Lame Amp Question - X'ing, Balanced Input, same as Bridging?

john65b · 11:53 AM

Hey all, I am quite sure this question has been asked, but cannot find a suitable answer...and this has been on my mind for a long time....

I was playing around with my inputs to my Aleph 5 clone and noticed in the Aleph 5 Manual it indicates an increase of 6db output using balanced in. A 6db output equates to a doubling in amp power output which makes sense because you are amplifying both - and + input signals as opposed to amplifying the + and Ground on Single ended input.

So first question, is it correct to say with Balanced input the Pass Aleph 5 is 120 watts/channel @ 4ohms, and the 60 watts/channel @4ohms with Single Ended input?

Now when an amp is "Bridge-able", it has the circuitry to to invert the + input signal to get the - signal, effectively getting the balanced input, and each + and - gets fed to the two single ended input amp channels (duh).

Next - X'ing an amp - When you "X" an amp, isn't it the same as bridging? Is there any concern over a 4 ohm speaker being a 2 ohm load on the amp?

And while we are at it, isn't there the same speaker impedance concern on all balanced input amplifiers?

Again, sorry for lame questions, but I am only a Mechanical Engineer.

Bill Fuss · 30th October 2010, 12:27 PM

Hi John,
The sensitivity of the amp can increase but the output power available is set by the voltage and current available in the output circuitry. Higher sensitivity or gain merely means that you reach maximum power with less input signal, but the max power is not affected.

The X amps are quite different than a simple bridged circuit, but yes, it is a bridged amp. Impedance concerns are generally the same until you get into an X amp.

30th October 2010, 11:46 AM	#1
john65b diyAudio Member Join Date: Jan 2005 Location: Chicago	Lame Amp Question - X'ing, Balanced Input, same as Bridging? Hey all, I am quite sure this question has been asked, but cannot find a suitable answer...and this has been on my mind for a long time.... I was playing around with my inputs to my Aleph 5 clone and noticed in the Aleph 5 Manual it indicates an increase of 6db output using balanced in. A 6db output equates to a doubling in amp power output which makes sense because you are amplifying both - and + input signals as opposed to amplifying the + and Ground on Single ended input. So first question, is it correct to say with Balanced input the Pass Aleph 5 is 120 watts/channel @ 4ohms, and the 60 watts/channel @4ohms with Single Ended input? Now when an amp is "Bridge-able", it has the circuitry to to invert the + input signal to get the - signal, effectively getting the balanced input, and each + and - gets fed to the two single ended input amp channels (duh). Next - X'ing an amp - When you "X" an amp, isn't it the same as bridging? Is there any concern over a 4 ohm speaker being a 2 ohm load on the amp? And while we are at it, isn't there the same speaker impedance concern on all balanced input amplifiers? Again, sorry for lame questions, but I am only a Mechanical Engineer. __________________ All right, but apart from the sanitation, medicine, education, wine, public order, irrigation, roads, the fresh water system and public health, what have the Romans ever done for us? Life of Brian Last edited by john65b; 30th October 2010 at 11:53 AM.

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30th October 2010, 12:27 PM	#2
Bill Fuss RIP Join Date: Oct 2005 Location: Central Florida	Hi John, The sensitivity of the amp can increase but the output power available is set by the voltage and current available in the output circuitry. Higher sensitivity or gain merely means that you reach maximum power with less input signal, but the max power is not affected. The X amps are quite different than a simple bridged circuit, but yes, it is a bridged amp. Impedance concerns are generally the same until you get into an X amp.