Is preamp remote volume a deal breaker for you?

Hi Al, If you put a 600 ohm resistance across a cable, which has capacitive, inductive and resistive aspects, the outcome is that the 600 ohm resistance becomes the primary aspect of what you are driving. The other things (which normally affect a cable when the amp input impedance is 100K or higher) get 'swamped out'.

This is how all high fidelity recordings are possible, BTW. If you have any recordings from the 1950s, what we have is a recording that sounds better the better you make your system. (Some people think that the best recordings were made in the 1950s). How did they do this without high-end cables? How could they run microphone signals over 200 feet and have them sound anything like HiFi over such a distance? The answer is that they used a low impedance termination on the line.

For example, I have a set of Neumann U-67 microphones. They use a small tube preamp to take the signal from the condenser element. This preamp is only a single triode gain stage- so its output impedance is high. But it drives an output transformer that is set to 150 ohms at its output. So many mic inputs on mixers and tape machines have a low input impedance like this. It allows the mic to drive *stupidly long* cables without any degradation at all, and the cost of the cable is kept to a minimum.

Now maybe I'm a little odd this way, but it seems to me that a system that would allow one to ditch expensive cables in favor of even better sound would be a good thing.

Mind you- if the terminations are not there, the 'better sound' I mentioned could well be lost to cable interaction.

Thanks, Ralph. That all makes sense, as I see it. I would add, though, that the values of those cable parameters, and their effects, will decrease as length decreases. I would therefore expect that in the case of a short cable, say a few feet long, and if the cable is reasonably well designed and is driven from a low impedance balanced output, that those effects would be insignificant both with and without the termination.

Best regards,
-- Al

Here are some quality remote controlled attenuators (the ubiquitous motorized Alps pot excluded) that can be added dto an active preamp.

http://www.tentlabs.com/Products/page31/page31.html

http://www.tubewizard.com/new_remote_volume_control_is_the.htm

http://www.marchandelec.com/att.html
(this one looks like the one used by Atma-sphere MP1)

http://bentaudio.com/index2.html

http://www.partsconnexion.com/tkd_73340.html

Dracule1, we investigated relay-operated volume controls and spent a lot of money in the process. They are quite good but a good quality rotary switch sounds better...

Al, one *would* think that the shorter the cable the better, but even in the case of 1 meter, I have seen similar benefits. The example I am thinking of is the tone arm cable, which is often only 1 meter (many audiophiles will go through quite a bit of effort and money finding the 'right' phono cable...). Since all cartridges are balanced sources, its possible to run the phono balanced to the preamp. If you are using a LOMC and have some sort of loading for it at the input of the preamp, the result is that you have a low-impedance balanced line and the cable will have no artifact. So an inexpensive cable in this situation will keep up with the most expensive with ease, as long as the cable is built right, which really has little to do with the cost.

Many people don't realize that LOMC cartridges, while having low voltage output, can have rather high current outputs, thus their ability to drive a 100 ohm resistor and the like.

Ralph and Al,
After being in and out of this business for 32 years, I don't often learn much new.... I appreciate you guys.
Thanks for the education.... again.
Tim