TAD ECC83/HG7025

I bought this valve for my Bugera T5 head ( which I moded some time ago in order to make it less bassy viz I added a 220pf capacitor on sound path and I decreased the cathode capacitor to 1uf) in order get a sound more ... something (I followed the tad description - Great warm clean tones, strong bass, punchy mids and fat overdrive with smooth top end.). My T5 runs a JJ ecc83S in V1 and a JJ EL84. It plays into a custom cab with a Fender Special Design 10-inch speaker. With this configuration, the amp sounds more than fine. I just wanted a bit more present sound. So I installed the new TAD ECC83/HG7025 valve and, surprise: the sound (frequency spectrum) has shifted significantly toward the treble. Almost I lost the bass, the high frequencies have a frying, crackling sound and so on. So nothing I expected... As a consequence, I had two options: either to start modding again in amp in order to tame this TAD or to put back the JJ ECC83S. I went for the second option. I'll keep the TAD, I'll see what uses I can find for it in the future.