Power supplies are more critical than you might think. We might blow your mind a little here… maybe you should sit down. Here goes:
A power supply in a stereo preamp (or amplifier) doesn’t just provide energy to let the amplifier function. The power supply IS the music that you hear.
Wait… what?
It would be reasonable to think that the music signal comes into a preamp from your music source (CD player or phono), gets amplified, and then gets directed to the output jacks, where it heads on out to your power amp. Isn’t that how it works?
Nope. Instead, the preamp copies the music signal that comes in from your music source, then amplifies it, and it is the amplified copy that is sent to the output jacks, and on to your power amp. And the “blank page” that receives the copy is the power supply. To be more accurate, the signal from your music source “modulates” the energy from the power supply. The modulated power supply signal is then sent to the output jacks, and travels on to your power amp.
This is how every preamp works, not just our preamps.
The power supply, therefore, literally becomes the music that you hear. This is one of several reasons that the power supply in a preamp is so important. It is why the quality of the capacitors producing the power for your preamp is so important. It’s why our patented power supply, GreenForce™, matters so much to the overall sound quality of Backert Labs preamps: its unusual design allows us to use higher-quality capacitors in our power supplies than any other manufacturer.
OK, what else?
Another reason the power supply is so important is that its job is to enable the amplifier in your preamp to respond exactly to the specific frequency and dynamic demands of the signal coming in from your music source.
The quality of that responsiveness depends on the source of the power. So let’s talk about the source, in other brands, and in a Backert Labs preamp.
99% of manufacturers use electrolytic capacitors for their power supplies. That’s a type that manufacturers never use in other sensitive parts of the preamp that handle the music signal. In our view, electrolytic caps are merely average-quality capacitors. They aren’t as linear, as “nimble” as a first-class capacitor when it comes to accurately responding to the complex signal that is your music.
So why do other manufacturers use electrolytic capacitors in their power supplies? They have to. They are relying on the capacitors to deliver all of the power, all of the energy, to run the amplifier section of the preamp. So they need the significant power that electrolytics provide. At Backert Labs, we don’t need capacitors to provide the “muscle” – our unique power supply relies on the far greater energy reserves in your AC line. That’s one of the advantages of our GreenForce power supply.
To give you an idea of how much a typical non-Backert-Labs power supply relies on its capacitors, let’s look at the “size” of the electrolytic capacitors that typically get used:
- For a tube linestage preamp, manufacturers might use electrolytics with 400, 500, or more microfarads to drive the audio signal power supply.
- But that’s on the low side… many manufacturers will use 1,000’s of microfarads.
- Why? Because they want “massive energy reserves” in their power supplies. You often hear language like this when companies talk about their power supplies.
At Backert Labs, the power supply for our Rhumba linestage uses less than 1 microfarad. Because of the unusual design of our power supply, we just don’t need the capacitors to do the work… we rely more on the AC line, which is continuous, and has power reserves that absolutely dwarf any capacitor.
The importance of the power supply is why Bob Backert invented the GreenForce power supply. It is used in every Backert Labs preamp. You can read more about GreenForce here.
