I-Tech 8000 fan issue

i-tech 8000 fans thermal

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#1 Val

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Posted 15 April 2013 - 01:41 PM

Saturday night i was running my itech 8000 on 4 Jbl Vrx 932s (2 per side) and after 2 hours the fan didn't come on (the fan inside the power supply didn't come on either). I put my hand by the back of the amp and it was pretty warm. I have 2 Xti4002s and a lab gruppen 7000 and the fans were all running on those. I checked in the menu for thermal errors, there weren't any.

Has any experience this before? I wasn't clipping the amp but it was definitely getting pushed (4 ohm load per channel)

I am running the latest firmware.

Thank you


#2 dakos



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Posted 15 April 2013 - 11:48 PM

Dear Val,
Is this a new thing? I thought I had a fan issue when the fans came on and would blow pretty fast when idle, no thermal faults, the amp was very gently warm to the touch but nothing else warm, I was so alarmed that I bought a fluke multimeter and opened up the amp only to find four good thermistors. When I started to load the amp it wasn't any warmer, and to my surprise the fans stopped blowing. I guess the amp is just working in this way.

#3 Val

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Posted 16 April 2013 - 12:10 AM

I guess it's a new thing because I've been in my storage space and fired the amp up and the fans were running. (sometimes really loud then they would turn down) Pretty sure that was before I did the firmware update.

I just don't want this thing to bomb on me at an event.

Is there a way to turn on the fans to make sure they are still working?

Thanks Val

#4 joust


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Posted 17 April 2013 - 11:16 AM

I doubt very much that both fans would fault at the same time. But it is not improbable (Murphy).
Which version of the firmware are you running?
Can you verify if both fans are still connected securely inside the amp?
On power up, inspect the fan from the outside (you can use a flashlight to get more light): the fan may wobble a tiny bit on the initial power on (similar to the CE series). This is normal.
You could inject signal (without loads) and observe if the fans start.

With a BCA amplifier, heat is not managed the same way as with an 'analog' amp. In an analog amp, heat is generated by the output devices with signal going through to the load. An oscillating fan will help to evacuate the heat to keep the output devices 'cool'. With no load, the heat generated by the output system will be set by the bias levels.
In a BCA amplifier, a little bit of heat is generated every time the output device changes 'state', even in idle mode! Hence, the Sleep mode: modulation is stopped until a new signal is detected and the amp comes out of Sleep. Most of the generated output power goes through unhindered (except for BCA simplification) from the output devices to the loads, without too much resistance. This is why, the IT8000 evacuates about the same amount of heat as an IT4000! So, as long as the output devices remain 'cool' even when delivering power, fans will be used sparringly.

Try this: inject some signal to the amplifier with no loads connected and leave it running (to stay out of Sleep). There may be instances when the fans will oscillate momentarily and then stop.