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Re: L1 Model 2 analog input +4dBu or -10dBV

Hi,

Since this is an amplifier with many dB of gain, the concept of unity does not exactly apply. We can not measure unity gain from input to output as a reference setting. We could do that on a line-level device where the output can be the same level as the input.

So you mentioned unity gain from the input jack to some internal point on the amplifer. What point are you referring to?

We could measure arbitrarily from the input jack to the DSP output, past the digital to analog converter and anti-aliasing filter, before the power amplifier. Is that what you are requesting?

The knob setting that would give you unity gain to that point is to the left of center. The 12 o'clock position gives you about 10 dB of gain to that point. Either is a good operating point for the amplifer in terms of noise and headroom, the things that matter to gain staging.

Doing my best to answer your questions. . .

As an aside, I may have used some terms in a way that caused some confusion. In my lexicon, "nominal" is a long term average or typical signal in a particular use. "Sensitivity" for an amplifier is the input signal level that gives you rated amplifier output.

Sensitivy is well above the "nominal" signal, because of the crest factor of the signal.

As an example, your mixer output may be a nominal +4 dBu with peaks to +24 dBu, if you are using all the headroom.

We have power amplifers that have a +24 dBu sensitivity setting (and other sensitivity ettings as well). That way, the highest signals from your mixer would go to the rated (or max) power of the amplifier, which is what is desired.
That setting would be a nominal +4 dBu, the sensitivity is +24dBu.

I hope this helps.

Cheers,
Bill
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Nov 6, 2013

Re: L1 Model 2 analog input +4dBu or -10dBV

Bill, are you suggesting that before any DSP or converters there is no preampfification or attenuation circuit which matches the input to the input of the converters/amplifier? I doubt that. The nominal input and unity I am referring to is simple, and I'm sure you know that. It is what the nominal input of the converter/amplifier would be if there was no knob and no control/circuit to attenuate or amplify an incoming signal. If you stripped away all this and the L1 only matched one input level, what would that level be? It is what almost every other manufacturer of amplifiers and active speakers publishes about their amps and active speakers and most even mark on the controls with a unity symbol.
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Re: L1 Model 2 analog input +4dBu or -10dBV

Bohemo,

Nope, I was certainly not denying any amplification or attenuation, but was just asking where you were interested in the unity gain measurement. You've replied that you want it from the input jack to the A to D converter as opposed to a measurement through the processor.

Input jack to Analog-to-digital converter gain is about unity at 12:00 on the knob.


Enjoy, and good luck!
Bill
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Nov 6, 2013

Re: L1 Model 2 analog input +4dBu or -10dBV

So for the first gain stage, unity is somewhere around 12:00 and the nominal line input level is roughly -10db. OK, thanks for your help Bill & Nick.

Cheers!