Zero-Box Autoformer

The Zero-Box autoformer that I ordered arrived yesterday. Here's a link to the website: Zero-Box

The reason for getting the Zero-Box was because my Yamaha B-1's don't like low impedence loads. They have a tendency to trip the overload protection circuit when the load is < 4 ohms. That was too restrictive for me, and knowing that McIntosh uses autoformers in many of their amps I searched the web and found zeroimpedence.

The Zero-Box I got is constructed from Birdseye Maple. It uses Cardas solid copper binding posts. I've been running the MX-10000 through the Zero-Box and I can't say that I hear a difference, which I consider positive.

I won't hook a B-1 up to them until I get one back from EchoWars. As an aside, EW got the B-1 that needed repair up and running. He still needs to recap it.

thats good to hear.

cool box btw.

By popular demand, a few pics:

do you notice any change in the sound?

I haven't noticed any difference so far. I'll switch them in and out over the next few weeks and do some critical listening.

Very nice pix.
We'll be waiting for a Zero-Box review.

The web site touts better sound due to tighter bass and better damping. Seems like you should have a somewhat different sound And WOW $1000 for the pair? Seems like you could have bought the right amp for that much.

Doing a quick and dirty test - running the right channel through the Zero-Box taps that double the ohms, and the left channel directly into the speaker. There is a definite difference: the output level of the right channel is noticeably less. Interestingly, the VU meters do not reflect that difference. Adjusting the pre-amp channel balance evens out the volume difference. The VU meters however show the right channel output is higher. To my ears the left and right channels also seem to have similar frequency response.

Upon further listening, the low end of the right channel (powered through the Zero-Box) does not extend as low as the left channel. In addition, the balance of frequencies on the right channel has shifted to the top end compared to the left channel. I'm puzzled by this shift in balance from low to high since the ohm load is doubled for all of the drivers, so it should maintain the same ohm ratio between the drivers.

Let's see if i can understand your problem... and, get back to the basics :

Impedance is the electrical characteristic of a speaker that restricts ("impedes") the flow of power from your receiver or amplifier. Impedance is the combination of the resistance of a speaker plus its reactance. (Reactance describes the electrical effect of the inductors and capacitors typically found in a speaker's crossover network. The drive elements themselves also have a "reactive" element.) The impedance value of a loudspeaker is expressed in Ohms.
Impedance attempts to quantify how difficult a speaker is to "drive," and thus describe its compatibility with various amplifiers.

The speaker's impedance influences the ratio of voltage and current. Here's an example:
I gave you 5 amperes and 40 volts multiplied together to get 200 watts. If we reduce the impedance of a speaker load by half, from 8-Ohms to 4-Ohms, but kept the power the same, we would find that the amount of current would multiply by the square root of 2 to 7.07 amperes and the voltage would reduce by the square root of 2 to 28.28 volts. Multiply 4 times 28.28 (volts) and you get the same 200 watts, but from the amplifier's point of view the job has gotten harder.

Impedance restricts the flow of power from your receiver or amplifier. So it stands to reason that less impedance would be better, right? More flowing power is always better, right? RIGHT?!
Not entirely...!
Truth is a low impedance load stresses a receiver or amp by asking it to put out more current, and that can be bad especially if your amplifier is incapable of putting out the amount of current the low impedance speaker demands.

After all this i think that is the mais reason you bought the Zero-Box, right...?

In sonic terms is possible that you won't listen great differences, but the problem is resolved. Now you prevent your amp from clipping.

Enjoy your sound.

This post has been edited by clint e. on May 09, 2007 06:47 am

Nice Clint. Good info.

Tanx mate.

The Zero-Boxes did not complement the MX-10000 driving the Infinities, they simply reduced the bass. Apparently the MX-10000 doesn't need any help running a low impedence load, in fact I think the amp likes low ohm loads.

The Zero-Boxes are now hooked up to an M-4 running the top-end of the Energies, with a B-2x running the low end directly. I'll play with that for awhile.

The sign of a good SS amp, acording to Krell´s Dan D´Agostino.

I was a bit surprised when you said your latest Yammies didn´t feel comfortable with low impedance loads. I feel better now.

Jorge