If you search the DIY tube forum I posted some mods I did on a AA-151. Basicly I gutted the amp removed the electrolitic power supply caps and put in Solen 47uf polies and a 6H choke. Later replaced the 6AN8 with 6H30 circuit. Sound stage goes to the moon and back. Tonal balance is a bit tward the bright side thanks to the Solens but not terribly so. MAybe oilers will keep a warner tone. I'm also using the Angela\Solen tin foil caps. The over all sound is more Hi-Fi than musical but I like Hi-Fi, nutt'n wrong with bandwidth, dynamics and sound stage.There are several 6BQ5 and 6V6 amps that sound great. 10-20 watts is nice too.