Monoprice Monolith 7-Channel Amplifier Review

[mattlach]

Well, the monolith amp was on my short list, but instead I had a momentary lapse of judgment and went crazy in the budget department....

I may need help...

 

[Asif1980]

Hello all, Happy Thanksgiving!

I received Monolith 7X200W power amplifier, XMC1 is my pre-processor and all my audio/video equipments are connected to Panamax power conditioner. I also own emotiva XPA gen3 3 channel amplifier.

I am getting hum noise from monolith amplifier but i don't get any such noise from emotiva xpa gen3 amplifier. When googled for the issue I learned its 60hz hum noise. How do I fix this hum noise issue?

Thank you.

 

[KEW]

Hello all, Happy Thanksgiving!

I received Monolith 7X200W power amplifier, XMC1 is my pre-processor and all my audio/video equipments are connected to Panamax power conditioner. I also own emotiva XPA gen3 3 channel amplifier.

I am getting hum noise from monolith amplifier but i don't get any such noise from emotiva xpa gen3 amplifier. When googled for the issue I learned its 60hz hum noise. How do I fix this hum noise issue?

Thank you.

I don't know how to best fix it, but I do know the first question to ask:
Is the hum coming over the speakers (ground loop) or is it coming directly from the amp (transformer hum)?

 

[Asif1980]

I don't know how to best fix it, but I do know the first question to ask:
Is the hum coming over the speakers (ground loop) or is it coming directly from the amp (transformer hum)?

It is directly coming from the AMP, I did some more internet reading and internet states it as mechanical hum.

 

[lovinthehd]

Could be something simple like a loose screw holding down the transformer but I'd contact Monoprice and exchange it myself....

 

[Mark M]

Ok so I pulled the trigger on one of these to hook up to my Onkyo TX-RZ900. It seems to make my system sound less warm and the highs are a bit harsh and fatiguing.

 

[RichB]

Ok so I pulled the trigger on one of these to hook up to my Onkyo TX-RZ900. It seems to make my system sound less warm and the highs are a bit harsh and fatiguing.

Is it harsh with our without the Monolith in the system?

- Rich

 

[Mark M]

Is it harsh with our without the Monolith in the system?

- Rich

It is harsh with the Monolith.

 

[AcuDefTechGuy]

It is harsh with the Monolith.

And this is in Direct Mode without any kind of EQ to boost the treble?

What speakers are you using with the amp?

The amp should be flat 20Hz-20kHz, so I doubt it is boosting the treble (8kHz-20kHz) to make the sound fatiguing, harsh, or bright.

Now if the speakers have a boost in the treble (like +5dB around 8kHz-16kHz) or if the room acoustics is causing a boost in the treble or the EQ is boosting the treble, then I can see a bright/harsh/fatiguing sound.

 

[Mark M]

And this is in Direct Mode without any kind of EQ to boost the treble?

What speakers are you using with the amp?

The amp should be flat 20Hz-20kHz, so I doubt it is boosting the treble (8kHz-20kHz) to make the sound fatiguing, harsh, or bright.

Now if the speakers have a boost in the treble (like +5dB around 8kHz-16kHz) or if the room acoustics is causing a boost in the treble or the EQ is boosting the treble, then I can see a bright/harsh/fatiguing sound.

I'm listening in Pure Audio mode which is the same as Direct mode.
There is no EQ enabled and the sub is not enabled in Pure audio mode.
I am using Elac Uni-fi UF5 towers.
I just feel that the sound is not as warm as just using my AVR. It almost sounds like the mids are lacking and the tweeters are brighter.

 

[RichB]

I agree with ADTG, run with Pure Direct Mode 2 channel and compare them.
I suspect the Monolith is more accurate and other sources may sound better.

- Rich

 

[Mark M]

I agree with ADTG, run with Pure Direct Mode 2 channel and compare them.
I suspect the Monolith is more accurate and other sources may sound better.

- Rich

I already am

 

[Steve81]

I already am

Did you re-run the Onkyo's calibration after installing the Monolith?

 

[Mark M]

Did you re-run the Onkyo's calibration after installing the Monolith?

No. But I don't use any of the Room Correction stuff anyway.

 

[Steve81]

No. But I don't use any of the Room Correction stuff anyway.

Might not hurt in any case, just to make sure trim levels are where they need to be.

 

[Mark M]

Might not hurt in any case, just to make sure trim levels are where they need to be.

Ok thank you. I'll do it now and report back.

 

[RichB]

Do you have an Oppo 10x or 20x series player?
If so, you could set it to variable output, LOWER THE VOLUME to 10, set the power on volume, and connect it directly to the amp.

This would eliminate the preamp section of the Onkyo as the cause.

- Rich

 

[Mark M]

Do you have an Oppo 10x or 20x series player?
If so, you could set it to variable output, LOWER THE VOLUME to 10, set the power on volume, and connect it directly to the amp.

This would eliminate the preamp section of the Onkyo as the cause.

- Rich

I wish I did

 

[RichB]

^ I don't have that amp but have had a number of built ATI Class A/B amps and I never found them to be harsh.
I suspect that either it is more accurate or the preamp section of the Onkyo is the issue.

Do you have a friend with any other gear or DAC with preamp outs and volume control?

- Rich

 

[PENG]

I'm listening in Pure Audio mode which is the same as Direct mode.

I just feel that the sound is not as warm as just using my AVR. It almost sounds like the mids are lacking and the tweeters are brighter.

It almost (not totally) sounds like the phase may be reversed in one or more of the channels. On time I have similar trouble and it turns out the RCA interconnect have the phase reversed on one channel, I had to open it up to fix it. It is unlikely, but worth checking.