S4 vs PDX4.150

[Flipx99 5,000+ posts]

I'm lost here.
He has a 9887, but is running passive. He wants PDX due to smaller footprint, but the S4a allows him to use just run amp, correct?

Why not just go active? In that case you'll still have to add a 2nd amp anyway.

Or am I missing something here?

The way I read it, he already has the S4a and an RE amp. He can go active either way.

The DD is more powerful than the pdx.

You can give insight on the pdx cuz that's what you run (iirc)

Set gains by volts.
Use ohms law. P=R*V^2

So, you know what power you want, you know resistance. Rearrange the equation and you get:

V= square root (P*R).

so, you're ultimately trying to dial in the voltage on the DMM to what you have calculated using that equation.

gotcha, my mistake

 

[bikinpunk 10+ year member]

The way I read it, he already has the S4a and an RE amp. He can go active either way.
The DD is more powerful than the pdx.

You can give insight on the pdx cuz that's what you run (iirc)

I'll let the OP re-specify what's going on...I read his post but the other posts after got me sidetracked.

Did you ever get to listen to anyone's car?

 

[jblayz1 10+ year member]

I'm lost here.
He has a 9887, but is running passive. He wants PDX due to smaller footprint, but the S4a allows him to use just run amp, correct?

Why not just go active? In that case you'll still have to add a 2nd amp anyway.

Or am I missing something here?

lol.

i'm active thru the 9887. yes i set the gains by volts. channels 1/2 are set to 14.1v(25 x 8 = 200 sqrt 14.1v) channels 3/4 to 28.3v(200 x 4 = 800 sqrt 28.28v). when i initially set the gains on channels 1/2 i set it to 10v. when i decided to turn up the gains on the 1/2 channels the initial setting wasn't 10v it read 11.3v. why would the gain change on it's own?? unless it has something to do with changing the negative wire from 8ga to 4ga. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[bikinpunk 10+ year member]

lol.
i'm active thru the 9887. yes i set the gains by volts. channels 1/2 are set to 14.1v(25 x 8 = 200 sqrt 14.1v) channels 3/4 to 28.3v(200 x 4 = 800 sqrt 28.28v). when i initially set the gains on channels 1/2 i set it to 10v. when i decided to turn up the gains on the 1/2 channels the initial setting wasn't 10v it read 11.3v. why would the gain change on it's own?? unless it has something to do with changing the negative wire from 8ga to 4ga. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

I'm not even talking about the gains.

What exactly are you wanting to find out here? Why are you considering chaning from the amp you have to PDX's?

I'm just trying to figure out what you want to do so I can give you some advice, lol.

 

[jblayz1 10+ year member]

if i go PDX it'll be more efficient. smaller footprint. and it doesn't seem you can go wrong with alpine + alpine. but if i stay with the S4 i give up efficiency for flexibility of a single amp and a bit more power. i think i've answered all my questions myself throughout this thread. //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif including why the gains changed settings.

 

[bikinpunk 10+ year member]

if i go PDX it'll be more efficient. smaller footprint. and it doesn't seem you can go wrong with alpine + alpine. but if i stay with the S4 i give up efficiency for flexibility of a single amp and a bit more power. i think i've answered all my questions myself throughout this thread. //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif including why the gains changed settings.

I was going to say that it seems like a pretty simple decision.

You're going to gain more efficiency but that's it. Actually, if you consider you'll be running two high efficiency amps, versus one low one...the 2 combined might not even make a difference.

 

[jblayz1 10+ year member]

true.

sorry if this thread seems stupid.