Relationship between driver and power tubes

[antigrunge]

One aspect often getting lost is the relationship between driver and power tubes. On my Wavac EC300b I use different driver tubes depending on which 300b tube I am using.
With Takatsukis the best result is achieved with Tungsol 6l6G coke bottles, using more high powered 6L6GCs (eg. JAN Philips 7581a or Svetlana Winged Cs) results in an overblown, harsh sound. Conversely using EAT 300bs with the coke bottles doesn’t work, resulting in early clipping and constrained dynamics. The EATs work best with Svelana Winged Cs, the even more high powered 7581as still feel overblown.

Given these findings, taking single power tube tests at face value without referencing the driver tubes seems problematic.

 

[sparkie]

One aspect often getting lost is the relationship between driver and power tubes. On my Wavac EC300b I use different driver tubes depending on which 300b tube I am using.
With Takatsukis the best result is achieved with Tungsol 6l6G coke bottles, using more high powered 6L6GCs (eg. JAN Philips 7581a or Svetlana Winged Cs) results in an overblown, harsh sound. Conversely using EAT 300bs with the coke bottles doesn’t work, resulting in early clipping and constrained dynamics. The EATs work best with Svelana Winged Cs, the even more high powered 7581as still feel overblown.

Given these findings, taking single power tube tests at face value without referencing the driver tubes seems problematic.

not every amp is easy to tube roll. But with this one, the biasing of the 6l6 stage comes into play and it seems like it is hot biased so only a few tubes work within the gain structure. I imagine there is bias adjustments and I would consult the manual or contacting the rep. will give you that info.