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New member Username: JurasskickPost Number: 1 Registered: Sep-05 | I'm running 2 Premier TS-W126C subs with an Infinity REF7541A. The amp has an input max of 5.5V. My Premier DEH-P740MP is pushing 6V. When I set the bass adjust to +2 or +3 (out of a -6 to +6 range) the amp shows clipping and goes in and out of power protect mode during large bass peaks when I run near half volume on the HU. I find it hard to belive that .5V is causing all this trouble. Is it possble that the amp is not getting enough power to handle the input? It's running 8ga. off a power dist. block. The only other major non-factory power draws are my (2) Sony XM-235 amps. 30A each. I have 4ga. line running from the battery into the power dist. block. When the Sony XM-235s were running the subs, I was able to be +6 on the HU's bass setting with the volume as high I could handle it without a problem. Think a 1-farad cap would solve my problems, or do I need to find a way to reduce my HU voltage? Pre-emptive thanks -RC |
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Platinum Member Username: GlasswolfWisteria, Lane USA Post Number: 10268 Registered: Dec-03 | the gain should be set all the way down, at the 5.5V setting. where do you have yours set? |
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New member Username: JurasskickPost Number: 2 Registered: Sep-05 | Does no good. By the time it's turned down enough to not clip, there is almost no output. I asked Infinity about the input sensitivity setting on the REF amp (what they call the gain) and the rep said it can only boost input, not reduce it. Which makes sense since it is called a gain. |
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Silver Member Username: Alias747MN Post Number: 662 Registered: Apr-05 | uhh.... sounds alot more like bass boost than the gain to me. If you truly have 6v pre-outs you should have plenty of output with the gain turned all the way down. BTW, if you have a sub level output adjustment on your HU, use that instead of turning the bass level up. |
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New member Username: JurasskickPost Number: 3 Registered: Sep-05 | I do adjust the bass using the HU. I did play with the "Input Sensitivity" setting on the amp some more and I am now able to go higher on the knob without the clipping problem. The REF7541A has no "Gain" setting, so I assumed "Input Sensitivity" means the same. I may be very mistaken here. I guess the big thing that I can't wrap my brain around is that the newer, more powerful, seemingly more capable Infinity amp can't handle the brunt of my HU, whereas my older Sony amps ran without a problem, no matter how much I threw at it. Admittedly, I'm no expert but this doesn't make any sense to me. My guesses were: a. The .5V over from the HU cannot be handled by the amp at higher volumes b. My two Sony's amps are pulling enough juice to deprive the Infinity of what it needs to run properly c. The amp is not as good as its numbers would lead me to believe I thank you all for your input and please pardon my lack of experience. I was spoiled by being lucky enough to have no problems before. 8' ) |
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New member Username: JurasskickPost Number: 4 Registered: Sep-05 | I wanted to throw out another question on this. If my problem were just bass boost and volume related, should the only symptom be clipping? I lean towards thinking its a power problem because on some bass heavy tracks the amp not only clips, but will enter power protection mode for about a second then, turn back on for a handful of seconds, then repeat. |
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Platinum Member Username: GlasswolfWisteria, Lane USA Post Number: 10282 Registered: Dec-03 | I get tired of explaining things, then having people argue with me about the answers, so I'll tell ya what.. go to www.bcae1.com and read the sections Perry has provided there on setting gain/input sensitivity on amplifiers. It explains exactly what everything means, and how to set it all properly. I just posted a reply to someone recently explaining exactly what "gain" means on an amplifier and what it does.. if that interests you, the advanced search feature of this forum could help you find that thread. I believe it's in the amplifier section here. the title was something like "what does gain mean" if I recall. the input sensitivity setting on the amp (commonly called the gain, though that's a misnomer) is an attenuation circuit. It just adds impedance to high voltage input signals to get them to match the input stage of the amplifier. |
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Platinum Member Username: GlasswolfWisteria, Lane USA Post Number: 10283 Registered: Dec-03 | PS if I recall, your Pioneer head unit is only 5.5V outs with the levels maxed on the ehad unit. with levels (output) set flat for boost, they are actually 4V preouts. maybe that'll help. |
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New member Username: JurasskickPost Number: 5 Registered: Sep-05 | Thanks again for your help Glass. Sorry to make you repeat. I did a lot of forum digging yesterday and found a lot of ideas. I was able to get it running fine with very infrequent clipping at levels higher than I'll use it. Now I'm not worried about it because I have some headroom. I called Pioneer about the voltage because their manual and site conflicted. My manual said 4V and their web-site said 6V. A Pioneer tech verified on the phone with me that it is in fact rated at 6V. Thanks again. |
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Platinum Member Username: GlasswolfWisteria, Lane USA Post Number: 10300 Registered: Dec-03 | you bet. the amp can flash the clip light now and then if it's a brief blink. you just don't really want it to stay on very long. the longer the amp clips, the more heat builds up in the coils of the speakers, causing possible damage. |
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New member Username: JurasskickPost Number: 7 Registered: Sep-05 | One of the posts on clipping mentioned that underpowered amps clip more easily. Should I check the power and grounds to my amp as well? My two Sony amps each have one 30A fuse and the Infinity has two 30A fuses. From what I understand they shouldn't get too close to those ratings when functioning normally, but I'm wondering... maybe I should be alternator shopping? According to ACDelco my alternator is either 100 or 105 amps. My car shows no obvious signs of being short on power like lights dimming or anything. I'm glad the setup is working fine now, but I'm always looking for more if it's in there. I'd hate to be underpowering my stuff. 8' ) |