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Discussion Starter · #1 ·
I haven't been able to find a whole lot in the way of product reviews or information on AudioControl's DQDX product, but purchased one to try to improve the sound in my 2014 Jeep Wrangler Unlimited.

My current system consists of the factory head-unit (the uConnect RHR-730n), a PAC CHY-23 interface to get front and rear RCA level outputs from it, and a JL Audio 6 channel, 700 watt power amp. (Factory bass subwoofer has been replaced with a Pioneer TS-SW2002D2, sound bar 6.5" speakers with Infinity Reference 6032si, and front dash 6.5" speakers with Alpine 610c.)

Especially since the PAC interface means loss of any EQ controls from the factory head-unit, I wanted the AudioControl DQDX to give back that functionality (at a much more granular level too, obviously).

So far, the DQDX has been nothing but frustration. Biggest problem is I seem to get odd behavior with the volume levels. Sometimes I start up the Jeep and everything sounds fine. Other times, it starts out with some audio distortion and/or noise (mostly coming from the right channels, for what it's worth?). It seems to clear itself up after 15 seconds or so of operation, but that's when I realize the volume control on the head-unit is incapable of turning the volume down to a low listening level. It's either all the way down to 0, where you get no sound and the display says "muted", or as soon as you turn it up to 1, it's playing at a fairly loud listening level.

I already went through the procedure AudioControl recommends to optimize the input levels, but wound up backing them off somewhat (to about 1/4 of the way turned up). The output levels are nowhere near maximized right now, and I had to turn them down to just above minimum settings to ensure the stereo can play softly, if desired.

It's almost acting as though the DQDX does some kind of initial sampling of the incoming signal from the PAC interface and tries to adjust the output levels accordingly ... but sometimes it gets bad data during the process (EG. Factory stereo takes a little too long to actually start playing sound after it's powered on?) and it winds up with the default levels up way too high.

I called AudioControl and spoke with the guy who answered the phone (forgot his name). I asked for "tech support" though and he said he could help me. Unfortunately, he was of little assistance, saying they didn't know any reason a PAC interface would have problems with the DQDX and my problem sounded highly unusual. He did state that the DQDX doesn't do any kind of automatic level adjustment (which makes sense by looking at its instruction manual and feature set, but not by the behavior I'm seeing here).

Any ideas from the forum? I'll probably just end up sending this back .... but everything else on it seems to work properly (EQ adjustments really do make it sound better, etc.), so I'm just not sure if it's really defective or not?
 

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I have not installed that Audio Control piece but I'm sure others will agree that there have been issues with the PAC interface.
 

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HI, twyrick -

It was me you spoke with on the phone. Sorry I was not able to assist you more. The trouble you're having may be related to the PAC piece as suggested above. The inputs on the DQDX are high impedance (20 kohms) and the PAC piece may malfunction when connected to such inputs. As I mentioned on the phone, we'll be happy to have a look at the DQDX to ensure all is well - or you may want return it to the seller for an exchange/refund. I don't believe the DQDX is defective, but I would suggest the DQ-61 instead for your application, which will allow you to run the factory radio outputs straight to your AudioControl processor. We have seen many DQ-61s installed in Jeep Wranglers with no trouble. If you have any other questions, please feel free to call me on (425) 775-8461.

Kind regards,
Dan
AudioControl
 

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Discussion Starter · #4 ·
Ok, this makes much more sense then!
The more I played around with the setup, the more I got the idea it's the PAC harness that's actually causing the issues. (Other people with PAC harness issues with completely different setups report the same behavior where the volume control on the head-unit essentially becomes non-functional except for turning it all the way to 0, muting the audio completely.)

The PAC harnesses must not like high impedance inputs, period.

I'm aware that the DQ-61 would probably work better under the circumstances, but I was hoping not to have to go that route since I already spent the money for the PAC interface AND because I didn't want to splice into that many factory wires to hook up a DQ-61. (Not only that, but if I do eventually go with an aftermarket head-unit, a DQ-61 would be the wrong device for the task at that point.)

There wouldn't be any way to put some sort of adapter between the RCA inputs on the DQDX and the cables coming from the PAC unit to change the impedance, would there?


HI, twyrick -

It was me you spoke with on the phone. Sorry I was not able to assist you more. The trouble you're having may be related to the PAC piece as suggested above. The inputs on the DQDX are high impedance (20 kohms) and the PAC piece may malfunction when connected to such inputs. As I mentioned on the phone, we'll be happy to have a look at the DQDX to ensure all is well - or you may want return it to the seller for an exchange/refund. I don't believe the DQDX is defective, but I would suggest the DQ-61 instead for your application, which will allow you to run the factory radio outputs straight to your AudioControl processor. We have seen many DQ-61s installed in Jeep Wranglers with no trouble. If you have any other questions, please feel free to call me on (425) 775-8461.

Kind regards,
Dan
AudioControl
 

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When we encounter amplifiers that behave similarly, or mute (for example) when connected to high impedance inputs), installing a resistor across the signal pair usually helps, but this will be quite tricky since your are not working with bare wire. After talking with our engineer, high impedance inputs may not be the cause.

Try this. Under the cover of the DQDX, there is a input jumper, labeled at J9, in the lower left corner of the board. The options are Balanced and Unbalanced. We ship the unit Unbalanced from the factory - try Balanced. Also, while you're under the cover, move the Grounding Isolation jumper to Ground (GND) - located on the far right edge of the board. Once you've made these changes, let me know if the situation has improved.

Dan
 

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Discussion Starter · #6 ·
Thanks!
I went out and tried making both of these jumper changes, and while it might be premature to declare it fixed? I think it may have helped.

Oddly though, after listening for a little while with the engine running, I turned it off, but left the key in the "accessory" position. And shortly after that, I started hearing a hiss coming from the rear channels (may have only been the right rear speaker, actually). It was slowly phasing up and down in pitch, sort of like a flanger effect for an electric guitar.

I also noticed that when I changed audio sources on the head unit (from its internal hard drive to my iPod classic), the sound dropped out for a moment, like the amplifier powered off briefly.

When we encounter amplifiers that behave similarly, or mute (for example) when connected to high impedance inputs), installing a resistor across the signal pair usually helps, but this will be quite tricky since your are not working with bare wire. After talking with our engineer, high impedance inputs may not be the cause.

Try this. Under the cover of the DQDX, there is a input jumper, labeled at J9, in the lower left corner of the board. The options are Balanced and Unbalanced. We ship the unit Unbalanced from the factory - try Balanced. Also, while you're under the cover, move the Grounding Isolation jumper to Ground (GND) - located on the far right edge of the board. Once you've made these changes, let me know if the situation has improved.

Dan
 

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Discussion Starter · #7 ·
Hi again. Just wanted to follow up on this thread, in case it's of any help to others (and to throw a new question out there while I'm at it).

I finally did get a working AudioControl DQDX in the Jeep. I wound up having to exchange units because I'm 99% sure the original was defective. (Would work properly for a little while and suddenly play very loudly through a rear speaker with a loud hiss accompanying the sound, and then go back to normal again.)

The one thing I've noticed, though, is I have to keep the input levels set close to the minimum to avoid introducing too much background hiss/noise. If I follow the procedure to maximize the levels, I get background noise that I can't seem to eliminate. With the input levels near minimum and output levels closer to maximum, though, I wind up with a pretty good setup. (Probably a side effect of using the PAC harness to get the RCA level outputs?)

The jumper configuration that wound up best for me was, indeed, moving J9 to "balanced", but leaving the grounding isolation jumper at the factory default.

Now, for my question? The one odd thing I've noticed is that when my factory head unit starts talking with the female GPS voice to give directions, it's really quiet and difficult to hear. (Seems strange, because it does momentarily "duck" the audio levels down before it speaks so it's not trying to talk over the top of loud music.... but it's still just really quiet. No matter how loud I try to turn the GPS voice level up (by turning the stereo volume knob while it's speaking), it makes no difference.

This didn't happen when I had just the power amp wired up and not the AudioControl.
 
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