Interesting I don’t find a bass flabby at all. IMHO it’s more a function of your system and speakers. I spent a lot of time on my ESS AMT 3’s , to get the bass tuneful, deep, and tight. They are fully acoustic suspension (sealed) 2x 10” long throw (11mm) paper cone woofers with foam surrounds. Ceramic treated and braced inner walls. Foamed lined inner walls and 2 types of damping material directly behind the woofers. The crossover uses all low ESR components to maximize efficiency, and reduce any negative interactions with the driving amplifier. It’s about 1 1/2 dB more efficeint the stock now. You really have to tune your speaker boxes by ear to get this. Manufactured unmodified speakers, you’re getting what they think is best. Modern versus vintage speakers well that’s a whole other story. The NOS TDA 1543 requires a certain system to sound its best. I think low power inefficient systems won’t sound very good with this DAC. I think the best way is comparing it is if tube equipment sounds good with your system...if it doesn’t then I would take a pass on NOS Dacs, or modify your system!!