Surprisingly Low Volume from Apollon NCx500 Amplifier?

[KidCrimson]

Long time lurker, first time poster.

I recently received an Apollon amplifier to power my Philharmonitor BMRs. It's replacing a Bryston 4B.

My first impression is that it just isn't loud. At maximum gain setting, using the pre out of my Marantz 2230, normal listening volume is achieved around noon on the pot (for those unfamiliar, the pot goes from around 7 to 5 on the clockface). I had assumed it would be ear splitting by that point.

I also tried it with my Anthem TLP 1. Same result. I need to get much closer to maximum volume than I'd like. It measures volume from -80dB to 8dB. To hit my normal, reasonable, listening volume I need to approach -15dB on the dial. And again, this with the Apollon at max gain setting.

I compared it to a Fossi V3 (volume pot at maximum) I have kicking around, and at -20dB on the dial the volumes are similar. I had expected the Apollon to be MUCH louder at the same volume setting.

I reached out to Apollon with the same question and received back the below...

"Please note that your Anthem has 3Vrms output at maximum volume. Our amp has 24dB at highest gain setting with RCA connection. The Bryston has 29dB. This is why it is louder, because of different sensitivity settings on each amp. At full volume on your Anthem our amp should reach full power with rca and highest gain setting with 3Vrms."

While that makes some sense, I still can't fathom why it seems to output the same volume as the Fossi.

What am I missing? Am I just thick and the above makes perfect sense?

 

[staticV3]

Hi @KidCrimson! Welcome to ASR.

Am I just thick and the above makes perfect sense?

Basically yes.

Comparing volume knob positions between different Amps makes no sense.

If you can achieve your desired volume with the Apollon Amp, then all is good, regardless of what position on a clock face you have to put its knob to.

If you can't, then it's most likely a classic case of gain mismatch: too little output voltage from your Marantz, combined with too little Amplifier gain from your Apollon Amp.

To fix that, simply put a preamp between the Marantz and Apollon, to amplify the Line voltage. Something like a Topping L30II.

 

[radix]

Which specific Nx500 is it? Doesn't it have sensitivity gain switch on the rear? What position is that in?

I believe the Bryston also has 2 input sensitivities, Which are you using?

 

[KidCrimson]

Hi @KidCrimson! Welcome to ASR.


Basically yes.

Comparing volume knob positions between different Amps makes no sense.

If you can achieve your desired volume with the Apollon Amp, then all is good, regardless of what position on a clock face you have to put its knob to.

If you can't, then it's most likely a classic case of gain mismatch: too little output voltage from your Marantz, combined with too little Amplifier gain from your Apollon Amp.

To fix that, simply put a preamp between the Marantz and Apollon, to amplify the Line voltage. Something like a Topping L30II.

Lol, I assumed it was my relative smooth braindedness. To be clear, I usually use the TLP 1. I just brought the Marantz in from the other room to see if it performed differently.

I had assumed, apparently incorrectly, that replacing my old power amp with a more powerful one would mean more volume across the dial. Like if you swapped the engine out of a Jetta and plopped in a Ferrari. I assumed there would be more apparent horsepower across the dial.

 

[KidCrimson]

Which specific Nx500 is it? Doesn't it have sensitivity gain switch on the rear? What position is that in?

I believe the Bryston also has 2 input sensitivities, Which are you using?

It's the Hypex NCx500 ST NCOREx Stereo Amplifier

Gain switches are at maximum.

I don't recall two input sensitivities on the Bryston. I sold it to fund this purchase, so can't handily verify or compare.

 

[staticV3]

I had assumed, apparently incorrectly, that replacing my old power amp with a more powerful one would mean more volume across the dial. Like if you swapped the engine out of a Jetta and plopped in a Ferrari. I assumed there would be more apparent horsepower across the dial.

Not how it works unfortunately.

Getting a more powerful Amp extends the redline, so to say.

The combination of Line voltage and Amp gain dictate how far up the RPM range you can push the Amp.

 

[KidCrimson]

Not how it works unfortunately.

Getting a more powerful Amp extends the redline, so to say.

Interesting. Thanks for the clarity.

 

[kemmler3D]

why it seems to output the same volume as the Fossi.

The Apollon can output higher voltage / wattage overall, but it has 5dB less gain than the Bryston. So at a given volume setting on the Marantz the Apollon is going to be quieter. Basically it's designed for a preamp or DAC with higher output. Not really an issue unless you are hearing unwanted noise or distortion coming from the Marantz.

 

[KidCrimson]

The Apollon can output higher voltage / wattage overall, but it has 5dB less gain than the Bryston. So at a given volume setting on the Marantz the Apollon is going to be quieter. Basically it's designed for a preamp or DAC with higher output. Not really an issue unless you are hearing unwanted noise or distortion coming from the Marantz.

Got it. Thank you. I appreciate you guys helping me understand.

 

[Chrispy]

Keep in mind that takes a doubling of power to gain merely 3dB spl advantage....and that's not a lot really.

 

[benh]

It's the Hypex NCx500 ST NCOREx Stereo Amplifier

Gain switches are at maximum.

I don't recall two input sensitivities on the Bryston. I sold it to fund this purchase, so can't handily verify or compare.

I am surprised... It's this one ? https://apollonaudio.com/product/hypex-ncx500-ncorex-st-stereo-amplifier/

The spec says the gains are 12,8/20,5/27,5/29 ... So 29dB should be there unless the gain differs between balanced and unbalanced inputs... I have one of them too and just checked the gain numbers match what's written next to the selectors on mine. So unless Tibor changed something (or you have a subtly different model) you should be at 29dB too on max setting

I'm running mine at 20dB gain from a WiiM Pro Plus (2V RCA) into 4Ohms (Piega Classic 3, 89dB sensitivity) and I plenty enough volume and not reaching a fraction of the amp power potential.