Why's my amp put out 1/4 of rated power?

um, the alpine is 50w/ch@ 4 ohm which is about 100w mono @ 4 ohms bridged, which is about 50w mono @ 8 ohms

the rockford is 75w/ch@ 4 ohms which is about 150w mono @4 ohm bridged, which is about 75w mono @ 8 ohms.

Sorry this doesn't help your problem at all.

As long as you have the multimeter, go to http://www.jlaudio.com/tutorials/index.html and check out the "setting gain" tutorial. It's quick and easy.

If either of these amps are 2 ohm stable while bridged, I would run it that way to the sub (more power eeeyaahhh)

Alpine MRV-T505 manual:

http://www.nrg1.com/Alp_bruksanvisninger/Owners/M/MRV-1505/68P90664W91-B.pdf

Seems to be a somewhat rare amp, hard to find info on it.  It's larger brother the MRV-1505 gets all the press. 

Notice that the MRV-T505 and the MRV-1505 are stable bridged to a 2 Ohm load, i.e. 1 Ohm per channel stereo.  It says you must move the switch to the low impedance position to run this way.  See swithc "b" in the manual.  Does anyone know if this will increase the power over output over a bridged 4 Ohm load, or is it just to give you more wiring options without altering the power output?

I tried running the amp with only the 10" bridged and the other speakers disconnected, no change.  Also tried the input mode selector switch in stereo and 1+2 and it didn't make much difference.  Am running with the amp's crossover set at about 80 Hz low-pass.

My amps are wired in a "daisy chain" fashion with the Alpine getting the wires first.  As in the power wire runs into the Alpine, then out of the Alpine to the Punch.  Same with the ground wire so they are grounded to teh same location.  RCA cables are obviously seperate as they come from an electronic crossover to split the frequencies before the amps.  So, if the Punch is getting adequate power, the Alpine should also since it is "upstream" of the Punch on the wires.

Thanks, any more ideas?

Mike

Figured out what the problem was.

Originally I set the gain using a "musical" CD, set HU at 30 out of 38, and adjusted gain on the amp until I got audible distortion.  The gain setting showed about 2.25 volts input, my RF 8120 deck specs say it puts out 2.4 volts, so I'd say the gain was close to where it needs to be.

After I read the JL Audio tutorial i searched the internet and found some test tome MP3's and burned a .wav of the 50 Hz tone and took it to the car and measured amp voltage without the speakers hook up as per JL.   I tested the amp bridged and got an AC voltage of 12.4 volts, which looks close to correct based on the numbers for the other amps shown on JL's site, so my gain setting using a music CD seems to be very close to what it should be.

I decided to play with the parametric EQ, which I had not touched before.  Turned it ON, maxed out the Q, set the center frequency at 50 Hz and maxed boost.  Low and behold, AC voltage with 50 Hz test tone jumped to close to 50 volts!  Hooked up the JL10W3 and it confirmed what I just saw.  Wonderful bass, cone excursion :-) 

Solution for future reference: Parametric EQ needed to be on and adjusted.

I probably don't want to leave the Q gain maxed on one frequency if I want SQ, right?

Thanks,

Mike