Gain question, volts running at 55

[dakotap 0]

Ok, I'm sort of a newb at the whole gain setting thing, I just got a Sundown SAZ-1500D from Chris at Db-R and I was setting it with the volt meter, 2 ohm load, 800 watts rms, should be about 40 volts. I tuned it there, with the bass boost all the way off, bass knob up to max. Hooked up the speakers, and It wasnt very loud. My Lanzar 230 was louder. So I did it by ear, listening for any clipping, and I started to barely hear any distortion so I backed off till it was a good clean sound. I retested with the voltmeter and it was at 55 volts. I'm running 2 Memphis M-Class 10's in a Memphis prefab ported box until I can get some 12's. Is it ok to run with the volts this high if I'm not hearing any kind of clipping?? Thanks guys for the help.

[BKOLFO4 29]

Those amps are under rated, but 1500 watts at 2 ohms seems high. With impedance rise, I doubt it is actually producing 1500 watts, but any increase in impedance would also decrease the rated output power of the amp. . .

Does you meter read true RMS? What frequency did you use? Were the subs connected while you measured?

Brian

[dakotap 0]

Those amps are under rated, but 1500 watts at 2 ohms seems high. With impedance rise, I doubt it is actually producing 1500 watts, but any increase in impedance would also decrease the rated output power of the amp. . .

Does you meter read true RMS? What frequency did you use? Were the subs connected while you measured?

Brian

When I meant 800rms I mean the amp is rated at 800 rms at 2 ohm, which is my speaker load. It makes 1500 watts only at 1 ohm. I'm on a 2 ohm load.

I used a 50hz test tone I got off of the gain setting tutorial on this site, with the speakers disconnected. If the amp makes 800 rms at 2 ohms, that means that the voltage should be at 40v according to the math. At that level though the speakers are not very loud. So I continued to turn up the gain and I started to hear a little clipping so I turned it down. Got a good clean sound, that I hear anyway, and unhooked speakers ran tone again and checked voltage and I was hitting 55v.

[///M5 2,833]

You sir are clipping the piss out of your amp. Good clean sound my arse.

[dakotap 0]

You sir are clipping the piss out of your amp. Good clean sound my arse.

Then I guess I'm going to turn it down. But I'm not hearing any distortion from my subs. Could be that memphis builds their prefabs to 40+ hz tuning

I need to get some better subs.

[///M5 2,833]

Distortion on subs isn't easy to hear.

[dakotap 0]

Distortion on subs isn't easy to hear.

Thanks for the help. I redid the voltage. It hits great on Rap and bass stuff, just when I was adjusting to my ears I was adjusting it to rock music. So I was cranking it higher than needed to get the substage sound I wanted. I set it back at 40v. Which by my math is the 800rms x 2 ohm = 1600 then find the sq rt of 1600 which would be 40v. I really cant wait till I get 1 or 2 12's. Thinking of 2 Fi SSD's or 1 Fi Q probably sealed.

Edited May 9, 2008 by dakotap

[shizzzon 461]

the funny thing is by setting your gain with dmm and listening for clipping, just 1 note isnt gonna cut it.

What if the resistance at 50hz was as close to 2 ohms as you are gonna get.

Different frequencies have different rise outputting different power.

Also, the higher the resistance is, the higher the voltage will be.

So, for example, if u had 55v and 14a when measured at 4ohms after rise, that would be - 770w

But at the same time, if u measured at 36hz, it might have been 48v and 20a after rise at 2.4ohms which would be - 960w

These arent real numbers BUT can be.

That's why setting an amp up with dmm isn't accurate.

For companies like JL audio and JBL amps that use crown technology and some Phoenix Gold amps, you can do this because of varying acceptable resistances all output same power.

[dakotap 0]

the funny thing is by setting your gain with dmm and listening for clipping, just 1 note isnt gonna cut it.

What if the resistance at 50hz was as close to 2 ohms as you are gonna get.

Different frequencies have different rise outputting different power.

Also, the higher the resistance is, the higher the voltage will be.

So, for example, if u had 55v and 14a when measured at 4ohms after rise, that would be - 770w

But at the same time, if u measured at 36hz, it might have been 48v and 20a after rise at 2.4ohms which would be - 960w

These arent real numbers BUT can be.

That's why setting an amp up with dmm isn't accurate.

For companies like JL audio and JBL amps that use crown technology and some Phoenix Gold amps, you can do this because of varying acceptable resistances all output same power.

Basically to know for sure it would have to be checked on an oscilloscope. And basically dont trust my ears.

[shizzzon 461]

exactly.

[JimJ 11]

Even with an amp like a PG or JL Slash series, impedance rise will often go out of the range that the amp produces the same amount of power...I have a 9 ohm spike that I never would have found if I didn't have a clamp meter at the time The Tantrum 1200.1 definitely isn't going to make full power there...