Favorite 300B: Sophia vs KR

"So maybe sacrilege but have a push pull 300b tube amp”

Ladavid,
The 300b is a great tube and no less so because it’s used in a push-pull amp.
Given the money I had just sunk into my amplifier when I acquired it, I decided to stay with the stock tubes for a while. Since then, in addition to adding the Sophia Royal Princesses, I upgraded the small tubes with the best that I could find. In my system, the improvement has been so great that I wish I hadn’t waited.

It might be somewhat more challenging to find 300b tubes for push-pull amps, like ours, because most 300b tube reviews are conducted with SET amps. I have been advised that the findings in those reviews might not coincide with ours, using push-pulls.

Phaelon,
You`re right , it`s a wonderful tube.SET or push pull, it does`nt matter. If it`s a well built/designed amplifier it will simply make music sound devine. Regarding your 2nd point it seems if anything running the 300b as a SET would be more demanding on the tube than splitting/sharing the signal as in a PP circuit. I don`t understand why a tube that functions well handling the full signal would be less good when asked to do less. It appears counter intuitive, at lease to me.
Best Regards,

Charles1dad, I actually feel sorry for my tech when he goes into detailed explanations with me. But he has worked with some very high end amp designers. What I did take away from our conversation is that it is enough that the demand the two designs place on the tube is different; regardless of which is more demanding.

I ordered 4 Shuguang Treasures for my amp. Pricey but grade b tubes came to $700 for the four. This is the down side to 300b amps is that a) the tubes do make a significant difference and b) you pay almost as much as the amp for good tubes. My new amp is a Mactone so a little more than the the price of tubes but seems to be all about the quality of the tubes with 300b amps. Will be interesting to see if the quality tubes make as good a difference with my push pull setup as they did when I upgraded tubes for my 300b set.

Ladavid,
If you find the time, I would appreciate you posting your thoughts on these tubes in the PP amp compared to use in your SET amp. I agree 300b tubes are`nt cheap but they outlast most pentode type tubes and IMO sound better if the amp is up to snuff.