Last year at Texas Heat Wave, I met the guys at Ground Zero USA. Saw a couple Reference amps and needed a change of pants, saw a great install or two, and snapped a few photos of the gear (which can be found on my website). Since then I’ve been wanting to try some of the gear, because I was pretty impressed with it. Things just didn’t work out, but after months of going back and forth with Scott I was finally able to reel in a pair of amps.
I chose to pick up a Ground Zero GZHA 4200XII and GZHA 2400XII. They are brand new casings, developed to take after the look of the Reference and Uranium amps. They are brushed metal, and intelligently designed for heat disappation. They have not only the fins on top, but what looks like solid metal from the top actually has a slot underneath it running through the case. Under those slots you can see a thicker tab of metal, which also runs side-to-side, and is what the MOSFETs are mounted to internally. Here’s a side profile picture:
Those side pieces are my least favorite thing about the amp, and really my only complaint. I think they look cheap. They are made of metal, but it’s some stamped metal that doesn’t match the sleek brushed aluminum of the rest of the chassis. Which isn’t a huge deal, it’s really the fan cutouts that really bother me. Those, IMO, make those side pieces look really cheap. I think they could have went with a different pattern and made it look much better.
Despite my animosity towards them, they are functional. The 4200XII does not have fans as it does not require them, but the 2400XII does. And you will notice that they are actually required, as there are components that are mounted to small heatsinks on the board. How these fans are controlled (always on, controlled by a thermostat, etc.) and how loud they are I have yet to find out.
The mounting tabs are on the front and rear, which I like. This, along with the connection/control placement, allows you to butt them up against each other, if you have the space, to make it look kinda like one longer amp.
The connections and controls are also on one side of the amp. I’ll call this the front, different from a lot of newer amps that use the sides for connections. As mentioned above, this allows different mounting configurations. It may or may not be beneficial in your particular install, but I prefer it.
The boards are clean. From what I can tell, nice quality components are used throughout, though I’m no expert on that, I’ll be the first to admit. The resistors are the box-type, normal film resistors covered in ceramic. This allows them to handle higher power loads, because they are able to shed heat better. The amps are a little deeper. They’re 11.5” deep, so larger than most. I attribute that to the connections being on one side, and not using daughter boards. I’m not a fan of daughter boards for the most part, I don’t know why, I know they’re functional and all that but I just don’t like seeing them. Also, the heatsinks for the components on the middle of the board aren’t exactly rare, but they’re not typically seen on most newer amps. They do necessitate the need for the active cooling.
Other than that the connections are pretty standard. Nice quality tiffany-style RCA connectors used. The potentiometers feel smooth, not loose at all but not too firm to turn, they feel like you should expect. Amps are internally fused.
Now for photos (can also be found on my website):
Ground Zero GZHA 2400XII
Ground Zero GZHA 4200XII
I don’t have a whole lot more to say at this point. I won’t be installing these for another almost two months probably, as I’m in the process of rebuilding the amp rack and I’ll be in Japan for three weeks starting next week. This was a visual review to this point, but mostly it’s a reminder for me to come back later and update with a listening review. I will be using the 2400XII bridged to a pair of Dayton HOs, and the 4200XII as a two channel bridged to a pair of TM65s. I'll be using a Soundstream REF2.370 for tweeters.
One last thing: customer service. GZ USA is absolutely on par with the best. I mentioned before that it’s been almost a year since I have been trying to get these. Well, I’ve been going back and forth with Scott for more than a couple months. He’s been cool throughout all of it, answered all of my stupid questions and me going back and forth on what I was wanting and basically anything you can think of. Literally hundreds of messages. I am the most indecisive person he’s probably talked to. I know I would be frustrated with myself if I were him. But I didn’t get any of that. Not only has he been supportive through the decision/ordering process, he makes sure I am happy with everything. I know if I have any issues they will get taken care of the right way and quick. Definitely highly recommend doing business with these guys. And that is what I have heard from everyone else who’s done business with them.
The GZ-train is leavin’, and I’m on board! WOO WOOOOO!!!!