About altec 604 E2

[pshchw]

What is the difference between 604 E and E2?

[Don McRitchie]

From what I understand, the 604-E2 is the same as the 604-8G. The E2 label was used by Altec for 604-8G's that were sold to Audio Techniques for use in their Big Red studio monitor. I'm pretty sure the E2 label was used on drivers sold to UREI as well, but I can't confirm this at the moment.

As far as the difference between the 604E and 604-8G, I don't think there is much beyond the use of a 16" frame on the latter compared to a 15" frame on the former. The 604E was introduced in 1967 as a 16 ohm driver. Around 1970, it was converted to 8 ohms, but was still considered an "E" version since it was labeled the 604E-8G. In 1974, the name was shortened to 604-8G when they adopted the 16" frame and I don't think there were any electrical or mechanical changes. BTW, this is why there never was an "F" series of 604 drivers.

[pshchw]

Thank you very much for your kind reply.