Carvin AC120S Power Conditioner

I recently purchased the Carvin AC120S power conditioner/switcher to use in my home studio. I was looking for a device that would sequence my equipment on and off automatically and this unit fit the bill. It has a master on/off switch making it impossible to accidentally leave a piece of equipment tuned on when you are finished with a recording session. Exactly what I was looking for. At the time of this writing I have been using the unit for about 5 weeks.
The AC120S was shipped quickly and arrived in a reasonable amount of time. First impressions of the device are that it is built solidly and made to last. The case is heavy duty and it has a really heavy duty power cord that you will never be able to overload. It is a professional looking piece of equipment and looks good in my rack. I was a little disappointed that there is no "Made in the USA" sticker anywhere on the unit, and as you will see below, it may not have been made in the USA.

I first tested the AC120S without any other equipment connected to it. Pressing the master power button on the front of the unit turns on the voltmeter and prepares the unit for operation. I immediately noticed that the voltmeter reading indicated that my line voltage was 130 to 132 volts. After checking this against a high quality voltmeter, I determined that my line voltage is actually 122 Volts and that the AC120S was reading about 8 to 10 volts too high. After consulting with Carvin tech support, I was told that there is an adjustment pot inside the unit. I was quickly able to calibrate the voltmeter and it now reads accurately. While I was inside the AC120S I did not notice any of the MOV (metal oxide varistors) transient surge protection devices that I would have expected to find.

The second thing that I noticed is that the sequenced timing when turning the outlets on and off is far less than advertised. With the time setting at 4 seconds there is a total of 25 seconds from the time the sequential start button is pressed until all of the outlets are on. I would expect this time to be 36 seconds. Of course, the 1,2 and 3 second options give even shorter times. Tech support did not have an answer for this and said they would email the people that manufacture it for them and let me know. This tells me that Carvin did not actually make the unit and it was most likely made outside the USA. After waiting several weeks for a reply I contacted tech support again and was told they have not heard from their supplier.

I mounted the AC120S in the top of my rack, connected equipment to the outlets on the back of the unit, and pressed the sequence button to start my equipment. When sequencing "on", occasionally, the first two or three outlets will sequence on and then all turn off at once. Pressing the sequence button a second time usually sequences everything on normally. Similarly, when sequencing "off" the number 1 & 2 outlets almost always turn off simultaneously without any delay between the two. The unit works perfectly, every time, if all of the equipment connected to the AC120S is turned off. It seems as if the AC120S is sensitive to the voltage spikes that occur as the equipment is powered on/off; the very thing that it is supposed to be protecting my equipment from. Tech support had no answer for this issue either and at this point I do not expect to hear from them again. There is no way to know if the AC120S will actually protect my equipment from a line surge or not. At this point I am using a commercially available surge suppressor in front of the AC120S to be on the safe side. When I get some spare time, I will probably go back and add an MOV across each of the 10 outlets and on the incoming power line.

There is a nice EMI/RFI filter inside the unit that I am sure will help filter out any EMI type noise that may be on the power line. The filter is a commercially available device, and I feel confident that it will work.
This was my first purchase from Carvin, and it will most likely be my last. The AC120S is not built as advertised and its operation is somewhat "flaky". I can only assume that this is typical of Carvin's equipment and I will stay far far away from anything else that has the Carvin name. Fortunately at $149.00 plus shipping it was not too expensive a lesson to learn and the unit at least works to some degree.