# Quick question regarding voltage output and gain

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#### mga2009

Hi,

First of all, I am not an engineer (in fact i am a lawyer) so please understand that I am not that technical, and I will not properly understand a highly technical reply.

So, to the question...

My DSP has an output sensitivity of 0.9Vrms and my amplifier has an input sensitivity between 0 - 1.42Vrms (according to spec sheet), so I think I will be OK, as the DSP output is enough to drive the amp normally, maybe not up to clipping it, but enough.

The thing is, what happens when I want to change the amp to a one requiring more Vrms (less sensitive) and balanced input??

Can I solve my problems installing between the DSP and the amp, an unbalanced to balanced converter with a +6dB gain?

I understand a dB value is a ratio of something, and citing this site:

http://eaw.com/docs/6_Technical_Information/StudyHall_and_TechNotes/dB_calculations.pdf

"If you simply state something in dB then you are only stating the ratio in between one thing and another. So you might say
the difference in two voltages is 6 dB but that only means one voltage is twice the other (6 dB = 2 times
voltage). It doesn't tell you anything about the actual voltages."

So, does it mean that if the unbalanced to balanced converter has a +6db gain means it will double the voltage of my DSP?? meaning it will output close to 1.8Vrms or 7.32dBu??

#### Galu

Hi! Call that a 'quick question'? I've seen what lawyers charge per hour and it may take more than an hour to adequately research an answer!

You are correct in that 6dB of voltage gain would change 0.9V to 1.8V. However, this calculation may be simplistic in an unbalanced to balanced conversion scenario.

Full details of the proposed setup would no doubt be required in order to confirm compatibility.

#### mga2009

Hi Galu! Thanks for the reply!

hehe, we lawyers are not all ambulance chasers!

Great calculator there! I was using the same page but a different calculator.

So, basically, to drive a less sensitive amp I will need a "gain stage" of +6db or more. Correct?

the setup consists of a cheap ADAU1701 DSP:
Buy Products Online from China Wholesalers at Aliexpress.com

Amp is Anaview Abletec ALC110-2300.

Also, another question regarding the amp... to drive an amp in BTL mode I always need a balanced signal? or is it possible to use a single ended?

#### Galu

Also, another question regarding the amp... to drive an amp in BTL mode I always need a balanced signal? or is it possible to use a single ended?
The amp's specs show the input connections for both single ended and balanced input signals. I'm ignorant of what BTL mode is!

#### mga2009

WONDOM ADAU1701 DSP Audio Digital Signal Processor Kernel Board - Audiophonics

Re your amp, do you mean ALC0100-2300 as per specs below?

http://www.anaview.com/sites/default/files/PDS ALC0100-2X00-G.pdf

Hope there's enough here for the experts to get their teeth into!

The DSP is the cheap green pcb ADAU1401/1701 from Aliexpress, which is basically the same as the Wondom.

About the amp, yes, you are correct... it's the ALC0100-2300.-

From what I understand, BTL it's a sort of "bridge" mode, where I can run a stereo amp in mono mode and double the power. These Anavie amps are 50wpc and can run at 100w mono@8ohm.

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#### mga2009

Am I correct in thinking that you can vary the input sensitivity of your amp (from 0 to 1.42V)? If so, this link may help you understand how to match it to the output from the DSP:

What is Input Sensitivity? – JL Audio Help Center - Search Articles

I don't think it's variable... i think it means the amp can work properly with a Vrms between those ranges... in fact 1.42Vrms it's the MAX. (and only when running @230VAC)

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