Matching Gain and sensitivity for triamp

[Fritz]

Im looking for amplification for a triamp setup and the channels must all have equal gain and sensitivity. Is it difficult to adjust these parameters?

Id like to run Pass amps for high and mid and P3A for bass. It seems that I could use an attenuator to reduce sensitivity in the amp that is more sensitive but that gain may be more difficult to adjust?
Any input would be very helpful

Thanks

Fritz

 

[Brett]

It seems that I could use an attenuator to reduce sensitivity in the amp that is more sensitive but that gain may be more difficult to adjust?

Hi Fritz,

I would add a pot to the input of each amp, each with a series resistor to get about 6dB of range in the control. Then using a signal generator and a meter or a CRO, set the levels to where they should be approximately. I've assumed you've calculated the amp gain and sensitivity of all your drivers.

The plug the system together and measure it to tweak it to the correct relationship / balance between the 3 amp and driver combos. If you have no acoustical measuring tools, pink noise is good to use to adjust by ear. Lots of test CDs have pink noise tracks.

Once it's set up finally to your satisfaction, remove the pot and resistor networks, measure them, and hardwire fixed resistors in place. There will be some (slight) sonic benefit to this, but it stops the controls being bumped, and means you can't become obsessive compulsive about it and make adjustments constantly.

 

[Fritz]

Thanks Brett, actually I think I only need to match the amps because the crossovers are already set up. So long as I can set the amps equal I should be done. Would I just look at voltage in vs voltage out, or do I have to control for current. Im unfamiliar with the standards for specififying these things.
The sensitivity for one of the amps Im considering is 1.22 volts for 100W@8ohm. But the other amps Im considering only output 50 watts

Thanks

 

[tiroth]

Measure the output voltages of the amps and set them to whatever ratio is appropriate.

 

[mrfeedback]

No Test Gear Required

Drive the three amplifiers with the same signal.
Connect a ground common wire between the three amplifiers.
Connect a speaker between the actives output terminals of any two amplifiers and adjust level control setups for minimum (zero) output from the speaker.

Eric.

 

[Fritz]

Great practical way to balance!

Thanks