How accurate are these? Anyone that has properly tested(Mr.Mackinnon)their amps output as per the birth sheet method please respond. In particular Rockford fosgate products of late.

 

The Rockford birth sheets should be correct as long as you are supplying them with enough current while testing.

 

I still have my Rockford birth sheet from like 6 years ago. On my 800aII.

It says driven into 2ohms. However one of my local smaller audio stores told me a while back that Rockford's will overheat if you run them at 2ohms. At least the older model that I have. Not sure about the newer ones. Anyway never knew for sure if it was true or not.

My birth sheet.



[ June 06, 2005, 07:16 PM: Message edited by: MrEastSide ]

 

The 800a2 was rated at 200x2@4ohm, 400x2@2ohm, and 800x1@4ohm bridged. Tested at 922rms at 2ohm stereo (figure is a combination of both channels) is easily beleavible.
It will run in these options just fine. Two ohm bridged and it will thermal off.
Hell of a nice amp also.

 

Are you guys testing with a resistor dummy load or an inductive load. What is usually done? I've always done my testing on a live sub to get an idea of the performance when a load with some dynamics is hooked up.
That been said, I have always been able to measure around the "Birthsheet rated" power.

 

The only problem with testing on a sub is that you aren't getting a true measure of the Watts that the sub is seeing, you're only seeing the VA that the amplifier is putting out. also, your impedance rise gets pretty large when testing with a sub, the only way to consistantly measure the output is with a resistor bank.

 

I have a punch 4004 that says 105 watts @ 4ohms on the birth sheet. Is that per channel at 4 ohms? If it is, and it is accurate then that's pretty good considering it's only rated for 50X4 @ 4ohm. So far(15 months) this amp has been very reliable even though I ran it for a year with channels 3&4 bridged into 2 ohms(not designed for that) running 2 12" subs, it never overheated and always sounded great.

 

^^^Sorry, just re-read the birth sheet and it does say 105 watts per channel at 4ohms using cea 2006 specifications and 633 watts at 2ohms total. Now I am wondering if the cea 2006 specs make them bridge 4 ch into 2 ch for the measurement. That would make the specs more realistic, in any case it is still a great amp.