YAQIN SD-CD3 Audio Upgrade Processor Review

The Yaqin SD-CD3 is a two tube buffer processor that enables you to combine and affix the tube sound to the signal where it can go along with either before or after the receiver or solid-state amplifier. It also allows tube rolling.


YAQIN SD-CD3 is a notable and reputable tube based audio equipment manufacturer from China. The company has been operating for more than 10 years in search for the perfect tube amplifier. Its SD-CD3 might come with a stiff price because tube amplifiers cost more than the transistorized ones. However, it has features which make it a better amplifier than the other one to deliver the perfect sound presentation. The sound quality the processor produced is greatly affected by the incredible features it has.

Features of the YAQIN SD-CD3

  • It comes with 6N8P cathode followers replaceable by 6SN7.
  • The copper wire comes with a superb deoxygenated enamel coating.
  • It uses excellent metal precision resistors and audiophile grade capacitors.
  • The power transformer is covered with silicon steel sheets.
  • It has an excellent aluminum and steel base frame and a logoed window panel.
  • Input and output interface utilize gold RCA jacks.
  • It has replaceable tubes.


  • Adding the sound quality the tube amp produces to digital audios makes the speaker sound seamlessly warmer.
  • There’s no need for bias adjustments.
  • It can be installed between a receiver or an amplifier, and an audio source.
  • Tube rolling allows you to find the right sound signature you seek.
  • It is compatible with different configurations.
  • It is well-built for a reasonable price point.
  • The gold plating for RCA jacks prevents corrosion to improve signal and non linearity.
  • A compatible audio source includes electric guitar, iPod, CD/DVD players, computer audio output, MP3 players.


  • It has no power supply drain resistor which supposedly drains the electric charge residual in the filter capacitor to avoid the possibility of getting injured from an electric shock.
  • Poor wire management might cause a terrible sound quality.
  • Upgrades can be quite costly.


Nothing is more relaxing than enjoying the leisure of listening to one’s favorite music. People strive for perfection. The sound system has evolved for many years to the point that tube buffer processors came to existence. It has contributed a lot when it comes to enhancing the quality of the sound produced by audio output devices. YAQIN SD-CD3 Audio Upgrade Processor is a two tube buffer processor that is inserted between a receiver or an amplifier, and an audio source to be able to bring the sound produced by the tubes to the signal and have it blended so that it can be used to collaborate with the solid-state amplifier or receiver.

SD-CD3 comes with quality parts and well-designed framework that gives it a sophisticated elegant look. It may prove expensive for upgrading the tubes to find the favorable sound quality but it is all worth it considering the warm and smooth sound quality it offers. However, SD-CD3 might have great qualities but some features are far from being perfect. The lack of a power supply drain resistor leaves users susceptible to a possible electric shock that SD-CD3 might cause.

Possible Alternatives to the YAQIN SD-CD3

With the tube rolling feature, tubes can be replaced with different alternatives. Using some 1955 VT231’s, the sound shifts from an ‘okay’ to a ‘wow’. It makes the liquidity of the sonic definition to sound amazingly warm considering the depth and the sound stage.

If you find the price quite expensive, you could always try a cheaper version that offers a satisfactory sound quality such as the P5-1 version 1.2, Little Bear’s tube preamp buffer. However, the stock tube just like that of the SD-CD3 may not offer the optimum sound performance you desire and might require you to spend for an upgrade; it does not support phono preamp and is used purposely for modifying, adding and coloring the sound.

If a tube buffer processor does not suit your liking, you could always resort to its top competitor which is a solid-state amplifier. It uses electronics: diodes and transistors, to amplify the signal which in return improves the sound quality of an audio source. It is not just only small, lightweight and portable but also comes at an affordable price. Unlike tube amps that require bias adjustment, and sockets and parts cleaning, it only requires less maintenance.


SD-CD3 works great as a tube buffer processor. It improves the depth and the sound stage which makes individual track components to be easily located and distinguished. Edgy instruments such as guitars, drums, and others, and the vocals are clearly presented and focused on in the sound space without having to appear distinct from each other. Any source’s quality can be improved further to its highest sound.

If you like to bring an ‘edge’ to digitally off your equipment’s sound performance while keeping its clarity and sonic definition, SD-CD3 is the perfect tube buffer processor to bring you to a breathtaking sound presentation. YAQIN did a great job by having its design to allow tube-rolling options, switching tubes to achieve the exact favorable and desirable sound quality. It doesn’t only bring you the joy of listening to your favorite music but is certainly nice looking with its sturdy, polished and well-designed structure accounting for its quality parts. The chassis looks great having to rival similar products with prices doubling or more than the right investment you’ll get with this terrific tube buffer processor. The SD-CD3 would make a great addition to your sound system.

1 thought on “YAQIN SD-CD3 Audio Upgrade Processor Review”

  1. Can this device be used in a preamp’s tape loop so it can be easily switched in and out of the signal path for all signal sources or can you connect a source unit (CD player, tuner, etc.) only to the buffer?

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