simschr Posted May 4, 2008 Share Posted May 4, 2008 Hello,We have an RCF ED1100 amplifier running a small PA setup which has worked fine for many months (we've had the amp for around 6 months now) but recently we've noticed a problem with the channel 1 output, it appears to be considerably quieter(?) than the other output, we have checked the mixer and all cables in the setup and appears to come down to the output on the amp. We don't really want to replace it as it costed a fair amount of money to purchase and wondered if anyone has experienced anything like this with an amp previously? Just before we have to spend money for the problem to be diagnosed. Thanks,Chris Link to comment Share on other sites More sharing options...
Simon Lewis Posted May 5, 2008 Share Posted May 5, 2008 I presume you've checked that when you swap the speaker leads or input leads over, the fault stays with the amp channel? If you bought it new, I'd guess it's still under warranty? Link to comment Share on other sites More sharing options...
simschr Posted May 5, 2008 Author Share Posted May 5, 2008 Indeed it does, when swapping the speaker lead and input to the other channel the output level is fine. Thanks for the help - I shall look further into the warranty. Thanks,Chris Link to comment Share on other sites More sharing options...
Solstace Posted May 6, 2008 Share Posted May 6, 2008 For any amp that's not under warranty and the fault is identified with the channel, then it might be worth popping it apart to check the input connectors are soldered properly. My thinking: I've had to take apart and re-solder five of my amplifiers this week (admittedly not RCF) having identified a 6dB drop in Channel 1 in each of them, as compared to Channel 2 fed with the same signal, driving the same speaker. Turned out that the XLR connector legs weren't fully soldered to the PCB, so the signal had gone one-legged! Link to comment Share on other sites More sharing options...
Lamplighter Posted May 6, 2008 Share Posted May 6, 2008 I have come across a design problem with the RCF DCA series amplifiers, when used in stereo mode the channel gains are notthe same. This is due to the inverting amplifier input that is part of the Bridge mode configuration still being connected to Channel 1. This loads the channel 1 more than channel 2, directly after the input attenuator. The effect is about 4 dB gain reduction on channel 1 when the attenuator is mid travel eg the most used position when matching amplifier to mixer output! Simplest cure is to fit a 10Kohm resistor between the slider and ground of the channel 2 attenuator. I'm not sure if this problem has been cured on the ED series.Brian Link to comment Share on other sites More sharing options...
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