Latest krell saga

[JackD201]

Hahahaha! Me too! I've got the Ambience 1200 ribbons and an LSA Integrated in our vacation condo. I was using myself as an example. LOL. Smooth and articulate but monster as an integrated the LSA is, I can't get any jump out of the 1200s. I could get jump from my 1.6QRs though so clearly sensitivity ratings don't tell the whole story...but we know that here.

 

[MarinJim]

I have my Burmester 911 MK3 up for sale on A-gon.

Hegel H30.

 

[Orb]

Orb-As always, thanks for your thoughtful reply and your experienced insight. Not too long ago, I owned the ARC LS17 and the ARC PH-3SE. Both were quiet enough that I could live with them and I would assume the LS27 would be quieter still. Noise was not an issue with either one of those pieces.

I know the Ayre preamp you mentioned has received a rave review from Stereophile and it was rated as being in their “Class A” of preamps. However, it has two balanced inputs and one balanced output which is the same as my KBL.

Here is what I like about the LS27 in terms of features:

1. Balanced inputs for all sources
2. Adjustable gain for all sources (3 levels of gain to choose from)
3. Only two tubes
4. Tube hour meter is one function of the display which is cool
5. Remote that adjusts input level, phase, and volume on the fly
6. Supposedly sounds better than the REF-3 according to ARC

You have heard the LS27 and compared it to the REF-5 and said that the differences were not huge. The LS17 was known as the “baby” REF-3 and now the LS27 is being called the “baby” REF-5. I hope the LS27 is closer to sounding like the REF-5 than the LS17 was close to sounding like the REF-3.

Ah good to hear about the LS17, and yes I feel the LS27 is a much bigger step up than the LS17 IMO, while also being subtly more neutral in a positive way and better performance to the Ref3 in terms of noise-hum.
Just remember as mentioned in the PM to test each of the gain settings to find your preference on the LS27.

Cheers
Orb

 

[Orb]

Ah before I forget, also make sure the Krell and tube preamp are compatible in terms of impedance; the 20k ohms load minimum requirement for as example the LS27 is pretty high and this can affect the perceived sound when the amp is not truly compatible, seems modern ARC amps are over 60k ohms on the single ended input.

Cheers
Orb

 

[MylesBAstor]

Ah before I forget, also make sure the Krell and tube preamp are compatible in terms of impedance; the 20k ohms load minimum requirement for as example the LS27 is pretty high and this can affect the perceived sound when the amp is not truly compatible, seems modern ARC amps are over 60k ohms on the single ended input.

Cheers
Orb

Most tube amps have an input impedance of >100K+ while many ss amps are around 20 K. Many tube preamps have high output impedances (600 ohms for instance) that often makes for some incompatibility between ss and tube electronics. Areas like dynamics and low frequencies tend to be suffer the most. New tube preamps, take the GAT for instance which doesn't use a tube buffer stage, has an output around 100 ohms making it compatible with most amp as well as the ability to drive all cables and lengths.

 

[Orb]

Most tube amps have an input impedance of >100K+ while many ss amps are around 20 K. Many tube preamps have high output impedances (600 ohms for instance) that often makes for some incompatibility between ss and tube electronics. Areas like dynamics and low frequencies tend to be suffer the most. New tube preamps, take the GAT for instance which doesn't use a tube buffer stage, has an output around 100 ohms making it compatible with most amp as well as the ability to drive all cables and lengths.

Yep agree but CJ preamps IMO will have too much noise level for Mark (they do for me), so it comes back to ARC tube preamps and the challenge of solid state compatibility.
I do not know what the KSA power amp impedance loading is, so something for Mark to consider (where ARC goes for the figure I quoted even on their solid state).

Cheers
Orb

 

[MylesBAstor]

Yep agree but CJ preamps IMO will have too much noise level for Mark (they do for me), so it comes back to ARC tube preamps and the challenge of solid state compatibility.
I do not know what the KSA power amp impedance loading is, so something for Mark to consider (where ARC goes for the figure I quoted even on their solid state).

Cheers
Orb

That's interesting since I find the GAT super quiet and transparent Again, noise also depends on the tube selection too.

 

[Orb]

Yes but is the GAT the same price as the LS27
I am talking about the normal range of CJ.
Otherwise it is like comparing the LS27 to the ARC 40th Anniversary preamp;.

I cannot comment on the GAT noise as I have not heard it or seen measurements, but it is outside the price discussion anyway.

Cheers
Orb

 

[MylesBAstor]

Yes but is the GAT the same price as the LS27
I am talking about the normal range of CJ.
Otherwise it is like comparing the LS27 to the ARC 40th Anniversary preamp;.

I cannot comment on the GAT noise as I have not heard it or seen measurements, but it is outside the price discussion anyway.

Cheers
Orb

OK I'll give you that as haven't heard the mid-range of cj offerings recently.

 

[Orb]

Well it is good to know though Myles about the GAT, something I will keep in mind if I ever go back to reference preamp/poweramp setup.
Thanks
Orb

 

[MylesBAstor]

Well it is good to know though Myles about the GAT, something I will keep in mind if I ever go back to reference preamp/poweramp setup.
Thanks
Orb

It would be actually interesting to hear the "newer" cj preamps like the GAT that use a MOSFET instead of a cathode follower at the output.

 

[microstrip]

Yep agree but CJ preamps IMO will have too much noise level for Mark (they do for me), so it comes back to ARC tube preamps and the challenge of solid state compatibility.
I do not know what the KSA power amp impedance loading is, so something for Mark to consider (where ARC goes for the figure I quoted even on their solid state).

Cheers
Orb

Orb,
Some old cj preamplifiers using the 12AX7 were noisy, but later preamplifiers using other tubes are noisefree - remember that the ACT2 series 2 was less noisy than the Audio Research Ref3 in unbalanced mode.

Noise from the preamplifier can be an issue with with high gain amplifiers and very efficient speakers. The KSA250 has moderate gain (26dB) balanced, 20 dB in RCA mode, so unless the speakers are very high efficiency noise will not be a problem.

One of my great experiences from the past was listening to a Krell KSA300s driven by a cj premier 14.

 

[Orb]

I would not disagree about noise of a Ref3 in unbalanced mode because it should be used balanced where its performance is better; in balanced mode the Ref3 has an A-weighted 94.7dB measurement with excellent wideband noise floor as well, and in balanced sounds better in general IMO just as the Ref5/etc does.
CJ is specific to single ended but still makes sense comparing to another product in its ideal setup (KSA supports XLR from what I remember so makes sense looking at ARC measurements and performance balanced).

Just my take on it, I do like CJ honest but if Mark is like me then any noise coming through is freaking annoying.
There is still noise from the LS27 but it is less than many other tube preamps IMO when using its balanced connection and similar priced preamps even taking 2nd hand into consideration such as the Ref3; hope that helps in the clarification
Cheers
Orb

Edit:
Actually it is a great point you raise as it is an important consideration for Mark if going single ended/RCA.

 

[Steve Williams]

Orb/Mep

I found that one way to minimize noise from the Ref3/Ref5 is to turn off the LCD display on the front panel but even still I had minimal if any noise in my system when I had my Ref3

 

[Orb]

Thanks Steve,
I found the Ref5 was fine for me even with the display on but interesting to know.

Thanks
Orb

 

[mep]

Since my KSA-250 has balanced inputs, I would run balanced connections to it from any preamp that had balanced outputs like my KBL or the LS27.

 

[Orb]

Mark,
before buying see if you can get ARC to comment if they will be releasing an SE version of the LS27.
They have released SE version of the LS17 now, so I would had thought the LS27 would soon be SE available,
Along with this would be upgrade cost of existing LS27 to SE model (if they do make it available on the LS27).

Cheers
Orb

 

[mep]

Orb-I'm sure the SE version is right around the corner. For the here and now, everything is sounding really good in my system.

 

[MarinJim]

^ Good to hear.

 

[Orb]

Glad to hear that Mark.
Cheers
Orb