In a previous post, I talk about a new amp project. Since this post, I bought several stuffs to build it. But while looking for parts, I talk with several people. And they convince me to build a push-pull instead of a single-end.
So, I got 4 outputs transformers (2 SE and 2 PP), I gonna try the PP first, and if this work great perhaps, I will sell the single transformers or build a second amp.
The main difference between single-end and push-pull, is distortion. In fact, SE produce a lot of harmonics, so a lot of distortion. Beside this is a bad idea for a power amp, this is really what a lot of people call a “real tube sound”. Anyways let’s start with a full featured push-pull, and perhaps came back to a simple SE just for the fun.
The main issue right now, is that push-pull are a lot of more complicated. I mean you can build a simple SE with only a spare components.. this is not the case of a push-pull. For a single channel, I need 2 tubes, 1 bias power-supply, a highly regulated power supply and a phase shifter ..
For the tubes, I decided to use some KT88. In fact, a friend give me a spare matched quad of NOS (plain old) Gold Lion tubes + the needed output transformers so .. This tube are really great for the HIFI. And they look really great !!!
For the input stage, I decided to do something not really common. In fact most tube amps use some ECC82 / ECC83 for the input stage. My choice is something little different cause, I want to use some bigger tube. A lot of people say the 6SN7 (or 12SN7) are great for this stuff too. And some high quality power amps tube this, so why not. After looking for a while for a good schematic, and tested severalls stuff, here the one I gonna build:
In the comming (soon I hope), I will describe the schem and the modification I made. Right now, I’m waiting for the power transformer (comming from US take a long time). In a next post, I will post some photos of my input test bench …
Enjoy light ?