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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/

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/