Homemade EL34/6ca7 Push Pull Tube amplifier with DIY Ultra linear Hi-Fi Output transformers.

With the help from a program that calculates OPT's to a hifi level, I made 2x Ultra linear OPT for EL34 Push-pull config. High voltage power transformer and low voltage heater transformer also homemade. Circuit drawing is partly drawn by me but the 'red' part between the 12ax7 and the 12au7 is 'stolen' from another hi-fi amp circuit. Explaining (or trying to) how to use the OPT software to design hifi transformers. The 'OPT design assistant' is freeware!
-No money spent on parts when making the transformers. Testing the voltages on the finished result and then testing the sound in the end. This amp is partly made from materials that is found in trashed electrical hardware, except for those components that has to be new or of a special type to make the amp work as a HiFi product. It took me many months to make, but thats partly because Im lazy. The amp is built into a wood box that I painted with black lacker. The paint job looks pretty bad but how it looks is not important.
The amp sounds really great so all the hard work I put into this project really paid off!!

Here are some pictures of the amp:
http://www.hifisentralen.no/forumet/a...

UPDATE Jan. 2018
This amplifier is finally finished built! It has gone from the one seen in this video to a fixed bias amp with double power and everything good a fixed bias amp has to it. check it out:
   • Homemade EL34 / 6CA7 PP Stereo Tube A...  



The data's in the diff sections of the OPT program is maybe hard to read but watch the video in HD and full screen and they are very clear and readable!!

Common cheap Tubes in use when making this video:

Left channel;
Svetlana - ecc83
Tungsol - ecc82
Electro Harmonix - EL34

Right channel;
Svetlana - ecc83
Tungsol - ecc82
Shu Guang - EL34


Other quality related components in use:

KMH filter caps
KMG kathode (bypass) caps
(all electrolytic caps @450v tolerance)
SCR and Audiophiler dc caps in signal line
All foil caps in filter, even the 422p and the 6.8n
(all foil caps @630v tolerance)
Carbon resistors always in the signal line
Alps Audio taper Stereo volume pot

Wire wound resistors used in the main power supply circuit between the caps. Metal film resistors in the high voltage anode feed and for the power tubes kathode witch
can handle about 10 watt for each tube.