Cuttin-Edge, On-the-Spot Reporting

Have You Seen?


As I was walking down the hallway of one of the exhibition floors at the Florida International Audio Expo this year, I spotted Gary Yacoubian outside SVS’s stuffed-full room. Yacoubian is president and CEO of SVS, which is famous for its high-value subwoofers. We’ve crossed paths at shows once or twice, but never had much in the way of face-to-face dealings. That said, I reviewed the company’s PC13-Ultra cylindrical powered subwoofer back in 2013. I just loved this all-business, overbuilt powerhouse, which, at $1699 (all prices in USD), proved to be a superb performer and a smoking bargain. In fact, I loved it so much I ended up buying the review sample, and it’s been lurking there, over my right shoulder, ever since.

SVS at Florida International Audio Expo 2024

The PC13-Ultra will never win any beauty contests. It’s a large cylinder, covered with a sock made from what looks like stretchy carpet. The grille on top is reminiscent of those found on car subwoofer cabinets. The base is a round disc of—most likely—MDF, with small stand-offs raising the driver off the ground. But that driver! It’s a massive unit with a 13.5″ cone, a cast basket, and a huge magnet. The built-in amplifier is equally massive, chugging out 1000 real-world watts.

Sub locationNow you know where my safe is

As I passed by Yacoubian at the Expo, I said: “I’m still loving my PC13-Ultra.” I didn’t expect much of a reply; maybe just a thumbs-up.

It didn’t go that way.

“Oh, you still have one of those?” replied Yacoubian. “Did you know we offer an amplifier upgrade kit for that sub? Brings it up nearly to the same spec as the PC-4000.”

I stopped and turned around. “You don’t say . . .”

“When we designed the PC-4000, we made sure it used the same-sized mounting hole as the old PC13, so it just bolts right in,” he continued. “We sell it at our cost of $399.99. Are you interested in getting one?”

Interested? Of course I was. A couple of emails later, I’d arranged for an upgraded amp to come my way.

Sealed box

The amplifier in my PC13-Ultra is no slouch. It’s a 1000W, DSP-controlled class-D plate amplifier, with a built-in crossover and a parametric equalizer that provides control over two different user-selectable frequencies.

Compare that, though, to the Sledge STA-1200D amplifier in the PC-4000—the new amplifier’s power supply has been upgraded with more capacitance and SVS’s power factor correction, which time-aligns and conditions the AC voltage, according to the company. Drive comes by way of 32A, 600V discrete MOSFETs.

Bagged amp

The DSP capability of the PC-4000’s amp has been upgraded via a high-resolution 50MHz Analog Devices audio chipset with double-precision 56-bit filtering. This chipset controls internal EQ, high- and low-pass filters, port tuning, and a multiband limiter/compressor. The Analog Devices chip also supports a comprehensive Bluetooth smartphone app, with a fully adjustable low-pass filter, controls for phase and polarity, three independent parametric EQs, room-gain compensation, port tuning, volume, and three memory presets.

SVS markets the Sledge amp as the STA-1200D upgrade kit for its Ultra Series subs. For optimized performance, individual DSP files are available for each of the Ultra subwoofer models that can be upgraded with the STA-1200D.

Amp opened

My reviewing duties at SoundStage! Ultra normally involve fully finished products—nearly everything arrives in my listening room polished, ready for primetime, ready to go. The most I usually have to do is remove a product from its box. Turntables need to be set up, I’ll give you that, but it’s a civilized process. It all gets a bit boring, really.

The STA-1200D kit arrived and I tore into it. At last, I had something to take apart! And then I had two parts to put together, creating order out of chaos, reversing entropy.

The actual process of removing the old amp and installing the new one was disappointingly simple. I used my Bosch 18V driver to remove the screws, and, with the help of the edge of a flat-head screwdriver, gently levered an edge loose. That done, the old amp pulled right out. The only connections to the amp were the two speaker wires, joined to the driver via blade connectors. A quick tug and they separated quite easily.

New ampNew STA-1200D on the left, original amplifier on the right

Once I had the old amp out, I could see right into the bowels of the sub. At the bottom, I could see the ass-end of the driver, the giant magnet, which filled almost the entire circumference of the cylinder. The ports were longer than I’d imagined—almost the full length of the enclosure.

Box guts

Installing the new amp was equally uneventful. I attached the supplied speaker connector to the amp via its quick-connect plug, and plugged the two speaker wires to its pigtail. Because I was feeling undervalued here, I wrapped each spade connector with a slice of electrical tape to eliminate any chance of shorts (and to increase my feeling of self-worth). Then I pushed the amp into the recess in the enclosure and secured it with the new set of screws that came with the kit. The holes lined up perfectly. I was done—maybe ten minutes total, including time to snap a few photos for this article.

I downloaded the SVS app onto my Samsung Galaxy S22 phone and flipped the power switch on the amp. The PC13-Ultra immediately appeared in the app, and I started to fiddle around. First order of business was to set the Port Tuning control to Extended, to match the physical one-port-blocked configuration.

SVS group

At this point I began to feel vaguely guilty. My sole use case for the PC13-Ultra at this time is to receive an LFE signal from my Anthem MRX 300 home-theater receiver. In this setup, the only available control is volume. The EQ, crossover, and room-gain tools are not functional. Still, that said, I do play a fair number of music videos, and the family sits down once a week to watch a blockbuster, so the PC13-Ultra has been well used over the past ten years.

So, I fired up the Windows XP laptop that I’m hanging on to for the sole reason that it still connects to the MRX 300 via the USB-to-RS232 dongle that seems to be the only way to control this receiver. I ran through the Anthem Room Correction process, and uploaded the new values to the receiver. At this point, I had a chance to compare the frequency response with the new amp to that of the old amp, which I’d measured a while back. The new amp looked like it was running smoother through the upper bass, some of which should be audible, even though ARC does its best to iron things out in that region.

ChartsOld amplifier on the left, new amplifier on the right

What I’ve always admired about the PC13-Ultra is its utter invisibility. I can’t hear it. It’s not in the room. What I do get, though, is bass, which seems to magically appear when it’s required. The sub is right behind me when I’m sat in the sweet spot, but even so, it provides absolutely no clues as to its proximity. Some subs can overpower the upper bass and reveal their presence in the room—but that’s not the case with the PC13-Ultra.

Since it’s wired up to my Anthem receiver and not to my reference system, I couldn’t really sink into music in the same way as I can via my VPI turntable or the Meitner Audio MA3 DAC/streamer. That said, Roon hooks up just fine to the Chromecast Audio that feeds the Anthem. In anticipation of the arrival of the STA-1200D kit, I spent a good while listening to a bunch of my favorite bass-heavy recordings through the surround system, and had a good time doing it. With the Anthem processing the incoming two-channel stream into a Pro Logic 5.1 output, I found myself temporarily enamored with hearing my music wrapped around me.

The overall sound quality of the Anthem-based system won’t give Ed and Amadeus Meitner any cause to lose sleep, but it’s not bad—not bad at all. But we’re not here for audiophile fripperies—how was the bass, Jason?

With the new amp driving the PC13-Ultra, it was just as impossible to localize the source of the bass, but now I heard a bit more pitch definition. Each low tone sounded more distinct. In my recent review on SoundStage! Ultra, I mentioned how the DALI Epikore 11 speakers excavated new bass definition from “Awake on Foreign Shores,” from Colin Stetson’s New History Warfare Vol. 2: Judges (LP, Constellation CST075). The upgraded SVS sub gave me that, too. The original amp gave me limitless low end—tighter than a fish’s ass, it was—but not quite the level of separation between lower harmonics that I received via its replacement.


And there was even more slam from the new amp. King Crimson’s “Space Groove II” (16-bit/44.1kHz FLAC, Discipline Global Mobile / Tidal), from the band’s giant interstellar jam session, ProjeKct Two, features Trey Gunn’s nutty, ten-string Warr Guitar, and it has bass extension like nothing else out there. After installing the STA-1200D amp, Gunn’s bass playing filled the room in a more organic way, with just a touch more emphasis on the leading edges of the notes.

The upshot is that my updated PC13-Ultra still sounds like it did before I opened it up. I re-read my 2013 review, and what I said then still holds. The aural differences I have mentioned are incremental, and don’t change the overall nature of the subwoofer. What has really changed is how I interact with it.

Before the upgrade, I accessed my PC13-Ultra’s amplifier and its associated DSP functionality via a single panel-mounted knob. The combination of its push-to-drill-down architecture and the single-line display made adjusting its parameters manageable but far from pleasurable. Now, the STA-1200D’s Bluetooth connectivity means I can goose the sub level if I want to, quickly and without moving from my sofa. I could always change it before, but I never did, because I’d have to reach around the side and try to find the knob without accidentally pushing it and entering into a menu. Ultimately, I never touched the thing. The SVS app rules, and I’m actively having fun with it.

Of course, it’s important to note that simply upgrading the amplifier doesn’t promote the PC13-Ultra all the way to PC-4000 status. While the subs are quite similar, the PC-4000 has an upgraded driver. Even so, the additional 200W is nice to have, and the additional control conferred by the smartphone app is extremely cool.

You can’t just order this upgrade on the company’s website, because SVS needs to know which Ultra sub it’s for—PC, SB, or PB—and whether you’re comfortable installing it yourself. So if you want to take advantage of this opportunity, you should nip on over to SVS’s website and check out the installation tutorial video first. If you want to go ahead, just shoot them an email.

That’s what the amp is, how it’s installed, how it sounds, and how you get it. The story here, though—what piqued my interest and made me so fascinated with this upgrade process—is that SVS even offers it. The PC-4000 retails for $2199.99, which is only $500 more than its predecessor, a decade on. For $100 less than the difference between the original price and that of the PC-4000, you can get most of the way to the functionality of the new model—ten years after the fact. SVS doesn’t have to offer this upgrade. The company could easily just keep shtum—“Oh, you want Bluetooth functionality? You’ll need to buy a new PC-4000.”

But SVS stands behind its products and seems happy to support them. In this world of planned obsolescence, that’s rare. That’s the story here, and it’s a good one.

Jason Thorpe
Senior Editor, SoundStage!