|
|
|
|
|
|
|
|
Examples of Home Built HI Fi
Tube Amplifiers
Building a tube amplifier does requires some skills with hand tools and at least some basic understanding of electronics. The high voltages necessary for tubes can be lethal, so if you are uncomfortable with electricity, let a electronics buff build one for you, or buy one of the ready made new amplifiers on the market. If you don't want to design your own circuits, schematics are available from many sources . Just do a search on the WEB under tube amplifiers, or tube amplifier schematics.
Recipe for a Tube Amplifier:
Take one Wilton cake pan with straight sides like the one shown below. Select a size that will handle your amp components. They come in sizes up to 12 inches per side and two or three inches deep. The following amplifier project was designed to be used with a computer or CD player and uses two single ended 6L6 tubes on the same chassis with 12AU7 preamplifiers. The amp uses an "Ultra Linear" output stage with negative feedback to the input stage cathode. It develops about 7 watts of high quality audio per channel, more than enough for the background listening it is used for. If you want a schematic of this amplifier email me at the address at the bottom of the home page.
Wilton cake pan 8X8X2 inches.
The components, transformers, tube sockets and other items are laid out for spacing and their positions drawn on the pan bottom with a pencil.
The cake pan chassis is punched, drilled and filed to fit the components.
This is the completed amplifier. The chassis was painted , the components mounted and wired. A single volume knob control both channels. The amp is used to provide computer audio to a pair of good speakers the construction of which will be covered in a future "Speaker Building " page on this site.
Below is one more example of a home built power amplifier. This one was also built on a Wilton Cake pan and uses 5881 tubes to develop 40 watts of audio per channel. It also helps to warm the den in winter.
80 Watt power amplifier on a large Wilton Cake Pan Chassis
The below Amplifier is a unique design based on an article in the very first issue of Popular Electronics, October of 1954. It uses a single dual triode 6BX7 operating in push-pull in each channel. The 6BX7 was a vertical sweep amplifier used in the Black & White TV days of the 1950s.The original design of the output stage circuit was modified and is now driven by a 12AX7 amp/phase splitter with 15 db of feedback, it produces eight clean watts per channel. The output transformers are from a long dead Sherwood S5000 amp.
Two 6BX7 tubes doing the work of four.
Subscribe to AudioXpress Magazine to Learn More About DIY Tube Amplifiers
End
