SLD44 Question

bruther · Post by **bruther** » Tue Dec 16, 2008 9:29 pm

In the SLD 44 manual it states that it will accept high speaker level inputs...does anyone know if it will accept low level speaker level inputs?

dwnrodeo · Post by **dwnrodeo** » Wed Dec 17, 2008 5:16 am

? Low level speaker inputs ?

It will accept either of two things.

1. RCA inputs from your head unit.
2. Speaker level inputs from your head unit.

Speaker outputs are considered high level and RCA outputs are considered low level because they are a lower voltage than the speaker outputs.

bruther · Post by **bruther** » Wed Dec 17, 2008 7:32 am

I'm confused.........I'm thinking of adding external amps/subs to my car and using the factory (Bose) head unit. What I have been reading is the speaker outputs from my factory head unit to the factory amp are low level( I've heard they are Less than < 2v).... When reading the manual for the SLD44 it states that it accepts high level inputs. SO my question is will it work for what I'm doing?

thedeal7235 · Post by **thedeal7235** » Wed Dec 17, 2008 2:09 pm

YES! thats part of what it was designed for, and im sure someones gonna say im wrong( only about this next part), but ull be able to increase the voltage to ur amps as well, usually people say the line driver is meant to match the voltage of ur head unit, but in ur case it will help to get some increase, but always use that increase sparingly, not meant as an amp type of gain

thedeal7235 · Post by **thedeal7235** » Wed Dec 17, 2008 2:13 pm

btw, goto the manuels section under car audio, look it up(processors, or accessories, i think, when u see the owners manuel, it will show u 3 different ways to hook it up, 1 with rcas, 1 with ur existing"factory" speaker connections, and with using it a 2outputs(first shows as a singal output) if i remember correctly-

bruther · Post by **bruther** » Wed Aug 19, 2009 6:59 am

After quite some time, I'm having a hard time matching the voltage output gains for each channel on the SLD-44.

Trying to tune each channel with the tuning pots SUCKS!!!!

Does anyone know what the minimum voltage is for the SLD-44 if I were to turn the output gains all the way down.....I can't seem to get each channel matched perfectly.
This is very frustrating.

cyberpunky · Post by **cyberpunky** » Wed Aug 19, 2009 7:19 am

From what your saying it seems like the low level (<2V) signal from your factory hu isnt a speaker level signal at all, as it was designed to fed into the factory amp. So if you are feeding it into spkr level inputs on your amp then its no wonder matching signal is a problem.

If this is the case, then you need to attach some rca connectors to the wires from HU and feed signal in via RCA inputs on amp, not spkr inputs. This should make it sound heaps better and setting gains easier too

Hope it helps
peace
Cyberpunky

bruther · Post by **bruther** » Wed Aug 19, 2009 8:35 am

G35drver.com wrote: The stock premium head unit has no internal amplifier. Instead, an amplifier is located in the trunk, under the left black support brace.

Other than amplifying the audio signals coming from the stock HU, the amplifier in the premium system also adds heavy equalization to the output signal going to the speakers.

Because the external amplifier adds the amplification and equalization to the audio signal, the audio signals leaving the stock HU can be treated as a very low voltage preamp signal. By very low voltage I mean that the audio signals as they leave the stock HU and enter the stock amp in the trunk are < 2V.

In addition to the low voltage of the signals leaving the stock HU, the signals are also not your standard type of signal. Unlike conventional single-ended (that's what they are called) signals, the G35 sound system utilizes differential-balanced (that's what they are called) signals. Without going into deep explaination, differential-balanced signals do not connect one side of the audio signal to chassis ground. Because of this, balanced-differential signals often times help to eliminate any voltage sensitivity between one input terminal and ground and greatly reduces the incidence of alternator whine in a typical car audio installation.

Most aftermarket amplifiers expect RCA-style connectors/connections on the input jacks. When bypassing the stock amplifier to connect an aftermarket amplifier, you will quickly realize that you are working with speaker wires, not RCAs. There are two ways to convert the speaker wires located in the trunk (where you are bypassing the stock amp) to RCAs (to connect to your aftermarket amp's input jacks).

1. Line Output Converter (LOC). This device simply has speaker wires coming out one side and RCA jacks on the other. After splicing into the appropriate input wires coming from the stock HU, you will be able to connect the RCA jacks on the LOC to the RCA input jacks on your amp using a standard RCA interconnect cable. NOTE: If your amp does NOT accept differential-balanced input signals on its input jacks, you MUST get a LOC that is capable of converting the differential-balanced signals in the G35 to the standard single-ended signals the aftermarket amp is expecting on its input jacks. Soundgate makes an amp that does this.

2. Splicing braided/twisted RCA cables (PREFERRED IF YOUR AMP ACCEPTS DIFFERENTIAL-BALANCED INPUTS!!!). If your amp accepts differential-balanced inputs on its RCA input jacks, all you must accomplish to connect your amp is to convert the speaker wires in the G35 to RCA-style connectors that your amp requires. While a LOC will accomplish this task, it is overkill and adds unnecessary complexity and possible noise into your system. If you have ever cut open a standard RCA cable, you will notice that there are two conductors, one of which is often VERY tiny. Splicing such a tiny conductor to a speaker wire is very difficult and does not yield quality sound for your inputs (which the entire system is dependant upon!) Look for twisted RCA cables, or braided RCA cables. These use thicker gauge wiring for both conductors. INOXS makes cables that work well for this.

This is the explanation I have about my cars speaker signals coming from the head unit. I was thinking of not having a processor and just splice RCA's onto the speaker level wires but I have been told that Titanium amps cannot accept the "balanced signal" my factory head unit sends out.
So I added the SLD-44. I am having a really hard time trying to tune the SLD-44 so the channels are matched. (It would be easier if the gains pots were not for each channel but for each pair so as to not have to try and match each channel.

So I was wondering what the min volts for the output signal is? The volts coming out of my factory head unit is supposed to be less than <2 volts so I want some boost but I cannot get each channel to be the same level. If I could get rid of the SLD-44 and just splice in RCA and plug directly into my amp I would but everyone has said the TI's will not accept my signals from the factory unit.

Thoughts?

Post by **stipud** » Wed Aug 19, 2009 8:47 am

This sounds exactly like my Saab 9-5...

It runs a balanced pre-out from the headunit to the stock amp. In order to connect to it, I first spliced RCA female ends into the stock wiring, with the + signal on the RCA pole, and the - signal on the RCA shield. I got an Audiocontrol Four.1, which has balanced inputs, and unbalanced outputs. So it takes in the stock low-level (aka pre-out) balanced signal, and outputs a ~5v unbalanced one, which I feed directly into my Ti500.4. Now I am not sure if the SLD44 accepts balanced input, and has unbalanced output, like the Audiocontrol unit does.

However, there is a workaround. Instead of putting the - signal on the RCA shield, you can connect the shield directly to the ground wire instead. You lose the noise rejection of the balanced signal this way, but it does work. Alternatively you can try a ground loop isolator to ground it as well.

bruther · Post by **bruther** » Wed Aug 19, 2009 9:07 am

stipud wrote: Now I am not sure if the SLD44 accepts balanced input, and has unbalanced output, like the Audiocontrol unit does.

I'm actually using the SLD-44 right now so it has to accept Balanced Signals because it is working fine. Its tuning that is a problem.......Plus I would like to wire directly to the amp instead of having the SLD-44........One of the key problems with using the SLD-44 is the tuning is a real pain in the ass. That's why I wanted to know what is the min Volts on the output side if I were to turn the gain control pots all the way down?

stipud wrote: However, there is a workaround. Instead of putting the - signal on the RCA shield, you can connect the shield directly to the ground wire instead. You lose the noise rejection of the balanced signal this way, but it does work. Alternatively you can try a ground loop isolator to ground it as well.

I'm confused....Can you dumb it down for me? What wire on RCA cables is the the center wire and which is the outer part of the RCA end? Is that the shield?

Post by **stipud** » Wed Aug 19, 2009 10:08 am

bruther wrote:I'm actually using the SLD-44 right now so it has to accept Balanced Signals because it is working fine. Its tuning that is a problem.......Plus I would like to wire directly to the amp instead of having the SLD-44........One of the key problems with using the SLD-44 is the tuning is a real pain in the ass. That's why I wanted to know what is the min Volts on the output side if I were to turn the gain control pots all the way down?

Voltage doesn't have to be exactly the same. Just get them close and it will be fine.

bruther wrote:I'm confused....Can you dumb it down for me? What wire on RCA cables is the the center wire and which is the outer part of the RCA end? Is that the shield?

The center is the "pole" and the outer part is the "shield"