DIY 5687 Tube Preamplifier

The latest addition to the DIY Audio Projects website is a fine looking tube preamplifier constructed by Vincent Wong. The tube preamp is based around a pair of 5687 twin triodes. Each channel uses both sections of a 5687 tube and LED biasing is used on each section.


To keep hum at a minimum, the filaments are heated using DC. The power supply is external to the preamp section and consists of a RCA-83 mercury rectifier and two 50H chokes.


For more project details including schematics and an enclosure construction guide, see: DIY 5687 LED Biased Tube Preamplifier.

Related Tube Preamplifier Projects:

• Mark's build of the DIY 12AX7 Tube Preamplifier Kit
• Bruce's build of the DIY 12AX7 Tube Preamp Kit
• Alan's simple DIY 12AX7 / 12AU7 Tube Preamplifier
  

What's Playing: Fleetwood Mac - Landslide

12AX7 Tube Preamplifier Kit

This is Mark's build of a simple and inexpensive 12AX7 tube preamplifier kit from Silicon Chip magazine. What makes this kit inexpensive (and interesting) is that power comes a switch mode power supply, which is fed from a 17 volt DC wall wart! To silence the skeptics of a switch mode power supply in a tube circuit, Mark has completed a number of measurements on the power supply as well as the preamp. Mark's modifications to the preamp kit include the addition of snubbers and upgraded capacitors. The end result is a simple DIY tube preamplifier that sounds great and will keep some money in your pocket for your next DIY Audio project.

For more detailed information about Mark's latest project, see the project page, a DIY 12AX7 Tube Preamp kit.

Related Posts:

• Bruce's DIY 12AX7 Tube Preamplifier Kit
  

What's Playing: Pearl Jam - Glorified G

Another K-12M Tube Amp

Since building a S-5 Electronics K-12M Tube Amplifier Kit, I have received several emails with questions and comments about this inexpensive tube amplifier. Well, Bruce has also built one of these popular and inexpensive Tube Amplifier Kits. In addition to finishing the simple kit, Bruce has completed a number of Modifications for the S-5 Electronics K-12M Tube Amp Kit. His modifications include many of VoltSecond's mods, new input and coupling caps, a beefed up power supply and upgraded output transformers wired in Ultra Linear (UL) Mode.


For more information and pictures of Bruce's experience with this kit, see his project page, More Modifications for the S-5 Electronics K-12M Tube Amplifier Kit.

For additional information about these and other inexpensive vacuum tube kits, see: S-5 Electronics K-8LS, K-12 and K-16 Tube Amplifier Kits.

Related Tube Amplifier Kits

• S-5 Electronics K-8LS Tube Amplifier Kit
• K-502 Valve (Vacuum Tube) Amplifier Kit
• S-5 Electronics K-12M Tube Amplifier Kit

What's Playing: Robbie Robertson - Sonny Got Caught In The Moonlight

DIY Audio Cables

New projects just added to the main website are a couple of simple DIY Audio Cable Projects.
The first project is a simple DIY Belden 83803 Mains Cable that I put together one evening. The mains cable consists of Belden 83803 wire, Marinco connectors and TechFlex for that nice audiophile finish.

DIY Belden 83803 Main Power Cable

The second DIY Cable project is Mark's simple recipe for DIY Silver Wire RCA Interconnect Cables. The design is very simple and requires only three pieces of insulated silver wire, heat shrink tubing and gold plated RCA connectors.

Silver RCA Interconnect Cables

DIY Hi-Fi Cable Projects

• Belden 89259 RCA Interconnect Cables
• DIY Shielded RCA Interconnect Cables
  
• Cross-connected Belden 89259 DIY Speaker Cables 
• DIY Low-Inductance Speaker Cables

What's Playing: Lisa Loeb - Do You Sleep?