I'm not sure if they're "right", but I just went over it again and they are what's shown in a service manual I downloaded for the 299 for the PI section. Thanks for the attachment. I need to brush up on my German - LOL
Because your schematic is from the Scott 299B. But more important: That schematic must be also OK than.
Now that you mention that, I see that. Good catch! I missed that. Thank you. For my purposes - since this is a DIY build from scratch - I guess it's more important to decide on a good starting point for the PI stage than where it came from. I sure didn't mean to mislead anyone or intentionally disregard the 'B' in the model nomenclature. A lot has been learned since these things were built. I hope to take advantage of some of that knowledge
Having gleaned so much useful information from of the long term contributors to this site, I think the main problem is that so much has been forgotten since these things were built! I have been trying tio understand old PA schematics from just before and after the war, and there are so many clever ruses that highlight the knowledge and experience of the generation that used tubes exclusively.
Interesting. I hadn't considered that but you're probably right in some regard. There are a few though that still love tubes and tube audio and continue to experiment and explore. There are a few here as far as I can tell and I have a couple good books written by "glass enthusiasts" so it's not totally gone. I'm grateful that these people so willingly and freely share their experience and ideas. In my first post I mentioned my ham radio hobby and with regard to tubes, a lot has been learned since the early days that have significantly improved signal quality and purity. My favorite home-brewed HF linear uses 4 813s in a cathode driven configuration but not in the "traditional" grounded grid manner, where the grids are just DC strapped to ground. It uses RF bypassed - stiffly regulated screen and bias supplies and 1st order harmonic distortion is better than -40db. At least a 10db improvement from the days of old. Hoping some of that experience combined with the experience of others here will result in a similar experience with my venture into HiFi audio. 🙂
There's definitely a lot of good experience and knowledge here!