Bogen CHB-10 and 7591 vs 7868 Vacuum Tube Comparison

In this episode I have another Bogen CHB-10, this one with the stock 7868 output tube. Then I compare the sound of the amp with another amp of this same model that I converted to a 7591 output tube. The tubes are electrically identical, but what about sonically? Can you tell a difference?

Here is a link to the video showing the repair of the other CHB-10 and the conversion from the 7868 output tube 7591 output tube:
https://youtu.be/OHf3j9p0KyU