Hiss problems w/ high level Inputs. Please advise..

How disappointing to hook up my new DLS amp to have a constant "Hiss" sound.  It happens in all channels when volume is set to 1 and up.

I understand that high level inputs are inferior to low level, but I can't believe how bad it is.  Its REAL bad if I turn up the input level on the Amp.  Anyway, any suggestions to fix this would be greatly appreaciated. 

Layout:

06 Accord  OEM HU
DLS 4 channel AMP
Using high level inputs directly to AMP  (18 gauge)
AMP Output are using existing OEM wiring harness to speakers (18 gauge)  THIS IS TEMPORARY until I install my RAAMMAT/Insolite and will install w/ proper wiring 
Speakers: Polk

Notes:
- I spliced the wires a few inches away from the radio harness connector
- I have bundled the High level input with the AMP outs since it goes through the same harness by the radio (Are there any potential noise problems with this?)
- The amp is being installed under the passenger seat
- The power wire (4 gauge) is running the grommet above the brake pedal , directly runs across to the passenger side under the dash, wire runs along floor and out to passenger seat area.
- Ground is located at a seat post

While the system is running , I unhook the high level inputs, and the hiss stops, which suggests that the noise is occuring the input high level input wires.

Previous posts suggests that high level input will always hiss.  Is this always true?  The hiss is real bad and the stock system actually sounds better.  And yes, the levels on the amp are turned all the way down and its still bad. 

Questions:

1) Can I better run the wires to eliminate the noise.  Or use a higher quality wire?  I am using standard 18 gauge for the high level inputs.

2) Not interested in a new HU at this time (also not interested in a signal processor), am I forced to use a high to low converter? 

3) What else can I do?  What's the next best thing?

Suggestions greatly appreaciated!






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If youre not wanting to buy a head unit or line driver, youre going to have to live with it.

The LOC will help but youll still have a high noise floor.

Macleod,

How did I know that you were going to say that!   

Doing some research, I found this little guy as a possible scenario. 

Have you heard good things about this unit?  Ebay is selling for around $75.. I can use one of the high level inputs to create two low level RCAs.  The AMP has good cross-overs to adjust the signal.  I'm not competing , just want some clean sound for the wife's car.

Might be a option..

High quality Line Driver w/ built-in High/Low signal converter

Two pairs of low level (RCA) inputs and outputs

One pair of high level (Speaker Level) inputs

Independently adjustable outputs capable of 11 volts RMS

Allows top quality OEM/Factory integration into an aftermarket sound system

Frequency Response: 10Hz to 40kHz (+/-0.5dB)

High Level Input THD+N: < .02% @ 1kHz, 8V RMS Output

Low Level Input THD+N: < .0002% @ 1kHz, 8V RMS Output

High Level Input S/N Ratio: 106dB

Low Level Input S/N Ratio: 110dB

there are some items that i came across on ebay that are able to stop hiss/pop sounds. i don't recall the names of them, but do a ebay search for noise filter or noise suppressor and you should find them. (not the ones that say ground loop)

Those probably wont work as this hiss isnt from a ground loop or a turn on pop, its just a high noise floor.

That Phoenix Gold would help a ton.  It will turn the speaker inputs into RCA outputs and boost the signal to 11 volts max. 

The Phoenix Gold products are very high quality goods..good choice.
 
                                 WheelBrokerAng 

I have a 3sixty.1 in my truck and it works real good.  So, I went ahead and bought one for the Accord.  I'll let you guys know how it works out.

I also bought a set of JL components for the front doors..

I am installing the AMP under the passenger seat and would like to mount the 3sixty.1 as close as possible.  Any mounting suggestions?

Thanks

Its a good idea to mount them as close as possible because you want your RCA's to be as short as possible.  The shorter they are the less likely they are to pick up noise.

You might want to mount them both in the trunk.  That way you can tap the rear speaker leads for inputs, and you can keep the amp and the 360 right next to each other and use 1.5' RCA's. 

The 360 has a line driver in it as well and should raise the noise floor considerably.      

Macleod,

Unfortunately, I don't have enough 4 gauge wire to go to the trunk.

I am thinking of mounting the 3 sixty under the drivers seat and passing a RCA to the amp under the passenger seat.  I have different length RCA cables so I can check for noise with respect to location.

Thanks for the suggestions. You said, "The 360 has a line driver in it as well and should raise the noise floor considerably. " Raising the noise floor is not a good thing, you are not suggesting that the 3sixty is worse than hooking up high levels to the AMP directly, correct? 

Mac:  Isn't it better to have shorter speaker leads and longer RCA's than vice versa?  I thought that the speaker leads are more prone to picking up noise.

quote:

ORIGINAL: bginvestor1

Macleod,

Unfortunately, I don't have enough 4 gauge wire to go to the trunk.

Run down to Walmart.  They have amp installation kits for dirt cheap.  Or you could run down to your local shop and buy 20 feet for $35 or so.

quote:

Thanks for the suggestions. You said, "The 360 has a line driver in it as well and should raise the noise floor considerably. " Raising the noise floor is not a good thing, you are not suggesting that the 3sixty is worse than hooking up high levels to the AMP directly, correct? 

Yeah, raise, lower.  I get confused.  I meant whatever means you get less noise! 

quote:

Mac:  Isn't it better to have shorter speaker leads and longer RCA's than vice versa?  I thought that the speaker leads are more prone to picking up noise.

Nah.  The noise youre getting from speaker wires isnt induced noise like alternator whine or such but rather the inherent noise they carry in their signal.  While speaker wires have strong voltage running thru them (which is what rejects the induced noise) the overall signal has a very low signal to noise ratio which means the noise (hiss) that is present in all signals is pretty loud compared to the actual music.  You wont hear this when its running a speaker but when it runs thru an amplifier the noise is amplified as well - plus its already been amplified once before at the source and thats where they get the vast majority of the noise.  Thats why RCA's are better for reproduction as they have very low noise compared to the music but because their voltage isnt as strong as a speaker wires theyre more suceptible to induced noise and since RCA signals arent amplified, they have virtually no noise inherent in them. 

So the shorter the RCA's, the less likely they are to pass by something that can induce some crud into the signal.  

Macleod,
 
Do you have your install shown on this forum?  Looks like a great system, I would like to check it out.

There is nothing much to show.  I have the speakers in the stock locations althought my doors have 4 layers of Dynamat on them and my door skins have not only Dynamat but pollyfill, modelling clay and foam in them.  The tweets are in the stock dash locations.

My sub is in a plain sealed box in the front of the trunk firing into the cabin. 

I have my amp board mounted vertically directly behind the sub so you cant see the sub at all. When you look in the trunk you just see the amp board with the amps and processor on them and its carpeted in trunk liner. 

I hate and suck at installation.  I enjoy the tuning and listening.  My installs are always bare minimum.  Just enough to make it solid and safe.  Very little creativity. 

quote:

ORIGINAL: MacLeod

That Phoenix Gold would help a ton.  It will turn the speaker inputs into RCA outputs and boost the signal to 11 volts max. 

Macleod so would this convert the voltage from a aftermarket Sony Xplod HU that only has 2.2 volt RCA preouts to 11 volts max?

To clarify, would this phoenix gold unit help a head unit with low voltage RCA preouts gain power/stability/sound quality?  Obviously a new HU would probably be the best option...

Thanks

the line driver is 8volts output, capable of 11..................... this is cheaper: http://cgi.ebay.com/HUGE-PLANET-AUDIO-PRE-AMP-2-CH-CHANNEL-LINE-DRIVER-NEW_W0QQitemZ120183687151QQihZ002QQcategoryZ14932QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Cheaper, yes.    PA vs. PG, no comparison!

Phoenix Gold is a better piece of gear - plus I stay far away from anything bought off Ebay.

And yes, a line driver will take the low voltage RCA output of say a Sony head unit and bump it up to whatever its spec'd for.