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Gio writes in to tell us about his latest vacuum tube-based audio amplifier design, the
5751 SRPP / EL84 (6BQ5) Push-Pull Tube Amp. If you've been itching to try your hand at building such a thing, this looks like it could be a good place to start. The circuit has been designed to have high enough gain to connect directly to an MP3 player, and they are using simpler parts to keep the cost of the project down.
Curious about what all those things in the name mean? Well, 5751 and EL84 are the model numbers for the vacuum tubes used in the project, and push-pull refers to the type of audio amplifier circuit that the project is based around.
Circuit schematics are included, however you need to be careful when working with this and any other vacuum tube projects, as the high voltage required to run them can be deadly.
Shorts internally could put plate voltages (205V DC) across your mp3 player. Your mp3 player will not be grateful. You might be dead. Be careful.
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there is almost zero risk of the tube grid conducting plate voltage. There is a reason they are also called valves. Even so the real risk is this being built by a n00b. It's not a good beginner project IMHO. While voltage is low by tube amp standards that power supply can give you a nasty nibble. For a first time project stick with either a simple tube pre-amp or a low watt single ended.
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That's a good point, a low-power preamp would be a much better beginner project!
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Hi guys, thanks for posting to this. Quick correction - the amp was put together by Bruce.
Yes, please do not attempt high voltage projects if you are not familiar with high voltage safety.
If you are new to tubes and would like to try out a simple inexpensive tube preamp / headphone amp this one is ideal and can be powered from a 9V battery so it is safe.
http://diyaudioprojects.com/Tubes/6418-Tube-Preamp-Headphone-Kit/
The kits ships from Australia and they have shipped to North America and Europe.
Cheers
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