I got this a JVC RX-6018V amp about a year ago, and it's always overloaded after about 40. I wanted to ask how to tell if a speaker is shorted, and what other possible rememedies there could be for this. I tried unhooking all of the speakers and ran it and it still overloaded. I'm not sure what to try, I'm quite an amateur at this.
Are you using 4 ohm speakers, with an 8 ohm receiver? This can cause the receiver to overheat,and go into protection mode. Especially at loud volumes. Is the receiver closed in to a tight area, in an entertainment center? If it doesn't have good air flow, it will get hot. You can try having a fan blow on it, to help keepit cool.
It is highly likely that you are using low impedance speakers on a high impedance amplifier. There are a couple things you can do. *Edited* The unit is a simple 8 ohm unit: http://books.jvcservice.com/download/399211694/23290.pdf The load presented is likely too low. I suggest getting new speakers, but... You can also try strapping a simple ceramic resistor in line. You should be able to find a suitable 4 ohm resistor at Radio Shack for just a couple dollars. Strap it in line on the positive cable. This is not terribly adviseable, from a purist standpoint. It will cause second order phase shifts. However, if you are not terribly anal, it will work just fine. What speakers exactly are you using?
The speakers I'm using are the stock JVC speakers it came with. In regards to the heating, the system doesn't seem to get hot and it is in a ventilated space.
In that case, sounds like a trip to the shop. If it's [bold]always[/bold] done it, you should have done something, while it was under warranty. Or is it still under warranty? Good luck!
Sometimes dynamic impedance can drop below specifications and thermal an amp. I built a set of mains for my theater using 8 ohm loads and it still thermaled my amp set to 8 ohms. I checked my dynamic load and found it dipped to 5 ohms with it set to referance and a dip to 50Hz. I initially opted to set my crossover HPF to 65Hz, but I lost too much image to deem that as a good way to go, so I set the amp to a 6 ohm load, and dropped the HPF back to 50Hz. Anyways, I looked the unit up and never saw it listed as a package, was it a store assembled package, or was it an actual HT in a box? It would be really great if you could drop the speakers out and check their static resistance (ZNOM). Use an ohm meter across the terminals without moving the cone. Moving the cone will cause impedance shifts. I can get a rough idea of dynamic impedance (of course, enclosure design and amplifier settings can have an effect on actual dynamic load, but it is close enough, to at least see if the coil is shorted). Trying to read the static through the crossover will give inaccurate readings (crossovers are networks of inductors, resistors, and capacitors which ultimately alter static resistance measurements), so it is imperative that the driver be measured alone. I suspect the issue to be woofer related more than tweeter, if there is a speaker issue at all.
