The Lightspeed LDR is wonderful provided your source and amplifier are appropriate for a zero gain, zero buffering preamp.
Either find a source that outputs closer to 4V, find an amp whose sensitivity is closer to whatever output voltage of your source, find another way to either add gain or lower sensitivity, or get an active.
I happen to think the Burson Buffer is a reasonable try to add gain to your system. It's actually what you're looking for, isn't it? An active, with gain and LDR volume control. The Burson Buffer adds 6db gain, and your Lightspeed LDR acts as volume control.
Having said that, an LDR is not the only means to deliver great sound, I happen to think the Coincident Statement Linestage and TRL Dude are better than the Lightspeed. But if your source and amplifiers are appropriate, I'd agree that there may be nothing better at the price point of the Lightspeed LDR.