7591 / 7868 Tubes
7591 and 7868 were from the same era, and they are electrically very similar. They are physically different so please select the right one for your amp.
Looking for 12AX7 preamp tubes too? Feel free to check out our 12AX7 product page
7591 tube was originally introduced in 1959. It is a high output audio power tube that is flexible and easy to design with. Consequently, 7591 and its siblings were used in a vast number of home audio equipment in the 1960s.
7591 vs 7868 Tubes
7591 and 7868 have the same internals, and electrically they are the same. They fit in different sockets so they cannot be interchanged. 7591 comes in octal base, while 7868 is in compactron package.
Height and Fit
Current production 7591 work and sound great, but they are a bit taller than original 7591 tubes. Please check the height for clearance in your amp. Electro-Harmonix 7868 pins are slightly fatter, making it a very tight fit in sockets. You will have to be very careful plugging it into your amp.