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CTs 1200 with pip usp3 card making popping, crackling noises. Video included. Please help

I'm having a weird problem with my Crown CTs 1200 that I just bought used from eBay. It was sold as a guaranteed working amp. Well it does work but for the first minute or so after turning it on it makes this popping crackling sound. As soon as I play a test tone the crackling goes away and the tone is nice and smooth. But after a couple minutes of having it on the noise mostly goes away but not completely. This problem happens even without anything hooked to the input of the amp . I plan on calling crown technical support Monday but just thought I'd check here first if someone thinks I got a bad amp. I really hope I don't have to send it back. Is this a common issue? Maybe the pip card is bad? Thanks

https://youtu.be/HmuvbWVC2Fc

Comments

  • nojoconojoco Posts: 31
    edited January 2022

    Does it do the same thing with the PIP card removed? Is it coming from both channels?
    The CTS line of amplifiers are designed for 70/100 volt systems. The speakers you have connected (in your video), are those 70 volt capable speakers?

  • dustint209dustint209 Posts: 2
    edited January 2022

    It is hooked up to a 4 ohm speaker. The manual shows wattage ratings for 70v, 100v, AND 2 ohm 4 ohm etc. And Ive seen other people use them in home theater systems. The amp pushes the speaker fine and sounds great when its cranked up. The popping sound is only when no signal is sent to the amp. I just removed the pip board and the pooping sound is gone. So i guess I have a bad card? I've seen a few on eBay that are "for parts or not working" so I assume they do go bad. Thanks for your help

    From the Crown CTs manual

    Direct constant-voltage
    (70V/140V) or low-impedance (2/4/8 ohm)
    operation. No switch required.

  • nojoconojoco Posts: 31

    Nice to see that amp can support ohm and voltage loads without switching. From what you described, it does sound like a bad PIP card. I'm sure a PIP card would be more affordable for a replacement than the entire amp. Good luck!

  • hello i dont think the unit is bad because i have been working with signals and always balanced stuff with computers working through most of the behaviors of daqs and amps and dsp aiming at audiophile level. what your describing actually was highlight extremely well in a new daq that arrived.

    essentially my hypothesis is after some time the drivers in the audio DAC tell the card to disconnect from the stream and the DAC goes into like a floating point sorta behavior. i suspect its a DAC and driver moronic code fail.

    i had 1 DAC unit that it was bad, screaming noise when audio stopped playin, i added som pull down resistors on the balanced input cables, bringing both +,- down to gnd. i think it dropped the static down by 70% when the floating voltage behavior occurs. essentially if you have no pull down and a floating voltage starts to occur, it gets sampled you might say by the amp input on the pip card. and played out the amp.

    for this specific dac i added a wmp bat file that starts when windows starts and plays silence to prevent the dac from disconnecting the audio stream.
    its a work around, i think only the uber expensive dacs have everything perfect, but theres still a windows code fail there......

    when i learn more i can update but from my observations, and oscilloscope meters and tests, that what i found.

  • "C:\Program Files (x86)\Windows Media Player\wmplayer.exe" --loop "C:\yQuiet\Silence.mp3"

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