DBX 286s HISS issue and found a fix?! Should I warranty it?

OneFlash

New member
Hello everyone! I'm experimenting an issue with my DBX 286s for some time, but it didn't bother me that much before because my mixer levels weren't set properly with PFL level set normally.

If I'm setting the DBX 286s Output to -26dB, the signal isn't peaking on PFL , but I have a very annoying HISS in the headphones when the fader on Mic channel #1 on mixer is set to 0.
I tryed different combinations, nothing worked, I heard my voice with annoying hiss noise on the background.
The DBX outputs that noise even if i unplug the microphone from it, so it's not coming from the mic, it's coming from the DBX itself.

If i set push the 26dB PAD button on the #1 mic channel on the Yamaha MG16XU, and raise the DBX to +0.5 dB, I can hear myself crystal clear, not even the littlest hiss in the headphones, just the ambient noise even if i push the fader to the top at +10dB.

Now the question is: Is my DBX defect? Or is just the signal more clean at [MENTION=30439]0db[/MENTION] output level?

Before I had a Behringer x1622 mixer, and i could'nt set the DBX to [MENTION=30439]0db[/MENTION] output, because the mixer didn't had any dB Pad function, so i had the mic sent with almost peaking semnal in the mixer and lowered the output so i can't hear the hiss that much.

Sould i warranty it, or it's normal? If you experiment the same problem with your DBX 286s you can try this if your mixer has a dB Pad function. Thanks!
 
What's PFL?

Neither my 286s nor 286 Project 1 are excessively noisy. I've plugged them into interfaces, a stand-alone recorder, and even the mic input of my camera and of all of the issues I've had, noise hasn't been one of them. They both sound clean and clear at either minimum output level or at 0 dB output level.

Are you feeding it into a line input on whichever device you're plugging it into? Excessive noise would make me think that it's being fed into a preamplified input and not a line input. If there's a line/inst switch or a line/mic switch on your interface or mixer, then I'd make sure it's switched to line.

And make sure to use a 1/4" TRS to 1/4" TRS cable to connect it to the line input of the receiving device. If you're going into an XLR jack, chances are that you are passing the signal through an unnecessary extra layer of amplification that will introduce noise. Same if you're feeding it into an instrument (Hi-Z) input.
 
The manual for the DBX 286s does not show a "Pre Fade Listen" button. Do you mean "Proc' Bypass"?

If you reduce the units output by 26dB (how BTW? cannot see a switch?) then in making up the gain you could well introduce noise.

The pre amp/processor is feeding a mixer line input I assume? Why would the processor be set to other than around 0dBu output?

Is the noise only present with the processor switched in? If so this can introduce noise if setting are not optimized. The manual goes into this.

But I will confess I find the post difficult to understand in many ways...

Dave.
 
Sorry, i wrote the post in a hurry, and i was'nt that clear.

I hear the hiss from the mixer control room - headphones. If i connect the DBX to the mixer channel #1, i activate PFL on the mixer. Set the OUTPUT Gain on DBX to -26dB ( this is the highest i can go before it clips on mixer). Now PFL off, fader to 0dB position, and i can hear hissing. Same on X1622 Behringer and MG16XU mixers.

On MG16XU i have a 26dB PAD function. I turn on the PAD button on #1 channel. Now i can't hear anything, the output from DBX seems to be too low. I raise the DBX Output Gain to 0, i can hear crystal clear, no noise at all, even if i crank up the gains higher.

Tested with TRS-TRS and TRS-XLR cables results are the same.

From what i read in the MG16XU manual, the PAD function is used to connect some Line-level devices (like DBX) for better compatibility....

I didn't tested on other DBX 286s unit, i have just one. Maybe you can test on yours and reply here if you have the same results.

Also tested the DBX with the Scarlett 2i2 1st gen and 2nd gen, TRS-TRS or TRS-XLR, 0 noise.
 
Still a bit confused Flash but if certain settings produce noise and others don't (but you get good sound and no overload) DON'T use those settings?

Maybe Google "Gain Staging"?

Dave.
 
Maybe Google "Gain Staging"?

Not 'Maybe', Dave, the OP needs to understand gain staging. ;)

OP. the output is a Line Level Output. You shouldn't be going into a Mic input. Be sure the channel on your mixer is set for Line In.

Also, it's quite possible you're using too much compression. Start with nothing then slowly dial a little compression until you get the sound you like.

The manual for this unit is pretty good. Read it cover to cover. If english isn't your first language, then be sure to take the time to translate it.
 
But I will confess I find the post difficult to understand in many ways

You are not the only one!

I can't figure out how the DBX is connected. You would normally connect a compressor as an insert. I wonder if this is the case.

OP should be able to connect the DBX, and without changing the default settings, be able to hear a clear, noise-free and undistorted signal.

I have a feeling the OP may be connecting thus:

Mike > DBX > mixer > output

Whereas it is better connected

Mike > Mixer > DBX > Mixer > output
 
According to the manual, this dbx is a mic pre. Unless I looked up the wrong unit. :eek:
 
According to the manual, this dbx is a mic pre. Unless I looked up the wrong unit. :eek:

Mic preamp with processing (channel strip). I have one and I seldom use it. I actually set it up with a Behringer mixer this morning to see if I could get some 'hiss'. I don't think the OP mentioned a mic connected to his, but I connected up an EV ND967 dynamic I had handy which has a fairly hot output. TRS to TRS cable from DBX to the line in on the Berry mixer.

If the gain on the DBX is set for the level meter to just about hit '0' on the LED meter, the output of the DBX hitting the mixer is too hot to adjust with the mixer gain and would clip occasionally (the mixer I used doesn't have a pad). Interestingly the DBX Output gain control only affects the output when the processing is engaged, thus the only way I had to lower what was hitting the mixer was by lowering the DBX's input gain which I have no problem with. I don't see if the OP had the processing engaged or not, but assume he may have as he was using the output gain control to control what was going to the mixer. With processing engaged it is possible to introduce hiss if not careful with a couple of the settings and the manual does make note of this.
With either no processing or with it engaged and minimal processing I did hear some faint hiss, but not an objectionable amount.

To note, I don't use this DBX with an SM7b or RE20 without an extra boost from a FetHead. Cranking the gain for an SM7b alone does get hissy with the DBX preamps.
 

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If, as you say Mark the DBX unit needs a certain level of gain to reach its optimum operating level that puts the OP in a bit of a bind. Compressors and other dynamic devices need to run at a certain level otherwise there is little or no effect.

You found that optimum level too hot for the Berry mixer and if that is the OP's problem he needs an in line attenuator and of around 10dB I would guess. Two problems, the attenuators need to be at line impedance, around 10k/10k balanced and fitted at the mixer end. Such widgets are very hard to find, almost everything is "600 Ohms"!

Secondly they need to be TRS jack and these are even rarer. XLR we are arse deep in. RCA even is readily available but jacks? Not a hope AFAICS.

The solution is pretty simple. Make some. Can't solder? Bloody learn! You will not progress far in this audio game relying on "off the shelf solutions" unless you are VERY rich.

Dave.

---------- Update ----------

If, as you say Mark the DBX unit needs a certain level of gain to reach its optimum operating level that puts the OP in a bit of a bind. Compressors and other dynamic devices need to run at a certain level otherwise there is little or no effect.

You found that optimum level too hot for the Berry mixer and if that is the OP's problem he needs an in line attenuator and of around 10dB I would guess. Two problems, the attenuators need to be at line impedance, around 10k/10k balanced and fitted at the mixer end. Such widgets are very hard to find, almost everything is "600 Ohms"!

Secondly they need to be TRS jack and these are even rarer. XLR we are arse deep in. RCA even is readily available but jacks? Not a hope AFAICS.

The solution is pretty simple. Make some. Can't solder? Bloody learn! You will not progress far in this audio game relying on "off the shelf solutions" unless you are VERY rich.

Dave.
 
I mentioned that dbx is connected to the mixer channel #1 with a TRS-TRS cable.
The DBX is used as a mic preamp.
DBX Output -> Mixer Line IN
The HISS is present even if i UNPLUG the mic from the DBX. So the mic is excluded.
The hiss is not affected by the DBX processing. If i press process bypass or turn down all knobs the hiss is still present.


As i said, if i set the DBX out to -26dB, the signal from the dbx is hissing. If i set the dbx to 0 and on mixer i Pad the signal with 26dB it is crystal clear.

Do you experience the same thing?
Also on Focusrite 2i2 - dbx output set to -26dB, the signal is clear.

Tested on 2 mixer, i think the problem is the line level equipment compatibility.
 
Hi... instead of using a line in input on the mixer.... try using an "insert" on the mixer if it has one. You should run a TRS 1/4 inch cable from the line output of the DBX to the insert on the mixer. Make sure the insert is one that's linked to one of the mixer's mic inputs... and only plug the cable into the first notch on the mixer... this will bypass the mixer mic channel's preamp so that your signal path only uses the mic pre of the DBX. This will prevent the hiss that would be generated from going through two mic pres . Good luck!!
 
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