$18k Tube preamp for large scale symphonies please

Philipwu, I have been able to sort out what kind of amp you have. Does it have a balanced input? How long do you need the interconnect cables to reach? Have you considered the effect that preamps have on the cables?

FWIW electronics do not care what signal you put through them; as long as it is a good preamp it will be equally good at doing intense classical as well as rock or jazz.

If you have a solid state amplifier some tube preamps may not be able to play bass properly. Some will do just fine.

I prefer tubes because it is easier to get them to sound like real music. If the preamp is not very fast I am unconvinced, but it must not be bright either. I like good bass extension, but I don't like the extra warmth that many tube preamps have in the mid bass. I want the sound to be neutral without editorializing. Deep bass seems to me the hardest thing for tube preamps to do right, but if they do that right there will be no solid state that can keep up.

If the preamp is fully balanced, doing phase reversal is a non-issue. We have had one our our preamps for the last 24 years.

If you are listening to a multi-track recording, the effect is not audible. It really has to be a true stereo recording to show up.

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....

Jwm, pretty sure we will have at least two types of cables there. They will both be about 40 feet long. Would that be sufficient for you?

Philipwu, I have to agree with Lenny here. If a preamp is competent, it will not matter what type of music you play. I suspect you are looking for something with good bandwidth and detail but if a preamp is competent it will provide those things.

So the Nagra is a contender if it can drive your amplifier comfortably without loss of bass. It is that latter issue that is a concern if you are using a transistor amp. Some transistor amps have lower input impedance values (!0K being typical); this coupled with some tube preamps (ARC for example) will result in less bass. To that end I would compare the output impedances of your contenders; those that have more than 1K at 20Hz would be out if you have a transistor amp as in the example I gave.

Happy New Year!

Hello Grannyring, you are correct. The higher the output impedance of any preamp, the shorter the IC should be.

However that does not explain bass response, but some of that depends on your speakers too, and whether you listen to recordings where the issues might show up. This is an area where audiophiles will say things like "this preamp has more impact than than that one" even when both preamps cut off at the same frequency. IOW, its in a realm of 'in comparison to what?"

What we are talking about here is issues with phase response, which behave to the ear more as a coloration than a frequency response issue, although when the phase is right you do get more impact.

Philipwu, I am not. The ability of a tube preamp to play the instruments with body and impact at the same time is the pervue of tubes and the bane of transistors. Sure, its easy for transistors to be fast (harder for tubes but what we are really talking about here is bandwidth and good tube preamps have as much bandwidth as transistors); the issue is how do you have speed and detail at the same time as being relaxed?

Too often I see brightness associated with detail and I see many audiophiles accept that to get good detail, it has to be bright. But it does not have to be that way- its possible to have more detail (than a bright preamp) and a relaxed, effortless but dynamic presentation all at the same time.