My first reaction when plugging in my Suhr classic to this amp was one of disappointment. To me the sound seemed closed in, maybe due to the increased mids, compared to the Deluxe original? I tried to compensate by increasing the treble control and dialling down the bass. That only made the treble sound harsh. Unfortunately, in line with the original tube amp, there is no mid tone control. This poor sound was most noticeable when using clean tones.
I was about to contact Thomann to send the amp back as I can get a better tone, but not as full a sound, with my little Yamaha thr10c. I sent some sound samples to a pal in N.Z. for a blind test and he also thought the Yamaha sounded better when using a Fender type tone!
What changed my mind was when I plugged in my Boss ME70 multi pedal and only using the EQ section managed to dial in a much brighter and open sound. Now we're in business!
Bear in mind, this is only my opinion and you may be perfectly happy with that pushed mids, clean tone sound.
If you have an Equalizer to hand, try plugging it in to reshape the tone.