Review: Paul Speltz ZeroBox autoformer Tweak

Category: Accessories

The Paul Speltz Zero-Box Autoformer: A Letter and Review

Dear Paul:

By way of introduction, I am a professional musician. For the past forty years, I have been a choral director at the university level. As a conductor, singer, and oboist, I know what a choir and orchestra sound like from the podium. My choirs have performed with the Buffalo Philharmonic (NY), Rochester Philharmonic (NY), Phoenix Symphony (AZ), Orchestra of Santa Fe (NM), El Paso Symphony (TX), and Lubbock Symphony (TX). My choirs have also appeared at major conventions including three appearances at the prestigious National Convention of the American Choral Directors Association and I have been a guest conductor at Avery Fisher Hall and Carnegie Hall in NYC. I am currently the Director of Choral Activities and the Mary Gibbs Jones Professor of Music at Baylor University (TX). I also conduct the Schola Cantorum of Texas (a semi-professional choir).

My current equipment includes:
Speakers: Magnepan MG20.1 (4-ohms)
Pre-Amplification: Audio Research Reference Phono, Audio Research Reference 2II pre-amp, and Bryston 10B Pro-sub Crossover
Amplication: Audio Research VT130SE tubed amp (midrange/treble) and Audio Research D400II solid-state amp (bass)
Analogue Source: Linn LP12, Lingo (new version), Trampoline, Cirkus, upgraded tone-arm cable, Ekos Arm, and Akiva Cartridge
Digital Source: Audio Research CD2
Cables: Analysis Plus Silver Oval interconnects, Analysis Plus Big Silver Nine speaker cables, and Speltz Anti-cable jumpers
Accessories: Paul Speltz Zero-Box Autoformer, VPI 16.5 Record Cleaning Machine, Hunt record brush, Zero-dust stylus cleaner, Zero-stat gun, Target racks, and Zoethecus amp stands
Collection: 5000 LPs and 500 CDs
Room: 19' x 23' x 10'

After reading of your Zero Autoformers on Audiogon and Audio Asylum, I was intrigued and perused all of the material on your website. For those new to autoformers, the placement of a Zero Autoformer between the amp and speaker allows for doubling, tripling, or quadrupling the impedance of a speaker as it is seen by the amplifier. Thus, a 4-ohm speaker can be seen as 8-ohms, 12-ohms, or 16-ohms. For information go to []. Since I am an "Audio Research Guy," the comments by Warren Gehl and Chris Osanna (Audio Research engineers) certainly piqued my interest. Knowing you have a 30-day trial period, I did the sensible thing and placed an order. The nicely finished Cherry Zero-Boxes arrived just two days before my birthday. "A nice birthday present," commented my wife. I immediately installed them in my system between the 4-ohm Magnepan MG20.1 speakers and the ARC VT130SE tube amplifier that feeds the midrange/treble. I left the bass connected to the ARC D400II solid-state amplifier. After about two hours of listening, my initial reaction was, "Well, they do need to burn in." The treble was somewhat dark and congested and the bass was fairly undefined and floppy. I went to bed a little disappointed. Not able to sleep, I re-read all of the materials I had downloaded from your website. At 2 a.m. it struck me: I had installed the Zero-Boxes backwards. The ARC VT130SE was trying to feed a 2-ohm MG20.1. I quietly got up and changed the connection to ensure the Zeros were on 2X to make the Maggies an 8-ohm speaker load. "Why did I get it wrong?" Your enclosed materials were VERY CLEAR. I think it was because the pictures of the MG20.1 on the Magnepan Factory Visit had the Zero-Boxes installed that way. Boy, is that picture misleading!

After two weeks of constant break-in and listening, I did "THE TEST." "What would happen when I removed the Zero-boxes out of my system?" "Would I keep them or send them back?" Removing the Zeros from the system, I used one record for the final test: Chabrier-Espana Rhapsody (Fremaux-Birmingham/EMI Q4ASD-3008). My wife and I both agreed, "We can't live without the Zero-Box in the system." THE DIFFERENCES WERE NOT SUBTLE. Keep in mind, this is a really fine system and we have been absolutely thrilled with the sound before the Zero-Boxes made the scene. What were the differences? Without the Zeros the midrange was shallower; the treble was more etched (even irritating by contrast); and the bass was more one-dimensional. Overall, the sound portrayed a "recording" of a concert. Upon reinstalling the Zeros, all of the improvements were again highlighted. The change in sound was qualitative rather than quantitative. Removing the Zeros had left a skeleton. With the Zeros, the skeleton was fleshed out. The treble became warmer and sweeter. On a side note, as soon as the needle hits the vinyl, "Missy," our listening companion and audiophile cat comes running to assume her place on the sofa facing the speakers. She especially appreciated the new treble warmth. With the Zeros in place, her normal ear twitches on piccolos and cymbals were at an absolute minimum. She so enjoyed the new sound that she insisted that my wife relinquish the "sweet spot" for listening sessions. But I digress. The mid-range took on an opulence and naturalness found in live performance. My wife commented, "It is like opening the window on a fine, spring day." The bass seemed to go much lower with added pitch definition and tonal accuracy. The orchestra was presenting a live performance; gone was the sense of playing a "recording" of the concert. As a professional conductor I know the "absolute sound" of live music and the Zeros allowed the system to more closely achieve a listening experience similar to the real thing. The sound had a new harmonic richness, but don't be mislead, the richness in no way obscured the low-level details of the performance. Inner details were beautifully realized. Moreover, the added richness did not lessen the wonderful toe-tapping speed of the Linn/Magnepan combination. In my opinion, the most significant effects of the Zeros are rich tonality, harmonic correctness, bass clarity, and freedom (ease) of sound. My system has never sounded better. One of the great problems with the Zeros is that if you don't try them, you may not know what you are missing.

Over the past two weeks, recording and after recording has shown a constant improvement in the system. Evident was the exquisite beauty of tone in Eclogue (Finzi); delicacy, clarity and freedom in Harp Concertos (Handel); the weight, depth, and dynamic range of full orchestra in Marco Spada (Auber), The Planets (Holst), and Symphony 9 (Schubert); the accuracy of the human voice in Chandos Anthems (Handel); and the subterranean bass in Felix Hell-Organ and Le Cid (Massenet).

Obviously, the ARC VT130SE really performs better on the 8-ohm tap; the sound becomes more relaxed with greater richness, clarity, and freedom. Listening to music is a major part of my life and the Zeros have made a significant contribution to raising my system to a new level. You would have to pry the Zeros out of my "cold, dead fingers" to get them back. To say "thank you" is totally inadequate to express my appreciation for what your product does but it will have to do. The Zero-Box would be a bargain at twice the price. In my system, the Zero Autoformer is not an accessory, IT IS A NECESSITY. I commend you for developing and making available this wonderful product. Highly recommended.


LPs in Heavy Rotation:
Adam-Giselle (Fistoulari-London/Mercury SRI-2-77003)
Auber-Marco Spada (Bonynge-London/London CS-6923)
Brahms/Dvorak-Serenades (Kertesz-London/Decca 593-007)
Finzi-Eclogue (Handley-New Philharmonia/Lyrita SRCS-92)
Handel-Chandos Anthems (Christopher-The Sixteen/Chandos ABRD-1293)
Handel-Harp Concertos (Robles-ASMF/Argo ZRG-930)
Holst-The Planets (Mehta-LA/Decca SXL-6529 Reissue)
Massenet-Le Cid (Fremaux-Birmingham/Klavier KS-522 Reissue)
Rachmaninoff-Piano Concerto 2 (Dorati-London/Mercury SR-90283 Reissue)
Saint-Saƫns-Danse Macabre (Fremaux-Birmingham/EMI Q4ASD-3008)
Schubert-Symphony 9 (Mehta-Israel/London CS-6948)
Shostakovich-Symphony 15 (Haitink-London Philharmonic/London CS-7130)

CDs in Heavy Rotation:
Bells for Stokowski (Junken-UT/Reference 104 CD)
Bernstein-Suite from Candide (Oue-Minnesota/Reference 87 CD)
Felix Hell-Organ (Reference 101 CD)
Ports of Call (Oue-Minnesota/Reference 80 CD)
Rachmaninoff-Symphonic Dances (Oue-Minnesota/Reference 96 CD)
Shostakovich-Symphony 5 (Maazel-Cleveland/Telarc 80067)
Vivaldi-For Diverse Instruments (Megegan/Reference 77 CD)
Webber-Evita (Original Broadway Cast/MCA 11007)
Excellent overview of a product that many of us are curious about. Paul's certainly getting some good press these days- deservedly so.