Sutherland Phono Loco phono preamplifier
This newest phono preamp from Sutherland is not for everyone. There are several unusual engineering decisions that many will be uncomfortable with.
However, those that can get past the obstacles will be rewarded with
a life-like, emotionally involving experience. Insight gained from the design of preceding phono preamps has opened up a new possibility.
The Sutherland Phono Loco is loco for users, dealers, reviewers, distributors, and Sutherland Engineering.
More importantly, the Phono Loco took full advantage of its off-the-chain design freedom. It delivers an exquisitely beautiful performance.
The initial prototype listening was so emotionally rich. It kicked in a stubborn determination to perfect the full performance possibilities. That’s when the project truly went loco. With performance as the arbiter of each design decision, the PHONO LOCO was steadfastly focused on delivering a seductive listening experience.
The PHONO LOCO was never designed or built to be a commodity. It has taken on a life and personality of it’s own.
—Some Loco Facts—
Marketing wise the Sutherland Phono Loco is a disaster.
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There was a complete disregard for market acceptability. All design decisions were based on optimal engineering. It was all about performance. Marketing was thrown under the bus.
Phono Loco is totally focused as a specialized transimpedance unit.
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There is no concession to flexibility and options. With that clutter removed, the circuit can be refined and optimized to ONE goal. The Phono Loco does not hedge it’s bets. It is ALL on transimpedance.
Do not waste your money on expensive RCA to XLR adapters.
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Get the correctly balanced XLR cable from a good cable manufacturer. If you are not willing to get a balanced cable for the input connections, you should buy a more conventional phono preamp.
The Phono Loco demands a balanced input signal.
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The circuit requires both connections from the cartridge coil to float with respect to ground. There was no bending around, or patching, or compromising to make it accept a single-ended signal.
—Loco FAQs—
Q: What Does Transimpedance Mean?
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A transimpedance amplifier input looks like a virtual short to the input signal. The input voltage is therefore zero. The input signal is the current going in/out of that virtual short. The input current is multiplied by the gain (in Ohms) to give an output voltage corresponding to the input current.
Q What Are The Phono Preamp’s Loading Options?
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There are no loading options or concerns. A current input stage (transimpedance) input is a virtual short. That topology obviates the need for load resistor selection. The current going into that short is then amplified.
Q: Will It Work With […] Cartridge?
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The Phono Loco works very well with most MC cartridges. But there is not yet a body of info available. Talk to us about which cartridge you want to use, and we will advise you!
Q: Can I Use an MM Cartridge?
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You are welcome to try, but it is unlikely to work very well!
Q: What is the Gain?
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Conventional voltage amplifiers express gain in dB (as the ratio between the input voltage and the output voltage). With a transimpedance amplifier, input is current and the output is voltage. For that topology, gain is expressed in Ohms. Gain is approximately 10k Ohms at 1 kHz.
Most MC cartridges will work well at the medium gain setting. There is also a low (voltage down 6dB) setting and a high (voltage up 6dB) setting.
Q: Will It Work With […] Cables?
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Most audio signal cables are designed to transfer voltage changes. The Phono Loco input voltage is zero and doesn’t change. What does change is current. That is generally a favorable condition for cable performance
Q: Since there is a unique interaction between the cartridge, phono cables, and Phono Loco, how do I avoid expensive experiments?—
At Command AV, we have the experience to help build a superb analog playback front end for you. We have explored various combinations. You won’t spend your money until you personally experience the right combination for you.
Sutherland Phono Loco SPECIFICATIONS
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GAIN SETTINGS:
PHONO LOCO is factory–set to medium gain. That should work very well in most situations. The usual concerns about cartridge output voltage do not apply here. Cartridges of varied output voltage specs tend to supply about the same level of drive current into a short. (Higher output voltages usually have higher resistance while lower output voltages usually have lower resistance.) Into a virtual short, most deliver about the same current signal.
If your particular situation would benefit from a gain adjustment, you can change it. Inside, on the red circuit boards, you will see a place for gain setting resistors.
The PHONO LOCO ships with 3k resistors installed for medium gain. You can boost the output voltage 6dB by removing those resistors. Or, you can reduce the output voltage 6dB by replacing the 3k resistors with 1k counterparts.
LOAD SETTINGS:
There are no loading adjustments in the PHONO LOCO. Your cartridge will see a load of zero Ohms. The input signal will be the current your cartridge produces into that virtual short. No need to worry about or fuss around with loading.
SIZE:
- 17” wide
- 17” deep
- 3 1/4″ high
WEIGHT
- 21 lbs.
WARRANTY
5 years parts and labor. Transferable. Only valid for units that have not been modified or abused.