What is the problem? You can’t turn the volume up high enough before distortion sets in?

Or is the problem that with the volume at maximum it sounds good but you can't go louder?

No I can turn it up to max just thought it should be way louder  with the Krell fpb600  I had a Denon 5800 reciever hooked up before. The krell is way more clearer and no distortion when turned up all the way compared to the Denon Avr5800

What is your preamp?

If your running single ended cables into the Krell then you need to examine the Krell balanced inputs and make sure the jumpers installed. Tom

What's the dB level measured at your listening position?

How do you know you are driving the amp to full power?  

If your running single ended cables into the Krell then you need to examine the Krell balanced inputs and make sure the jumpers installed. Tom

So important.

Also, run it balanced it that's an option for best sq. Cheers,

Spencer

Thanks I'm using the Denon Avr5800 as the preamp. I dont know if I'm driving to full load but I have Denon cranked all way up 06 db 

My krell ksa 300s didn't work very well with my marantz sr7007 AVR, it didn't sound very good and the preamp outputs didn't drive it to full power. I bought a dedicated preamp and it is so much better now.

Will try a dedicated preamp thanks.It does sound great though thanks

Make sure all cables are correct. Get a dedicated preamp. Will supply proper voltage. Don’t turn all way up. Ur speakers will blow. 
 

all the way up. ?  Really?   Hahahahaha

I’m using the Denon Avr5800 as the preamp.

The Krell FPB600 required input 3.4V for its 600W rated power @ 8ohm.

The Denon AVR5800 pre-out rated output voltage is 1.2V so it only can drive the FPB600 up to 78W @ 8ohm.

Wow thanks for the info. Where did you get the stats at I was looking for it on the Denon 5800

The specs are easy to find, except the output voltage they don't usually show that spec on avr's.

I must get a great a preamp that can deliver more than the 3.4 volts it needs for the kKrell to deliver 600 watts into 8 ohms. Wow should get alot louder.

I’m using the Denon Avr5800 as the preamp. I dont know if I’m driving to full load but I have Denon cranked all way up 06 db

Some might think that if a digital source can output a voltage of 2V, crank the volume of the Denon all the way up to +6dB the pre-out should output a voltage of 4V, BUT THAT’S NOT ALWAYS THE CASE!

https://benchmarkmedia.com/blogs/application_notes/19947905-the-audio-path-in-consumer-grade-audio-products?_pos=1&_sid=1805d554a&_ss=r

I must get a great a preamp that can deliver more than the 3.4 volts it needs for the Krell to deliver 600 watts into 8 ohms.

👍

Thanks for the link very informative 

So did you ever ck to see if the jumpers are connected on the Krell"s balanced inputs?? They look like large rounded staples looped from 2 of the 3 pin outs. If there are none of these connected you will not get the drive your expecting even with a real deal preamp.Tom

Yea I'm sorry for not saying it before.Bought the amp used was recapped before I bought it Krell verified they also sent me the jumper clips because it was make a hum when volume was all the way down. Hum totally went away with jumpers

Ok good to know..now for a preamp? Tom

Yeah now the search begins

What is your budget for a preamp?

2k used

Get a NAD C658, what I use, it's so good it makes me tinkle.

Will look into it thanks.

Hey guys want to report back on preamp pickup a cClasse ct ssp  preamp. Well the volume is much louder so much so if I crank it up to loud it trips the 20 amp breaker for my Kell fpb600. Sounds great. Although I cant figure out to adjust the bass/treble/equalizer. Do sound good the way it is but would be nice to figure it out . Using it a 2 channel with sub. Thanks

If it has bass and treble controls, I would be surprised. Generally not an audiophile thing. Your DAC should have different filters that can help. 

I’m betting we will next hear tweeter and a couple midranges are,making a (pencil hits notebook paper) sound, from frying voicecoils from too much power, the crossovers can only take so much.

600rms is a lot of power! Be careful, watch the,volume, I can’t get even halfway on volume, and it’s either too loud or it starts to mildly distort, so naturally. Keep an eye on the=Volume.
you did it correctly with those wicked bada$$ amps! 100 or 200 WPC, juuuuussst, don’t have the sheer brute force I needed. It’s the absolutely,effortless airy , perfectly controlled sound. No strain, whatsoever.

enjoy those amps, I would have them checked by Krell , even if the guy u bought from said so, just for piece of mind, those amps were on my radar years ago,

enjoy, get a good solid preamp for those amps, there is a ton of good used stuff out there. Happy listening.  
no worries, my speakers are rated at 250W peak, and use 650W monos,as well!

I just swapped out my B and K pro10-mc (newer version) for the Sanders Preamp. 

much more detail, AND, I WAS GETTING STATIC, CLICKING CONSTANTLY from tweeters.,….unplugged the hdmi , and DEAD, QUIET, NOT EVEN HISS WHEN ear is right in front of the tweeter. I’m happy. This is my basement system.

When I picked up the Classe ct-ssp preamp also got some xlr cables. The sound is phenomenal now and has the punch I am very happy now. Even the better half  said wow the stereo sounds great now also

Also sorry for saying it trips the Krell 20 amp breaker. I meant to say the 20 amp household breaker in the panel dedicated broker Then to run 10 gauge with 30 amp like Kell recommends 

I had a Krell FPB600 for ten years. Best sound with balanced cable to the preamp. I liked it best with a tube preamp (Aesthetix Io with volume). There is some protection circuit/jumper to protect against preamp misbehavior, I removed them, got better sound, and never had a problem. The one problem I did have, was that it sounded best at a volume level that was too loud for me (more pure class A at higher volume). But it is a great amp, and in some ways I miss it. Far better than two Krell KAV line amps I had, before the 600.

And yes, the FPB600 loved a dedicated line, it got even more authoritative, deep and precise. In my 15 ampere line it never triggered the fuse - but that is in Europe, at 220-230 volts.