The quote from Mr Hagerman about the 5751 may indicate that the 12AX7 it would replace is involved in the RIAA correction filter, as well as adding gain. Since the 5751 might change slightly the output impedance of the stage, it might also affect RIAA, resulting in a sonic coloration that has nothing to do with the brand or vintage of the 5751 chosen.
Hagerman Trumpet MC (12AX7 Tube Suggestions)
I have recently acquired a Hagerman Trunpet MC and I am extremely pleased with it.
Desire to assemble some 12AX7 sets of (Almost) NOS Tubes to Tube Roll. 12AU7 positions are purchased but the 12AX7 Tubes are a minefield and somewhat costly after my research.
First question; Have any Owners here used the 5751 Tube in the 12AX7 positions?
Second question; Have any Owners here had any sonic success with 12AX7 USA Brands such as Sylvania as an example. I am reading mixed longevity views on the RCA Blackplates and not many good comments on the GE types.
I am very gunshy on the Re-Issue 12AX7 Tubes also.
I primarily listen to Classic Rock, Progressive Rock, Folk, and some Classical.
Suggestions would be much appreciated.