Krell - What a Joke

[chris357]

my hts 7.1 isnt to heavy at all, however the 3250 amp is a beast and my HT is upstairs in my loft and I did it by myself.

now my epik empire, that took 2 people and a hand truck to get it upstairs..

i think for 30k they shoudl send a super model along as the second person to help get it out of the box

my only thing with the krell stuff is that I'm tight on money now so i'm having second thoughts on if i should have bought it or not.. or shoudl i sel it and get something cheaper..

on the otherside.. is now i own it and i dont really need anything more at the moment.. but it does sound amazing!!!!!!

anyway sorry to hijack your thread on my mindless thoughts

 

[gene]

In critical applications, a 100% differential balanced circuit design can offer better signal integrity by avoiding the extra amplifier stages or transformers required for front-end unbalancing and back-end rebalancing. Fully balanced internal circuitry has been promoted as yielding 3dB better dynamic range.

Actually you could see up to 6dB of improved SNR for fully differential vs unbalanced circuitry.

The Krell likely is balanced if you use the balanced inputs and balanced outputs. I doubt they didn't carry the differential stages through that entire path at this price but it wouldn't surprise me. I am still trying to figure out who makes the Krell and if its just another clone or not.

 

[MidnightSensi]

What is a 'fully differential' circuit?


...

As far as the manual saying use two people, it's probably something a lawyer asked them to put in there.

 

[AcuDefTechGuy]

i think for 30k they shoudl send a super model along as the second person to help get it out of the box

In that case, I will need 3 babes to help me lift it.

my only thing with the krell stuff is that I'm tight on money now so i'm having second thoughts on if i should have bought it or not.. or shoudl i sel it and get something cheaper..

on the otherside.. is now i own it and i dont really need anything more at the moment.. but it does sound amazing!!!!!!

You only live ONCE, right?

So live it up.

The important thing is you are ENJOYING it every single day! So it is worth every penny.

 

[AcuDefTechGuy]

What is a 'fully differential' circuit?


...

As far as the manual saying use two people, it's probably something a lawyer asked them to put in there.

From ATI:

A truly differential drive amplifier, consists of two complete amplifiers for each channel: one + amplifier and - amplifier. The positive input signal is amplified by the positive amplifier and the negative input signal is amplified by the negative amplifier when a balanced signal is applied to the input. There is no ground reference since the output signal is derived from the combination of the positive signal and the negative signal. A differential drive amplifier is sensitive to the difference between the positive and negative input signals resulting in those signals common to the input being cancelled. The input stages of each channel of the amplifier are of differential design all on one substrate resulting in the reduction of hum and turn-on/turn-off pops. This is referred to as "common mode rejection".

By virtue of "common mode rejection", the "Pure Balance"® amplifier exhibits lower noise, lower distortion, and immunity to stray electronic fields and anomalies in the input signal from outside interference. The resulting benefit in music reproduction is more silence between each musical note. In home theater applications, the result is a deeper, cleaner soundstage. An apparently larger dynamic range results because of the enhanced silence between sounds. Clarity is improved significantly because of lower distortion and the differences between loud and soft passages are more pronounced. The Slew rate is doubled in differential drive amplifiers as compared to single-ended designs. The slew rate in high-end amplifiers has always been considered important. The highest possible slew rate is desirous, so having twice the slew rate is a significant benefit. A high slew rate allows for sharp attacks on all your transient frequencies resulting in more realistic sensations from either music or sound effects. Another virtue of the differential drive amplifier is that it requires only one-half the rail voltage for a given power output rating into 8 ohms as compared to a single ended amplifier. Reducing the rail voltage by one-half will allow the output transistors to work in a more linear fashion, thus improving the transient performance of the amplifier. This results in much richer transients in the music; cellos sound like cellos, flutes sound like flutes, clarinets sound like clarinets and acoustic guitar recordings will exhibit the same phenomenal richness as experienced at live concerts.

 

[AcuDefTechGuy]

I don't understand why companies preach pure-balance/fully-balanced topology, but only offer this in their amps and NOT in their pre-pros???

Take ATI for example. They dedicate a huge section of their website on their "pure balance" design. They have a $2K amp that is pure-balanced from input to output. But their $5K pre-pro is NOT pure-balance???

 

[MidnightSensi]

I don't understand why companies preach pure-balance/fully-balanced topology, but only offer this in their amps and NOT in their pre-pros???

Take ATI for example. They dedicate a huge section of their website on their "pure balance" design. They have a $2K amp that is pure-balanced from input to output. But their $5K pre-pro is NOT pure-balance???

Well, at the balanced outputs any induced noise should be cancelled.

Maybe the advantage is that unbalancing on the inputs and balancing at the outputs has a parasitic loss of signal... so without those circuits you get more gain from the amplifier? The pre-pro wouldn't amplify like a amplifier does, so, the benefit of that wouldn't be as great. Just a guess...

Any noise induced inline should be cancelled at the outputs, so, I'm not sure where that advantage would be.

 

[AcuDefTechGuy]

Well, at the balanced outputs any induced noise should be cancelled.

Maybe the advantage is that unbalancing on the inputs and balancing at the outputs has a parasitic loss of signal... so without those circuits you get more gain from the amplifier? The pre-pro wouldn't amplify like a amplifier does, so, the benefit of that wouldn't be as great. Just a guess...

Any noise induced inline should be cancelled at the outputs, so, I'm not sure where that advantage would be.

I guess we have the "Practical" vs. the "Absolute".

In absolute terms, a 100% fully balanced stage has the theoretical advantage.

However, in practical terms, a 100% fully balanced stage is not necessary.

As you mentioned, the most important thing is that balanced Input on the amplifier.

I guess people could use those XLR-male-to-RCA connectors and connect the unbalanced Outputs of their pre-pros/receivers to the balanced Inputs of their amplifiers and get the same "practical" results.

Or connect their half-balanced Outputs to their full-balanced Inputs.

 

[chris357]

In that case, I will need 3 babes to help me lift it.

now you are talking, in fact the babes are the remote.. you tell them what you want and they get up and push the buttons of course the pre amp is on the bottom shelf




You only live ONCE, right?

So live it up.

The important thing is you are ENJOYING it every single day! So it is worth every penny.

very good point and yes I do use it every day!!!!!

 

[AcuDefTechGuy]

Must be a great life to take issue with a suggestion a friend helps lift an expensive item out of its box.................charmed life for sure.

I wouldn't want to risk having the DAWG or Seth=L touching my body in the process of helping me lift an amp!

But I wouldn't mind a super hot babe friend (or two) help me anytime.

 

[chris357]

Actually you could see up to 6dB of improved SNR for fully differential vs unbalanced circuitry.

The Krell likely is balanced if you use the balanced inputs and balanced outputs. I doubt they didn't carry the differential stages through that entire path at this price but it wouldn't surprise me. I am still trying to figure out who makes the Krell and if its just another clone or not.

I hope they arent pulling a lex.. but getting the same thing for alot less woudl be cool

 

[AcuDefTechGuy]

I would just love to see an Audioholics Professional review of this Krell 707 by Gene!

But the odds of that happening is very unbalanced.

 

[MidnightSensi]

I guess we have the "Practical" vs. the "Absolute".

In absolute terms, a 100% fully balanced stage has the theoretical advantage.

However, in practical terms, a 100% fully balanced stage is not necessary.

As you mentioned, the most important thing is that balanced Input on the amplifier.

I guess people could use those XLR-male-to-RCA connectors and connect the unbalanced Outputs of their pre-pros/receivers to the balanced Inputs of their amplifiers and get the same "practical" results.

Or connect their half-balanced Outputs to their full-balanced Inputs.

I know with my 'externally' balanced system (all my stuff uses balanced connections but I assume isn't internally balanced), there is still a faint hiss at maybe 1 to 1.5~ meters from my speakers. At 98db/watt, this is actually pretty good and means my gain is well optimized, but maybe if my amps were internally balanced the noise floor would be even quieter. Still, at my listening position I hear no hiss...and since most speakers aren't as sensitive as mine (especially high dollar ones), makes you wonder...if I need more dynamics...maybe I should just turn it up...since my amps certainly aren't the limiting factor of my dynamics.

 

[bandphan]

I would just love to see an Audioholics Professional review of this Krell 707 by Gene!

But the odds of that happening is very unbalanced.

if Dan were still there it would be more likely.

 

[Warpdrv]

I guess it also comes down to - is this really all that important to you.... My D2v, as Anthem did state is not fully balanced end to end, but everything sounds really great to me... I have absolutely no noise bleeding through from my amps nor any grounding issues out through my speakers or subs... In fact, when I replaced my Pioneer reciever (Pre-Pro) and moved to the D2v with balanced outputs the noise I did have being transmitted through from my Pioneer was completely eliminated.... I was very happy I made the move... My system is completely dead quiet.

I guess my point is, how far do you really want to chase this and is it really worth the vast amount of money to find no perceivable difference in the end...?

I can appreciate you wanting to make the move to the Denon - it a very nice piece, though with all your HTPC's IMO it may be overkill on features you will likely never use. That is one of the reasons I went with the D2v, I just didn't need all those bells and whistles like streaming content. YMMV of coarse...

 

[JerryLove]

From ATI:

A truly differential drive amplifier, consists of two complete amplifiers for each channel: one + amplifier and - amplifier. The positive input signal is amplified by the positive amplifier and the negative input signal is amplified by the negative amplifier when a balanced signal is applied to the input. There is no ground reference since the output signal is derived from the combination of the positive signal and the negative signal.

Unless you derive from the *inverse* of one signal, you'll cancel out everything *except* the interference, which will be doubled.

The question becomes: "is it inherently cleaner to recombine low voltage or high voltage signals?"

Though it seems to me you could make an even better argument keeping everyting in a single digital domain until the amp.

 

[MidnightSensi]

Unless you derive from the *inverse* of one signal, you'll cancel out everything *except* the interference, which will be doubled.

The question becomes: "is it inherently cleaner to recombine low voltage or high voltage signals?"

Though it seems to me you could make an even better argument keeping everyting in a single digital domain until the amp.

They are out of phase, so what is induced in both is cancelled at the end. That's why balanced cables are better for long cable runs/upstream noise.

Now, I think Warp's point is if it is going to cancel the noise downstream anyways, does it really help to keep it out through the unit?

 

[njedpx3]

This is what it says in the $30,000 Krell Evolution 707 Pre-pro Manual:

Two people are needed to remove an Evolution 707 from its shipping box safely and easily.
The Evolution 707 weighs 49 lbs (22 kg).

My Denon receiver weights 63 lbs.

And 2 people are needed to remove a girly 49 lbs Krell?

What a joke!

I think the 2 people are included free with the 3-day, 12 man HT Krell install team

Peace,

Forest Man

 

[mtrycrafts]

This is what it says in the $30,000 Krell Evolution 707 Pre-pro Manual:

Two people are needed to remove an Evolution 707 from its shipping box safely and easily.
The Evolution 707 weighs 49 lbs (22 kg).

My Denon receiver weights 63 lbs....

Protest to Denon that their manual needs a note that three people need to take that receiver out of the box.

 

[highfigh]

Though it seems to me you could make an even better argument keeping everyting in a single digital domain until the amp.

Ever hear of a system called Frox? They were around for a short time in the early '90s and the signal from their modified Sony 200 disc CD changer went to the preamp using the digital output, the preamp was all in digital domain (including the 12 band graphic equalizer) and the signal to all amp inputs was digital. Each channel had its own DAC.