Vinyl enthusiasts know that the quality of their turntable setup can make or break their listening experience.
One crucial component of that setup is the phono stage, which amplifies the low-level signal from the cartridge to a line-level signal that can be sent to a preamp or receiver.
But not all phono stages are created equal.
One type of phono stage that has gained popularity in recent years is the current mode phono stage.
In this article, we’ll explore what makes a current mode phono stage different from other types of phono stages, and why it might be worth considering for your own setup.
So sit back, grab your favorite vinyl record, and let’s dive in!
What Is A Current Mode Phono Stage
A current mode phono stage is a type of phono stage that uses a unique method of amplification to boost the low-level signal from a turntable cartridge.
In a traditional voltage mode phono stage, the output voltage of the cartridge causes the preamp’s input device to generate a current proportional to this voltage. This current is then converted into another, higher voltage.
However, in a current mode phono stage, the input device presents the cartridge with a very low impedance, almost like a short circuit. The cartridge generator then dumps a current into this impedance, and this same current is further converted to a higher voltage in the circuit.
This method of amplification has several benefits. First, it provides more damping, which can help smooth out any peaky MC cartridges. Second, it can provide a more accurate representation of the original recording, as it minimizes any noise or distortion that may be introduced in the amplification process.
What Is A Phono Stage?
A phono stage, also known as a phono preamp, is an essential component in any vinyl playback system. Its primary function is to amplify the low-level signal produced by a turntable cartridge to a level that can be processed by a standard line-level input on an amplifier or receiver.
A typical voltage-mode phono stage amplifies the voltage output of the cartridge with less concern paid to the amount of current the cartridge delivers. However, a current-mode phono stage uses a unique method of amplification that presents the cartridge with a very low impedance, allowing for more accurate and efficient amplification of the current signal.
The Importance Of A High-quality Phono Stage
A high-quality phono stage is essential for any serious vinyl enthusiast. While it may be the smallest and most affordable component in a stereo system, it plays a crucial role in delivering the best possible sound quality from your vinyl records.
The Well Tempered Labs Phono Stage, for example, sets new standards in both value and performance. Its unique implementation of RIAA processing provides a new and better interpretation of vinyl record replay, making analogue both relevant and viable for any enthusiastic music listener. With an extremely broad range of easy to adjust settings, it is compatible and indeed optimal with virtually any phono cartridge and amplifier on the market today.
Similarly, the Chord Electronics Huei is a top pick for its simple and effective design matched with excellent audio quality and handy features. Its overall sound quality is wide, ballsy, clear, and arguably better than just about any other preamp on the market. A high-quality phono stage like this can make a significant difference in the overall sound of your system.
It’s important to note that while a phono stage is vital, it is not the most critical component in terms of overall sound quality. Both your speakers and turntable will have a greater impact on sound quality, so allocate a larger portion of your budget to these items to get higher-quality sound.
When choosing a phono stage, consider the type of cartridge you have. Moving magnet cartridges have high output voltage, typically in the range of 4-8 millivolts. For high-output cartridges like these, set your preamp’s gain on the low side. A setting of 40 dB is a good place to start. You might try a slightly higher setting, but the higher you go, the more noise you’ll hear.
On the other hand, low output moving coil cartridges typically have output voltage below 2.5 mV. These require higher gain settings (60 dB or higher) to amplify the signal effectively. A high-quality phono stage like a current mode phono stage can handle both types of cartridges effectively.
Understanding Current Mode Phono Stages
To better understand current mode phono stages, it’s important to first understand the basic principles of phono stages. A phono stage, also known as a phono preamp, is an electronic device that amplifies the low-level signal from a turntable cartridge to a line-level signal that can be played back through speakers or headphones.
In a traditional voltage mode phono stage, the input device generates a current proportional to the output voltage of the cartridge. This current is then converted into a higher voltage using amplification circuits. However, this method can introduce noise and distortion into the signal.
A current mode phono stage takes a different approach. Instead of generating a voltage, it presents the cartridge with a very low impedance, almost like a short circuit. This causes the cartridge generator to dump a current into this impedance, which is then converted into a higher voltage in the circuit.
This method of amplification has several advantages over traditional voltage mode phono stages. First, it provides more damping, which can help smooth out any peaky MC cartridges. Second, it can provide a more accurate representation of the original recording, as it minimizes any noise or distortion that may be introduced in the amplification process.
How Current Mode Phono Stages Differ From Other Types
Compared to other types of phono stages, current mode phono stages have a unique advantage in their ability to provide better accuracy and lower distortion. This is due to their use of current instead of voltage as the primary amplification method.
Voltage mode phono stages, for example, rely on voltage amplification to boost the signal from the cartridge. However, this can introduce more noise and distortion into the signal, particularly at low levels. Current mode phono stages, on the other hand, can provide a cleaner signal with less distortion.
Another difference is in the impedance matching. In voltage mode phono stages, the impedance is matched to the cartridge’s output voltage. In current mode phono stages, the impedance is matched to the cartridge’s output current. This can result in a better match between the preamp and cartridge, leading to improved sound quality.
Benefits Of Using A Current Mode Phono Stage
Using a current mode phono stage has several benefits that make it an attractive option for audiophiles.
Firstly, a properly designed current-mode phonostage can provide a near-zero-ohm input load, which the cartridge sees as a near-short-circuit. As such, the voltage output of the cartridge becomes less important than the cartridge’s internal impedance and the amount of current it is supplying to the phonostage. This can result in a more accurate and faithful reproduction of the original recording.
Secondly, using a current mode input provides a superior signal-to-noise ratio compared to a conventional voltage input. This is because the current from the cartridge is amplified by a discrete transistor-based trans-impedance amplifier. This method of amplification minimizes any noise or distortion that may be introduced in the amplification process.
Thirdly, using a current mode input eliminates the need to match impedance, which can be a time-consuming and frustrating process. Multiple gain settings are available on each input to accommodate the variation of resistance among cartridges.
Lastly, using a current mode phono stage can provide more damping, which can help smooth out any peaky MC cartridges. This can result in a more dynamic and engaging listening experience.
Considerations When Choosing A Phono Stage For Your Setup
When it comes to choosing a phono stage for your setup, there are a few key considerations to keep in mind. Here are some factors to consider:
1. Cartridge compatibility: Make sure that the phono stage you choose is compatible with your turntable cartridge. Some phono stages are designed specifically for moving magnet (MM) cartridges, while others are designed for moving coil (MC) cartridges. Be sure to choose a phono stage that matches your cartridge type.
2. Sound quality: The quality of your phono stage can have a significant impact on the overall sound quality of your system. While cheaper phono stages can get the job done, investing in a higher-quality phono stage can result in a more detailed and dynamic sound.
3. Space and setup: Consider the size and placement of your phono stage in relation to the rest of your setup. Some phono stages are compact and can be easily tucked away, while others may require more space and careful placement for optimal performance.
4. Budget: Phono stages can range in price from under $50 to over $500. Determine your budget before making a purchase, and consider how much you’re willing to invest in improving your system’s sound quality.
By taking these factors into account, you can choose the right phono stage for your setup and enjoy high-quality vinyl playback for years to come.
