$18k Tube preamp for large scale symphonies please

Bill (Grannyring), the two ways in which high output impedance of a line level component are most likely to have audibly significant consequences are:

1)Interaction of VARIATION of that impedance, as a function of frequency, with the load impedance, resulting in degradation of frequency response flatness and other effects.

If the output impedance is very low in relation to the load impedance, it assures that variations of that impedance will be insignificant in relation to the load impedance. But if the output impedance is relatively high, it does not NECESSARILY mean that those variations will be large enough to become problematical. A hypothetical output impedance that is purely resistive (as opposed to the impedance having significant capacitive or inductive components) will have no variation as a function of frequency, and assuming that the load impedance also does not vary significantly as a function of frequency the only consequence of that output impedance being high would be a slight gain reduction.

2)Interaction of that high output impedance with cable parameters, especially capacitance. If the interconnect cable is kept short, and a low capacitance cable is chosen, those effects will be minimized.

Happy New Year!

-- Al

Thanks Al. In the situations I have heard the IC's were 1 meter and low capacitance. Perhaps this has also played a role.

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.

I have not gone through all the posts but just want to state the somewhat obvious. If you are going to spend the kind of money you listed for a preamp, you absolutely need to demo the gear in your system to understand the synergy (or lack there of). While I like the build and sound qualities of Shindo I would never be presumptious enough to think that there is a "best" of anything in regards to audio. My experience is that personal taste varies considerably in this hobby. Once you get a list of candidates, try to listen to them in your system and ignore all opinions but your own. I know this is not earthshattering advice but I am amazed at how many people buy very expensive products blind based on 2nd hand information.

hi Atmasphere,
just reading thru one of your earlier post, you said "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". BUT i think SPECTRAL Audio would have no problem with speed if you are refering to that...