# remote wire voltage reduced = sq reduction?



## 60ndown (Feb 8, 2007)

ive been running, an in-dash eq, 3 way electronic x over and 2 amps (4 components) off the 1 hu remote wire for about a year, everything came on and worked normally except occasionally (twice a week) a BAD humm would come from the system @ turn on, id turn it off and on again and no problems. 

today i installed a relay type thing ($12), is it possible (or psycoacoustics) that there is an improvement in sq now that each component is getting a stronger signal via the remote wire?


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## Oliver (Jun 25, 2007)

Send me some of what you're doing lukeboa


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## ryan s (Dec 19, 2006)

a$$hole said:


> Send me some of what you're doing lukeboa


x2 pass that around :laugh:

The remote turn on just tells the amps "hey...turn on." I don't believe you can have a half-on amp...


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## 60ndown (Feb 8, 2007)

meh, i can see how a weak signal might impact a devices potential.when a car battery starts to die, the car still runs (its on) but performance declines. if my voltage was so depleted it might have been failing to fully juice a capacitor or something?

or not


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## ryan s (Dec 19, 2006)

Well, either the battery can start the car or it can't


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## Oliver (Jun 25, 2007)

ditto ^^^


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## 60ndown (Feb 8, 2007)

meh, the alternator can start to fail, reducing voltage, car will still run but lights will dim etc. 

you have to remember im not a tweaker like most here, ive had this set up UNCHANGED for about a year, im extremely familiar with the way it sounds, 

i put in this relay device and-- things sound better .....

like the absence of some low level clipping, more detail, cleaner, image is higher too.

cant explain it, can hear it.


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## benny (Apr 7, 2008)

You sure nothing else got changed when you put in t he relay?


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## 60ndown (Feb 8, 2007)

benny said:


> You sure nothing else got changed when you put in t he relay?


wel i did empty the van


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## Robin W. (Feb 18, 2010)

There is a very slim chance that the remote voltage was right around the cut off point of turning it on/not turning it on, if it was quickly cycling a component on/off but the power supply capacitors kept it on long enough for the next "on" cycle to kick in it would function and possibly at a reduced level of performance. This is a pretty long shot though, as most things will turn on or atleast remain on at a quite low remote voltage level.


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## Candisa (Sep 15, 2007)

That must be it indeed. The headunit doesn't have to give that much current over it's remote-wire anymore, so the pre-amps get a more stable power --> cleaner signal.

Isabelle


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## MarkZ (Dec 5, 2005)

Robin, there are turn-on delays that would prevent it from behaving like that. There would be a noticeable disruption in the sound.

60, no, your remote wire just flips a switch. That's all. But, as the others have mentioned, it could be a symptom of some other problem with the HU or the electrical system.


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## Robin W. (Feb 18, 2010)

MarkZ said:


> Robin, there are turn-on delays that would prevent it from behaving like that. There would be a noticeable disruption in the sound.
> 
> 60, no, your remote wire just flips a switch. That's all. But, as the others have mentioned, it could be a symptom of some other problem with the HU or the electrical system.



Not all amps have a turn on delay (meaning 1/4-1/2 second turn on, not instant) and most processors have virtually no delay, I've been able to replicate this but it was with a 5-6v remote voltage. But that was simply for testing the limits of the remote turn on voltage range, with a low current source at the right voltage the processor can start to oscillate, turning on and causing a small voltage drop of the remote line turning the processor off, causing the voltage to return to normal, turning on then off again... you get the picture. 

There are amps that have a pronounced turn on delay that would make this very noticable as you say. The Arc KS300.x have a good 2-4 second turn on time, I've never actually measured it but it's the longest of any amp I've ever owned.


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## 60ndown (Feb 8, 2007)

well ive spent a few hours now listening to it and there does seem to me to be a significant but subtle difference. it does sound cleaner/more dynamic. 

much of what is suggested as a possibility above makes sense to me.

id need some electrical testing equipment and some knowledge to investigate further, i have neither.

ill trust my ears and consider it $12 well spent.

and the bad humm that would happen occasionally has not happened since the relay was installed..

??

this makes sense to me



cajunner said:


> My hypothesis is that the built-in circuit in the head unit was drawing too much power from the signal path circuits.
> 
> 4 units of turn on, depending on wire losses and lengths, and age and relative power required for relay, could conceivably draw enough power to impact the internal voltage of the head unit, causing a low voltage condition.
> 
> ...


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## MarkZ (Dec 5, 2005)

Robin, I don't know of any amps presently made that don't have a delay of some sort. You need to have one so that the switcher doesn't self destruct. As the caps discharge on an "off" cycle, the voltage will be reduced. If you don't have a delay or a softstart implemented, they'll detect this in the feedback loop as an undervoltage condition and will ramp up the switching until kablooey! It can be fast, but it still has to be there. I'd be surprised if his amp was switching on and off so fast that it manifested as a decrease in "SQ".


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## 60ndown (Feb 8, 2007)

im thinking the issue was power drain in the hu.



MarkZ said:


> Robin, I don't know of any amps presently made that don't have a delay of some sort. You need to have one so that the switcher doesn't self destruct. As the caps discharge on an "off" cycle, the voltage will be reduced. If you don't have a delay or a softstart implemented, they'll detect this in the feedback loop as an undervoltage condition and will ramp up the switching until kablooey! It can be fast, but it still has to be there. I'd be surprised if his amp was switching on and off so fast that it manifested as a decrease in "SQ".


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## mears (Jul 27, 2009)

MarkZ said:


> Robin, there are turn-on delays that would prevent it from behaving like that. There would be a noticeable disruption in the sound.
> 
> 60, no, your remote wire just flips a switch. That's all. But, as the others have mentioned, it could be a symptom of some other problem with the HU or the electrical system.


This


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## Robin W. (Feb 18, 2010)

MarkZ said:


> Robin, I don't know of any amps presently made that don't have a delay of some sort. You need to have one so that the switcher doesn't self destruct. As the caps discharge on an "off" cycle, the voltage will be reduced. If you don't have a delay or a softstart implemented, they'll detect this in the feedback loop as an undervoltage condition and will ramp up the switching until kablooey! It can be fast, but it still has to be there. I'd be surprised if his amp was switching on and off so fast that it manifested as a decrease in "SQ".


I've seen it happen so it is 100% possible, feel free to agree or not.
But you can try it yourself, setup a simple system Deck/amp/speaker (use some crappy speakers incase something goes wrong) setup a switch on the remote line to the amp, (this assumes the amp has no muting circuitry for turn on/off) Turn the amp on, play music, now let the deck keep playing and turn off the amp, depending on the rail capacitors it may play for a very short time, 1/2 second or it may play for a few seconds. Now keep switching the amp on/off as close to that time as possible. It will keep playing music, however as the rail voltage starts to colapse there will be distortion etc.

The more accurate way to test this would be to use a variable low current supply or throw a resistor in series with a variable voltage supply to simulate low current (IE something that has a voltage drop under increasing load) now ramp up the voltage slowly until the amp turns on, depending on the amp you may find a place where it will start to turn on/off by itself. Give it a listen, won't sound that great as the rails begin to colapse. 

The only thing required is rail caps large enough to maintain voltage long enough for the turn on cycle to replenish them this would happen within a certain power range as to not deplete the caps to slowly or quickly. In the system I encountered the diy installer had used very small wire, with multiple poor connections all trying to turn on a couple amps and processors. The resistance in the line was enough to drop the voltage to the cut off point of at least one of the amps, and at the right volume it would oscillate. Other times it was fine, and too loud it would turn off, on, off very noticably.

On a side note I'm happy that the OP has found a solution to his problem.


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## MarkZ (Dec 5, 2005)

What amp was this, Robin?


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## Robin W. (Feb 18, 2010)

MarkZ said:


> What amp was this, Robin?


I don't remember exactly, but it was a "big" MA Audio or Pyramid 4 channel from around 2000 or 2001, plexi window etc. Power and ground was decent, but all the remote connections were very poor. Once that was fixed the system worked well for what it was.


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