Post by Paul (TRANE) on Feb 15, 2008 19:58:48 GMT -7
Here is what I have found but I am not an expert. However this is on several web sites but, of course, that does not make it true either.
7189 - is an Industrial Version with a 400 V plate rating vs. 300 V for EL84/6BQ5. You can use the 7189 in place of the EL84 but can not use an EL84 in a device designed for the 7189. Make sure they are NOT 7189A tubes though. The 7189A is rated at 440 volts plate, but it has a different pinout. This make this tube incompatible with 6BQ5/EL84 circuits in most cases.
Thank you Paul, good info. I guess my next question would be would 7189's sound good in a Maz? Would they give more headroom? Do these need the extra plate voltage to sound good? I don't really know how a self-biasing circuit works and how well it would adapt to that tube.