lowered by heat.

The only thing I know of that really likes heat, is indeed, the Cat.

I had one sponteniously combust on me after it lay in front of a fireplace for a couple hours.

After having lived with Atmasphere MA-1s for a long time, I can sympathize with those of you who keep amps that require you to adjust your life in negative ways to live with them. (I used to spend time with women like that too.)

After many years, though, I did myself a favor and replaced them (the MA-1s, that is) with two Sunfire 600s (used) and hooked them up with Marigo Ultra 5 power cords. They generate no heat, I can leave them on all the time, and the sound is far superior.

So, my advice is to get rid of your life-impairing amps and find something else. You can do better, and you can live a happier, more normal life without them.

Loosening the fin bolts a "smigeon" is an interesting thought - can't hurt to give that a try. Collectively you have convinced me that a cooling fan is NOT a good idea. These are Krell fpb 350's that I really like - a while ago I let a pair of fpb 250's go and seriously regret it - they didn't click!! At least I now know that I'm not the only one suffering with clicks disease.

Thanks to each of you!

You let a cat spontaneously combust. Could you be anymore illustrative?? My word !
As for the fan and clicks ask Krell to tell you what you can do beside ignoring it which you can't. Be very firm and ask them to get an engineer to tell you that you may or may not use the fan . The big McIntosh amps had fans and may still but as the others have said the Chinese Oops I mean U.S. engineers have taken that into account. Just don't use ice and don't let a cat get toasty on the amps that would warm them even moreso.
Another idea is to go back to the 250s if they had enough juice for you. I bet a whole bunch of click loving 250 owners would trade up for 350s.
BTW who or what is Krell is it a derivative of an English root. I know Baleen whales and Whale sharks etc. eat "krill" a tiney shrimplike sea creature. Krell is owned by an Italian American. I think his is name Dan D'Agostino.

Again, I urge caution.
ALL amps without fans as a designed in feature are passively cooled. The idea is that warm air rises and pulls cool air in from the bottom. Running under normal conditions in a 75f house, this should be enough. Stick kitty on top and finish the job by clogging it up with cat-hair and dust bunnies and you've got an overheating recipe.
Extreme use, like averaging about 1/3 power will stress SS to the max. Add a clog or 2 and there you go.
IF a fan is used, I don't think it should blow AT THE TOP of any gear. This will force air backwards down into the unit and restrict natural convection. Still air in the amp will just get hotter.
Many years ago I designed and built a small (4"box fan) that fit snugly on the back of my Carver Cube. It blew OUT, sucking air thru the amplifier. I could and did run it all day long just short of clipping without it cooking.
In general, I would say that pulling air up/out of an amp with internal heatsinks and pulling air over external heatsinks would be best.

I'll contact Krell and find out what options are available and let all of you know the reply. While I'm at it I can ask the D'Agostinos where the word "Krell" came from. That too would be interesting.

Try using fans to draw the heat away. I use Noctua fans - they are Swiss made computer case fans and the quietest around. The other brand would be Scythe, which are also quiet compared to most fans but a little noiser than the Noctua. At $20 a fan, it may be worth it.

Classic.
Thanks for tips on quiet fans. I may have need sooner than later.
Also, your fan use sounds correct. 'Draw the heat out'.

An annual cleaning / dust clog hunt may not be a bad idea, either.

Classicjazz - do you set the Noctuas on top of the amp to pull heat out of the inside or along side to pull heat from the fins?

OK - Here is what Raymond, a servce rep and Krell said: Do not use fans or loosen fin bolts. A remedy would be to send in the amps to Krell for installation of heatsink tape. I am trying to find out if this could be a DIY.

He neglected to respond to my question about the origin of the word "Krell". I'll keep pushing.!! LOL!

Krell advises that the heatsink tape is installed internally thus requiring dismantling of the amp. Guess I'll just learn to tune out the click.

What is heatsink tape made of? If it is conductive you really should let Krell place it, otherwise you could be one hairball away from tradgedy.

Not to worry Mechans - I wouldn't dare try it as a DIY! LOL! I have absolutely no idea what the heatsink tape is made of . . . guess that would be another question for Krell.

I believe the "Krell" name comes from a science fiction movie.

You Guys are KILLING me.

The Krell were a mythical race in the '50s SciFi classic
'Forbidden Planet'.
Just my opin, but one of the most literate / intelligent well paced SciFi flicks ever.
A great cast including a very young Ann Francis among many others, including Leslie Nielsen in an early, serious role.

And, from the Audiophile standpoint an incredibly interesting soundtrack with all Theramin music/effects. (pre MOOG by several decades) Must hear on good system, but you already knew THAT.

The Krell were the whole point of that film – they became so technologically advanced that they created a machine that could make their thoughts turn into reality – while they obviously created the machine with the best of intentions – to completely eliminate any suffering or pain in their society … when they turned the machine on it took only one day to completely destroy their civilization and Krell race was then extinct. The movie was written in the 50’s – the beginning of the nuclear age – and it was meant to serve as a warning that our relentless pursuit of science and technological advancement could have dire consequences. It also carried a more profound message regarding the inherently evil and corrupt nature of power – the Krell achieved ultimate power only to have it result in their complete annihilation

i am scared of my amp now...

Richard,

Some film critics have interpreted the Krell as a metaphor for communist hegemony. Does your amp tend to image left of center? If so, take the wife and kids and run...

Marty

Actually, Forbidden Planet was based on Shakespeares 'The Tempest'.

Wow! I have learned WAY more than I bargained for when I was only looking for info about cooling my Krells. LOL. . . From what I am reading The Krells may still be alive today, in our living rooms . . just waiting for their supreme commander to give the signal to morph into superior beings and "think" our systems into something way beyond our wildest dreams. . . or turn us into molecular dust.

It's odd the way that audiophiles do just the opposite. They think that their stereos don't sound as good as they could and relentlessly try to improve them. For many it's a futile effort to achieve something they have already, great sound. The average system that an audiogon member has sounds good, period especially when viewed on an absolute scale. The top 1% of all the sound reproduction extant I'd venture. Is it Krellian perfection? No and never will be for many.
Me- I am happy... I think... you know the other day something just didn't click (pun).....the sound no longer ...I might need to...roll the tubes again... no it's those analytic speakers biting you again ... no it's....the room but ... Oh no

HAHAHA! Mechans - you are on the right track - I am happy too and don't see the need for change . . . .except that I just upgraded my headphones and headphone amp and there is the dire need for a better . . . . . .other than that, I'm done . . .today!