Hi all. This is my first post. I'm also quite new to tube amps but really like what I hear. I am busy building myself a tube amp for my car. As i'm quite inexperienced I've taken advise from a friend to follow the simple circuit diagram of the Dynaco ST-70. All is going well and I have all the parts including the chassis. Where I am feeling a bit concerned is in the preamp/phase splitter tube. The original circuit requests a 7199 that is totally unavailable in my part of the world. With a slight mod I could use the 6U8. When I google the 6U8 I seem to find very negative opinions on it. Could someone advise me on whether this tube is in fact ok or if there is another tube or even 2 tubes (one for the preamp and one for the phase stlitting) that I could use instead. If so possible diagram on connecting up would be appreciated. Thanks. Craig.