Volts ?

[SHOemup233 10+ year member]

I will be tuning an amp for a friend shortly and was wondering the voltage I should look to hit with the DMM.

He has a kenwood kac9103d. http://www.sonicelectronix.com/item_8515_Kenwood+KAC-9103D.html

It's rated for 900 watts at 2 ohms, but only has 2 30 Amps fuses.

What are the realistic power ratings I should look for and the voltage I should hit on the DMM?

THanks

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[Atimm693 10+ year member]

Do you mean input voltage or how much power the amp makes?

Two 30 amp fuses means the amp is really overrated.

Using ohms law, Amps*Volts=watts, 60*13.5=810. After you factor in effiency (70%), you get 567. Also remember this is the max amount of current before the fuses blow, which means you're not going to get even that.

 

[SHOemup233 10+ year member]

Yeah. I just tuned it to 14 volts a channel, so 28 volts to both.

He wasn't very happy with how loud it was and he told me it used to be at least "triple as loud."

I explained to him all the basic stuff though, and told him what he should do to get louder. He wants to be at least as loud as me. The steps I told him were: get a new amp. then new subs and box.

He's returning the kenwood tomorrow for the 290 he payed for it at best buy, and getting the 1200D, for 250. Ha, a much higher quality amp and he saves 40 bucks.

He wants to get loud, and will have 1000 watts to throw around for 2 12's, and it looks like he has prolly 3-3.5 feet to work with. I recommended maybe the SD2.5's, or FI ssd's. Any other suggestions?

 

[n2audio 5,000+ posts]

Two 30 amp fuses means the amp is really overrated.

Using ohms law, Amps*Volts=watts, 60*13.5=810. After you factor in effiency (70%), you get 567. Also remember this is the max amount of current before the fuses blow, which means you're not going to get even that.

it's really not at all that straightforward.

for one - fuses don't blow the second they see rated current. It's quite possible they can pass 2x rated current for a few seconds without blowing.

Plus, you don't know how Kenwood chose to use fuses on this particular amp. Are they a form of protection designed to blow at the first sign of severe stress, or are they designed only as protection against a short in the case of amp failure.

The fact of the matter is I've never seen a kenwood not do rated power. It probably won't do 900w at 12.5v, but it will do it at 14.

I've seen a lesser quality amp than Kenwood with 2x30's do over 900w rms on a professional independent test bench, and it was a class a/b.