Seta - Balanced Direct Coupled Ultra Wide Bandwidth Phono Preamplifiers

       The current-mode (transimpedance input) Lino C phono preamplifier.

       Balanced inputs / balanced and unbalanced outputs, low noise internal AGM rechargeable battery power supply, precision (+/- 0.1 dB) RIAA EQ,
       Click for more information or to purchase the Lino C 2.0 or NEW Lino C 3.3.


Seta - Balanced Direct Coupled Ultra Wide Bandwidth Phono Preamplifiers

       Our flagship - the Seta® L20. Now introducing the L20 mk2.

       Read more about this revolutionary current-mode / voltage-mode phono preamplifier here.


Seta®

Balanced Direct Coupled Battery Powered Ultra Wide Bandwidth Ultra Low Distortion Low Noise Preamplifiers

Customer comments on our Seta Model L: "I've evaluated the RIAA out and compared to my Aesthetix Rhea Signature phono amp. I have to tell you that I'm amazed at how good the Seta L RIAA circuit is. Fantastic resolution and bandwidth plus depth. I've already sold my Aesthetix Rhea Signature phono amp - your Seta L rendered it redundant! If I'd known how good the Seta was I would have purchased long before now but then, you only know what you know.

By occupation, I'm a professional aerospace engineer so I like technical challenge too. I take my hat off to you and wonder how you have found the time to design such amazing hardware and software products. If you were a Brit over here, I'm sure you would have won a Queen's award for innovation by now. Keep up the good work! "


Channel D     Channel D

Stereophile 2020 Editor's Choice Recommended Components (Class "A") - Lino C 2.0
2019 Absolute Sound Golden Ear Award - Lino C 2.0
Stereophile 2010 - 2019 Editor's Choice Recommended Components (Class "A") - Seta Model L
The Absolute Sound - 2015 - 2020 Editors' Choice Award - Seta Model L


Lino™ - Balanced Direct Coupled Wide Bandwidth Low Distortion Ultra Low Noise MC Preamplifier

Channel D
Positive Feedback Online 2015 Brutus Award - Lino


Channel D Phono Preamplifiers


Channel D Seta phono preamplifiers offer a fully balanced (from input to output), low-noise direct coupled (DC) differential circuit design providing the users of Pure Vinyl™software with the end-to-end route to the superb performance of "flat" vinyl reproduction (linear amplification followed by software RIAA correction).
  • "Flat" outputs perfect for use with Pure Vinyl software RIAA correction
  • Ultra wide bandwidth (up to 20 MHz / 20,000 kHz / 20,000,000 Hz) delivers stunning improvements in smoothness, clarity, definition and 3-D imaging
  • Precision RIAA Correction provides simultaneous "Flat" and conventional RIAA Corrected, independently buffered and balanced (XLR) and single ended (RCA) outputs

About Seta

Listening evaluations using a variety of reference systems and program material show that an important key to accurate reproduction of vinyl audio involves greatly increasing the signal bandwidth of the preamplifier front end (the first stage of amplification touching the signal from the phono cartridge).

Why? First of all, high quality phono cartridges are capable of reproducing signals well over two octaves above the audio frequency range.

While such signals are inaudible, the preamplifier also must work to amplify these signals, which are boosted over 20 dB above midrange levels (because of the standard vinyl treble pre-emphasis curve used in the mastering process). A preamplifier unable to handle out of band signals will distort in the ultrasonic region. This distortion will carry over into the audio range, affecting the reproduction of the midrange and treble.

Futhermore, the audibility of one of the most maligned deficiencies of vinyl, "pops and clicks," is a function of and can be exacerbated by the design of the preamplifier. The reason is that the transient signals caused by the stylus striking a scratch or foreign object in the groove have, in addition to large amplitude, a very fast risetime, and are unlike any musical signal. The fast risetime can cause slewing distortion in traditional narrow bandwidth or inexpensive phono preamplifiers, magnifying the audibility of pops and clicks. This nonlinear coloration from a less capable preamplifier is at least partially responsible for causing many music lovers to shun recordings in the vinyl medium! The Seta wide bandwidth design employs a fast-responding front end gain stage with a slew rate of over 500 volts per microsecond (Model L), making it immune to transient distortions induced by pops and clicks, minimizing their impact on the listening experience. (The slew rate of the Seta output is deliberately limited to avoid causing slew rate distortion in any following components.)

How much bandwidth is enough?

The rule of thumb for linear signal reproduction is ten times (an order of magnitude) greater than the signal of interest. With that criterion, the amplifier is able to linearly reproduce out of band signals, while preserving the integrity of the midrange and treble without the "haze" caused by, and characteristic of, ultrasonic intermodulation distortion. Going still further, extending the bandwidth by two orders of magnitude delivers a stunning improvement in three-dimensionality and imaging. This principle is continued by the Seta L20, which has a signal bandwidth three orders of magnitude (1000 times) that of audible frequencies.

Why don't more phono stages have ultra wide (megahertz) bandwidth? Why do some line stage preamplifiers have megahertz bandwidth? It's one thing to design a line stage preamplifier, and quite another to design a phono stage. The difference is the extreme amount of gain required in a phono stage - around 100 times (40 dB) greater than a typical line stage. A trade off exists between gain, signal bandwidth, noise and distortion. In most phono stages, the required high gain means that the other design parameters must be engineered more conservatively. This was the case until the introduction of our 5 megahertz bandwidth Seta Model L in 2007. The lower gain required for a line stage makes it easier to design with wide bandwidth. For instance, our special-purpose Buffer Amplifier products, introduced in 2012, are essentially simplified line stages - and have a 20 megahertz bandwidth - without resorting to the new (and much more expensive to implement) design methodologies employed in our 20 megahertz bandwidth Seta L20.

Surface Mount vs. Through-Hole Components

To dispel misinformation which we've seen on the Internet and in print advertising: surface mount components provide the shortest signal paths and highly optimized circuit layouts, with low stray inductance, low stray capacitance, low temperature coefficients, high stability, improved unit to unit consistency and consequently better performance than old-fashioned through-hole circuit components. Surface mount manufacturing is not strictly the outcome of short-sighted "value engineering" - it is the result of the never-ending quest for increased performance of electronic components and circuits; lower manufacturing costs are a welcome side effect. There are cheap surface mount components just as there are cheap through-hole components, both of which deliver inferior performance. However, the performance of all through-hole parts are eclipsed by the best surface mount components, as used in our preamplifiers. Further, certain types of high-performance circuits simply cannot be created with through-hole components, especially those requiring ultra wide bandwidth.

There is one specific exception where through-hole parts deliver better performance: high performance film capacitors. The solid organic polymer dielectric used in all high performance film capacitors cannot withstand the high temperatures encountered during surface mount manufacturing. In response, alternative high-temperature-compatible organic polymer dielectrics have been introduced, such as polyphenylene sulfide (PPS). We have evaluated these parts and have found them markedly inferior to other film capacitors, such as the metallized polypropylene type that we use for RIAA and filtering circuits. PPS has poor thermal stability, making it impossible to hand select PPS components for precision tuned circuits, because the values of PPS capacitors change too much when exposed to the heat from soldering. They also have inferior dielectric absorption and dissipation factor (causing a loss of definition and veiling) and DC leakage compared to metallized polypropylene - we have measured the DC leakage changing substantially depending on the atmospheric humidity! They are also not available in higher values, leading to less than optimal circuit designs (even if they otherwise matched the performance of other polymer film capacitors). Accordlngly, surface mount film capacitors (and only surface-mount film capacitors) are ill-suited to high performance audio.

Of course, as any electrical engineer who has worked with practical circuits knows, high performance through-hole film capacitors (partly because of being large-sized, through-hole type parts, but also because the permittivity of the dielectric material used decreases with frequency) cannot be used for critical (and essential) high frequency power supply bypassing - they become inductive at relatively low (several hundred kHz) frequencies. This is where MLCCs (multilayer inorganic dielectric capacitors - we'll use the "dirty word" here - ceramic; but rest assured that today's 21st century ceramic capacitors use exotic materials such as zirconium tin titanate / C0G and barium titanate / X7R that are definitely not "your father's ceramic capacitor") really shine, because of having exceptionally low inductance (and ESR, equivalent series resistance). This is a direct consequence of their miniaturized size, internally having hundreds of layers of electrodes separated by dielectric - an amazing feat of manufacturing achieved only in the last several years. On the other hand, inorganic dielectrics are definitely unsuitable for use directly within the audio signal path because of dielectric absorption, higher dissipation and their generally wider capacitance tolerance (tight tolerance is needed for precision filter circuits such as rumble filters or RIAA EQ), plus susceptibility to microphony (because the X7R dielectric used in the lowest inductance parts exhibits piezoelectric activity). However, these drawbacks are unimportant considerations for power supply bypassing, where low ESR, low inductance and small size are of paramount importance.

Feature Benefit
Ultra-wide linear signal bandwidth (-3 dB at 20 MHz, Seta L20; -3 dB at 5 MHz, Model L; -3 dB at 1 MHz, Piccola); Direct Coupled circuitry. No Capacitors in signal path Improved Smoothness, Clarity, Definition and 3-Dimensional Imaging
Fully Balanced, Complementary Circuitry Reduced Noise and Distortion
Minimum Signal Path Design Preserves Signal Integrity
Low Impedance AGM Internal Rechargeable Battery 50 Ampere, Deep Power Reserve Preserves Signal Dynamics
FET or Bipolar Hybrid Circuit Topology (Model H or Model L) Performance Tailored to MM or MC Cartridges
Video Bandwidth, Balanced Low Impedance Output Amplifier High Noise Immunity; Not Affected by Connected Equipment or Length of Output Interconnect

Seta preamplifier's hybrid, video - bandwidth amplifier modules are electronically and acoustically isolated and kept at a stable operating temperature and environment (constant humidity) by enclosing and sealing them in a block machined from a solid piece of oxygen-free high conductivity copper. Each module is carefully tested and characterized before and after being hermetically sealed in the copper block.   Seta preamplifier's hybrid, video - bandwidth amplifier modules are electronically and acoustically isolated and kept at a stable operating temperature and environment (constant humidity) by enclosing and sealing them in a block machined from a solid piece of oxygen-free high conductivity copper. Each module is carefully tested and characterized before and after being hermetically sealed in the copper block.
Seta Model L / H preamplifier's hybrid, video - bandwidth amplifier modules are electronically and acoustically isolated and kept at a stable operating temperature and environment (constant humidity) by enclosing and sealing them in a block machined from a solid piece of oxygen-free high conductivity copper. Each module is carefully tested and characterized before and after being hermetically sealed in the copper block.

Noise

Seta preamplifiers, besides (or should we say, despite?) providing the widest bandwidth of any phono preamplifiers available, also feature low noise that ranks among or better than the world's finest phono stages. Here is a comparison of measurements performed by Stereophile (including issue dates for verification) of the signal to noise ratio (SNR) of moving coil phono preamplifiers, including our Seta Model L. Higher numbers are better. The quietest are highlighted in boldface.

Phono Preamplifier (MC Input) Unweighted SNR A - Weighted SNR From SP Issue: Accolades
Channel D Seta Model L 59 dB* 67 dB* August 2010 Stereophile Class A Recommended Component
Boulder 1008 60 dB 64.75 dB July 2010 Stereophile Class A Recommended Component
Vitus Audio MP-P201 Masterpiece 53.6 dB 62.8 dB September 2010 Stereophile Class A+ Recommended Component
Nagra VPS not reported 61 dB September 2008 Stereophile Class A Recommended Component
Boulder 2008 not reported 49 dB July 2002 Stereophile Class A+ Recommended Component
*The signal to noise ratio has been improved in the year 2015 and later production by approximately 4 dB from the numbers shown above obtained from the August 2010 Stereophile review, and are reflected in our current published specifications, e.g., 71 dB A-Weighted SNR for the Seta Model L.

Measurements of distortion levels, bandwidth and RIAA accuracy are best gleaned from reading the associated reviews, but the Seta Model L ranks near the top, if not at the top of the list in this regard. For further confirmation, see John Atkinson's follow up review of the Model L (December 2013 Stereophile, download here) with additional highly favorable distortion and RIAA accuracy measurements. Note: In that report, John also made another measurement of the signal to noise ratio, but unfortunately had the Seta configured for single ended rather than balanced mode, resulting in diminished performance in the noise measurement!

Seta - Balanced Direct Coupled Ultra Wide Bandwidth Phono Preamplifiers
Seta - Balanced Direct Coupled Ultra Wide Bandwidth Phono Preamplifiers
Seta - Balanced Direct Coupled Ultra Wide Bandwidth Phono Preamplifiers

Seta Plus (available in natural anodized aluminum, or gorgeous red powder coat finish, as shown). Includes heavy, milled aluminum chassis and lower impedance battery power supply.

Inside the Seta L


Seta - Balanced Direct Coupled Ultra Wide Bandwidth Phono Preamplifiers
Seta - Balanced Direct Coupled Ultra Wide Bandwidth Phono Preamplifiers
    1. Left and Right channel differential amplifier input stage circuitry.
    2. Left and right channel differential balanced output buffers.
    (1) and (2) are encapsulated inside the milled solid copper block, and are the heart of the Seta L.

    (1) and (2) comprise the painstakingly designed, critical amplification circuits of the Seta L preamplifier, where all of the magic happens. They are simple in principle, and contain the minimum needed amount of circuitry for the task. The outputs of (2) directly drive the Flat balanced outputs.

    All of the following circuitry is needed for making a product that functions as well in your listening room as it does in our controlled testing environment:

    3. Specially selected small-signal relays featuring ultra-low coil dissipation. Signal contacts are made from a special gold-palladium alloy. Used for gain switching (tied to signal block 2); mounted on underside of circuit board.
    4. Input overvoltage and electrostatic discharge protection.
    5. Potentiometer for TRIM cartridge balance function, tied to signal block 1.
    6. Jumpers for selecting transimpedance or voltage mode.
    7. Input regulation and multi-stage filtering for battery charging supply.
    8. Galvanic isolation.
    9. Battery conditioning and charging circuitry.
    10. Input signal level detector, for activating the galvanic isolation (and disconnecting the charging supply) when a signal is present.
    11. Precision, fully balanced RIAA EQ filter.
    12. DC servos.
    13. 10 Hz high pass filter.
    14. Low impedance buffers / output driver for RIAA outputs.
    15. Differential to single ended summing amplifier, for generating the Unbalanced outputs.
    16. Logic circuitry for gain switching and charging lock. LED signal present / signal gain / battery condition / power indicators.

    The total signal gain from input to output is selectable from the front panel: +55, +58, +61 or +65 dB. Gain in transimpedance mode with low impedance MC cartridges is generally substantially greater than this.

    17. RIAA balanced / unbalanced output bridge board.

Circuit Design

The Seta front end circuitry is tailored to preserve the strengths of the characteristics of different cartridge types. A low noise, high impedance FET front-end is used in the Seta Model H for moving-magnet and other high output cartridges (a special-order product), while an ultra-fast, ultra low noise bipolar transistor front end is used in the Seta Model L for low impedance, low output moving coil cartridges.

The circuit topology is fully differential, balanced direct-coupled circuitry from input to output. The front-end active circuitry is surrounded on five sides by a sub-enclosure machined from a solid block of copper. This provides electronic and acoustical noise isolation plus thermal stabilization. Bare copper metal surfaces are coated with a clear lacquer to prevent oxidation (and to maintain their beautiful color).

Unlike many other preamplifier designs: the rated (-3 dB) bandwidth is independent of gain.

The Seta Piccola phono stage uses carefully selected, ultra low distortion, low noise ICs also in a fully balanced configuration with a bandwidth of 1 MHz (-3 dB).

All Seta products use 0.1 percent tolerance precision low noise metal film resistors in all critical areas.

Rechargeable Battery Power Supply

The low-impedance, internally located AGM rechargeable battery is capable of supplying 50 amperes of current, outperforming other types of batteries used in audio applications. The battery is conditioned and kept float-charged by a proprietary, uniquely designed rail balancing circuit, rather than use an "off the shelf" microprocessor based conditioning and monitoring circuit, which would introduce unwanted noise. Locating the battery inside the preamplifier chassis also insures that the battery is in the same electrical environment as the sensitive front-end circuitry, eliminating potential sources of noise pickup. The external charging supply is automatically disconnected when an input signal is detected.

Mechanical

All connectors are the best available, professional quality Neutrik gold contact XLR and WBT gold contact helical conductor wide bandwidth RCA (Model L / H). Pushbutton actuated, sealed gold contact small signal relays are used to change gain settings (four different gain settings, Seta Model L / H). A unique rear-panel rotary balance trim control with a precision 2 dB range provides for fine cartridge channel balancing (the trim setting is not affected by the overall gain).

Interior Close-up View of Seta (a prototype unit from 2008), showing Solid Copper Front-End Circuitry Isolation Block   New Seta Model L / Model H Preamplifier Modules
Interior close-up view of Seta prototype (from ca. 2008) solid copper front-end circuitry isolation block (left photo);
New preamplifier modules (right photo)

Measurements

Of course, the "last word" in the evaluation of audio products should be done by using the best "measurement:" real-world, listening-based evaluation. However, we believe that careful measurements also are essential, if only to insure that the product you receive actually conforms to the designer's original vision and intent.

Click for technical measurements and specifications comparison of our phono preamps.

Seta preamplifiers incorporate many unique or unusual design features contributing to their high performance

  • Ultra low impedance AGM rechargeable batteries used as charge storage reservoir and power supply filter; proprietary, exclusive charging and maintenance circuitry specially designed by Channel D and proven, refined and used exclusively in our phono stage designs for over 5 years
  • State of the art, premium quality low - ESR polymer dielectric electrolytic and tantalum filter capacitors
  • Ultra precision (0.1% tolerance) metal film low noise 1206 / MELF surface mount resistors used throughout
  • Ultra low distortion, low impedance differential output stage with greater than 40 MHz signal bandwidth
  • RIAA Compensation Network with precision, hand matched components
  • True single ended outputs obtained by differential summing and balanced signal input for lowest possible noise (high common mode rejection) on single ended connections
  • All Channel D Seta preamplifier products feature a signal bandwidth of DC to 1 MHz (-3 dB) or greater

Seta Ultra Wide Bandwidth Direct Coupled Balanced Preamplifier Product Line

Seta Model L
For Low Output Moving Coil Cartridges
(DC to 5 MHz bandwidth, < 0.0001% THD 10 Hz - 40 kHz)
Buy		 Seta Model H
For Moving Magnet Cartridges
(DC to 1 MHz bandwidth, < 0.0007% THD 10 Hz - 40 kHz)
Buy		 Seta Piccola mk2
For Moving Magnet and Moving Coil Cartridges
(DC to 1 MHz bandwidth, < 0.0003% THD 20 Hz - 20 kHz)
Buy
  • Delivers stunning improvements in sound staging, detail and 3-D imaging
  • Fully Balanced, Complementary Design from Input to Output; can be used with balanced or single ended turntables and other equipment
  • Pure Linear, Straight-Wire Signal Gain, designed to be used in conjunction with Pure Vinyl software and A/D Interface (for RIAA curve correction)
  • Software RIAA Correction eliminates the need for capacitors in the signal path
  • Circuitry Optimized For Cartridge Type (Bipolar for Seta Model L/MC; FET for Seta Model H/MM; Piccola uses high speed low noise monolithic circuitry)
  • Gain Settings (Seta Model L/H) are accessible from front panel
  • Load Settings (Seta Model L) accessible from rear panel
  • Solid copper shielding and temperature stabilization block (Seta Model L/H; Buffer)
  • Premium, precision components in signal path (0.1 % metal film resistors; metallized polypropylene film cartridge loading capacitors)
  • Rechargeable battery powered (low impedance AGM type, with output current capability of 50 amperes)
  • Designed and Assembled in U.S.A.

Seta Model L and Seta Model H (including Plus model)

Model L - Fully Balanced, Ultra Wide Bandwidth 5 MHz "Flat" Phono Preamplifier for Low Output / Low Impedance Moving Coil Cartridges; Low Impedance, Low Current-Noise Hybrid Bipolar Input; High Performance, Low Noise Internal AGM Battery Power Supply.
Model H - Fully Balanced, Ultra Wide Bandwidth 1 MHz "Flat" Phono Preamplifier for High Output / High Impedance Cartridges; High Impedance, Low Voltage-Noise Hybrid FET Input; High Performance, Low Noise Internal AGM Battery Power Supply

Seta Model L, Seta Model H
Seta Model H / L front; Model L rear view.

Specifications
Gain 55, 58, 61, 65 dB (Model L); 35, 38, 41, 44 dB (Model H)
Frequency Response (-3 dB) DC to over 5 MHz (Model L); DC to over 1 MHz (Model H); any gain setting
Seta Model H
Input Load Capacitance		 Min. capacitance 10 pF balanced, 20 pF single-ended; factory configured for 160/170 pF; includes plug-in components for an additional 47, 100, 150 or 220 pF; Seta L/MC capacitance 12 pF
Seta Model H/MM
Max. Input Resistance		 89 k ohms; factory configured at 47 k ohms; custom plug-in resistors also can be installed
Seta Model L
Max. Input Resistance		 2 k ohms; rear panel rotary switches for selecting 25/50/100/150/200/500/1k ohms; custom value plug-in resistors also can be installed internally
Distortion < 0.001% (Model L/MC), < 0.007% (Model H/MM). 10 Hz to 40 kHz, with 600 Ohm or greater load
Inputs Neutrik Gold Pin XLR Balanced; RCA (Balanced; functions as single-ended to balanced adaptor)
Outputs Neutrik Gold Pin XLR Balanced
Output Impedance less than 40 ohms
RIAA Compensation Curve (with Hardware RIAA Correction Module) Accuracy ± 0.1 dB; *RIAA module option includes balanced XLR and unbalanced RCA output connectors

Dimensions
Power Consumption less than 5 watts idle / float (Model L / H AGM Battery); less than 15 watts (AGM recharging)
Weight 6.5 pounds
Size 12" x 2" x 7" (W x H x D)

Seta Piccola Mk2

Fully Balanced, Ultra Wide Bandwidth 1 MHz "Flat" Phono Preamplifier for Moving Magnet and Low Output Moving Coil Cartridges; High Performance, Low Noise Internal AGM Battery Power Supply. Unbalanced RIAA Outputs on RCA Connectors.



Seta Piccola Mk2

Specifications
Gain 55, 58, 61, 64, 67, 70 dB (MC); 35, 38, 41, 44 dB (MM)
Frequency Response (-3 dB) DC to over 1 MHz; any gain setting
Input Load Capacitance Min. capacitance 15 pF; jumper selectable 165 pF installed
Maximum Input Resistance 47000 ohms MM, 2000 ohms MC; internal switches for other values (60, 70, 100, 140, 200 and 500 ohms) plus sockets for user installable resistors
Distortion < 0.001%, 20 Hz to 20 kHz, with 600 Ohm or greater load
Inputs Neutrik Gold Pin XLR Balanced (Single-ended to balanced adapters included)
Outputs Neutrik Gold Pin XLR Balanced (Flat signal)
Output Impedance less than 40 ohms
RIAA Accuracy ± 0.07 dB

Dimensions
Power Consumption Less than 3 watts idle / float; less than 5 watts operating
Weight 4.5 pounds
Size 5" x 3.7" x 5.5" (W x H x D)


(Above) Seta Piccola Mk2 rear panel, RIAA outputs on unbalanced RCA connectors; Flat outputs on XLR connectors

Buy

Reviews

"It's an understatement to say that I was impressed by the Seta Model L [...] It measured more like a piece of laboratory equipment than a typical high-end component, and sounded superb to boot." - John Atkinson, Stereophile December 2013 Click Here to Download a Copy of the Review

"...if my "legendary" Vendetta phono preamp ever gives up the ghost I could be very content using the Seta as its replacement." - Steven Stone, The Absolute Sound - December 2013 Click Here to Download a Copy of the Review

"CLASS A" RECOMMENDED COMPONENT (Editors' Top Picks - Phono Preamplifiers, Seta Model L) Stereophile - October 2010 (Class A Recommended Component as of the latest Recommended Components issue, April 2017)

EDITORS' CHOICE AWARDS (Seta Model L) The Absolute Sound - 2015 - 2017

"[The Seta Model L] is a quiet, remarkably neutral-sounding, extremely well-built phono preamplifier... [the Seta with Pure Vinyl's digital RIAA] was fundamentally accurate in terms of tonality and space, and its low- level resolution was remarkable."
Michael Fremer, Stereophile, August 2010 Full review

"A very linear circuit? [no intermodulation products in] the spectrum of the [Seta Model L's] flat output... no distortion harmonics can be seen above the noise floor, even when the load impedance is reduced to a punishing 600 ohms!"
John Atkinson, Stereophile, August 2010 Measurements