Monday, August 30, 2010

Why Vacuum Tubes?

This is the Famous Telefunken ECC803S Vacuum Tubes

There are a lot of people open his eye big to look at me and had a strange question why I use Vacuum tubes on my Amplifier, my reply is Simply warm and real music reproduction by using Tubes. Not Transistor, MOSFET, or IC...could come and dare to make some similar good music as the tubes do!!

There are still certain area that Transistor is not working satisfactorily. These are

A. High-power RF applications
Many big radio stations continue to use big power tubes, especially for power levels above 10,000 watts and for frequencies above 50 MHz. High-power UHF TV stations and large FM broadcast stations are almost exclusively powered by tubes. The reason is cost and efficiency--only at low frequencies are transistors more efficient and less expensive than tubes. Making a big solid-state transmitter requires wiring hundreds or thousands of power transistors in parallel in groups of 4 or 5 at a time, then mixing their power outputs together in a cascade of combiner transformers. Plus, they require large heat-sinks to keep them cool. An equivalent tube transmitter can use only one tube, requires no combiner (which wastes some power), and can be cooled with forced air or water, thus making it smaller than the solid-state transmitter.
This equation becomes even more pronounced at microwave frequencies. Nearly all commercial communication satellites use a traveling-wave tube for their "downlink" power amplifiers. The "uplink" ground stations also use TWTs. And for high power outputs, the tube seems to reign unchallenged. Exotic transistors still are used only for small-signal amplification and for power outputs of less than 40 watts, even after considerable advances in the technology. The low cost of RF power generated by tubes has kept them economically viable, in the face of advancing science.
B. Guitar amps
In general, only very low-cost guitar amplifiers (and a few specialized professional models) are predominantly solid-state. We have estimated that at least 80% of the market for high-ticket guitar amps insists on all-tube or hybrid models. Especially popular with serious professional musicians are modern versions of classic Fender, Marshall and Vox models from the 1950s and 1960s. This business is thought to represent at least $100 million worldwide as of 1997.
Why tube amplifiers? It's the tone that musicians want. The amplifier and speaker become part of the musical instrument. The peculiar distortion and speaker-damping characteristics of a beam-tetrode or pentode amp, with an output transformer to match the speaker load, is unique and difficult to simulate with solid-state devices, unless very complex topologies or a digital signal processor are used. These methods apparently have not been successful; professional guitarists keep returning to tube amplifiers.
Even the wildest rock musicians seem to be very conservative about the actual equipment they use to make their music. And their preferences keep specifying the proven technology of vacuum tubes.
C. Professional audio
The recording studio is somewhat influenced by the prevalence of tube guitar amps in the hands of musicians. Also, classic condenser microphones, microphone preamplifiers, limiters, equalizers and other devices have become valuable collectibles, as various recording engineers discover the value of tube equipment in obtaining special sound effects. The result has been huge growth in the sales and advertising of tube- equipped audio processors for recording use. Although still a minor movement within the multi-billion-dollar recording industry, tubed recording-studio equipment probably enjoys double-digit sales growth today.


D. High-end audio
At its low point in the early 1970s, the sales of tube hi-fi equipment were barely detectable against the bulk of the consumer-electronics boom. Yet even in spite of the closure of American and European tube factories thereafter, since 1985 the sales of "high-end" audio components have boomed. And right along with them have boomed the sales of vacuum-tube audio equipment for home use. The use of tubes in this regime has been very controversial in engineering circles, yet the demand for tube hi-fi equipment continues to grow.
It is funny that some of the major Transistoried power amplifier with output of more than 300W a channel has to go for connecting 24 unit of Power transistor in parallel at output stage, can I ask how to enure each of the 24 transistor is identitical in the electrical and frequency response characteristers!? No way then how to ensure their performance is aligned!? How to ensure their current drift with different change in A/V due to Temperature curve are not identical.
Quall used a Computer to calculate, compute the Right Amount of biasing point for each of the transsitor, can thei computer cancel the difference of each if the current vs Bias response!? No way, how to ensure the sound of music can be compared with Single 100W power vacuum tubes that has a stable biasing point just by itself!?

Remarks,
The above infrmation is partly obtained from the website, for more understanding on how does the tube work, you can visit this website!
http://www.vacuumtubes.net/How_Vacuum_Tubes_Work.htm


Feverip

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