PS Audio StellarGold Stereo Preamplifier Review

PS Audio was founded in 1973 by Paul McGowan. He left the company for a while and then returned in 1997. A couple of decades later, he is still there, and the company manufactures and markets just about every kind of audio product there is. DACs, transports, power regenerators, preamps, power amps, speakers, cables . . . they have it all.

Most importantly, their stuff is very good. Their new StellarGold Stereo Preamplifier is an example. I obtained one for review, and was amazed at the performance. All at a very reasonable $3,999 USD.

The StellarGold preamplifier has a very classy look to it, with a low profile that will easily fit on any shelf. You can click on any of the photos and bench test spectra to see them at a larger size. In regards to the circuit, Paul McGowan had this to say, “We use a linear power supply and scads of local multi-stage analog voltage regulators. The real secret to this product is the amp circuit itself. With a slew rate exceeding 100V/µS and a current feedback design with minimal closed-loop feedback, this is one of the most open-sounding preamps I have yet to experience!”

The front panel has the standby/on button on the left that lights up in blue when pressed to turn it on. The main on/off toggle is on the rear panel.

On the right-hand side is an LED display that shows the volume setting in digits and the input mode which is chosen by the small button at the left-hand side of the LED display.

The rear panel, shown below, has two sets of inputs and outputs, with true-balanced XLR and RCA connections available for all inputs and outputs. The two sets of outputs were very convenient for me, as I had one set of outputs going to the power amplifiers (Pass Labs Xs 300 monoblocks) and one set going to two subwoofers (Paradigm Reference Signature SUB 2).

The grounded three-prong 120 v AC socket is on the left end with the main power on/off toggle. I found that with the toggle on all the time and the front panel on/off button left on standby, the preamp maintained a slight warmth, so it is pretty much ready to go when turned on for use.

There are sets of PS Links and Triggers on the left for communications with other components.

The included remote control is very sleek, and it has buttons not only for the StellarGold preamplifier but for other PS Audio components as well, such as Power Plant power regenerators and phono preamps.

I listened to the PS Audio StellarGold Preamplifier using an OPPO UDP-205 disc player and Qobuz music streaming from a laptop to the OPPO UDP-205 USB-B input. A hard drive containing all of my stored digital music was connected to one of the OPPO UD-205 USB-A inputs. Power amplifiers were Pass Labs Xs 300 monoblocks. Speakers were MartinLogan CLX full-range electrostatics. A pair of Paradigm Reference Signature Sub 2 subwoofers were connected to the second set of XLR outputs on the back of the StellarGold preamplifier. I use subwoofers in this system because electrostatic speakers do not have a lot of deep bass capability. Of course, when I review speakers, I do not use the subs.

Some consumers would classify the PS Audio StellarGold sound as “clinical,” “analytical,” “cold,” or “dry.” The corollary of these adjectives is “very low distortion.” Tube amplifiers add midrange bloom and even-ordered harmonics that mask transient edginess and make the sound “warm.” You can add midrange to the sound by using a good EQ add-on to a digital music player such as Audirvana. When I want to adjust the tonality of streamed music (Qobuz), say, for an evening of background music with guests, I use MAAT Linear-EQ which lets me add EQ without altering the phase. Of course, I did not use EQ when doing the listening tests with the StellarGold preamplifier. This example is just for illustration, and the EQ setting here was +5.6 dB at 500 Hz with a Q of 0.71. The lower the Q, the wider the spread of the EQ. Although midrange is generally defined as 500 Hz to 2 kHz, I preferred the center frequency of the EQ to be at 500 Hz. It sounded more natural to me. Note that this does not replicate the warm midrange of tubes, it just adds some of the character. Midrange bloom can also refer to attenuated low frequencies which is the case with one of my tube preamplifiers. That is why when testing components, I always listen to an album containing pipe organ music.

I used the XLR balanced inputs and XLR balanced outputs for the bench tests. At a volume setting of 75, the output voltage matched the input voltage, and I used that setting for all tests except where noted. Streamers and disc players generally output at between 2 and 3 Volts, and I used 1 Volt and 2 Volts input on most tests. Outputs were at those same input voltages for most tests.

Let’s take a look at the usual first bench test that I use for most products: a 1 kHz sine wave. In this case, 1 Volt input, 1 Volt output. Both THD and THD+N are less than 0.001%. Distortion products are below -120 dBV. This is excellent!

With 2 Volts in and 2 Volts out, distortion is even lower. Keep in mind, that this would be driving your power amplifier to a high volume level.

At 10 kHz, 1 Volt In and 1 Volt out, distortion is still very low.

And at 2 Volts in, 2 Volts Out, a little more distortion, but still below 0.001%.

Our last sine wave test is with 20 kHz. Here, 1 Volt in, 1 Volt Out. Slightly more distortion than 1 kHz and 10 kHz, and yet, still less than 0.001%. The StellarGold has some real muscle!

When the voltage is turned up to 2 Volts In, 2 Volts out, the 0.001% result is passed, but it is, notwithstanding, a fine result.

IMD (60 Hz, 7 kHz) with 1 Volt in and 1 Volt out is shown below in Figure 7. Even with the noise floor at -130 dB, there are no visible IM peaks on either side of the 7 kHz signal peak.

Raising the input and output to 2 Volts, IMD stays the same, very, very low.

A series of 19 kHz and 20 kHz tests are shown below, with the first one at 1 Volt in and 1 Volt out (Figure 9).

Figure 10 below zooms in on the IM peaks surrounding the 19 kHz and 20 kHz sine wave test signal peaks. There are three visible peaks on either side, and they are all below -110 dB which is far below audibility.

At 2 Volts in and 2 Volts out, the side peaks are a bit higher.

Zooming in, we can see the details. There are four visible IM peaks on either side. The largest one is at -106 dB. This is really good performance.

If we set the input voltage to 1 Volt and adjust the volume control to output 2 Volts (Vol 87), we have gain. However, the distortion spectrum is still extremely low, as shown in Figure 13 below.

Here is a 10th Decade spectrum with 1 Volt input and 2 Volts output. Distortion in the midrange is very low. This gives a very clear and detailed sound.

The Frequency Response is flat to 20 kHz (Figure 15 below). The 0.4 dB roll-off at 45 kHz is due to the 24/96 FFT sampling in the spectrum analyzer.

Crosstalk was -120 dB (top right corner in Figure 16 below) at 1 Volt output on one channel and no output on the second channel.

The PS Audio StellarGold Stereo Preamplifier is a top performer. Its low distortion delivers detail and clarity beyond its price. It is a gem that a certain audiophile audience will very much appreciate.