Just completed the building of 808 single end amplifier. It was built using the chassis of the former 805 tube amplifier. The aim is to simplify the construction of the mentioned unit as all I need was to mount the power and output transformers for the 808 tube without further modification on the other parts. The internal circuit reconstruction was also much simplified since the configuration was quite similar. There was no need to built another bias board, only a resistor was put on both regulator IC and the bias voltage can be adjusted between 30-50V which is what needed for the job.

I am using HATT AUDIO interstage transformer which gives very good result.
The performance of the 808 tube amplifier is remarkable. The sound is full of energy and alive. It really sings. You can fell that the singer is performing with passion and you just want to continue playing your favorite CDs.

I think that there is not much 808 tube amplifiers appearing on the market today though there must be hundreds of these amps being made by DIYs in Japan in the 80s or 90s. At least I knew one nice gentleman from Japan who had owned one unit in around 1995. He said that its performance was excellent and now I learnt that it is honestly quite true.

This unit was modified to use the 808 tube. The one with all TANGO transformers looks and sounds better and therefore there is no need to keep another similar unit. The HATT AUDIO output transformers on these unit was designed for the WE-212 tubes, and I shall start the project if one pair of 212 tubes is available at reasonable price. The price of STC-4212 tubes is now double since 1995.
The power, output and interstage transformers are taken off and reserved for another project. I had once seen one pair used Tango 10887 output transformers on the second hand market, and therefore it may be possible to built another piece of 805 amplifier in the future. Let’s wait and see.