Help setting gains for x600.1

[aeronautica86 10+ year member]

I'm using an alpine cda-9811, 4v preouts; a pair of svc 4ohm rl-i8s in sealed boxes, so I'm running the PG x600.1 at 2 ohms. Since I first hooked up the amp about a week ago I have never been satisfied with the output of the subs but haven't had time to set the gains properly (I've been running the gain at about 1/3 and very little bass boost just to be safe).

I just attempted to set the gain according to the amplifer setting tutorial with a dmm and I'm getting some wierd results. First of all, do I need to put the test leads in one set of the speaker termials or should I put the + lead into the + terminal of one set and the - lead into the negative terminal of the second set? (as if I were bridging the amp)?

When I tested I put the test leads into the + and - terminals of the first set of speaker terminals of the amp and left the other two untouched.

The gain on this amp ranges from .2 to 8. I set my dmm to read AC Voltage as per the tutorial. With the gain set at .2 the dmm read 25.1, and when set at 8 it read .9

When I play music in the car I get almost no output at .2 and a decent bit (but still not as much I had imagined) at 8 (I only turned the gain all the way up very briefly a few days ago to see what the output would be like)

I was playing a 60hz -3 db test tone at 25/35, with no bass boost on either the amp or HU; My dmm is also autoranging.

Any ideas on what's going on here?

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[xluben 10+ year member]

well, first off you should get the most output at 0.2V setting and least at 8V.

with the x600.1 you need to leave the speaker leads connected when you turn on the car! after the car is on and the amp powers up, then unhook the subs from the amp. if you unhook the subs and then turn it on, the xe.load will be bypassed and you will get higher voltage readings (therefore you're subs will get less power when hooked back up).

make sure the multimeter is set to AC volts (~ on mine). i have an alpine cda-9856 and i used the same test tone and same settings on my hu, and i needed to turn the gain up a little past 3/4 (0.2V being all the way up, remember) to get a 40V reading (and 800W output). use a single set of outputs on the amp to take the readings.

 

[aeronautica86 10+ year member]

hmm, this is odd, since I'm definately getting more output when the amp is set to 8 (slot on screw pointing toward the eight), but the voltage reads higher at .2 (slot on screw pointing toward the .2), but even at .2 I'm only getting ~25V.

If I leave the speakers connected when I turn on the car and then hook up the dmm, wouldn't the readings be different than when using subs, considering the fact that I'm not disconnecting and reconnecting them once I turn the amp on?

 

[xluben 10+ year member]

i can't believe zfactor didn't answer this yet //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

when you turn on the car and the amp powers up it senses the load, and adjusts the rail voltage so that the amp will put out the same power at 1-4 ohms. so if you were to disconnect the speakers and then turn the car on it will output a higher voltage when you set the gains, and then when you hook the speakers back up and turn you car on it will output a lower voltage. you can try it and you'll see. if you have the gains at 40V set with a 2 ohm load, and then turn the car on with no load, the voltage will go up to 60V. if you search online for x600.1 mod you should be able to find info on how to get up to 1800W @ 2 ohms out of it!!! but it's NOT recommended by PG techs (but they do verify that it works), because it leaves the amp unprotected and can be damaged.

you should get 75V+ with the gain's all the way up to 0.2V (at least i did). how do you have the subs wired? which outputs are you using to measure the voltages?

hope i can help you out, i just set my gains today (i needesd a new fuse for my multimeter).

 

[xluben 10+ year member]

i guess i forgot to mention that with alpine head units you need to set the subwoofer output to +15 because it is labeled backwards (+15 is really 0, and 0 is really -15), so set it to +15, and that is the un-attenuated signal (but not boosted). that could be causing your low voltage problems.

let me know how it goes!

 

[zfactor 10+ year member]

yeah been away for a bit... trun the car on with the speakers connected to the amp..let the amp "boot" up (fully turn on, disconnect the speakers then adjust as needed... as ^^ mentioned it will depend on the deck's output.. the xenon's seem to need the gain knob to be higher then the numbers on the dial would indicate unsure fully why but it does seem to have a small area in the gain knob where it makes a very large jump with just a tiny bit of a turn...

if you leave them disconnected the amp will be doing about 1200 watts at 2ohms.. it will get very warm though.. as long as caution is used i have personally been told by pg it should run this way all day long without issues. they know what the damage caused by this looks like though. so if the amp is warranty it will not be covered if this is done.. and they know exactly what to look for when they get it since this secret got out... the pair i run i have at 2ohm bypassed and they run all day never had an issue. the thermal led will still function telling you when heat is an issue by blinking but the amps protection circuits are now being bypassed due to this mod and will not shut the amp down if there is a heat or short issue..so essentially meltdown from heat if that is the issue. but yeah i benched one at 1236 watts at 2 ohms with xe-load bypassed... again do this with caution if you are unsure of when an amp is clipping or distorting do not do it..