If you have an amp that will use a variety of these tubes, it won't be a true reflection of each various one, from another number family.
IOW, an amp that can use a KT88/6550 type, and an EL34/6CA7 type, can't reflect the true sonics of each type.
Switching brands of each type can make your amp sound totally different.
The overall design of the amp will have a great influence on the sound also.
In general, the KT88/6550 do have a more detailed and dynamic sound, and can almost sound like a solid state in the right amp.
The EL34 is more euphoric, and seems to focus mostly on the midrange. It can still give deep bass, and extended treble.
With all things being equal, the 6SN7/6SL7 is considered the best by most. The 12AX7/12AU7 a close second best.
These two are similar, but the 12AX7/12AU7 was made smaller, to fit the miniature tube bottle, and socket. The 6SN7/6SL7 is the older, larger octal type.
The 6922/6DJ8, the third choice by a lot of audiophiles who have had a large variety of tube amps over the years.
IOW, an amp that can use a KT88/6550 type, and an EL34/6CA7 type, can't reflect the true sonics of each type.
Switching brands of each type can make your amp sound totally different.
The overall design of the amp will have a great influence on the sound also.
In general, the KT88/6550 do have a more detailed and dynamic sound, and can almost sound like a solid state in the right amp.
The EL34 is more euphoric, and seems to focus mostly on the midrange. It can still give deep bass, and extended treble.
With all things being equal, the 6SN7/6SL7 is considered the best by most. The 12AX7/12AU7 a close second best.
These two are similar, but the 12AX7/12AU7 was made smaller, to fit the miniature tube bottle, and socket. The 6SN7/6SL7 is the older, larger octal type.
The 6922/6DJ8, the third choice by a lot of audiophiles who have had a large variety of tube amps over the years.