Here is a whitepaper from Decware that may help you understand sensitivity matching.
https://www.decware.com/paper55.htm
https://www.decware.com/paper55.htm
Question on Preamp Outputs.
I was hoping that you guys can answer a question.
My preamp, a Marantz 8802a has a max output of 2.4 volts balanced output. I am looking into a McIntosh Amp that is rated for a higher input potential. I am generally pleased with my Marantz. Below are the specs pf the McIntosh and the Marantz.
McIntosh MC462
Power Output Minimum sine wave continuous average power output per channel, with both channels operating is: 450 watts into 2 ohm load 450 watts into 4 ohm load 450 watts into 8 ohm load Output Load Impedance 2, 4 or 8 ohms Rated Power Band 20Hz to 20,000Hz Total Harmonic Distortion 0.005% maximum harmonic distortion at any power level from 250 milliwatts to rated power, 20Hz to 20,000Hz Dynamic Headroom 3.0dB Frequency Response +0, -0.25dB from 20Hz to 20,000Hz +0, -3.0dB from 10Hz to 100,000Hz Input Sensitivity (for rated output) 4.2 Volts Balanced 2.1 Volts Unbalanced
Marantz 8802a
Analog Input sensitivity/Input impedance: Unbalanced RCA input:200 mV/47 kΩ/kohms Balanced XLR input:400 mV/94 kΩ/kohms Frequency response: 10 Hz – 100 kHz — +1, –3 dB (Direct mode) S/N: 105 dB (IHF–A weighted, Direct mode) Distortion: 0.005 % (20 Hz – 20 kHz) (Direct mode) Rated output: Unbalanced RCA pre-output : 1.2 V Balanced XLR pre-output: 2.4 V 0 Digital D/A output: Rated output — 2 V (at 0 dB playback) Total harmonic distortion — 0.008 % (1 kHz, at 0 dB) S/N ratio — 102 dB Dynamic range — 100 dB Digital input: Format — Digital audio interface 0 Phono equalizer Input sensitivity: 2.5 mV RIAA deviation: ±1 dB (20 Hz to 20 kHz) S/N: 74 dB （IHF-A、with 5 mV input) Rated output: 150 mV Distortion factor: 0.03 % (1 kHz, 3 V)
Since my Pre has 2.4 volts , what does that mean in the grand scheme? Aside from getting a better dedicate two channel preamp .. I know I should, but that will come later.
Thank you In advance.
Rick
My preamp, a Marantz 8802a has a max output of 2.4 volts balanced output. I am looking into a McIntosh Amp that is rated for a higher input potential. I am generally pleased with my Marantz. Below are the specs pf the McIntosh and the Marantz.
McIntosh MC462
Power Output Minimum sine wave continuous average power output per channel, with both channels operating is: 450 watts into 2 ohm load 450 watts into 4 ohm load 450 watts into 8 ohm load Output Load Impedance 2, 4 or 8 ohms Rated Power Band 20Hz to 20,000Hz Total Harmonic Distortion 0.005% maximum harmonic distortion at any power level from 250 milliwatts to rated power, 20Hz to 20,000Hz Dynamic Headroom 3.0dB Frequency Response +0, -0.25dB from 20Hz to 20,000Hz +0, -3.0dB from 10Hz to 100,000Hz Input Sensitivity (for rated output) 4.2 Volts Balanced 2.1 Volts Unbalanced
Marantz 8802a
Analog Input sensitivity/Input impedance: Unbalanced RCA input:200 mV/47 kΩ/kohms Balanced XLR input:400 mV/94 kΩ/kohms Frequency response: 10 Hz – 100 kHz — +1, –3 dB (Direct mode) S/N: 105 dB (IHF–A weighted, Direct mode) Distortion: 0.005 % (20 Hz – 20 kHz) (Direct mode) Rated output: Unbalanced RCA pre-output : 1.2 V Balanced XLR pre-output: 2.4 V 0 Digital D/A output: Rated output — 2 V (at 0 dB playback) Total harmonic distortion — 0.008 % (1 kHz, at 0 dB) S/N ratio — 102 dB Dynamic range — 100 dB Digital input: Format — Digital audio interface 0 Phono equalizer Input sensitivity: 2.5 mV RIAA deviation: ±1 dB (20 Hz to 20 kHz) S/N: 74 dB （IHF-A、with 5 mV input) Rated output: 150 mV Distortion factor: 0.03 % (1 kHz, 3 V)
Since my Pre has 2.4 volts , what does that mean in the grand scheme? Aside from getting a better dedicate two channel preamp .. I know I should, but that will come later.
Thank you In advance.
Rick
39 responses Add your response
People here will say "this preamp or that preamp" will sound "better"! They will claim that their "golden ears" told them this! The 8802 is an excellent measuring - and sounding! - preamp! Plus it has a phono stage - something lacking in many current preamps. I expect that the 8802 will be "transparent" to the source! Replacing it would be a sideways move at best! |
Amazon has some adapters: GXR - 134 from zZounds for $8.65 each. However you may experience distortion when using an XLR/RCA adapter because they shunt pin 3 to ground at the unbalanced end. Pins 2 and 3 are out-of-phase signals. Some amps won't tolerate having an out-of-phase signal connected to their input ground! |
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jasonbourne52 The MC462 has different gain on balanced and unbalanced input. https://www.stereophile.com/content/mcintosh-laboratory-mc462-power-amplifier-measurements |
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His pre outputs 2.4V for balanced output. His amp outputs 450W for 4.2V balanced input. Amplifier’s output voltage will be a linear function of the input voltage. It has to be or amplifier will have huge distortions. Output power P = V^2 / R If you drive this balanced input with 2.4V instead of 4.2V output will become 24V instead of 42V and power will be (24^2) / 4 = 144W instead of (42^2) /4 = 441W |
So what? This amp has double gain at unbalanced input (26dB vs 20dB), for the output power to be 450W at nominal voltage at given input, but output voltage will be a linear function of input voltage at given input. If you lower voltage at given input by 50% output voltage will become 50%. 1/2 of the output voltage produces 1/4 of the output power. |
As for the output being always 450W. It is always 450W because for different speaker load transformer has different output voltage (amp has different gain). 8ohm speaker would normally produce half of the 4ohm speaker, but amp’s gain for 8ohm output is higher. We are not talking about this. We are talking about amp with speaker fixed to one output and pre fixed to one input. |
I think that XLR/balanced outputs are over-rated! They are only useful if you need to run 10, 20, 30 ... feet cables! At one or two meters "No diffawrance" as the French chef said!The benefit of balanced lines exists even if the connection is only 6". What the balanced line system was designed to do (and meets its design goals) is to eliminate ground loop hum (by ignoring ground) and eliminate cable colorations which also allows for long cables. Getting rid of cable interactions and ground loop (noise) issues is there even if the cable is only 6". |