Original toroidal autoformer. Can transform a 4 ohm speaker into an 8 ohm, 12 ohm, or 16 ohm speaker. Very helpful in matching speakers to amplifiers.
It is well understood the importance of getting a well matched amplifier for your speakers, or vice versa; getting the proper speakers for your amplifier. Now you can make virtually any amp/speaker combination work well together with the ZEROs.
Bill has been using these autoformers in many set-ups where optimum performance is the goal of himself and customers alike.
'Surprisingly, even very big powerful amplifiers built to be able to drive low impedance, low sensitivity speakers, perform better when driven into a speaker where the impedance has been raised 2 or 3 times...to 8 and sometimes 12 ohms.
In my experience tube amplifiers that have 4 ohm taps perform better when connected to their 8 ohm tap and then into the autoformer to multiply the 4 omh impedence of the connected speaker to 8 ohms.
Also this allows amplifiers, that switch between ultralinear and triode mode, to be used in triode mode.
As at November 2019 I am driving the Magnepan reference 30.7's in triode mode from the Rogue Audio M-180 Dark Mono blocks in this way...this set-up, and the ensuing level of performance, would not be possible, without the addition of the autoformers'.
The ZEROs are the simplest type of transformer called an auto transformer or autoformer. They are used to multiply the impedance of any speaker so that it "feels" like the optimum load for the amplifier being used. They are very helpful in matching speakers to amplifiers. By adjusting the speaker's impedance, both the damping factor and the maximum power transfer of the amp/speaker can be tailored for best sound. Almost all amplifiers sound better when driving a higher impedance speaker, simply because amplifiers produce less distortion when driving less current.
Made of the same original toroidal autoformer; has the ability to multiply a speakers impedance by 2x, 3x, or 4x. For example, the ZERO can transform a 4 ohm speaker into an 8 ohm, 12 ohm, or 16 ohm speaker depending on which two of four leads/connections are connected to the amplifier. They are very helpful in matching speakers to amplifiers, even amplifiers that already have a variety of output taps available realise benefits.
The "Naked" ZERO-Autoformers have 18 inch (46cm) leads of 12 gauge copper wire, along with spade terminals attached on each lead. For those with mono block amplifiers, the 36 inch (92cm) total span should be long enough to connect directly between the amp and speaker. For those who need longer wires, utilise existing speaker cables connected to the ZERO-Autoformers with a set of binding posts as shown at the bottom of this page.
The ZERO-Autoformers can be connected to your existing speaker cables for longer runs. Use a set of binding posts to connect together your existing speaker cables to the coloured pair of ZEROs leads for the desired speaker impedance multiplying factor.
2x = YELLOW (+) BLUE (-)
3x = YELLOW (+) BROWN (-)
4x = GRAY (+) BROWN (-)
Notice that the music signal is not passing through the binding posts. Their quality is not critical since they are only being used to tightly hold together your speaker cables to the ZERO-Autoformer leads.