Welcome to USAudioMart, a classifieds site for used audio and hifi. Postings are free for hobbyists. Register today and start selling/buying audio gear!

> Classifieds > > > ZERO- Autoformers

SOLD - FOR SALE: ZERO- Autoformers

Item #649387297
Info: ZERO- Autoformers

Asking Price:
USD $400.00
Retail Price: USD $560.00
Payment method: Paypal
Shipping weight: 20.00 (lbs) Calculate Shipping
Condition: 9 - Excellent (?)
Date Posted: Oct 23, 17 3:09pm (PST)
Edited: Nov 22, 17 4:09pm
About Seller: Big Bruno
South Rockwood, MI
United States
[other classified ads]
Product Brand: Speltz Zero-Autoformer
Product Model: ZERO-Automformer
Feedback Received: 6  See details
100% Positive Feedback
External Feedback: fogertyken (305)
Days in System:30
Avg. Views/Day:8.40

The feedback period is over for this ad, so feedback is no longer allowed. For details please read this FAQ entry.
Share |


Sponsored post - log in to remove this ad.
** This Ad is Marked as SOLD by seller and cannot be responded to. **

ZERO- Autoformers “ZERO” Sells for $560 a pair plus shipping cost.
Sell for $400 a pair. Plus shipping costs of $30.
The pictures shows 2 pairs, one pair has been sold.

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, because amplifiers produce less distortion when driving less current.

The ZEROs are a great way to get better amplifier performance when driving low impedance speakers
• Multiply any speaker's impedance by 2x, 3x, or 4x
• Example: a 4 ohm speaker becomes 8, 12, or 16 ohms
• Replaces existing short speaker cable when using monoblock amplifiers
• Made in USA (one pair at a time in Lake Elmo MN)
Typical Reported Sound Improvements:
• Lower distortion "sounds cleaner" (due to an easier load on the amplifier)
• Firmer bass (due to an increased damping factor)
• Higher resolution (due to an easier load on the amplifier)
• More extended and better focused high frequency
• Use with any low impedance speaker
• A problem solving device for when there is an Amplifier/Speaker mismatch
• Popular when driving Magnepan speakers with Tube Amplifiers
• Enables using a tube amplifier's better sounding 8 ohm output tap when driving 4 ohm speakers (popular with Audio Research Corp. tube amp owners)
Greatly Increases Smaller OTL (output transformer less) Amplifiers' Output Power:
• Get 50 watts/ch out of the 30 watt Atma-Sphere S-30 amp
• Get 80 watts out of the 60 watt Atma-Sphere M-60 amp.

DICK OLSHER of EnjoyTheMusic.com said:
One immediate benefit is control over the loudspeaker's current demand." "The ZERO, in my opinion, represents an important new product category that allows music lovers to actively modify and control the amplifier-loudspeaker interface"

WAYNE DONLLEY of EnjoyTheMusic.com said:
"Being able to play the system at much higher levels without audible strain was now even more of a kick." "Altogether, the greater sense of power and control, cleaner and deeper bass, and more precise spatial presentation were impressive."

"The ZERO Autoformers are a tweaker's delight. However, unlike some questionable audiophile accessories that are alleged to work through some inexplicable, metaphysical means, the ZEROs do work, they work very well, and their functionality can be demonstrated and explained through ordinary physics."
"I guess I have been among the most skeptical in thinking that ZEROs would do nothing for my Quads given that speaker's impedance curve. Though I've had them set up for only a couple of days now, it is apparent that I was quite mistaken. The most profound difference is in the mid and upper bass, which has both tightened up and has become more 'organic'. I never have figured out what the latter term really means in sound reproduction, but I guess you know it when you hear it. Deep cello and double bass simply sound more real - and they sounded pretty damn good to begin with
"The more I listen to the system with the ZEROS in, the more I like them. Please note that this applies to my new M-60s just as much as my former S-30. This is a great product and a true bargain."

"Got the ZERO-Boxes. Talk about return on investment. It just has to be the best $$$ I've spent considering all the money that I have blown in the past 30 years. I only played with them for about 5 hours and can't wait till they are fully broken in. I am still debating between 3X and 4X and at the moment I am inclined to use the 4X despite that the mid bass is just a hint drier than I would like. I have the Amati Homage (nominal 4ohm with a dip of 1 ohm at about 400Hz) driven by Tenor 75WP. The Zero really brings out the best of the OTL, of Tenor in term of airiness and openness while retaining excellent control of the bass. I was inches away from dumping the Amati but the ZEROs sorta save its day. I believe I have talked a few of my fellow audiophiles into giving it a shot. Thanks."

“I set up my amp and the ZEROs to double the damping factor because the Cary amp has a high output impedance, a little more than half the tap value, I understand. A whole new world of bass clarity appeared. This was not at all subtle. I was hearing surprising bass depth, space, air, and delineation I never heard before. The overall listening experience was quite improved. I tried various taps and found that the X2 impedance multiplier sounds the best.”

“My speakers are the Soliloquy's 5.3, which are an easy 8 ohm load, thus making it a 16 ohm load. This set up was sounding perfectly well, I thought, until I heard the Zero's. My preamp is a GG built from scratch and the Bel Canto Design DAC driven by a Sony 7700 DVD/CD player. After evaluating the Zero's I am not sending them back. Every aspect of the reproduction is enhanced, specially in the smoothness department. All the resolution, detail retrieval and dynamic aspects are kept but with much more refinement. The stage is also bigger."

" I put them into my system and even though they are not even broken in yet, I heard an immediate improvement in my stereo. I used the 4x setting on my 3.5 2A3 amps, driving Quad ESL63 speakers. The bass is deep and VERY tight, plucked strings have more of a percussive sound, and the sound is cleaned up overall....it really makes me shake my head in disbelief that I am getting this kind of sound out of a pair of 3-8 watt 2A3 amps.
"I'm still very impressed with the sound of my stereo since adding the zeros into the equation. Everything sounds so natural, effortless, organic.”


US Audio Mart is FREE!