Purifi 3-Channel Amp has introduced radio Interference

[HarmonicTHD]

Btw. With your current gain setting of 12.5dB your 1ET400 only puts out 9W (instead of 400w) into 8ohms when you fully crank up your X8500. That simply doesn’t work. You might even be clipping your x8500 outs too. You need to set the gain to 25dB as described in the manual.

 

[Acerun]

I still don't think that explains why my speakers turned into radio stations. Anyways, I'm done with this amplifier.

I think I'm going to use my 252s for surround and center and I'm going to get a badass two channel stereo amp from a different provider. NCX500 or Purifi.

 

[HarmonicTHD]

I still don't think that explains why my speakers turned into radio stations. Anyways, I'm done with this amplifier.

I think I'm going to use my 252s for surround and center and I'm going to get a badass two channel stereo amp from a different provider. NCX500 or Purifi.

Oh it could explain your noise otherwise I wouldn’t have suggested it.

The default jumper setting lets the signal through directly. When engaging the buffer board and setting the correct gain as described in the manual the signal passes through the buffer board which might as well contain that resistor to ground someone talked about earlier and therefore get rid of the RF. (Buffer boards often have higher input resistance, but of course I am not sure this one does). After all Amir measured these amp boards also with a buffer board engaged and with a gain of 27dB and it did not show any audible noise (124dB SNR).

But suite yourself. Just keep in mind any other amp will also need a buffer board with gain around 25 to 26dB and not 12.5dB when connecting to an AVR.

 

[Acerun]

Oh it could explain your noise otherwise I wouldn’t have suggested it.

The default setting lets the signal through directly. When engaging the buffer board and setting the correct gain as described in the manual the signal passes through the buffer board which might as well contain that resistor to ground someone talked about earlier and therefore get rid of the RF. After all Amir measured these amp boards also with a buffer board engaged and with a gain of 27dB and it did not show any audible noise (124dB SNR).

But suite yourself. Just keep in mind any other amp will also need a buffer board with gain around 25 to 26dB.

I appreciate it. I also think it's strange that @Audiophonics had a million ways to communicate with me during this whole ordeal and for the most part chose not to. Very vaguely at best. Not really the kind of company I want to work with going forward.

 

[HarmonicTHD]

I appreciate it. I also think it's strange that @Audiophonics had a million ways to communicate with me during this whole ordeal and for the most part chose not to. Very vaguely at best. Not really the kind of company I want to work with going forward.

Yes that is indeed not really encouraging. They should have asked you straight away for the input voltage and at least pointed out the wrong gain setting.

Unless of course the buffer board indeed does nothing with regard to RF suppression. Again, I am just assuming and not knowing this. But it would have been very easy to find out especially considering the time you already spent on this.

Good luck.

 

[Acerun]

Yes that is indeed not really encouraging. They should have asked you straight away for the input voltage and at least pointed out the wrong gain setting.

Unless of course the buffer board indeed does nothing with regard to RF suppression. Again, I am just assuming and not knowing this. But it would have been very easy to find out especially considering the time you already spent on this.

Good luck.

Five times I told @Audiophonics about RF interference and they were deers in the headlights.

 

[Acerun]

Btw. With your current gain setting of 12.5dB your 1ET400 only puts out 9W (instead of 400w) into 8ohms when you fully crank up your X8500. That simply doesn’t work. You might even be clipping your x8500 outs too. You need to set the gain to 25dB as described in the manual.

I only listen up to 80db

 

[HarmonicTHD]

I only listen up to 80db

You listen to 80dB average. But what about the peaks? Classical music has up to 20dB DR creating peaks to 100dB SPL. For that you need 100 times the power. Your gain setting is wrong at 12.5dB, the manual of your amp clearly states that (see my link above). And no I can’t anything for the fact that Audiophincs has bad customer service.

 

[Acerun]

You listen to 80dB average. But what about the peaks? Classical music has up to 20dB DR creating peaks to 100dB SPL. For that you need 100 times the power. Your gain setting is wrong at 12.5dB, the manual of your amp clearly states that (see my link above). And no I can’t anything for the fact that Audiophincs has bad customer service.

I'm pretty sure there is no RF filter with a change in the buffer board because they could have told me that in 2 seconds. In fact, they could have told me about changing the jumpers as I specifically told them the AVR that I was using. So if I can't get a response from the manufacturer on this again this is a moot conversation. The unit is going back.

 

[Acerun]

I'm pretty sure there is no RF filter with a change in the buffer board because they could have told me that in 2 seconds. In fact, they could have told me about changing the jumpers as I specifically told them the AVR that I was using. So if I can't get a response from the manufacturer on this again this is a moot conversation. The unit is going back.

But I completely appreciate you!

 

[Acerun]

But I completely appreciate you!

Maybe I'll try to do it tomorrow for giggles.

 

[HarmonicTHD]

Maybe I'll try to do it tomorrow for giggles.

Yeah for peace of mind. And if it works, you can still send it back, just to make a point about their incompetence. ;-)

 

[MaxwellsEq]

Maybe I'll try to do it tomorrow for giggles.

Do it. It takes a handful of minutes. My Purifi also has a buffer board with 4 different gain settings and is set to 27dB by default. You absolutely should have this set to the correct settings (an I think it should leave the factory set to a sensible default).

 

[Acerun]

Btw. With your current gain setting of 12.5dB your 1ET400 only puts out 9W (instead of 400w) into 8ohms when you fully crank up your X8500. That simply doesn’t work. You might even be clipping your x8500 outs too. You need to set the gain to 25dB as described in the manual.

This is the default on the unit

• Gain of + 12.5dB, for a total of 25.3dB (default) - Maximum power reached with a signal of ~ 2.2V RMS

 

[MaxwellsEq]

This is the default on the unit

• Gain of + 12.5dB, for a total of 25.3dB (default) - Maximum power reached with a signal of ~ 2.2V RMS

In that case, there is a buffer with gain in the circuit, because the amplifier module's default gain is about 12dB from memory.

By the way, Amir measured the difference between different buffer boards on Purifi amplifiers. It's worth reading.

 

[Acerun]

In that case, there is a buffer with gain in the circuit, because the amplifier module's default gain is about 12dB from memory.

By the way, Amir measured the difference between different buffer boards on Purifi amplifiers. It's worth reading.

Right, I'm already at 25.3db by default which which makes way more sense to me. The amp shows plenty of power.

 

[HarmonicTHD]

This is the default on the unit

• Gain of + 12.5dB, for a total of 25.3dB (default) - Maximum power reached with a signal of ~ 2.2V RMS

You are right. I double checked. Sorry.

 

[Acerun]

From, Amir regarding the output of the Denon and Purifi.

"Yes, otherwise you won't get full power. Medium gain requires 4 volts and high gain, 9 volts to reach full power. Denon starts to lose is performance at 1.5 volt."

The NCX500 solves a lot of problems for a guy who is using a Denon and listens at about 80db

I just hope it sounds as good as the Purifi with all of its troubles.

 

[Acerun]

Audiophonics is suggesting that the OPA is bad...whatever OPA is...Oh...it's Op Amp probably. I'm having some trouble getting them to simply provide me a return label.

 

[Acerun]

Onward. Thank you for the help and feedback.