Review and Measurements of Project Polaris HP Amp

[maty]

[ Listening Impressions

Okay. So what does it sound like? Actually… Not bad… But coming from an ultra-clean headphone amp (think THD below -130 dB), I find the T2 lacking in clarity. At low to moderate volume levels with relatively simple music, the T2 performs quite well. However, even at these volume levels, I find, that the T2 renders the voices of some singers (such as Mark Knopfler on Dire Straits “Brothers in Arms” and Chris Stapleton on “From a Room Volume 2”) with a bit of fuzziness, in particular on unvoiced (hard) consonants. On more complex or louder passages, the lack of precision in the T2 shines through. Thus, distorted electric guitar is rendered with a little extra grunge, snare drums get muddied, and cymbals are rendered slightly less metallic and slightly more fizzy than those instruments sound like live. If I crank it loud, I also find it quite easy to get the T2 to distort on the peaks... ]

That is the problem with H2 about -73 dB. To play ALL kind of music is better idea without harmonics at -90 dB. If we could choose the sound profile based on the music we would have a winning product.

 

[solderdude]

Of course... not one of Maty's words have anything to do with the Polaris... just for the record.

If one wants flat and colorless there are thousands of other amps to choose from and color it with digital plugins.

 

[maty]

I wrote here about H2 dominant profile. These two comments complement what was written before, providing very good an interesting information.

About Project Polaris HP Amp, is a bad purchase. Surely much better than those cheap Asians but... Only for tube lovers and that listen to mediocre sound quality recordings how are the current modern commercial recordings, with DR < or << 10 dB.

Those who listen to very good recordings with high dynamic range better refrain from buying.

 

[solderdude]

Reading your ramblings is a bad decision

 

[maty]

Based on the measurements published here. And all these deficiencies, when using headphones will be noticed more than others tube amps but with speakers.

If you want to modify / color the sound, if the source is a computer, it is cheaper and better to use software that uses a DSP, PEQ, ... 64-bit.

 

[JJB70]

This is clearly not an amplifier intended for everyone, the designers set out to do something different, have made clear the unusual aim and appear to have satisfied their design brief admirably. It isn't for me but if people want the sort of sound associated with valves this is a better way of doing it than actually using valves I think. The price is reasonable, given some audiophile boutique brands charge many thousands of dollars to deliver a valve-ey sound I think $300 is good value.

 

[pwjazz]

Thanks for all the responses! I've learned a lot from Amir's reviews and the forums here.



Agreed. I imagined a digital source to avoid multiple DA/AD conversions. But I can see plenty of people wanting to stay in the analog domain.



Really good point. I didn't mean to imply that the world only needs one amp, but it's fun to explore how easy or hard it is to mimic one sound signature with different hardware, especially if your preference varies with content. I only have an SS amp right now (JDS Atom), but already experience some of this between different headphones, e.g. the Fostex TH-X00 vs. Hifiman HE650 sound pretty different, and my preference depends on genre.



Cool. I'm not surprised to learn that such plugins exist. I haven't explored such thing before but I'll check out the iZotope Ozone plugin.



Thanks for the additional details!

I sometimes enjoy using the bass enhancer in PulseEffects. It's the same as this https://calf-studio-gear.org/doc/Bass Enhancer.html

Basically it thickens up the low end by adding harmonic distortion rather than increasing the fundamental.

 

[Veri]

Based on the measurements published here. And all these deficiencies, when using headphones will be noticed more than others tube amps but with speakers.

If you want to modify / color the sound, if the source is a computer, it is cheaper and better to use software that uses a DSP, PEQ, ... 64-bit.

What is your obsession with 64-bit?? Plenty of actual music is mastered with 32-bit processing

Heck any professional mixing software can wrap 32-bit effects in 64-bit environment ...

 

[ZeDestructor]

Besides.. this would basically mean that we can safely say ALL but one powerful low distortion amp needs to be sold and no-one has a choice as all other amps are obsolete till the next one with better numbers comes out.

Isn't that the ultimate objective in many ways though? It certainly is for me at any rate

The output power level and output impedance feature cannot be mimicked by digital emulation and are an important part of the design and its capabilities.

Couldn't thse be replicated using a small, low-power tube preamp stuck between the DAC and the amp and a pot of some sort inline circuit (could be just a pot, could be more complex with caps and coils) with the output to raise/lower impedance and phase to suit?

 

[Bald1]

This is one purchase I made without regard to measurements but instead sound and especially the synergy with the Sennheiser Hd580/600/650 family. From my knothole it succeeded admirably. Oh FWIW I opted for the solderdude conservative bandwidth option.

 

[solderdude]

Couldn't these be replicated using a small, low-power tube preamp stuck between the DAC and the amp and a pot of some sort inline circuit (could be just a pot, could be more complex with caps and coils) with the output to raise/lower impedance and phase to suit?

You can stick a resistor or potmeter in series with any amp and make a variable output R or make something with a switch or resistors.
Then you can also add tube buffers in front, or use DSP and play with bandwidth.
But the amplifier used must be at least as powerful as the Polaris.
You need to add stuff though and you can't mimic the looks.
The Polaris is one device that can easily be configured in quite a few audible ways and using attenuation modules you can use it with a lot of different headphones and music sources.
Flexibility with a hint of tube-ness and more than enough power is what it does in one device.

 

[SuperValue]

Sorry about the thread resurrection, I just bought this amp and it's fantastic so far. Out of curiosity, if I set the output impedence to the 120 ohm setting, is that in effect, emulating an OTL tube amp? Or is there something else going on in amps like the Bottlehead?

 

[solderdude]

It is akin to emulating something close to a bottlehead OTL but with less harmonic distortion.
You can also set it to the smaller bandwidths. (the one tested here as the not standard 'aggressive' bandwidth settings.
For some headphones a higher output can actually help. In others it makes the sound worse.
That's why it is user select-able (0.1, 35 and 120) and why you can adjust the bandwidth.

 

[rocksteady]

Cheap SS integrated with the famous profile. Much better idea than buying a cheap Chinese amp, with tubes or SS.

[Polish] https://audio.com.pl/testy/stereo/wzmacniacze-stereo/3078-denon-pma-800ne

There are a Youtube review vs Marantz PM6005. The winner is Denon.

[Customer reviews] https://www.amazon.com/Denon-PMA-80...erType=all_reviews&sortBy=recent&pageNumber=1

PS: I do not trust in the THD+N measurements of this site.

Hi there.

Reviving an Old thread, if I may. A few questions:

1. What "Famous" profile are you referring to?

2. Any idea as to the Headphone Jack's Output Impedance?

3. Is the headphone section derived from the Speaker Outputs, through the use of Resistors, or does it employ a simple Op-amp based separated module?

Finally, I wouldn't exactly describe a circa €550 Amp as cheap, even though I don't deny that it looks a good value.

Cheers.

 

[Katji]

! wow, I'm glad this was bumped up. Amazing, those features, like ss Allens and Meanwell PSand Vishay and...waow.

 

[solderdude]

Hi there.

Reviving an Old thread, if I may. A few questions:

1. What "Famous" profile are you referring to?

2. Any idea as to the Headphone Jack's Output Impedance?

3. Is the headphone section derived from the Speaker Outputs, through the use of Resistors, or does it employ a simple Op-amp based separated module?

Finally, I wouldn't exactly describe a circa €550 Amp as cheap, even though I don't deny that it looks a good value.

Cheers.

1: he heard it somewhere or himself. Funny thing is the profile differs per output level.

2: Yes... 360 ohm but quite certain Maty is a speaker guy.

3: from speaker out through 2x180ohm in series.

 

[rocksteady]

1: he heard it somewhere or himself. Funny thing is the profile differs per output level.

2: Yes... 360 ohm but quite certain Maty is a speaker guy.

3: from speaker out through 2x180ohm in series.View attachment 147346

1: he heard it somewhere or himself. Funny thing is the profile differs per output level.

2: Yes... 360 ohm but quite certain Maty is a speaker guy.

3: from speaker out through 2x180ohm in series.View attachment 147346

Thank you for chiming in. Wow! That is very high indeed! I was expecting something in the region of 120-180 Ohm. That wouldn’t play well with the vast majority of headphones, except perhaps for the vintage (600 ohm) AKG, Beyer or Sennheiser. Oh well, nevermind.
I am now seriously considering the purchase of a Project Polaris precisely to listen to my collection of the aforementioned, which are renowned to play at their best when seeing a relatively High Output impedance, typically around 120 Ohm.
The only factor that makes me hesitate are those pesky, high import taxes and duties! It’s horrendous over here in Europe!

 

[solderdude]

You can lower the output R of that amp to 120ohm by simply paralleling a 180 ohm resistor to the used headphone.

 

[rocksteady]

You can lower the output R of that amp to 120ohm by simply paralleling a 180 ohm resistor to the used headphone.

Thanks for the suggestion, but I rather not mess with my headphones. I will simply skip that Integrated Amp.

 

[solderdude]

You can make a short extension cable with the resistor in it.