Iv had an itech 6000, based in Australia, for about 18 months now, and haven't had any issues with it until lately.
The issue began about 6 weeks ago at a gig. It runs with 4ohm loads per channel, and the output is clipping at what the output meter in sys arch says is around -18db, and cannot get anymore output from the amp. On the front panel, the amp is skipping the -20 and -10db leds and going straight to clip, with NO thermal led lighting. Lately, the amp has also had the fans running at full speed right from turn on.
This happens, both the output limiting, and the full speed fan, whether the amp is running off a 20kva 3ph generator, (amp gets 245V according to sys arch), or whether on mains power supply ( sys arch reads 240V). Nothing has changed in the signal chain on the input stage,and the load is the same, from when the amp has been running in the last 18 months until now. I have 2 xti4000's running daisy chained off the analogue xlr inputs, which have no issues.
The amp runs with a fast attack -3db compressor, with 10:1 comp ratio in the DSP, and 1200W rms power limiter per channel. It is being used to power 4 martin WSX subs, ideally with 1500W per bin (2 bins per side,to give a 4ohm load) from 35-100hz. But i dont think the amp is giving more than a couple hundred watts per channel at the moment. I swapped it out with one of the xti4000's just for a test and the xti pushed the subs much harder than the itech.
The amp gets used outdoors, but has never been in a wet environment, and is cleaned after every gig, with the front air filters being washed. I have swapped the amp to different phases on the 3ph generator with no different results, which leads me to believe it is an internal fault in the amp. I have changed DSP profiles on the amp, with the same results, whether i bypass as much of the dsp as possible or not (including disablling the RMS limiter and the input compressor). I have also tested the amp with different input signals, changed the input sensitivity, to range the input meters from around half, to full and just clipping, with the same results on the output. I have tested with 4 and 8 ohm loads on the output with the same results. Toggling the clip limiter on Sys Arch makes no difference either. During a recent test, the amp was doin the same limiting and high fan speed problems, so i turned it off. But when i went to turn it back on there was power on the power switch, but no fans would spin up, and nor would the LCD panel on the front panel turn on.
Any information at all would be greatly appreciated. Note that the amp was purchased as b-stock 'new' online from the US, so i understand shipping back to, and return from, US for warranty is at my own cost. Just wondering if there is any other alternatives, or something simple i could have missed, before having to send the amp in for a service.
Thankyou for your time, and any help you can afford me.
Cheers from Australia,
ps. on another note, the amp has performed rock solid until this fault, and i would still highly recommend crown to anyone.