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Low Wattage Guitar Amplifier Kits

DIY-Central.com Administrator — Mon, 04 Jan 2010 17:02:59 GMT

Featured above are working builds of the 8 Watt Ardmore and 1/2 Watt Gilmore Jr Kits designed by Gerhart Amplification tone wizard, Gary Gerhart. Everything is included except solder (use 60/40 rosin core solder, no flux). The chassis are finished for the Customer with all holes being drilled and punched. Note the stainless steel PEM nuts press fitted into the chassis for a solid, quality build. Kits feature a Mil-Std black anodize chassis, Mercury Magnetics power transformers, Gerhart Amplification's proprietary output transformers manufactured by Mercury Magnetics and all stainless steel chassis hardware. The assembly manual guides the builder through each step. The Gilmore Jr or Ardmore Kit are an excellent choice for those who are building for the first time, yet challenging enough for those who have built kits before. Guytronix stands poised and ready to assist the builder throughout the assembly process.

Click here for more details. http://www.guytronix.com/

Miniature Vacuum Tube Preamplifier

DIY-Central.com Administrator — Sun, 03 Jan 2010 22:35:23 GMT

Look at this... A low cost tube preamplifier using two low power consumption Raytheon JAN6418 sub-miniature pentodes. Kit is supplied with PCB and on-board components. Made by Oatley Electronics.com

Push-Pull Vacuum Tube Amplifier

DIY-Central.com Administrator — Sat, 02 Jan 2010 22:31:27 GMT

This 6V6 amp was built following the push-pull (PP) EL84 / 6V6 Dynaco A-410 output transformer schematic. There are a few minor deviations from the original schematics. Instead of Dynaco transformers, Hammond 1608A audio output transformers and a Hammond 272HX power transformer were used. The EL84 / 6V6 PP Dynaco A-410 output transformer schematic showed a 1000 ohm feedback resistor which resulted in bad amplifier oscillation. Feedback resistor Values between about 6 and 10 k-ohm worked well and I settled on 10k. A 5Y3 rectifier would have been to small for a stereo amp so a JJ GZ34 rectifier was used. It became necessary to put a 100 ohm resistor before the first power supply capacitor to bring down the B+ to about 325 volts as I was getting in excess of 345 volts (there is less voltage drop through a GZ34 versus a 5Y3).

Click here for project details. http://diyaudioprojects.com/Schematics/DIY-Push-Pull-PP-6V6-Tube-Amplifier/

Vacuum Tube Amp Kit

DIY-Central.com Administrator — Tue, 22 Dec 2009 17:37:06 GMT

DIY'ers today have it good! There's lots of projects available on the net to build. Here's a Tube Amp Kit by OddWatt Audi.

The manufacturers specifications for the kit are as follows:

Rated Power Output: 25 watts (RMS)
Input Sensitivity: 1.5V (at rated power)
Input Impedance 100 k-ohm
Input Terminal: Line Level RCA
Speaker Output Taps: 4 and 8 ohms
Distortion: less than 0.5% through half power, 1% at full power
Frequency Response: 8Hz to 20 kHz +0/-1db at any rated power
Signal to Noise Ratio: less than 80dB
Tubes: Gold Lion KT88, NOS JAN Philips 5751
Supply Voltage: 120VAC 50/60Hz
Power Consumption: 130 watts (each monoblock)
Weight: 6.3 kg (each monoblock amp)
Dimensions: 205 mm (W) X 225 mm (H) X 300 mm (D

http://diyaudioprojects.com/Tubes/5751-KT88-Tube-Amp-Kit/

DIY Tube Microphone

DIY-Central.com Administrator — Wed, 02 Dec 2009 14:54:33 GMT

A DIY Tube Microphone.... and yes, it's a KIT! What's even more awesome about this is the microphone body, grille and other stuff is included in the KIT. Anybody that's into building DIY microphones know this is the most hardest thing to DIY... the microphone case. Not the electronics, not the power supply but the mechanical enclosure! So this kit packages everything nicely.

From the writeup:

Beautifully machined (unpainted) brass microphone body and head-grill assembly
Internal mounting cage assembly to mount circuit board, capsule, transformer and connector housings.

Components included

1 - 32mm/1in large diaphragm pressure gradient capsule (assembled)
1 - Plastic capsule mount
1 - Pre-amp circuit PCB
1 - Tube socket PCB
1 - Vacuum tube, 12AX7
1 - 9-pin tube socket
1 - 7-pin XLR male connector
2 - Ceramic insulators for both ends of C4

1 - Film Resistor, 1/2 W 10KΩ
1 - Film Resistor, 2W 100KΩ
2 - Film Resistor, 1/2 W 270KΩ
2 - Resistor, 51M
1 - Resistor, 200M
1 - Film Resistor, RJ 1/2 W 3KΩ
1 - Resistor, 1 KM
3 - Capacitor, 1μ/400V
2 - Capacitor, .022μ/630V
1 - Capacitor, 1000 pF/630V
1 - Capacitor, 100μ/25V
3 - Capacitor, 0.1μ/63V
1 - Capacitor, 1000μ/10V
1 - Ceramic Capacitor, 2pF
1 - Transformer, turns ratio 10:1

1 - Fully assembled power supply
1 - Power cable for power supply
1 - 7-pin microphone cable

Printed documents
Schematic

I bought this kit on eBay and sure hope to find the time to build it. I'll post pictures of my build.