Gold Lion AX7 in tube preamp

I have purchased a number of new tubes, especially 12ax7, 5751, el34 and kt77 and have to say that by the end of the listening session they were pretty much sounding as they were going to.

Once purchased a set of relatively inexpensive 12ax7s based on a recommendation by a member here.  They sounded bad when first used and stayed that way.

@yogiboy 

Using a Jolida Fusion preamp with some upgrades into a Benchmark AHB2. 

Are you sure that a 12ax7 is the correct replacement tube for that preamp? 

For warmish/tubey sound;

Amperex 12 AX7

Mullard 12AX7

RCA 12AX7 long plate

@yogiboy 

Yes it’s the correct replacement.