One of the upgrades was a VMP output transformer, the exact same model we are using on our Valliant 5.
The tone of this transformer is smoother, louder and has a tad more bottom, and resulted from an extended research made for Leonidas Amps.
The other was an old Oxford AlNiCo 6" Speaker, that showed up to be a very nice addition to this little combo. A big difference from the ceramic speaker.
Even tough it still has a few issues compared to the Valliant 5(like hum, harsher tone...) , with a few mods it is a nice portable practice amp.
