Krell recalls select amplifiers to cool off the sound

Deep-pocketed audiophiles sporting Krell gear in their equipment racks love to gloat about the sound pouring from their amplifiers biased towards Class A, but that sonic bliss comes with a huge thermal pricetag. So much so, that Krell has issued a recall for its KAV-250a, KAV-250a/3, KAV-500i and KAV-1500 amps due to overheating concerns. For their trouble, affected owners will get certification of a fuse replacement and a $100 check. Mere mortals like us who aren't in the Krell club might chortle about money and sense, but on the other hand, we can't remember the last time our more mass-market receivers were ever offered this kind of service -- and some of them have run awfully hot; we're looking at you, Onkyo.

[mugatu Posted Jul 23rd 2009 11:08AM]

"Deep-pocketed audiophiles sporting Krell gear in their equipment racks love to gloat about the sound pouring from their amplifiers..."

Amps are funny things. Most people who haven't owned one before think little about the amp stage of the sound experience. I had always used a fairly good integrated AV receiver for my surround sound but after recently buying a separate class A/B amp (not A like the Krell in the article) I can tell you the sound change was remarkable. Why would the amp that only supplies power between the processor and the speakers change sound quality? Good question, but it definitely does. Krell buyers or buyers of any other class-A amp aren't crazy. I can only imagine how good a hot running class-A amp sounds over even my new A/B amp. Definitely too much heat though .. or so I hear (figuratively).

[nrb Posted Jul 23rd 2009 11:35AM]

"Why would the amp that only supplies power between the processor and the speakers change sound quality? Good question, but it definitely does."

The amp has to deal with speakers, which are not linear. As the speaker moves, it changes it's impedance. Different speakers, do this differently. Some speakers, like mine, do it wildly. I found that receivers and integrated amps generally couldn't handle them properly. My amp does a much better job.

"I can only imagine how good a hot running class-A amp sounds over even my new A/B amp."

Don't read too much into A vs A/B. My amp is a bit odd, but you can think of it as a 50wpc class A amp that has A/B power in reserve. It's a neat amp. I've heard some very good A/B amps that will knock it out of the water. Granted, they cost many thousands of dollars.

[mugatu Posted Jul 23rd 2009 12:20PM]

@nrb

Great post, thanks. It's an unusual thing - amps. The general population at EngadgetHD and those who buy integrated and even HTIB surround sound systems don't know about the sound quality issues that happen when upgrading to separates (buying an amp as opposed to an integrated all-in-one receiver like a Dennon or Pioneer). I was perfectly happy with my integrated receiver and probably still would be, but the amp I bought really made a difference in sound. Better bass, more open sound stage, all those annoying terms you read about are true. I would almost like to have heard a few more amps before buying the one I did because the sound can change so dramatically based on brand. I bought one on clearance for the price and am happy I did (tight budget) but the audio bug has bit and I'm wondering. Still novice on amps and separates, fun experience though.

[(Unverified) Posted Jul 23rd 2009 12:21PM]

All of the amps in question are only Class A/B. Krell Full Power Balanced line are Class A biased.

[(Unverified) Posted Jul 23rd 2009 5:58PM]

Agreed! ONKYO amps run too hot.
So much so, I stopped offering them.

Customers get nervous when hot gear lives in cabinets.

(These cabinets in particular had fans in them too!)

Go Denon!