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-   -   help unusual problem soundstream reference 500sx blue board (http://www.diyaudio.com/forums/car-audio/213724-help-unusual-problem-soundstream-reference-500sx-blue-board.html)

russdeanlee 2nd June 2012 07:55 AM

help unusual problem soundstream reference 500sx blue board
 
old school blue board soundstream reference 500sx problem.
very weird amp works fine for about 1-2 minutes then all the sudden there is some static and popping sound that is slightly lounder than the audio playing. happens on every mode and every channel. if i disconnect the power and power it back on the next day same thing happens. i get a clean sounding amp for 1-2min and then the static appears again. been trying to fix this for a long time now and just can't figure it out thanks in advance to any help, be greatly appreciated.

russdeanlee 3rd June 2012 04:38 AM

aye buddy sounds like no one likes you here in this forum
 
aye buddy sounds like no one likes you here in this forum to answer your question. you must of done something to have everyone hate you. will someone please help me out or is this problem no one has encounter before?

1moreamp 3rd June 2012 08:13 AM

I would try to resolder the FEB channel driver boards back properly. This is the only instance I ever had issues like those your posting about. There may be bad solder joints elsewhere but for the most part I have always found the vertical FEB channel driver boards are the issue.

The host of typical issue are the switches , the FEB boards, for the most part. Other then that you will have to pull the board and inspect for broken solder joints if wiggling the FEB boards does not tell you what you want to know, and fiddling with all the switches also...hope this helps :)

russdeanlee 3rd June 2012 10:21 AM

thanks for ur help
 
thanks for ur help i have done this already but will do it again its weird though always after about a minute of clean sound the static pops starts sounding making me think my speakers are blowing up.

anyways i have a handful of soundstream reference amps having turn on and turn off pops how can i get rid of this. its makes my system sound cheap. would using balance line in fix this?

could it be the caps next to the rca? i'm assuming it is caused by my 5volt rca outputs to the amps.

brandes.cm 3rd June 2012 05:29 PM

Do you have a scope, noisy signal is tough to track down without one.

Lighten the load on the outputs, does it take longer to get the noise? Only use one channel.

1moreamp 3rd June 2012 05:38 PM

1 Attachment(s)
Turn on pop is usually associated with high level in rush signals from the HU and or the signal processors. Most all amps have muting circuitry but this is ineffective if the turn on delay is too short. PPI, PG and most others all use some sort of muting control inside.
A solution is to use a delay capacitor on the amps turn on to solve the issue. PG made a device called a TIdd-5 and Tidd-10 to also address the issues. Although rare to find now they do work and I own one myself. Please see attached pdf file for a description.
I tried to upload a simple capacitor add on delay pdf but the site won't let me probably due to some abnormality of the pdf file. But adding a simple 1N4002 diode inline with the turn on signals and a [470uf = 2 seconds, 1000uf = 4 seconds and a 2200uf = 8 seconds delay,] electrolytic cap will delay turn on to signal processors and amps. Or just buy one of the many turn on delay boxs sold by companies for car alarms and such. they will all work just fine, and give you a larger turn on delay thus allowing all the pop noise from the front of the system top subside before the main amps fire up.

As for your static issues on your SS amps it could be dozens of things causing your issues. I suggest you setup the amp on a bench and power it up with music into speakers and use some freeze spray to try and locate intermittent faults and or just wiggle and tap with the plastic handle of a screwdriver till you find the issues. But I am inclined to think you have bad solder joints first by force of habit over the years of servicing these amps... hope some of this helps, but without being able to bench your gear myself its all conjecture at this point...:)

1moreamp 3rd June 2012 06:58 PM

" aye buddy sounds like no one likes you here in this forum"


Some of us here are very busy working on other gear for folks and often even have a personal life to contend with also. [ Sleeping, relaxing, dinner, household chores etc...] So please try not to feel that you are being singled out and or treated poorly just because some of us are busy. We all do this for free and in our spare time just to try and help others as possible. Its not personal so please don't take it that way....:o

MatthewS 3rd June 2012 09:50 PM

When you vaguely state the amplifier itself produces this sound, you leave me to assume all channels. When that is the case I look towards sections all channels have in common. If it were just the driver cards, the odds alone that the trouble is there and producing the exact same results across the board are very very low. That would be like assuming you have the exact same cold solder joint on each board.

I have heard op-amps do some strange things when driven near or beyond maximum operating voltage. Some exactly as your describe, an overbearing and dominating snap, crackle, pop. Buy your not being very specific with a group of people who like specifics. So either elaborate more or start by measuring the +/- supply voltages to one of the op-amps when it is cold and operating properly, and them another when the trouble is active.

Either way when something happens on a time scale I consider it 'drifting' and the drift's that come to mind are voltage, or component spec. Both of which can be caused by several outside influences, or just a bad single part in general. Start by posting the voltages, and any more details you have. Does it happens in every crossover mode, etc.

And like 1moreamp said, nobody around here is paid directly or indirectly by you or anyone else for their time. A sense of entitlement in life won't get you very far.

- Matt

russdeanlee 6th June 2012 12:35 AM

thanks to all who has helped me out
 
when you say add a bigger cap to delay the turn on pop will this also control the turn off pop or are they 2 different caps? yes the static sound is coming from all channel all crossover setting and all modes. i think i might of fixed it i dont get the static anymore if there is audio being played but if i dont have the rca plugged in i get static sound coming from speakers but as soon as i plug in rca it goes away and another thing i forgot to mention is that the amp is always on high current mode even with 4ohm load in stereo powering midrange speakers i can't get it to go high power.
i got rid of the static by just touching up everything that looked like cold solder joints with flux and adding new solder to it. thanks for the help again.

1moreamp 6th June 2012 05:25 AM

Quote:

Originally Posted by russdeanlee (Post 3049610)
when you say add a bigger cap to delay the turn on pop will this also control the turn off pop or are they 2 different caps? yes the static sound is coming from all channel all crossover setting and all modes. i think i might of fixed it i dont get the static anymore if there is audio being played but if i dont have the rca plugged in i get static sound coming from speakers but as soon as i plug in rca it goes away and another thing i forgot to mention is that the amp is always on high current mode even with 4ohm load in stereo powering midrange speakers i can't get it to go high power.
i got rid of the static by just touching up everything that looked like cold solder joints with flux and adding new solder to it. thanks for the help again.


The delay cap won't effect shut down issues only mute fets and or signal line shunting to ground can handle that. That is why I recommended the TIdd device it allows for different on and off setups to your gear.

Your high current mode is likely a sense transistor across each channels output that has been fried by a failure. I only have 500s info and its Q47 Left and Q46 Right tied thru Q46 together to the op-amps U7A. These detect the V drop across the emitter resistors and trigger the auto mode selection to occur thru op-amps U7A which is a TLO72. It is likely that one or more of those transistors fried if and when the amp channel failed before... Its a simple circuit way less then the amp itself,. And it drives the mode leds directly for either mode operation.

You description of the amp lacks any real history so I am guessing it had failed a channel in its past and somehow the power/ mode selector was overlooked in the repair. < best guess > Have a good one...:)


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