$18k Tube preamp for large scale symphonies please

Phillip, What you are talking about here is low IM (InterModulation) distortion in the preamp.

Its one thing to have low noise, that is the noise floor with no signal. Its another thing to not have the preamp editorialize with the signal. That is the low IM distortion.

You need very clean power supplies and good bandwidth, plus a simple and linear active circuit to get there.

One thing that you may not have considered is the effect of the interconnect on the sound of the system. Interconnects can contribute to the 'dark background' aspect as well. It is the job of the line section in the preamp to control the interconnect cable. Most preamps whether active or passive do a poor job of this. What is ideal is if changing the cable makes no difference at all regardless of the cable.

You will not find such a preamp that uses RCAs but they do exist if the preamp is balanced (the balanced line system was created to eliminate interconnect cable artifacts). Something to think about....

Atmasphere, why don't you bring 3 different balanced interconnects to CES and let us see if you can hear differences. This can be done after hours.

Philipwu,

I was in your position shopping for a preamp. I demoed pre (Einstein, Shindo Vosne-Romanee, Doshi ...) for months, in most cases it was in unfamiliar systems and they all sounded excellent. I could live with any of them and finally settled on a VAC SigMKIIa.

The sound you desire can be achieved through tube rolling with a GOOD preamp. The VAC SigMKIIa is very sensitive to tube rolling. With stock tubes, sound is soft, round, a bit veiled ... IN GENERAL, if you want transparency, open, dynamics ... use German tubes. Full body, sweet ... British tubes and a combo of both, Amperex, Philip Hollland. I use German tubes and also upgrading the fuse will improve the sound dramatically.

I suggest purchase a pre with EASY tube rolling options and dial in the sound you desire. Another good pre is Atma MP-1. I never demo but recommened to me by trusted ears. 6sn7 based so easy to roll.

If you plan to use your pre with many different amps, get one with low output impedance. From my experience, the ability for a pre to drive an amp properly is most important for excellent complete sound.

hi Knghifi,
Thanks,your comments are very informative. could you describe your impression of Doshi if you can recall,what is its strength? any comparison would even be better, even if it is in a different system. just curious why many hail Doshi as supreme. i know individual taste varies hence your decision on VAC Sig.
BTW, you heard Dude before? your inputs are appreciated.
Regards.

Philipwu, I will try and help you hear the sound of the Dude (latest generation) with my words. The Dude is a full bodied, dynamic beast of audio. The stage is big, bold and effortless. The music is powerful, robust and never constrained.

In it's latest generation the Dude is richly resolving bringing out all of music's finer details and nuances. It seems to handle and pull off two things that are very hard to do at the same time.

1) Clear window to the music with SOTA resolving ability.
2) But the Dude is not light or overly airy. It is full bodied and the Dude portrays music with the meat, body and density I hear in the natural instrument and voice.

Tube choice is also important with any of these preamps. The Dude responds very well to tube rolling. Place Marconi 6sn7 tubes and you fatten the sound with a slightly warm personality. Use nice 1940 RCA's and the Dude is more resolving and intimate.

The bass is absolutely stunning in power and articulation. A real strength in this preamp.

Great thread with many great preamp choices. Life is a blessing!

Merry Christmass to all!