prior to the current generation of monolith amps, they only had RCA inputs, and the sensitivity for full rated power was 1.6V then.
So thats why I was wondering if 1.6V is for RCA input, then why isnt XLR sensitivity higher since it is balanced?
I am sorry I hope I am not sounding too contrarian, I just am having trouble understanding why the voltage rating is the same of balanced and inbalanced inputs.
Everywhere else I read you double voltage for balanced XLR conections..
You are mixing a few questions:
1) What are correct voltage sensitivity setting for the HTP-1 for the Monolith amplifiers.
The gain of the Monolith amplifies appears to be the same with RCA or XLR inputs. This means the voltage sensitivities for the Monolith power amplifiers are the same for XLR and RCA inputs..
The correct sensitivity settings for the HTP-1 appear to be:
1.6V XLR, the same as the input sensitivity specification for the power amplifier.
3.2V RCA. this will yield 1.6V from an XLR to RCA adapter cable.
2) How are the voltage settings of the HTP-1 determined? Independent of the HTP-1, why do the voltages sensitivity ratings of power amplifiers vary between power amplifiers.
You need to understand that the settings for the HTP-1 are to set the
output voltage of the HTP-1, not the input voltage to the power amplifier. The output voltage is normally not set by the consumer in a consumer level AVP. Monoprice is setting this voltage evidently in an attempt to maximize the S/N ratio of the HTP-1.
The voltage output from the XLR outputs on the HTP-1 is twice the output from an RCA adapter used with the HTP-1 since the adapter uses only the (+) output of the XLR output. This reduction in voltage would be true from the output of any equipment, not just the HTP-1, when using an adapter cable from any normal XLR output to RCA. Often equipment will have separate XLR and RCA outputs with all sorts of different characteristics, but the HTP-1 only has XLR outputs.
The Monolith power amplifiers have one of the two common input sensitivities for XLR and RCA inputs. You will see other combinations of sensitivities for XLR and RCA inputs if you research enough power amplifiers.
1) Monolith power amplifier likely design:
RCA input goes straight to the internal power amplifier, perhaps through input buffer with a gain of 0dB, that is 2V in and 2V out to the power amplifier.
XLR input goes through a differential amplifier to convert to a single-ended (RCA) input. This differential amplifier subtracts the (-) input from the + input. For example, a 2V (+1V and -1V) differential (XLR) input, +1V - (-1V) = 2V to the internal power amplifier.
As you can see 2V input on the RCA or XLR inputs to the power amplifier means a 2V input to the internal power amplifier. This means
the power amplifier sensitivity is the same for RCA and XLR inputs. This power amplifier sensitivity is
not the setting of the HTP-1.
For the HTP-1 the sensitivity setting to get 2V from an XLR output would be 2V. To get 2V from the RCA output the sensitivity setting would be 4V since the RCA output is 1/2 (-6dB) of the XLR output.
These are the settings of the HTP-1.
2) Another option that reduces the XLR signal level inside the power amplifier. This reduction is perhaps because the raw XLR input level is too high for the internal circuitry of the power amplifier or is otherwise undesirable. This difference in design has nothing to do with the HTP-1, it only affects the settings of the HTP-1.
Here the RCA input goes straight to the internal power amplifier, perhaps through input buffer with a gain of 0dB, that is 2V in and 2V out to the power amplifier. Also, 1V in and 1V output.
XLR input goes through a differential amplifier that has a gain of -6dB (1/2), to convert to a single-ended (RCA) input. This differential amplifier subtracts the (-) input from the + input. For example, 2V differential (XLR) input, +1V - (-1V) = 2V - 6dB (x1/2) = 1V to the internal power amplifier.
Another XLR example: 4V differential (XLR) input, +2V - (-2V) = 4V - 6dB = 2V to the internal power amplifier.
As you can see twice the XLR input voltage is required to obtain the same voltage for input to the internal power amplifier.
If the amplifier has a 100W rated output for 1V input (and 1V internally) on the RCA's the
sensitivity rating for the power amplifier for an RCA input will be 1V.
The
sensitivity rating for the XLR input for the power amplifier will be 2V because 2V yields 1V internally to drive the internal power amplifier.
For the HTP-1 the sensitivity setting of the HTP-1 to get 2V from the XLR outputs would be 2V. To get 1V from the RCA converter cable would also be 2V since the RCA output is 1/2 the XLR output level.
These are the sensitivity settings of the HTP-1. The HTP-1 sensitivity settings are now the same for each type of power amplifier input, although the sensitivity specification for the power amplifier RCA and XLR inputs are different.