[pr0b3r]

After spending several days with my P1 and attempting comparisons to the G1 by memory, I can say that in the stock configuration, the P1 is brutally neutral and honest, and will, without apology, reveal any source file warts or shortfalls. It is not what I would pick if I just wanted to chill and daydream, however given quality recordings, it will sing with a clarity and honesty that is matched by very few players, regardless of price.

Although it is opamp-rollable, simply changing opamps at random will not make a night and day difference in the SQ. Much of what we hear is a synergy between the active devices (DAC, opamps, etc) and the many other circuitry components.

In my opinion, the most important sonic characteristic of any music device is accuracy of timbre. If, for example, a piano doesn't sound like a piano, nothing else matters, including frequency response, imaging, distortion or any other measurable or psychoacoustic factor.

The P1 circuit design does produce very accurate timbre with instrumental, percussion and vocal voices. Given the accuracy of this most important factor, we can consider other issues such as imaging, soundstage depth and width. These factors can be shaped to some extent in an amplifier circuit by the correct choice of active components, such as opamps, tubes, etc. As the perception of soundstage depth is primarily due to the difference in amplitude between instruments or vocalist front to back, an opamp must be able to play accurately and evenly at differing volume levels simultaneously. (In live performances, our vision also helps our ears to accurately perceive a sense of depth).

With all that said, I found the stock sound to be a bit brash and assertive for my taste, as if I was seated in the front row of an energetic performance. For those whose genre of choice is rock, this will likely prove quite satisfying. My preferences lean more towards classical and acoustic music, so I spent considerable time searching for an opamp that might be able to shade the sound a bit more to my preferences.

When evaluating opamps, some general guidelines to be observed are matching voltage requirements to supply voltage, low distortion, low offset voltage ( which can often be heard as a scratching sound when rotating the volume control without music playing) and, IMO most importantly, the ability to reproduce a perfect square-wave response without pre or post ringing. Any appreciable ringing can be perceived as a harshness or brittleness in percussive transients. There are relative few opamps that can actually reproduce a clean, accurate square-wave. Invariably, I have found those opamps which can to have the most natural and pleasing sound, especially when installed in a circuit of good design (which the P1 clearly possesses)

I used the following phones and IEM's to evaluate the P1 during my numerous sessions of opamp rolling: AQ Nighthawk, q-Jays v2 (dual BA), Pinnacle P1 (dynamic driver), Shozy BK earbuds, and MG5Pro {custom dynamic) IEM. I used only .wav files including various orchestral instruments as well as male and female vocalists with whom I am quite familiar. I also used some binaural recordings of thunder to get a sense of extremely low frequency ability.

Upon opening the case of the P1, I discovered that it is the bottom that should be removed, leaving the top with the buttons still attached to the front and back plates. Once uncovered, it revealed a beautiful board design with much attention clearly devoted to optimum component layout. The DIP socket for the only rollable opamp has a cap near each end which may pose a space issue for SOIC opamps soldered to an adapter. A good option is to use a DIP style opamp, taking care to ensure that it is a DUAL-channel and is inserted correctly.

Not being a big fan of the stock Muses opamp series, it was my goal to search for something smoother that delivered a presentation that moved me a few rows back when listening at my normal volume level.
,
Some of the opamps that I evaluated and made the cut to the finals were the LTC6241HV, EL8201, AD744, AD8616, and LME49860.
I felt that all of these delivered excellent overall performance with modest power requirements. None of them noticeably changed the frequency response, but rather made subtle changes to imaging, soundstage width and depth and perception of realism.

In the end, however, the overall winner was the AD8022. It has close to perfect square-wave response, very low distortion, extremely low-noise, high output and low quiescent current, in other words, about everything one could desire in an opamp used for audio purposes. I am pleased to report that when installed in the P1, it sounded as good as it looked on paper! Very smooth, with no frequency spikes or drops, bass that is almost palpable and a sense of realism that the others didn't quite deliver to my ears! Try it, I hope you will like it as much as I do.

Your feedback makes me want to have one, either the G1 or the P1. I just posted a screen grab of this on our local group. Thanks @HiFlight!

 

[gr8soundz]

Great mini review @HiFlight . Thanks.

The P1 should be just what I'm looking for. NOS multi-bit dacs/daps are becoming more and more rare. If the level of accuracy is similar to my desktop ladder dac I'm ok with it; not easy finding an affordable portable with that type of sound quality.

 

[HiFlight]

Just a couple of additional comments that I should have included in my previous post:

While the USB/DAC function works just fine, the USB does require power from your host device as it is not powered by the P1 internal battery. Best used for desktop rather than portable listening. The line-out works really well and is a constant level not varied by the volume control.

My only negative comment is that when the P1 encounters a file that it can't play, it generates a very loud continuous rasping sound much like listening to a sawtooth waveform. My preference would be for the P1 to just silently ignore the problem file. Given the lack of screen, it is nearly impossible to identify the culprit file.



The P1 when paired with the Revamp A1 via line-out to line-in is comparable in sound quality to a really nice desktop setup. Sizewise, the two match perfectly and make a very tidy bundle.

 

[gr8soundz]

Keep the info coming......

Does the battery still charge when in USB DAC mode or is it bypassed entirely?

What size/type of micro SD cards are you using (SDHC or SDXC)?

 

[HiFlight]

The battery still charges when in the USB DAC mode.
I am using a 64 gb SDXC card.

 

[golov17]

After spending several days with my P1 and attempting comparisons to the G1 by memory, I can say that in the stock configuration, the P1 is brutally neutral and honest, and will, without apology, reveal any source file warts or shortfalls. It is not what I would pick if I just wanted to chill and daydream, however given quality recordings, it will sing with a clarity and honesty that is matched by very few players, regardless of price.

Although it is opamp-rollable, simply changing opamps at random will not make a night and day difference in the SQ. Much of what we hear is a synergy between the active devices (DAC, opamps, etc) and the many other circuitry components.

In my opinion, the most important sonic characteristic of any music device is accuracy of timbre. If, for example, a piano doesn't sound like a piano, nothing else matters, including frequency response, imaging, distortion or any other measurable or psychoacoustic factor.

The P1 circuit design does produce very accurate timbre with instrumental, percussion and vocal voices. Given the accuracy of this most important factor, we can consider other issues such as imaging, soundstage depth and width. These factors can be shaped to some extent in an amplifier circuit by the correct choice of active components, such as opamps, tubes, etc. As the perception of soundstage depth is primarily due to the difference in amplitude between instruments or vocalist front to back, an opamp must be able to play accurately and evenly at differing volume levels simultaneously. (In live performances, our vision also helps our ears to accurately perceive a sense of depth).

With all that said, I found the stock sound to be a bit brash and assertive for my taste, as if I was seated in the front row of an energetic performance. For those whose genre of choice is rock, this will likely prove quite satisfying. My preferences lean more towards classical and acoustic music, so I spent considerable time searching for an opamp that might be able to shade the sound a bit more to my preferences.

When evaluating opamps, some general guidelines to be observed are matching voltage requirements to supply voltage, low distortion, low offset voltage ( which can often be heard as a scratching sound when rotating the volume control without music playing) and, IMO most importantly, the ability to reproduce a perfect square-wave response without pre or post ringing. Any appreciable ringing can be perceived as a harshness or brittleness in percussive transients. There are relative few opamps that can actually reproduce a clean, accurate square-wave. Invariably, I have found those opamps which can to have the most natural and pleasing sound, especially when installed in a circuit of good design (which the P1 clearly possesses)

I used the following phones and IEM's to evaluate the P1 during my numerous sessions of opamp rolling: AQ Nighthawk, q-Jays v2 (dual BA), Pinnacle P1 (dynamic driver), Shozy BK earbuds, and MG5Pro {custom dynamic) IEM. I used only .wav files including various orchestral instruments as well as male and female vocalists with whom I am quite familiar. I also used some binaural recordings of thunder to get a sense of extremely low frequency ability.

Upon opening the case of the P1, I discovered that it is the bottom that should be removed, leaving the top with the buttons still attached to the front and back plates. Once uncovered, it revealed a beautiful board design with much attention clearly devoted to optimum component layout. The DIP socket for the only rollable opamp has a cap near each end which may pose a space issue for SOIC opamps soldered to an adapter. A good option is to use a DIP style opamp, taking care to ensure that it is a DUAL-channel and is inserted correctly.

Not being a big fan of the stock Muses opamp series, it was my goal to search for something smoother that delivered a presentation that moved me a few rows back when listening at my normal volume level.
,
Some of the opamps that I evaluated and made the cut to the finals were the LTC6241HV, EL8201, AD744, AD8616, and LME49860.
I felt that all of these delivered excellent overall performance with modest power requirements. None of them noticeably changed the frequency response, but rather made subtle changes to imaging, soundstage width and depth and perception of realism.

In the end, however, the overall winner was the AD8022. It has close to perfect square-wave response, very low distortion, extremely low-noise, high output and low quiescent current, in other words, about everything one could desire in an opamp used for audio purposes. I am pleased to report that when installed in the P1, it sounded as good as it looked on paper! Very smooth, with no frequency spikes or drops, bass that is almost palpable and a sense of realism that the others didn't quite deliver to my ears! Try it, I hope you will like it as much as I do.

You tried Burson?

 

[nmatheis]

Actually yes, about sound characteristic. G1 is what people's majority wanted. But P1 is more to what sound characteristic that I want.
G1 is fun, from 3 batch total produced. Most people will like at first try.
But for P1?
I let you decide after long term listening

And @nmatheis actually the P1 highlight in parts, is using NOS Philips DAC, TI SoundPlus I/V and NJR Muses

Thanks for the reply and correction, TJ!

After spending several days with my P1 and attempting comparisons to the G1 by memory, I can say that in the stock configuration, the P1 is brutally neutral and honest, and will, without apology, reveal any source file warts or shortfalls. It is not what I would pick if I just wanted to chill and daydream, however given quality recordings, it will sing with a clarity and honesty that is matched by very few players, regardless of price.

Although it is opamp-rollable, simply changing opamps at random will not make a night and day difference in the SQ. Much of what we hear is a synergy between the active devices (DAC, opamps, etc) and the many other circuitry components.

In my opinion, the most important sonic characteristic of any music device is accuracy of timbre. If, for example, a piano doesn't sound like a piano, nothing else matters, including frequency response, imaging, distortion or any other measurable or psychoacoustic factor.

The P1 circuit design does produce very accurate timbre with instrumental, percussion and vocal voices. Given the accuracy of this most important factor, we can consider other issues such as imaging, soundstage depth and width. These factors can be shaped to some extent in an amplifier circuit by the correct choice of active components, such as opamps, tubes, etc. As the perception of soundstage depth is primarily due to the difference in amplitude between instruments or vocalist front to back, an opamp must be able to play accurately and evenly at differing volume levels simultaneously. (In live performances, our vision also helps our ears to accurately perceive a sense of depth).

With all that said, I found the stock sound to be a bit brash and assertive for my taste, as if I was seated in the front row of an energetic performance. For those whose genre of choice is rock, this will likely prove quite satisfying. My preferences lean more towards classical and acoustic music, so I spent considerable time searching for an opamp that might be able to shade the sound a bit more to my preferences.

When evaluating opamps, some general guidelines to be observed are matching voltage requirements to supply voltage, low distortion, low offset voltage ( which can often be heard as a scratching sound when rotating the volume control without music playing) and, IMO most importantly, the ability to reproduce a perfect square-wave response without pre or post ringing. Any appreciable ringing can be perceived as a harshness or brittleness in percussive transients. There are relative few opamps that can actually reproduce a clean, accurate square-wave. Invariably, I have found those opamps which can to have the most natural and pleasing sound, especially when installed in a circuit of good design (which the P1 clearly possesses)

I used the following phones and IEM's to evaluate the P1 during my numerous sessions of opamp rolling: AQ Nighthawk, q-Jays v2 (dual BA), Pinnacle P1 (dynamic driver), Shozy BK earbuds, and MG5Pro {custom dynamic) IEM. I used only .wav files including various orchestral instruments as well as male and female vocalists with whom I am quite familiar. I also used some binaural recordings of thunder to get a sense of extremely low frequency ability.

Upon opening the case of the P1, I discovered that it is the bottom that should be removed, leaving the top with the buttons still attached to the front and back plates. Once uncovered, it revealed a beautiful board design with much attention clearly devoted to optimum component layout. The DIP socket for the only rollable opamp has a cap near each end which may pose a space issue for SOIC opamps soldered to an adapter. A good option is to use a DIP style opamp, taking care to ensure that it is a DUAL-channel and is inserted correctly.

Not being a big fan of the stock Muses opamp series, it was my goal to search for something smoother that delivered a presentation that moved me a few rows back when listening at my normal volume level.
,
Some of the opamps that I evaluated and made the cut to the finals were the LTC6241HV, EL8201, AD744, AD8616, and LME49860.
I felt that all of these delivered excellent overall performance with modest power requirements. None of them noticeably changed the frequency response, but rather made subtle changes to imaging, soundstage width and depth and perception of realism.

In the end, however, the overall winner was the AD8022. It has close to perfect square-wave response, very low distortion, extremely low-noise, high output and low quiescent current, in other words, about everything one could desire in an opamp used for audio purposes. I am pleased to report that when installed in the P1, it sounded as good as it looked on paper! Very smooth, with no frequency spikes or drops, bass that is almost palpable and a sense of realism that the others didn't quite deliver to my ears! Try it, I hope you will like it as much as I do.

Super nice impressions @HiFlight!

I'll give AD8022 a try for sure, although I don't find the stock sound "brutally" honest. I enjoy it, and I think it could be a difference in the gear we use. I've used MEE P1 and Q-Jays 2, and I find MEE P1 quite bright unless I use triple flange or foam tips. I find Q-Jays 2 treble too hot. I imagine that plus personal preference is influencing our perceptions. I've also tried some of the opamps you sent me for G1, and they smooth out the sound a bit much for my setup. Different strokes for different folks!

Your feedback makes me want to have one, either the G1 or the P1. I just posted a screen grab of this on our local group. Thanks @HiFlight!

Yes, get one my man

Just a couple of additional comments that I should have included in my previous post:

While the USB/DAC function works just fine, the USB does require power from your host device as it is not powered by the P1 internal battery. Best used for desktop rather than portable listening. The line-out works really well and is a constant level not varied by the volume control.

My only negative comment is that when the P1 encounters a file that it can't play, it generates a very loud continuous rasping sound much like listening to a sawtooth waveform. My preference would be for the P1 to just silently ignore the problem file. Given the lack of screen, it is nearly impossible to identify the culprit file.



The P1 when paired with the Revamp A1 via line-out to line-in is comparable in sound quality to a really nice desktop setup. Sizewise, the two match perfectly and make a very tidy bundle.

Agree that decoding needs help for non-wav files.

Totally agree that P1 (or G1 for that matter) plus A1 is something special!

 

[HiFlight]

You tried Burson?

Won't fit.

 

[Dark Helmet]

Won't fit.

Can you post a pic of the lack of space?

 

[HiFlight]

Can you post a pic of the lack of space?

I will try to post a pix of the socket area tomorrow but a 10mm SOIC adapter just barely fits in the space available and I don't think the cover will fit over the 7.3mm Burson height. (V5i-d dimensions 11mm x 11mm x 7.3mm)

 

[Deftone]

That picture of the T1 in post #3 is TJ's prototype amp using the Korg Nutube.

"Nutube, similar to a conventional vacuum tube, has an anode grid filament structure, and operates exactly as a triode vacuum tube. Also similar to a vacuum tube, it creates the same characteristic rich overtones. By applying their vacuum fluorescent display technology, Noritake Itron Corp., a Noritake Co. Ltd affiliated company, have devised a structure which achieves substantial power saving, miniaturization, and quality improvements when compared with a conventional vacuum tube."

Ooo interesting stuff, id like to hear an amp based around this some day.

 

[nmatheis]

Still waiting on T1, bro

 

[silverfishla]

Ooo interesting stuff, id like to hear an amp based around this some day.

Pmillett.com has a nutube DIY headphone amp build project to build yourself. I just bought the tube and board on eBay for $50. Parts list from Mouser is like $115 for all the rest. You can sub parts as you like. There's a thread on here about it somewhere but you'll have to Google....

 

[HiFlight]

After settling on my choice of opamp, I have been spending many hours listening to my P1 with different phones that I have on hand. It seems as though I have become more accustomed to the sound of the P1 or the additional hours of use have further refined the SQ. Perhaps it is a combination of both, but at this point, of all my DAP's, the P1 is the one I reach for the most. I just find the holographic presentation to sound extremely realistic and makes my other players seem really two-dimensional.

I suspect this ability to create such a perception of space and superb timbre is due in no small part to the multi-bit DAC used by TJ in his circuit design as it sounds just as spacious and expansive when using the line-out to either my A1 or PB3 (balanced).

It would be most interesting to conduct blind testing of the P1 VS an unidentified multi-thousand $$$ boutique player and see what shakes out!!!

 

[ranfan]

For IEM, how will SQ improve (if any) using the P1 with A1 amp?