Iv just swapped out the speaker for a Warehouse Vintage 30 and also changed the 5 tubes for Tungsol KT 66 and 12 AX7 re issue.

The sound at first was amazing - but after about 45 mins the sound deteriorates to a bass muddy sound which the eq settings make little differance.
This was happening b4 the swaps which i hoped would cure the problem.

Help in what direction to look next would be appreciated

Thanks in advance