30 years ago I was running a then-new DB Systems DB1a preamp on motorcycle batteries. I replaced the -33vdc regulated power supply with 3 series 12v motorcycle batteries and a drop resistor, and trickle-charged them with the regulated supply during idle time. At the time, the DB Systems pre was the lowest measured distortion product on the market, of any kind. It was a real advance in solid state preamps then, exceedingly clean though by today's standards the circuit's high negative feedback is sonically evident.
Well, the powering this preamp with batteries wasn't a subtle improvement over the regulated supply. It was vast. The spatially flattened soundstage blossomed into 3 full dimensions. Tonally, the ultra-clean sound lost its sterility and gained body. Transient attack was more energetic and robust. Bass, already among the best of any preamp then, became even more articulate and tonally more differentiated instrument to instrument. There wasn't a single sonic aspect of that preamp's sound that wasn't discernibly improved. The only downside was losing steam after about 8 hours of listening. Even non-audiophiles easily detected the difference. I was using Dahlquist DQ10s then, with tube amps. Stax electrostatic headphones revealed what I was hearing on speakers to be an incomplete representation of how much better the battery supply was on the DB pre.
The designer, Dave Hadaway, thought I was nuts at the time.
Phil
