Jack Hidley

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About Jack Hidley

  1. A while ago, I did a lot of testing on three of my Xti2000 amplifiers. All testing was done with the AC line voltage stabilized at 120VAC and monitored. An AP system 2700 was used with an AES17 LP filter. I tested them into 4 and 8 ohms single channel/stereo and bridged mono. Above 30Hz, they have no problem meeting their power specifications. Below 30Hz, the power output drops off quickly. On the lab bench into resistors, they basically work fine. When used into actual loudspeaker loads, it is a different story. If you apply any EQ below 30Hz, there is some type of protection that goes off in the amplifier, shutting it down. Unfortunately, there is no indication of any kind as to what type of protection has been triggered. This is a major problem. I have eliminated all of the things that I can. AC line voltage, amplifier temperature, load impedance, etc. I have spoken to Crown about this twice and they have no idea what could be going on. All three amplifiers exhibit the exact same problem. Also using System Architect with the amplifiers is impossible as they go offline anytime there is any significant power draw from the power supply. Yes, my USB hub is powered. Clearly there is something wrong with the power supply regulation of the USB receiver circuit in the amplifier. If I had known about the low frequency power/protection issues, I would have just purchased Xti4000s instead.
  2. I suspect that during QC, Crown uses the Speakon outputs for testing the amplifier output. They should add a conductance test between the binding posts and the Speakon outputs. That would have caught this problem.
  3. You probably have a ground loop between your XLS amplifier and either your cable TV or satellite service. There are a couple ways to deal with this. Removing the third prong on the power amplifier isn't safe and usually only partially solves the problem. #1 Use an audio isolation transformer between the subwoofer output of your receiver and the input of your XLS power amplifier. Best solution from a noise standpoint. #2 If you have cable TV service, disconnect the coax cable from your system. If the problem goes away, get an isolation transformer for the cable system, such as a Jensen VRD-1FF. #3 Build a properly wired RCA (unbalanced) to XLR/TRS (balanced) interconnect. You can't buy these. No one makes them properly. Go here and make the cable according to figure 2.1. This is the cheapest solution. http://www.jensentransformers.com/an/an003.pdf To make this cable, you MUST use a three conductor cable and connect the shield and - audio phase at the RCA end. It is usually easiest to just start with an XLR to XLR cable and replace one XLR with the RCA connector. It amazes me that reputable companies, even Crown, continue to tell people to make this cable the incorrect way.
  4. Problem found, and fixed. http://home.comcast.net/~jhidley/IMG_5716.jpg I think someone was trying to save some money on solder:) Jack Hidley
  5. No output of any type. Not even hiss. Jack Hidley
  6. I recently purchased 3 XTi 2000 amplifiers. I've updated the firmware with SA. Two of the amplifiers work fine. On the third, there is no output from CH2. The signal present LED on the front panel illuminates correctly. No fault indicators are on. DSP is turned off. I've twisted the input attenuators around a bunch and shaken them a bit. No change. Not knowing the internal architecture of the unit, my question is this. Are these symptoms consistent with the defective or loose ribbon cable issue? Jack Hidley