[Audiophile34]

I have read different opinions here and on "the shack" about the correct set up for the gain level on the berinhger ep4000.


It was (and still is) my opinion that you can get the maximum output from the amp, even with the gains at quarter level.. As long as you can send it enough input signal.


But I have read that the correct way is to max out the gains on the amp and adjust the output level from your AVR..


Can someone please once and for all explain this so the topic can be put to rest in my brain, I cannot help but wonder if I am short changing my sub system buy having the gains not maxed out.


I can drive the clip lights on, but is that just meaning I am clipping the input?


So confused....


Thanks in advance,


Jared.

 

[Looneybomber]

Clipping the input is not too likely. The EP handles what, ~10v input before clipping/overloading? Not many AVR's are going to achieve that. The normal problem is not having a strong enough output signal from the AVR. Penn had that problem, never getting clip lights.


Personally, I have the gains somewhere in the middle and adjust my subwoofer output on the AVR to be as close to -0db...But I also have a pre/pro between the two with a little bit of gain.


Having the gain cranked to max on the amp makes it more susceptible to noise. It's not a problem for everyone, but for some it is.

 

[LTD02]

"It was (and still is) my opinion that you can get the maximum output from the amp, even with the gains at quarter level.. As long as you can send it enough input signal."


you are right.


there are several ways to set it up though.


one way works backward from the gains "full up" and adjusts the gain structure so as to minimize clipping in the signal chain.


the better way is to maximize the signal going through the signal chain, then adjust the gains to the point where they are as high as they can go without clipping.


if you just set the gains to max and then send it a hot signal, you will be clipping all over the place.


with the gains all the way up, you only need 1.23 v (the rated input sensitivity) to get maximum power in 8 ohms. any more than that and it will just result in clipping. since the ep4000 has a 50x multiplier:


1.23 v input x 50 multiplier = 61.5 volts output.


power = e^2/r


so, 61.5 volts ^2 / 8 ohms = 472 watts per channel at 8 ohms.


if you have the gains all the way up and send 5 volts input, the amp will try to produce:


5 volts in * 50 multiplier = 250 volts output

250^2/8 = 7,812 watts per channel at 8 ohms, which would be clipping city.

 

[Garric33]

There are other reasons for not setting up your gain structure with the gain control of the EP4000 at max. Among these would be passing a signal with maximum SNR to the EP4000. If the signal from the preprocessor is very weak, it will have a low SNR. Your EP4000 will then be amplifying a signal with low SNR, which means the output signal will have low SNR as well.


What this means is that you will want to pass a fairly hot signal throughout the signal chain. This is my understanding - someone correct me if I am wrong.

 

[LTD02]

yeah garric, that is right. best to keep the signal as high as possible throught the chain and then adjust the amp gain controls at the end. that way you will have maximum signal to noise. if you go the other route by starting with gain controls all the way up and then turning down the signal, you can end up amplifying the noise floor much more than it needs to be.

 

[Looneybomber]



Quote:
Originally Posted by Garric33 /forum/post/20905458


What this means is that you will want to pass a fairly hot signal throughout the signal chain. This is my understanding - someone correct me if I am wrong.

Yep. This was the movement in car audio back in the 90's - going from 0.5v preamp outs to 4-5v outputs. I even remember a Sony ES deck, copper lined, with 8v outs.


As LTD pointed out, send a signal as close to clipping as possible to the amp to maximize dynamic range while minimizing noise. Adjust amplifier gains accordingly.