posted
1 question 3 parts A. I have a sony 910 going to a xdp4000x processor sony and the place i purchased the equipment says i have 4volts going to each amp regardless of whatvolume the head unit is set at.(is this true) B. Another retailer said that they're fibbing and that outputs are rated with volumes up until clipping & with bass and treble fully boosted. In addition he says my amps aren't seeing 4volts. Whose telling the truth and how can i tell if my amp is recieving or putting out a clipped signal? C. I have ammats d300hc with 2 crstal cmp 12's and i keep burning the voice coils. i had the same set up with ppi2350 and i had no problem. I was told that im probably sending a clipped signal to amp from the head unit. I'm thinking the gain is too high on my amp. Its about 1/2 way up. Mmats tech says amps accpets 800mv-2.5volts so where should gain be set and what could be the problem.
posted
OK I have a go at this A. No, this is not true. B. Probably not true either C. I think the gain is probably too high also.
Now a little explanation since just giving you the answers wasn't exactly helpful. I'll start at the amp. Your MMATS amp will do 1200 watts at full output, the gain control sets the signal voltage at which this will happen. If you have it at 800mV when the RCA voltage is at 800mV the amp will be producing full power. If you have the gain at 2.5V you get full power when the RCA voltage is 2.5V. If you have a pre-amp voltage higher than your gain setting you will be clipping the output of the amp. Now to your head unit. The 4Volt number is probably the maximum voltage that the HU can output on the RCA's, this may be clipped or not, it may be peak or RMS, it is hard to tell. Anyway the RCA voltage will depend on the volume setting, how the CD was recorded and other factors. Most normal music produces pretty low RCA voltage. So lets pretend that at full volume your HU produces 4V, at half volume you have 1V. If you have your amp gain control at 1 V your amp will produce its full power with the HU volume halfway. Any volume setting past that will cause the amp to be clipping. With the gain setting at 2.5 Volts you will still get clipping at full volume, but you can have a higher HU volume setting before the amp will clip. The only way to check for clipping is to use an oscilloscope on the amp outputs and use a test tone to generate an unclipped signal from your HU.
I hope I helped you out some, let me know if anything is unclear or you still have questions.
posted
If you're still having troubles with this, I have you answer. if that amp has a maximum rms input voltage of 2.5 you ARE clipping it. because that XDP4000x has an 8 volt maximum preout voltage reguardless of input signal. the reason your ppi amp didn't clip is because of the 12v input signal capability.....as a test, run your system w/out the eq, just from the deck(and xover if needed) and see if that solves your problem.....if so.....and you want to sell your eq, email me because I want it....hehe
posted
Hi, the sony mobile es cdx c 910 is a good deck. This head unit puts out 4 volts rms meaning it puts out 4 volts with no clipping. I have two 910s and i have never had any problems with signal clipping. My guess would be that the amps gain is to hig because u have to much singnal in. I know this is a problem with the mmats amp. We installed a mmats amp in a car and we couldnt set the gain over 1/2 way up. The guy came back and said we installed it wrong because it quite working. This was very wrong, the problem was he turned up the gain to over 3/4. the amp had a big hole burned into the board of it. So we took the amp out.. sent it in to mmats, got it back and put back into car and said DO NOT turn the gain up over what we have it set at or u will burn it up again. just a thought. be very carfull that u dont do the same thing. gain has almost nothing to do with out put. U can have gain set at 1/4 and have full output if u have alot of volts going into it like with a line driver or a high voltage deck with 6 or more volts. peace DK
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