Push Pull 6550 monoblocks DIY project


Push Pull 6550 DIY audio tube amps

The idea of building a DIY audio vacuum tube amplifier based on high-quality materials begins in the early 90's. Initially had to answer the question "Classic Push Pull or a Single ended amp ?" So starting the design somewhere in 1994 I decided to design οn a blank piece of paper, a pair of monoblocks push pull tube amps with a power supply in a separate chassis which would not use solid materials but rectifier tubes.

In the first photo appears the two channels of my tube amps DIY design which consists of 2 mono blocks with a tube power supply in a separate chassis.


The construction began in 1995 and completed in 1997.It's based on the draft circuit layout dynaco st70 but with several variations.These concern both the use of materials and in topology, because from the start I decided that the construction be implemented in three different units, two for the power amplifier , and one for the tube Power supply unit.
The whole project is housed in three P-shaped chassis which have been coated by 10mm thick rose wood attached to an internal "nerve".
The chassis is aluminum, thickness of 2mm and screwed on the side walls of the wooden coating with stainless screws.

In Power supply unit, because of the transformer weigh used to transverse aluminum are veins to avoid possible damage of the chassis.

The design is simple (Push-Pull) uses the 6550 power output tube, while the phase splitter and the driver stage uses an EF86, and an ECC83 per channel respectively.
You can find the 6550 Svetlana tube data in tube data pages.




Tube amp schematic
This is the final schematic diagram

and the PSU

costas sarris