need help tuning amp that is going to be bridged...

[Slowww3kgt 10+ year member]

Im going to bridge a mb quart pab 4100 to a set of mb quart qsd 216's I know the equation you use to figure out what voltage to set your gain at is sqrt(rms*resistance). Do I use the rms rating the amp would put out if it were in 4 channel mode which is 100X4 or do I use the rating its going to put out bridged at 4 ohms which is 300X2? I would appreciate any help Thank you

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[Slowww3kgt 10+ year member]

anybody able to help at all?

 

[pjhabit 10+ year member]

Wouldn't either way work? You wouldn't have the probes in the same terminals, if you know what I'm sayin'? Why don't you try it both ways & see if the setting is similar on both accounts? Then post back w/ results.

 

[NightDrifter05 10+ year member]

You're supposed to use the ohm load that the amp will be see'ing so in this case 4ohms. Think about if, if you have the amp bridged and it does 300x2 that's 600rms and you set it for the unbridged 100x4 rating that is only 400rms so you wouldn't be getting the full power.

 

[pjhabit 10+ year member]

You're supposed to use the ohm load that the amp will be see'ing so in this case 4ohms. Think about if, if you have the amp bridged and it does 300x2 that's 600rms and you set it for the unbridged 100x4 rating that is only 400rms so you wouldn't be getting the full power.

Not following you here. The gain is used to match the hu's pre-out voltage. If you match it "unbridged" or bridged the hu's pre-out doesn't change.

 

[Slowww3kgt 10+ year member]

Ill go ahead and try it with both once I get the car back from the ***** shop. Thanks guys I really appreciate it

 

[n2audio 5,000+ posts]

see what you get both ways...

For 300 @ 4 you should be setting it to 34.6v.

For 100 @ 4 it's 20v.

Just probe the bridged terminals while you set it at ~36, then check the unbridged terminals and see if it's around 20. Should be pretty close.