William94 Posted July 8, 2020 Report Share Posted July 8, 2020 2019 Toyota Camry with JBL premium radio. i have installed PAC amp pro4 TY13 that intercepts the radio signal between the factory head unit and the factory amp and supplies 6ch RCA to my aftermarket amp. (Cannot remove factory Amp due to data bus for infotainment purposes) my problem is that My DD1 won’t detect clipping. I have played the -0db 40hz and 1000hz. And I even tried -5db test track through the CD and Bluetooth into the head unit and it detects the signal every time. But no distortion all the way up to 62 max. my aftermarket amp is Audio control d6.1200. Which has a MILC light. Which the way I understand it detects clipping on the signal coming in. It shows distortion at 49. If I plug my DD1 into the RCA coming from the amp pro. No distortion. if I use the test probes and touch a speaker wire coming from the head unit before it gets to the factory amp, and amp pro. Still detects a signal. But no distortion at max volume. so my question is. What could I be doing wrong? There is no way a factory radio does not have any distortion. Should I be checking the signal anywhere else with my DD1. I am just trying to find my max head unit volume. Does anyone know the accuracy of the MILC light on audio control amps? any help is appreciated. Quote Link to comment Share on other sites More sharing options...
1point21gigawatts Posted July 9, 2020 Report Share Posted July 9, 2020 To check the if the amp is sending distortion to the speakers and/or subwoofers you have to plug the probes into the speaker inputs on the amp. The factory head unit isn’t the device sending off the rca signal so that head unit doesn’t matter. The loc that is sending the rca signal is what matters when checking if that device is sending distortion to the amp. You plug on of the rca plug that goes into that amp into the dd1 plug that the probes plug into and test the loc like that. Quote “How can we help you?” “And don’t forget to tell them that the customer isn’t always right.” Link to comment Share on other sites More sharing options...
William94 Posted July 9, 2020 Author Report Share Posted July 9, 2020 Thank you for the reply, I have tried removing a RCA from the amp and plugging it into the DD1 directly and it detects the correct signal. but even all the way to max volume the distortion light never comes on, (but my amp has a clipping light and it comes on). again this is playing 40 hz 0db and 1khz test tones. i know its full range RCA because i can see it on my input RTA on my DSP software in the amp. so i know i am getting all the way down to 40hz through that RCA channel. Any other ideas to find my max unclipped signal volume on the HU? Quote Link to comment Share on other sites More sharing options...
MrSkippyJ Posted July 9, 2020 Report Share Posted July 9, 2020 (edited) If it was me in this case, I would check everything at the speaker outputs of the amp. Use the 0db test tones to test everything in line prior to the amp, then use the either the -5,-10, or -15 tracks (probably the -5 or -10) to set the output of the amp. Just make sure the gain is as low as possible when checking everything upsteam of the amp. Making sure the headunit output is as clean as possible is possibly the most important thing. Edited July 9, 2020 by MrSkippyJ Quote F150: Stock 2019 Harley Road Glide: Amp: TM400Xad - 4 channel 400 watt Processor: DSR1 Fairing (Front) 6.5s -MMats PA601cx Lid (Rear) 6x9s - TMS69 Link to comment Share on other sites More sharing options...
1point21gigawatts Posted July 9, 2020 Report Share Posted July 9, 2020 (edited) You will have to it through the speaker inputs before the loc with the leads to find that factory head unit’s clipping point. Disconnect that speaker and use them wires (that come from that head unit) to find the clipping point. Use a 9v battery to find out which wire is positive and which is negative to make sure the phase is correct. Edited July 9, 2020 by 1point21gigawatts Quote “How can we help you?” “And don’t forget to tell them that the customer isn’t always right.” Link to comment Share on other sites More sharing options...
MrSkippyJ Posted July 9, 2020 Report Share Posted July 9, 2020 no shit you can do it like that. he said he did that. He was confused why that way showed no distortion all the way up at 62 but at the amp it showed distortion sooner at 49. So I suggested the other way to check the head units distortion that is also mentioned in the DD-1 instructions. What's important is what is coming out of the amp. If it says it's distorting at 49 then that is the level you use. Quote F150: Stock 2019 Harley Road Glide: Amp: TM400Xad - 4 channel 400 watt Processor: DSR1 Fairing (Front) 6.5s -MMats PA601cx Lid (Rear) 6x9s - TMS69 Link to comment Share on other sites More sharing options...
1point21gigawatts Posted July 9, 2020 Report Share Posted July 9, 2020 (edited) He said he checked the rca’s for distortion, not the speaker outputs. His amp showed distortion sooner at 49 because he has the gain turned up too much. If he turns the gain back then he won’t see distortion at full volume. He should be tuning that amp at full volume since there isn’t any distortion. But he has to check the head unit output first. The only way to test the head unit it’s self is to test the input to the factory amp coming from the factory head unit with the leads of the dd-1. Because him testing after the factory amp like he has been doing is only telling him that that factory amp isn’t distorting. It isn’t tell him shit about that head unit. He has to test the inputs going into the factory amp. He would have to use a factory wiring diagram. But I’m almost positive that a newer factory head unit isn’t putting out any distortion whatsoever at full volume of the EQs are flat. But you never know until you check. Edited July 9, 2020 by 1point21gigawatts Quote “How can we help you?” “And don’t forget to tell them that the customer isn’t always right.” Link to comment Share on other sites More sharing options...
William94 Posted July 9, 2020 Author Report Share Posted July 9, 2020 Alright guys. I have checked it multiple different locations. This is why I am confused. I have checked it before the factory amp (crutchfield and the amp pro had wore diagrams) . I have not checked it after the factory amp because I have no way of controlling the gain settings on the factory amp. I have checked the RCA coming out of the LOC (amp pro4). No distortion on any of these methods with my DD1. I will try checking the speaker outputs on the aftermarket amp at minimum gain setting to see if I can determine the maximum clean signal coming from the head unit. It’s just alittle confusing because it is a DSP amp. So the gain(input sensitivity) goes from -20 Up to +12 dB I believe. So would I want to go all the way to -20 on the input sensitivity or check it at 0db. Hell. I’ll just try both. Quote Link to comment Share on other sites More sharing options...
1point21gigawatts Posted July 9, 2020 Report Share Posted July 9, 2020 Use the dd-1 to check the input going into the factory amplifier that comes from the factory head unit. That’ll tell you the head units clipping point. And make sure the EQs are flat or at zero or whatever. You will need a factory wiring diagram to do so. But I don’t understand why a company would tune a factory amplifier on a distorted signal coming from the head unit. But you never know. But even if you find a clipping point on that factory head unit, how are you gonna incorporate it to the aftermarket amp since that factory amp is in middle of that circuit? Makes no sense. Quote “How can we help you?” “And don’t forget to tell them that the customer isn’t always right.” Link to comment Share on other sites More sharing options...
William94 Posted July 9, 2020 Author Report Share Posted July 9, 2020 That’s why I have posted this. I have checked that. I used the right front door speaker coming from the factory head unit before the factory amplifier. Test probes to positive and negative. -0db test track. And it detects the signal. But never shows distortion all the way up to 62 Quote Link to comment Share on other sites More sharing options...
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