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PS Audio GCC-250 Control Amplifier

A Candid Look at PS’s New Gain Cell Technology

 

June 2005


After reading the recent glowing reviews of the PS Audio HCA-2 digital amplifier, and learning more about the Gain Cell Technology used in their new “G-Series” control amps, I couldn’t help wondering how advanced these new amplifiers might be. Just look at this quote from their website, and you’ll understand what I mean:

The GCC Control Amplifiers are similar to the classic integrated amplifiers but without all the compromises associated with an integrated. Actually a cleaner, simpler audio path than even separates, Control Amplifiers will become the standard by which even separates will soon be judged on.

Despite the not-so-perfect grammar, I was hooked and wouldn’t rest until I’d heard one of these stylish, svelte dynamos for myself.

The G-Series amplifiers use analogue Gain Cell Technology at the input stage, which couples to an SDAT Class-D digital output stage. There are three models in the G-Series, rated from 100Wpc to 500Wpc into 8-ohm loads. The GCC-250 (which is the subject of this article) is in the middle of the series and is rated at 250-wpc into 8Ohms and 500-wpc into a 4-Ohm load.

Features
The GCC-250 has a total of five inputs: one balanced (XLR) and four single-ended (RCA). There is also a pair of buffered RCA outputs intended for running a powered subwoofer or a second amplifier in a bi-amp system. On the rear panel a female IEC connector is provided for use with after-market AC cords, and a three-position dimmer switch sets the mood of the front panel lighting. The unique, heavy-duty speaker binding posts will accept banana plugs, bare wire, or spade connectors. They house an internal locking mechanism that tightens around the male banana as you twist it. This works better with some types of bananas than others, but should provide a secure connection regardless. A circuit breaker and a 12V trigger complete the rear panel features.

The front panel is clean, elegant, and thoughtfully laid out with tastefully beveled outer flanks. It contains the remote sensor, up/down input selector, mute button and a sexy, smooth-turning volume knob. A blue LED display/menu is in the center. The characters are clear, but smallish -- not that easy for my middle-aged eyes to see from 12 feet away. The clever new PS logo doubles as the power switch.

The small plastic remote worked well (once I replaced the dead batteries that came with the review sample with new batteries from my private stash). With the remote, you can adjust the volume and balance, choose your input, mute the sound, invert the polarity of the signal, and power the unit on or off. There’s a Home Theater Bypass feature and again, a dimmer to allow you to set the mood. Actually it’s a very useful device.

A couple of unique features worth mentioning are the ability to name your own inputs, and the ability to gain-match the inputs so that they will appear to have the same relative volume setting. I chose simple names for my inputs like “CD” and “PHONO,” but the more creative among you could name them, “DAT,” “DIS,” “GIZMO,” or even “ALICIA KEYS!”

The Adventure Begins
I installed the GCC-250 in my system using the same SignalCable speaker cables and Silver Resolution interconnects that I had been using with my reference amplifier. The one exception was that I was able to use an after-market AC cord on the PS amp where I was limited to using the captive AC cord on my reference amp.

As fate would have it, the first thing I found out about the GCC-250 was that it is extremely sensitive to the quality of the AC it is being fed, and to the particular AC cord that is employed. The first cord I tried sounded very bright. Switching to a SignalCable 10-guage MagicPower cable did much to improve the frequency balance but I still felt that there was room for improvement in other areas.

I tried the stock black power cable that PS supplies with the amplifier just to get a base-line performance standard and found that the stock cable is fairly neutral sounding but that the SignalCable MagicPower cable was a definite improvement.

About that time, I shared my preliminary impressions with PS Audio’s commander-in-chief, Paul McGowan. When I intimated to Paul (via e-mail) that I was using the venerable Tripplite IB-8 AC filter/surge protector on his pride and joy, I could have almost sworn I heard him laughing from several states away. As I recall, his response was something like, “Excellent, throw that thing in the trash right away, would you!”

Paul immediately sent me a PS Ultimate Power Cell (UPC 200) AC conditioner. I figured it couldn’t hurt to try it and it would give me the added flexibility of being able to use the Ultimate Power Cell in its High-Current mode to isolate and supply clean power to the GCC-250 exclusively. I thought it important to isolate the GCC-250 as much as possible because A): it is partially a digital device that can feed power-line trash/interference back into the AC line; and, B): it can draw a moderate amount of power if it is played loudly enough. As it happened, the UPC improved dynamic contrasts and enhanced the performance the PS amp, and my reference amp, as well.

I initially installed the UPC using a couple of PS Audio Xstream power cords that Paul had loaned me. However, I found that the combination of a 1-meter Guerrilla Audio power cord between the wall and UPC, and a 2-meter SignalCable MagicPower cord from the UPC to the GCC-250 sounded more relaxed and natural to my ears. This combo gave the best results of all that I tried, so I used it for the bulk of my listening. Suffice it to say that the GCC-250 is VERY power-cord sensitive.

To further tweak the sound, I tried different feet on the GCC-250 as the manual suggests but found that its stock feet sounded better than BDR cones, wood blocks, and whatever else I tried. Going with the stock feet on a competent surface appears to be the ticket. That said, the Ultimate Power Cell responded readily to feet tweaks and after some experimenting, I settled on a small tiger-wood block under the UPC, which enabled the system to sound its best in the high frequencies.

If you do not pay close attention to your system’s AC quality and isolation, power cord-synergy, and the mechanical coupling of your various ancillary gear, you can expect the GCC-250’s high-frequencies to sound strange; and the pace, rhythm, and timing (PRAT) aspects will likewise suffer. These set-up details also pertain to other amplifiers, but should be observed more critically with the GCC-250.

The Sound
As outlined above, I spent a considerable amount of time optimizing the GCC-250’s performance in my system. My gut feeling is that the GCC-250 is performing as well, or very nearly as well, as its design parameters will allow. Both the amplifier and the Ultimate Power Cell required at least a solid week (or more) of break-in time before I could get serious about the evaluation. Here’s the skinny, in depth.

One of the first things I noticed about the GCC-250 is that its character is very consistent whether you play it at low or high volume levels and anywhere in between. Under high-drive conditions with complex material, the amp maintains its composure presenting each instrument and sound as distinctly and clearly as the recording permits. It enables one to hear low-level nuances that get buried in the mix with lesser amplifiers. You’ll hear details within the layered soundstage that you may not have noticed before, ever.

The amplifier also does a credible job of keeping the two stereo channels separate (when it’s intended), and in that regard it reminds me more of a good dual-mono design than of a single-chassis amplifier. Also, in many stereo recordings there are sounds that appear to float back and forth between the right and left channels. The GCC-250 is excellent at presenting such information, letting you follow the traveling instruments or sounds without any doubt as to where they are located at any particular moment.

I must tell you that the GCC-250 is the quietest amplifier that I’ve ever had in my system. Sounds just appear out of nowhere no matter how soft or loud they may be. This is partly the reason that the amplifier presents such a wealth of inner detail. When I put my ear directly on my speaker’s grill I cannot hear one iota of hiss, buzz, hum, or any other sound, even with the volume turned up. PS Audio claims a signal to noise ratio of minus 120 dB and I have no reason to doubt it.

System dynamics are outstanding with the PS amp. Both macro-dynamic and micro-dynamic contrasts are well preserved. A good example is Ray Charles’ voice on his Genius Loves Company CD [Concord/Hear CCD-2248-2]. Every syllable from a whisper to a roar is deftly reproduced by GCC-250. There’s no compression, no distortion, and no hardening of the sound. It’s just Ray’s glorious voice, the way the Lord intended. And speaking of vocals, the GCC-250 does a very respectable job of reproducing male, female, and all backing vocalists. The detail and tonality are convincing and the lyric comprehension is first rate. Previously difficult to understand lyrical passages are unraveled with irreverent nonchalance by the unpretentious PS.


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PS Audio GCC-250 Control Amplifier