TI2 1600.5 headunit volume 0 pop

[Imk'ed]

Hello people, my first message on here. I just bought a ti21600.5 and i have an odd issue which im hoping you guys can help me with. When i switch on my hu (alpine 9855r) and soon as it loads up and sound starts playing if i straight away reduce volume to 0 it makes a pop through speakers, it will only do this once and im sure it doesnt do it again until i switch it off then on again. Another thing is it has to be done within a few seconds of switching on, if i switch it on and let it play for 10 secs then reduce volume to 0 it doesnt do it. Its an odd thing never had anything like it and it only doesit with this amp, im guessing its something to do with the hu muting circuit and maybe the balanced differential inputs on amp?

Sorry for long post any help would be great and if yourrunning same amp if you could test it and see if it does it would be a great help thanks.

[kg1961]

Try your ipod or phone to see if it the deck

[Imk'ed]

Ok cool, i'll try another head unit and see if that makes a difference

[MW3]

The problem is the headunit. Add a ground loop isolator and it will fix the problem.

Ti2 1600.5 uses a balanced input, this means the RCA shield feeds the input of the amplifier. Some Alpine and Pioneer amplifiers send voltage spikes down the RCA shield, a balanced input amplifier will amplify this voltage spike.

My guess is most headunit manufactures assume amplifiers use an unbalanced input where the shield goes to ground and does not feed the input of the amplifier.

[kg1961]

Morgan your back

[MW3]

I never left. I answer the posts where someone needs help or has a question...

I don't get too involved in posts about buying older gear, topics that have been cover many times. As most the senior guys here usually post the correct answer anyway.

But if you email with specifics I would be happy to give suggestions on just about any topic.

[Imk'ed]

Good stuff! Glad to know amplifiers ok! Im thinking off putting my stock hu back in with a audiocontrol lcq1 and i will buy a better on at a later date. Another quick question morgan, i did actually try a pioneer double din hu and it was fine on this mute click issue but it was a noisy hu i could hear disc changing track etc that doesnt bother me as i was just using it as a test but while i was testing it i had the headunit temporarily connected and the rcas were connected aswel and i disconnected the head unit wiring and then first reconnected the positive then the negative. Remember rcas were connected aswel, maybe im being paranoid but because i connected the headunit positive first and the rcas were connected would the headunit try and ground through my amp and damage anything? The headunit stayed off until i connected the hu ground but could it damage anything trying to ground through amp?

[Imk'ed]

Ive worked out two possible scenarios that could cause pop. Before this amp i had a jl hd900/5 that has balanced inputs but had no pops. First scenario as morgan stated is a spike that is amplified through rca ground but i think on headunit side rca is grounded so maybe not that. Second scenario is that im sure the headunit muting circuit mutes the positive of the rca to ground and not the shield as it would have to mute unbalanced amplifiers, and so its that whats causing pop the positive of rca is being grounded and i bet its discharging a cap inside amp as if i try it again straight after doing it it doesnt pop but if i play music decently loud and then do anything on headunit that engages the muting circuit it pops. To me this makes sense as the pop has a delay in popping after its popped kind of like a delay a capacitor would cause while its charging up. I apologise if this is non sense lol but it kinda makes sense, so there must be capacitors on the input of amp being discharged when positive of rca grounds and it takes 10-15 seconds of playing music again to charge caps to repeat pop.

[Imk'ed]

Morgan any help sir?

[Imk'ed]

Anyone else had experience?