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I own Bliss Hifi, a high-end audio boutique based in Minnesota. This Thoress Phono Enhancer (Parametric Phono Equalizer MK III) is in on consignment from one of my local clients. This is a single-owner unit in like-new condition and is barely broken in, purchased new in March 2026 and is in perfect working order. The owner acquired it primarily for its ability to play 78RPM records with historically accurate equalization curves, but found it was not getting enough use alongside his primary phono stage.

The unit comes with its original box and manual.

The Thoress Phono Enhancer is unlike anything else in high-end audio. It is not just a phono stage. It is a time machine for vinyl. Every major record label before the RIAA standard was adopted in 1954 used its own proprietary equalization curve when cutting records: Columbia, Decca, EMI, RCA, and dozens of others each had their own prescription for how bass and treble were manipulated during the cutting process. Playing those records back through a standard RIAA phono stage means you are hearing them with the wrong equalization, and the tonal balance is simply incorrect. The Thoress solves this with three six-position rotary selectors that independently control the bass roll-off, bass turnover, and treble roll-off frequencies of the de-emphasis curve. Between them, you can dial in virtually any equalization curve ever used in the history of recorded music. For 78RPM collectors, this is the only phono stage that lets you hear those pressings the way they were intended to sound. But the Phono Enhancer is not a one-trick specialist. With the selectors in their default positions, it performs highly accurate RIAA de-emphasis and functions as a world-class phono preamplifier in its own right. The single-ended, zero-feedback tube circuit using 12J5GT and PC86 tubes is hand-built with point-to-point wiring in Germany by Reinhard Thoress, and the sonic character is pure, dimensional, and richly textured in the way that only the best single-ended tube designs can deliver. It provides both MM and MC gain without the use of a step-up transformer, handling everything from high-output moving magnets to low-output moving coils with excellent signal-to-noise performance. Six phono inputs (five MC, one MM) with selectable loading make it practical as the hub of a multi-turntable or multi-cartridge system. The parametric EQ also serves as a remarkably sophisticated and musically transparent tone control for modern pressings that suffer from poor mastering or thin tonal balance. This is a phono stage that rewards curiosity and makes you want to pull records off the shelf you have not touched in years.

Happy to answer any questions. Thanks for your consideration.

Check my stellar feedback and buy with confidence. This listing includes free insured shipping across the CONUS. As this is a passthrough sale that I am brokering on behalf of my client, I prefer to accept payments via PayPal F&F, Venmo Gift, or personal check, but this also gives you the opportunity to attain this at my lowest possible price. Credit card payments are also possible for a 3.1% convenience charge.

More about the unit:
The Thoress Phono Enhancer (Parametric Phono Equalizer MK III) is a reference-grade vacuum tube phono preamplifier designed and handcrafted by Reinhard Thoress in Germany. It is built entirely with point-to-point wiring, ensuring reliability, low noise performance, and ease of service. The circuit topology is single-ended, zero-feedback throughout, using a tube complement of 2 x 12J5GT (or 6J5GT) and 2 x PC86. The amplifier provides both MM (Moving Magnet) and MC (Moving Coil) gain in purely active operation, without the use of step-up transformers, achieving excellent signal-to-noise performance across all gain settings. Six phono inputs are provided, with a default gain pattern of five MC inputs and one MM input (a pattern of one MC and five MM can be specified on request). MC cartridge loading options are 100, 200, 300, 500, and 1,000 ohms, selectable per input. The MM input is loaded at 47k ohms. The defining feature of the Phono Enhancer is its parametric phono equalization system. Three six-position rotary tone selectors (TCSW1, TCSW2, TCSW3) independently control the three edge frequencies (f1, f2, f3) of the phono de-emphasis characteristic: bass roll-off, bass turnover, and treble roll-off. This allows the user to dial in virtually any equalization curve used by any record label throughout history, including pre-microgroove 78RPM era curves from Columbia, Decca, EMI, RCA, and others. With all selectors in their default positions, the amplifier performs highly accurate RIAA de-emphasis. The parametric system also functions as a musically transparent, non-destructive tone adjustment facility for compensating poor mastering or tonal imbalances in modern pressings, shaping the playback curve itself rather than applying conventional tone control circuitry after the fact. Real-to-reel tape NAB and IEC equalization curves (for various tape velocities) can be installed alongside phono settings upon request for users seeking ultimate tape playback. Output impedance is low enough to drive long interconnect cables and power amplifiers with input impedances as low as 10,000 ohms. Output is single-ended RCA. The Phono Enhancer provides sufficient gain to drive certain integrated amplifiers directly, bypassing the need for additional line amplification, provided speaker efficiency is adequate. Handcrafted in Germany with meticulous attention to component selection and construction quality.

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