Learn about the basic technology behind vacuum tube amplification and how this time-tested technology can offer what we call "audio magic."
Vacuum Tube Technology Overview
The basic purpose of audio amplification is to increase the current and voltage of an audio input signal and send the expanded signal to the speakers. There are four basic types of audio amplifiers:
- Solid state: Utilizing mosfett, op amps, or J-FETs in the power output stage.
- Digital: Also refer to as power modulation or Class D amplifier.
- Hybrid: Utilizes vacuum tubes for the preamplifier and solid state for the power output.
- Vacuum tube: Utilizes vacuum tubes in the power output state.
Each technology type has operational and performance strengths and weaknesses. Suffice it to say, each technology type has its own individualized performance parameters that are unique to its operational aspects. We would also suggest that in the area of audio reproduction, vacuum tube technology represents a unique sound which is holographic, lush without being mushy, clear and transparent without being strident, and dynamic without being fatiguing. One of the typical benefits of tube technology is that a high level of audio performance can be achieved at a cost effective price point.
In vacuum tube technology, there are two basic tube amplifier designs. One design is the Single end triode (also referred to as Class A or SET) in which one vacuum tube is used per channel to amplify the audio signal. Within the tube, a small signal is placed on the grid which causes a large fluctuation of voltage. Thus, the small amount of signal controls the larger power so that the signal is replicated at a larger level of energy. Another design is the push pull amplifier (Class AB). Rather than using one tube, the push pull amplifier uses more than one tube per channel. One tube will amplify the positive portion of the signal and the other tube will amplify the negative portion. The push pull design provides greater wattage than the single ended amplifier. This is a very simplified rendition of how a tube amplifier works. For the detailed technical operations of audio amplifiers, we recommend engineering web sites.
In the past ten years, there have been four major technical developments that encourage the use of performance vacuum tube audio equipment. These developments are:
- Improvement in source components: Presently the consumer has a wide choice of sources ranging from a myriad of digital formats, to vinyl and tape. There are many opinions regarding the superior source however, one factor is apparent, quality source material is readily available.
- Improvement of audio recording: The techniques and equipment available for recording media material is at a very high level of quality.
- Improvement of cable components. The components of any musical system are attached with cable that allows the audio signal to pass from one component to another. In the past, cheap-high-resistance cable was used, and even with good components the sound was limited.
- Dramatic improvement in speaker technology. The advent of computer assisted design and advanced materials has resulted in significant sound quality at reasonable prices.
In conjunction with these improvements, it is possible to assemble an audio system with a vacuum tube amplifier at a reasonable price. The result is what some people refer to as “audio magic”. We encourage any person looking for a new audio or audio/video system to spend time listening to different technologies to find the equipment that is right for them. The reward is listening pleasure for years to come.
There was a time when digit referred to the fingers on one’s hand. Now the “0s” and “1s” of digital machine language has blossomed into processes of useful tools in communication, medicine, research, work place, manufacturing. Digitalization has relined how we live, work and play. In turn, digital’s impact on audio has been significant. Ranging from Ipods to computers to Smart phones provide different formats and different forms of music, games, voice and video. There is a great deal of sound and fury regarding digital as a bona fide hi end source of sound. No matter the discussions, digital has brought good sound, convenience, affordability and availability to the average person. We get it. We also think that the future for digital in hi-end audio will be significant as recording and reproduction techniques and equipment improve over the years.
At Jolida, we have focused a design effort on producing digital products that will be useful to our clients. Our objectives in this effort are:
1. Cost: One of the issues with a developing technology is obsolescence. In order to soften this factor, it was our intention to produce hi value but affordable units since they will eventually be replaced with updated units by our clients over time. Please note that we think the obsolescence is somewhat neutralized with the aspect of quality sound found even in our older models. We have been producing DACs for four years and we have moved from the DAC I to DAC II to DAC III to the DAC III W.
2. Hi End sound at a value price: Jolida uses quality chips and design to achieve these goals. First we use vacuum tubes as amplification and we do not have solid state in the signal path. This enhances the analog nature of the sound and provides a very smooth and rich presentation. In all our DAC units, we have galvanic isolation in the signal path which reduces the ground clutter that comes from digital sources.
3. Functionality: We have DACs that can be used in conjunction with computers, smart phones whether hard wired or Bluetooth wireless. With the Fusion DAC Pre, the unit not only has an active tube preamplifier, it has a full DAC with wireless function as well. Our Fusion DAC transport has a full DAC and CD transport as well as a true balanced circuit.
4. Tweaking the Sound: One of the interesting features of our DAC is that the sound can be altered just by changing the vacuum tubes that are in the unit. We think the change is due to the quality of our circuits. Of course the addition of other parts can have an effect as well but they tend to be more permanent.