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Hey guys, i'm new to the site, and I've got something that's really bugging me i'm hoping someone can help me out with. I'm trying to set the gain on my sundown scv-3000 using a DMM, and i'm not getting the voltage I think I need. My HU is a Pioneer DEH-80PRS, which is supposed to have 5v preamps. I have two Fi SSD 12's, both wired down to 2 ohms individual, with a total of 1 ohm at the amp. So as I understand it to set gain using a DMM the total AC voltage should equal the squareroot of (wattsxohms). By my math, with 3000 watts at 1 ohm, with both subs disconnected I should be getting about 54.7 volts with the gain set properly, the problem is even with gain turned to max i'm only getting about 45 volts, and with 5v preamp outputs i shouldn't need to be anywhere near max gain right? I have the HU volume at 45, which is about 3/4 volume, all subsonic/LPF/bass boost/remote gain knob etc are all disconnected or set to 0 on both the amp and the HU. Im playing a 50 hz test tone while tuning. I simply dont understand why i'm having to max out the gain setting while still falling short of voltage, especially while having relatively high voltage preamp outputs. Any input or advice is much appreciated. Sorry if this is something easy/ stupid/ or just a noob question.

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52 minutes ago, shasta95441 said:

Hey guys, i'm new to the site, and I've got something that's really bugging me i'm hoping someone can help me out with. I'm trying to set the gain on my sundown scv-3000 using a DMM, and i'm not getting the voltage I think I need. My HU is a Pioneer DEH-80PRS, which is supposed to have 5v preamps. I have two Fi SSD 12's, both wired down to 2 ohms individual, with a total of 1 ohm at the amp. So as I understand it to set gain using a DMM the total AC voltage should equal the squareroot of (wattsxohms). By my math, with 3000 watts at 1 ohm, with both subs disconnected I should be getting about 54.7 volts with the gain set properly, the problem is even with gain turned to max i'm only getting about 45 volts, and with 5v preamp outputs i shouldn't need to be anywhere near max gain right? I have the HU volume at 45, which is about 3/4 volume, all subsonic/LPF/bass boost/remote gain knob etc are all disconnected or set to 0 on both the amp and the HU. Im playing a 50 hz test tone while tuning. I simply dont understand why i'm having to max out the gain setting while still falling short of voltage, especially while having relatively high voltage preamp outputs. Any input or advice is much appreciated. Sorry if this is something easy/ stupid/ or just a noob question.

You should never have to max out the gains to set them, so something is a muck here. 

 

So the 3/4 volume trick works great for headunits you don't know the distortion point on, but that unit - the 80 PRS - does not distort lol. At least mine does not according to a DD-1 unless you up the output level through settings beyond stock. Try putting your headunit to 61 and try it again. Also the 80 PRS has a standard and a network mode, what mode are you in? 

I've never set with a DMM but I would think the efficiency of the amp would decrease the amount of watts to maybe 70-80% of the total? Making the sqroot of (3000 x .8 [efficiency]) or sqroot (2400) = 48.98 ? 

 

Some stuff to check:

-Check what your RCAs are coming from in the back of the 80 PRS, make sure you are connected to the subs/bass output as the manual states. 

-What are your settings on your amp? LPF? Subsonic? LPF should be all the way up and subsonic should be all the way down, fine tune these after setting your gain. 

-What is the voltage on the DC side of your amp terminals? If the car is on and your below 14v check your grounds.

 

Goodluck man! 

 

 


My Daily 8th gen Civic Coupe

https://www.stevemeadedesigns.com/board/topic/211131-honda-civic-coupe-08-2k-daily-headaches/ (Build Log)

Gear (specifics on build log)

Pioneer 80 PRS / RF P600x4 / DC 2k / Mechman 240 A / XS D3400 + D5100R / Two SA-12(D4) / RF T2 Components / Sky High Wiring (OFC)

~3.6 Cubed Net / 34 Hz Tuned / Center Port

 

 

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He doesn't need to account for efficiency when setting with a multi meter. But I missed the spot about him having the volume only 3/4 that you mentioned. I think that's probably the issue.

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Be on the safe side and go 2 notches below max volume.

 

If head unit max is 40. Set at 38.

Also make sure your using a quality test tone that's done with proper levels 

I recommend a Rockford clean setup CD.

Also if your lp on amp is under 50hz your going to see lower voltage big time.

Set deck at 80hz down and lp on amp at around 100. Then run your track. After all said and done then tweak your amps lp.

Be careful with the leafs going to meter, I've been shock real good by big amps speaker terminals.

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Ok guys, so I have my LPF on the amp and HU set as high as they’ll go. Subsonic on amp is set as low as it will go. Bass boost is set to 0. I will set the HU volume to 60/62 and then re tune gain using DMM, shooting for 54.7 volts or slightly less to be safe (square root (3000wattx1ohm))=54.7 volts. I’ll listen for distortion as well but I think this is gonna work. Then after it’s all said and done I’ll set my LPF and sub sonic to desired levels. Sound good? I’ll let you all know how it goes!

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Ok guys, I set the volume to 60/62, re set gains, sitting at a hair over 50 volts with the gain turned up about 3/4’s of the way. I bought a very cheap eBay oscilloscope for what it’s worth... doesn’t show any clipping until I hit about 55 volts. Though this is better, that much gain still seems like too much for 5v pre amp outputs. The lowest gain setting on the amp is 6v I figure I should be just a hair above that. I checked the headunit, it is in standard mode, not network mode. Anyways, what do you guys think?

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