• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). There are daily reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Monoprice HTP-1 Home Theater Processor Review

krizvi786

Member
Joined
Jun 29, 2020
Messages
60
Likes
33
OK, took one step forward and possibly a few back. Here are the results:

View attachment 49940

The Biased setting does fix the low level issue. But in the process of setting up the test again, ran into the opposite problem. As you see, above 0 DB value on volume control you get some kind of compressor in action. It is not possible to get 4 volts output without going over 0 dB.

There is some talk about combination of analog and digital gain control. That may be at play here. As noted there is a setting for "Amplifier Sensitivity" but doesn't fix the problem.

I can see the same problem with the volume control barely changing the output level even though dBs count up on the display....






Question:

I have HTP-1 with Monolith 9x amp.

I am using XLR connections.

Do I set input sensitivity to 1.6V for XLR?

I thought 1.6V sensitivity was for RCA. So my question is do I double it for XLR and set to 3.2V?

Thanks a ton.
 

TimoJ

Active Member
Joined
Dec 9, 2019
Messages
275
Likes
247
Location
Finland
Question:

I have HTP-1 with Monolith 9x amp.

I am using XLR connections.

Do I set input sensitivity to 1.6V for XLR?

I thought 1.6V sensitivity was for RCA. So my question is do I double it for XLR and set to 3.2V?

Thanks a ton.
You set it to 1.6V, that is balanced (XLR) output voltage.
 

TimoJ

Active Member
Joined
Dec 9, 2019
Messages
275
Likes
247
Location
Finland
Just a follow up, so that means I get 1.6V when it says 0db on the volume knob on the HTP-1? Is that the right way to look at it?
Yes and no. With 0dBFS input signal and all processing off, you get 1.6V. Things may change if you use PEQ, loudness, tone control and Dirac.
 

bigguyca

Senior Member
Joined
Jul 6, 2019
Messages
458
Likes
573
You use 1.6V. Same setting for RCA or XLR input.

Just to clarify:

Wouldn't a 1.6V sensitivity setting give 1.6V from an XLR and .8V from an XLR to RCA adapter cable. To get 1.6V from the XLR To RCA adapter cable wouldn't a sensitivity setting of 3.2V would be required?

The gain of the Monoprice Monolith amplifiers appears to be the same using XLR or RCA inputs. If the RCA inputs were used for some reason wouldn't a sensitivity setting of 3.2V be required?

This same 3.2V sensitivity setting would seem to be required for any power amplifier that required a 1.6V signal level into an RCA input.
 

krizvi786

Member
Joined
Jun 29, 2020
Messages
60
Likes
33
Just to clarify:

Wouldn't a 1.6V sensitivity setting give 1.6V from an XLR and .8V from an XLR to RCA adapter cable. To get 1.6V from the XLR To RCA adapter cable wouldn't a sensitivity setting of 3.2V would be required?

The gain of the Monoprice Monolith amplifiers appears to be the same using XLR or RCA inputs. If the RCA inputs were used for some reason wouldn't a sensitivity setting of 3.2V be required?

This same 3.2V sensitivity setting would seem to be required for any power amplifier that required a 1.6V signal level into an RCA input.


*that is exactly my question*

Amir, can you chime in please?
 

krizvi786

Member
Joined
Jun 29, 2020
Messages
60
Likes
33
*that is exactly my question*

Amir, can you chime in please?

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..
 

krizvi786

Member
Joined
Jun 29, 2020
Messages
60
Likes
33
Nice, Monoprice just deleted my negative review of HTP-1 giving them 3/5 stars for the lack of phone support.

Great way to get 5/5 reviews Monoprice!
 

bigguyca

Senior Member
Joined
Jul 6, 2019
Messages
458
Likes
573
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.
 

krizvi786

Member
Joined
Jun 29, 2020
Messages
60
Likes
33
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.


Thank you very much! That helps a ton. I do wonder why Monoprice states that the setting should be 1.6V regargless of RCA vs. XLR?
 

bigguyca

Senior Member
Joined
Jul 6, 2019
Messages
458
Likes
573
Thank you very much! That helps a ton. I do wonder why Monoprice states that the setting should be 1.6V regargless of RCA vs. XLR?

Per your question: Don't know.

Here is an other issue:

The HTP-1 User's Manual on the HTP-1 site from January 24, 2020, states on page 34: "Consumer amplifiers with unbalanced inputs typically have a sensitivity of about 6V." 6V is nonsense. A typical sensitivity of .6V, in case the 6V is a typo, is also not reasonable.

https://downloads.monoprice.com/files/manuals/37887_Manual_200124.pdf

Such errors, that are outstanding for months that may seem small, are troubling. This especially the case when there is has been, and continues to be, confusion surrounding amplifier input sensitivity settings.
 

TimoJ

Active Member
Joined
Dec 9, 2019
Messages
275
Likes
247
Location
Finland
Per your question: Don't know.

Here is an other issue:

The HTP-1 User's Manual on the HTP-1 site from January 24, 2020, states on page 34: "Consumer amplifiers with unbalanced inputs typically have a sensitivity of about 6V." 6V is nonsense. A typical sensitivity of .6V, in case the 6V is a typo, is also not reasonable.

https://downloads.monoprice.com/files/manuals/37887_Manual_200124.pdf

Such errors, that are outstanding for months that may seem small, are troubling. This especially the case when there is has been, and continues to be, confusion surrounding amplifier input sensitivity settings.
That is 9 months old manual, HTP-1's build-in pdf-manual doesn't have that text. Also, there is no more input sensitivity setting, it's now called maximum output level (with Vrms under the value).
 

bigguyca

Senior Member
Joined
Jul 6, 2019
Messages
458
Likes
573
That is 9 months old manual, HTP-1's build-in pdf-manual doesn't have that text. Also, there is no more input sensitivity setting, it's now called maximum output level (with Vrms under the value).


Why doesn't Monoprice care enough to update the online manual? You were close, the online manual is 9 - 1 = 8 months old. What else is incorrect online?

That said, it's good that Monoprice changed the labeling of the output voltage. The previous labeling made no sense and confused a lot of people. Of course the original output voltage was given as 7V, but that was a dream.

Has Monoprice also redone the DAC IC to XLR output circuit and circuit board to eliminate IMO the unfortunate gain structure?
 

MonolithGuy

Member
Manufacturer
Joined
Nov 12, 2018
Messages
19
Likes
94
Why doesn't Monoprice care enough to update the online manual? You were close, the online manual is 9 - 1 = 8 months old. What else is incorrect online?

That said, it's good that Monoprice changed the labeling of the output voltage. The previous labeling made no sense and confused a lot of people. Of course the original output voltage was given as 7V, but that was a dream.
Unfortunately, we have been adding too many features to keep it up to date. We will publish a newone in October, that will need to be updated once DTS X Pro gets added, etc.

The good thing is the manual that's built into the unit is up to date with all the latest information.
 

peng

Major Contributor
Forum Donor
Joined
May 12, 2019
Messages
2,799
Likes
2,305
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..

That used to be the case for the ATI amps too but the newer models now have the same sensitivity for both RCA and XLR inputs because they claimed the new design allowed them to normalized the input, whatever that meant.

Anyway, if you have time to read, below links to the post#99 in which I asked questions about the ATI amp's confusing gain/sensitivity specs and got my answer in post#104.

https://forums.audioholics.com/foru...-to-be-a-denon-avr.119013/page-5#post-1417194

https://forums.audioholics.com/foru...-to-be-a-denon-avr.119013/page-6#post-1417210

That solved most of the issue/confusion, but if you look at the latest sensitivity specs on their website, the sensitivity specs still don't add up. For me, their sloppiness in their specs is reason enough for me to stay away from their amps, though I recognized they are a leading power amp manufacturer. I would still recommend their amps but I won't ever buy one until they get more serious with their specs, that's just me...

Since Monolith, and some Outlaw power amps are made by ATI, I suspect that would be the reason why the sensitivity specs of some of those products are not very clear either.
 

Vasr

Major Contributor
Joined
Jun 27, 2020
Messages
1,409
Likes
1,872
That solved most of the issue/confusion, but if you look at the latest sensitivity specs on their website, the sensitivity specs still don't add up. For me, their sloppiness in their specs is reason enough for me to stay away from their amps, though I recognized they are a leading power amp manufacturer. I would still recommend their amps but I won't ever buy one until they get more serious with their specs, that's just me...

Seems to me that all the marketing arms of these amp companies (at least those that care about THX) are trying to get that 28.8V into 8ohm THX sensitivity number into the published specs rather than for full rated power (it may coincide with it for some but not necessarily) and having trouble migrating from legacy specs.

If an amp isn't a fully balanced design, then effectively it is taking half the input from balanced and applying the same gain (number) as unbalanced. So, it makes sense to just state one number for both input sensitivity and gain... unless they had a different treatment for both paths without "normalizing" as they call it. The input sensitivity for XLR will be interpreted as the number per leg (Parasound states as such explicitly).

Is there some math not adding up here?
 
Top Bottom