The first time you plug in the power cords, you’ll find a sticker over each of the IEC inputs warning you to change the power setting on the bottom of each component. They all work at either 115 volts or 230 volts, and a sliding switch on the bottom sets the proper voltage. They all come set at 230 volts, so for U.S. power you’ll need to move the orange switch to the 115-volt position.
The HPA-9 has an internal adjustment for the phono connection that lets you use a moving-magnet or moving-coil cartridge. It comes set for moving-magnet carts, but I’ll explain in detail how to reach the adjustment for moving-coils, since it’s not addressed in the manual. First, you must remove the case. Unscrew the four Philips screws on each side of the case. Slide the case back to release the clamp that attaches the case to the front of the chassis near the faceplate. Lift off the case. Near the back of the chassis you’ll see a small sliding switch labeled mm/mc. If you want to use an mc cartridge, slide the switch to that position. Replace the case, attach the leads from your turntable to the phono inputs on the back of the HPA-9, attach the ground wire if there is one, and turn the selector switch on the front of the HPA-9 to the Phono position. You’re ready to listen to LPs! The mc is designed for a cartridge with a 0.4mV output and a 100-ohm load, which are very common values for mc carts.
The DAC-9 remote control is obviously a budget unit, but quite thoughtfully designed with plenty of flexibility. Since it has 99 discrete settings, the volume control has a very gradual effect; as a result changes seem rather slow. The remote does have buttons for each of the digital and analog inputs, so you can select those directly—no scrolling through all the inputs until you reach the one you want to hear, which some remotes require. That’s convenient. There’s also a mute, which comes in handy when the phone rings. You can also turn off the DAC-9’s display; if you do, a single LED remains lit to show you the unit is turned on.
The HPA-9 has three headphone jacks, one for earphones and two for full-sized headphones. I tried some Sony XBA-H1 earphones (in-ear monitors), along with NAD Viso HP50, HiFiMan HE400, and AKG K701 headphones. The least sensitive of these were the HiFiMan HP400s, but the HPA-9 drove them to levels far louder than I cared to listen to.
I used Clarity Cables Organic speaker cables to connect the speakers to the STA-9s. In monoblock configuration, you use the two speaker terminals near the edge of the chassis, so the cables’ spade lugs were a snap to connect, but for stereo mode, I suspect banana plugs would be easier to use, since the speaker terminals are fairly close together—an unavoidable result of using such a small chassis. Purist Audio Dimensions Venustas unbalanced interconnects linked the DAC-9 to the STA-9s, while Clarity Cables Organic interconnects connected the output of the HPA-9 to the analog input of the DAC-9. Crystal Cable’s Piccolo and Crystal Connect cables, respectively, connected the tuner and turntable to the HPA-9 headphone amp’s inputs.
The STA-9s, set up as monoblocks, were the most powerful amplifiers I’ve used, but unlike amps with Class AB output sections, they got only moderately warm to the touch. They were extremely quiet, fortunately—as are most amplifiers today.
I gave the 9-series gear at least 200 hours of break-in. The KEF LS50 speakers have a smooth but extended high-frequency response, and if your system is edgy, they will let you know. But there was a problem; hooked up as described, the output of the DAC-9 drove the STA-9 amplifiers, so when I played a digital source through the DAC-9, I couldn’t play it through the HPA-9. So to break in the HPA-9, I plugged in some headphones (the HiFiMan HE400s), turned on my FM tuner as an analog source, and played it through the ’phones. It sounded a bit weird to have two sources playing in the room, but it was just for the break-in period.
The 9-series components consist of three separate functional designs, and trying to operate them as a single system revealed some glitches. The fact that the HPA-9 had all the analog inputs, including the phono section and a volume control, while the DAC-9 had the master volume control was a little weird. Several times, I found myself cranking up the volume on the DAC-9 only to find I really needed to crank up the volume on the HPA-9. I guess you’d eventually get used to it. It would have been nice if there had been a remote control for the HPA-9, or better still, if the DAC-9 remote had also operated the HPA-9. If you bought the HPA-9 to use as a headphone amp, you would probably find the controls just fine. I wondered if it would have made more sense to combine the DAC and headphone amp; that combination is quite common, and appeals to those who listen to computers through headphones a lot. Then the phono preamplifier could have stood alone as a separate product. Oh, well, those are personal views; if I were an audio designer, I’d be making a lot more money than a reviewer.
Given their prices, you would probably not expect the STA-9, HPA-9, and DAC-9 to be audio jewelry, and you’d be right. A few parts seemed a bit cheap, like the source selection and volume control knobs, but generally construction was solid and attractive for the price.