ompany materials present P-1 as a “Digital Speaker/Headphone Processor”. However, when I looked at it during the Audio Video Show 2015 exhibition and then listened to, I saw and heard a headphone amplifier equipped with a digital signal processor called the “P-3 MK IE Processor Chip” which corrects the imperfections of different types of headphones.
It is because our attitude and intentions regarding the use of a product which consists of a few devices determine the category to which we assign it. If the P-1 function (speaker correction) is more important to us, then we will call the device a “digital signal processor/headphone amplifier”. If we are interested in a headphone amplifier, then it will be a “headphone amplifier/signal processor”, or even simply a “headphone amplifier”.

The manufacturer mentions the following areas that the processor influences the most:

• sound dynamics,
• musical separation of instruments,
• the positioning of musical instruments on the sound stage,
• space and acoustics of recording venues,
• bass control,
• micro-detail reproduction.

The description is supplemented with a detailed list of features regarding the functionality of the P-1:

• the unique P-3 MK IE Processor Chip,
• 64-bit calculation precision, 32-bit
• the dynamics – 105 dB
• incredible improvement of neutrality, bass and focus,
• increased space and improved detail reproduction,
• creating excellent big sound from small speakers,
• not demanding for the source, amplifier and cables,
• improved room acoustics,
• improved A/D and D/A processing,
• over 120 speaker/headphone settings
• preamplifier function: 2 RCA analog inputs, 2.5 Vrms max
• RCA output, 2 Vrms max
• headphone amplifier for 16 – 600 Ω load,
• dimensions (W x H x D): 125 x 60 x 190 mm,
• weight: 2 kg.

P-1 as a headphone amplifier

As it can be seen, the preamplifier function can be added to the processor and headphone amplifier function. It is because, I think, the P-1 was created as an element of a cool “desktop” system with a computer in the main role, small speakers and headphones close at hand. In such a role, we would make use of all the three functions of the P-1. Let me remind you that Ancient Audio offers two top-class near field speakers, designed to work with a computer: Studio Oslo and Master Oslo. Although they are equipped with analog correction circuits, i.e. a kind of analog “processors”, the functioning of the digital P-3 MK IE circuit is incomparably more precise and its range of use is more versatile.

Taking it all into account, I used the P-1 in its secondary role (from the point of view of the manufacturer), as a headphone amplifier. This decision was influenced by my interests. I am a “headphone man” and everything that can potentially improve the quality of sound of the music that I listen to in this way, instantly attracts my attention. Headphone sound correction is a way of making headphones more “civilized” and adapting them to one’s own needs.
I do not know if you remember, but Mark Robinson wrote for “High Fidelity” in his reportage from Japan that he has been correcting the sound of headphones with the use of computer programs for years (more HERE). The P-1 gives us a possibility of doing something similar, but in a much more elegant and compact form.

P-1 as a processor

The P-1 is a small device which owns its style to Jarek Waszczyszyn, Ancient Audio owner and constructor. The prototype was the P-3 processor we wrote about in a Krakow Sonic Society meeting coverage. At the front there is a brass plate with engraved inscriptions. There is also a small aluminum knob, two toggle switches and a headphone jack. So, it is the style of the 1970s. The device is placed on a small granite plate which is another Jarek’s “hallmark”. At the back there are two RCA inputs and an RCA output. A mini jack hidden under the power cable is used to install programs with processor settings.

The back panel also houses one more element that Jarek is emotionally attached to: a “recovered” non-removable power cable. In Oslo speakers, Jarek used a power cable taken from a scrapped lighting lamp, while here we have a cable from a recycled hair-dryer. I am sure that Ancient Audio is going to be awarded a suitable medal by ecological organizations for promoting the reuse of electrical components.

It is a curiosity that the P-1 has been designed for the user to be able to remove the upper panel safely, in a way similar to removing the tube cover in tube amplifiers. The components are painted with black varnish and all connections are hidden under a printed circuit board.

JAROMIR WASZCZYSZYN
Owner, constructor

Where has it come from?

The P-3 processor has its admirers and owners. Its influence on the sound of speakers is enormous. However, its price (40,000 PLN) has been too high for many potential users. So, this is how a prototype of a less complex device was created. Its heart is the P-3 MK IE processor. It has the same capabilities, program and structure as the representative P-3 MKI, but its memory contains 125 settings (instead of 250) and it uses an economical version of the housing (hence the "E" at the end of the name). So, what has been reduced in comparison to the P-3? The P-1 has simpler A/C and C/A converters, output stage, amplifier and control.

P-1 prototype

There was also a prototype with XLR connectors and easy program selection

“Easy” is a relative term. It occurred to me somehow that instead of programming a simple controller it will be much faster to solder a few diodes. That led to creating a pocket model of “Enigma”.

However, there was also a headphone “trait”. Having written his review of the P-3 with Raidho speakers, Piotr Ryka started questioning me about headphones. By that time, I had stayed away from headphones, although once I had taken an “unborn” headphone amplifier (but one equipped with V-Caps) to Wojtek Pacuła.

The experience with speakers made me aware of how much they can be improved using a processor. So, I made an attempt with the Fostex TH 900 headphones. Fostex headphones are very good, but something in their sound irritated me a bit. So, the P-3 processor had to be reprogrammed to be used with headphones.
It is all much simpler with headphones than with speakers. First of all, the problem of room influence disappears. Headphones themselves are generally based on one full band transducer. There are fewer problems with headphone housing than with speaker housing. After a few days the program was ready.

Fostex correction proved beneficial, as the irritating sharpness of sound disappeared. The sound became more filled and spacious. That would probably have been the end, if another company owned by a friend had not asked me to continue my headphone experiments. The test set was constructed, as usual, according to the MiniMax rule: minimum aesthetics, maximum music:

There was little to do to move on from the prototype to make a “2 in 1”, i.e. a column/speaker processor. It was premiered during the Audio Video Show 2015 exhibition. The processor was used with a tablet and the HyperX Cloud headphones. It was a quick test to check if people like it. They did... As I have mentioned, adapting a program to headphones is much simpler than in the case of speakers. I mastered the headphones that Wojtek chose for tests in one evening. I spent another evening on making small corrections. The rest was the pleasure of playing music on HiFiMAN headphones with the processor. As for now, the database is limited. If anyone would like to correct their favorite headphones, they can simply send them to us. After the program has been tuned, they will be sent back with the processor.

The programmable DSP circuit that constitutes a basis for the P-1 can “remember” 125 different correction speaker/headphone characteristics. In real world it is not necessary, as Jarek Waszczyszyn conducts measurements and introduces changes to the program by himself, separately for each user. It is hard to call it an especially effective method, but it is definitely the most precise one. Before the test, Jarek took some headphones from my collection and prepared a correction program with reference to these headphones. Changing modes is easy – it is enough to put the DIP switches situated next to the processor chip in an appropriate configuration. Jarek prepared a legend for the headphones that I had given to him and placed it on the upper panel of the amplifier, from the inside.

The P-1 headphone amplifier was first listened to in order to compare the sound without the processor and with the processor. Unfortunately, it is not known whether in the “off” position (processor switched off) signal flows without being converted by A/D and D/A converters or it is converted anyway.
The next step was to compare the sound of the amplifier with the processor switched on, with a reference amplifier. In this case it was the Bakoon Products International HPA-21 headphone amplifier. It is a battery-powered device with a current headphone output, that cost 13 500 PLN at the time of the test.

I used the following headphones during the test:

• HiFiMAN HE-6, planar magnetic headphones, impedance: 50 Ω, efficiency: 83.5 dB, test HERE | headphone cable: Forza Audio Works Noir, review HERE
• Sennheiser HD800, dynamic headphones, impedance: 300 Ω, efficiency: 102 dB/V | headphone cable: Forza Audio Works Noir
• Beyerdynamic DT990 Pro (1988 version), dynamic headphones, impedance: 600 Ω, efficiency: 96 dB, test HERE (Polish)
• Beyerdynamic DT770 Pro Limited Edition 32 Ohms, dynamic headphones, impedance: 32 Ω, efficiency: 96 dB
• AKG K721 Studio, dynamic headphones, impedance: 55 Ω, efficiency: 92 dB | headphone cable: Oyaide HPC-35

It is characteristic for computer programs that they are constantly improved. On the one hand, it is their disadvantage, as it is assumed since the very beginning that they are imperfect. On the other hand, it is an advantage, as it allows to improve their operation in the future, without the need to change the product that they operate within. It is the same in the case of the P-3 processor that constitutes the basis for the tested headphone amplifier.

I heard it for the first time during a meeting of the Krakow Sonic Society, when it was used to correct Dynaudio speakers. Based on this text, it can be said that the participants had mixed feelings about it. I think it partly resulted from the fact that Jarek was just at the beginning of his quest at that time.
In the P-1 we get much more advanced correction algorithms, although it is easy to notice that the changes introduced by the processor are very similar to those in the A-3 that we heard at Tomek’s. However, the advantages of correction are undeniable this time. Depending on the type of headphones used, the changes ranged between “interesting” and “very interesting” to “fascinating”.

Interesting

It was interesting to listen to the DT770 Pro Beyerdynamic and K271 Studio AKG headphones. The former ones are, in my opinion, not a very good choice. Their sound is very light and its resolution is low. They are characterized by high detail and can show a well-focused sound picture, also when it comes to its location on the “stage”. In this case, the P-1 works mainly as a frequency correction device. Using the processor resulted in obtaining better tonal balance, achieved through the deepening of sound. The musical message as a whole had a greater volume and it was more “solid”. Individual instruments also became greater in volume and were not as “plastic” as before.

However, I did not notice any special breakthrough. The P-1does not turn headphones whose sound I do not like into high-end headphones – it does not work like this. It is true it tamed them, correcting many aspects of their performance. However, I have not become their fan. Although the changes were heading in the direction which I thought was right, they were just changes and not a “transformation”. The DT770 Pro did not magically become the HD800 Sennheiser headphones.

It was similar in the case of AKG headphones. Similarly to Beyerdynamic headphones, they originated in the studio and their sound has specific properties. It is mostly about their selectivity and clarity, as well as high power durability. In contrast to the TD770 Pro, I used them quite often when I was still working in a studio and I know that with a suitable headphone amplifier they can render really interesting sound. An example of such an amplifier was the Funk Tonstudiotechnik LAP-2.V3, an amplifier designed for recording studios. However, these headphones often also give quite flat and not very engaging sound.

The sound undergoes a total transformation with the Ancient Audio amplifier – both for the better and for the worse. First of all, the outstanding selectivity and detail are gone. The sound settled much lower – it is something that occurs in the case of all headphones connected to the P-1. However, with the AKG the depth of this change was incredible. It was in the case of this model that the signal level with the processor was much lower than without it. This shows well how much correction was introduced.

I think that it is the key to understanding what the given headphones can do and what they cannot do. The P-1 introduces changes that are as deep as needed by a given model. Changes introduced in the DT770 Pro in the 32-ohm version and in the AKG K271 Studio were the greatest. That confirmed what I had already known before: these are the “weakest” of all the headphones that I had asked to prepare the correction algorithm for. It appears that the better the design, the more sophisticated the construction, the less correction was needed, but also that, which is very important, that the final effect was best with the latter.

It is not a paradox, but a simple extension of a rule known from other fields of audio: the higher on the quality scale we are, the smaller changes a system needs to perform at its full capacity. At the same time, these little corrections contribute to the greatest final effect – they are small, but also the most important steps.

Fascinating

It is about what I heard, to some extent, with the DT990 Pro and, fully, with the HD800 Sennheiser and the HE-6 HiFiMAN. The latter are very difficult to drive. A few high-class watts are the minimum that they should be provided with. If we do not take care of it, they will produce thin and vociferous sound. The P-1 is not strong enough to correct them in the case of every type of music. In the case of classical music, where little signal compression is used, it was possible to quite quickly reach the point at which the output circuit was over-przesterowany. However, even then the sound was high-class, it was excellent. In the case of pop and rock it was different, it was possible to turn the volume up so much that the overdriving was no audible and the message was excellent. So, it is worth trying out other magnetostatic headphones with the P-1, ones that require less power.

The HD800 headphones are another story – not that resolved, not that dynamic, but it was the P-1 that made them come as close to the HE-6 as possible. I listened to this combination for a very long time, with different music and a great pleasure. Without any correction, Bakoon delivered even deeper and more resolved sound. Instruments and vocals had more breathing space, they were better projected and their sound images were more tangible. The difference in price (more than double) did not result, in any way, in a huge difference in sound. When I listened to the P-1 for a longer time, without making comparisons with the HPA-21, the difference would disappear to such an extent that I did not worry I lacked something.

The sound was smooth and fluid, just like from the best tube amplifiers. The dynamics was incredible and surprising each time. Add to it the number of details, slight changes in tone, movements, air and tape noise... I had had no idea that Sennheiser headphones can do that. I assume that this is equally true for the HD600, HD650 and HD700 models. The processor did something that the best sources, amplifiers and cables (e.g. the Siltech Triple Crown) do – it darkened the sound, increasing the amount of information. The P-1 lets you hear that the brightening of sound that producers often make use of is a fake, deception. The fact that it seems to us that we then get more details is a cheat – we are simply tricked. The dark, deep sound of the Ancient Audio amplifier controlling the HD800 is THE right one.

Conclusions

6000 PLN is a very high price to pay for a headphone amplifier. However, the P-1 is something else. It is a processor designed for speaker correction with an “attached” headphone amplifier. Additionally, it is also a line preamplifier. So, it is a pity that it does not have a digital input, as then it could also work as a DAC, which would be of use in the case of computer systems. Apparently, however, one cannot have everything. As Jarek told me, 6000 PLN is the lowest price that can be offered by such a small manufacture for such a high-class correction system.

However, while listening to it with the best headphones that I have at home (unfortunately, I did not have time to listen to it with the Audeze LCD-3), I knew that I was given a powerful tool – one that you can go on improving forever. The sound was so sophisticated that only top-class and many times more expensive solutions offered by other manufacturers offer something that is yet better. However, which is interesting, these devices aim at producing sound of the same kind as is intended in the case of corrections made by the processor in the P-1. It is the first device of this type in the catalogue of Ancient Audio and it is already very successful.

The P-1 has the form of a small rectangular prism. It would be very lightweight if it was not for a granite plate to which the chassis is attached. It is made of bent metal, has the shape of the letter C, with bent front and rear panels. A brass plate with descriptions is attached to the front. There is a power switch, a switch which activates the correction program and a volume knob. The program switch can be placed in three positions: in the central one correction is switched off and the device operates as a line amplifier. There is one group of programs in the upper position and another one in the lower position. Such a solution proves effective when we quickly want to switch programs between two devices, e.g. headphones and speakers.

The descriptions of connectors on the rear panel are attached to a marble plate. There is an RCA line input with the so-called “pass-through”, an RCA line output, as well as a mini jack (3.75 mm diameter) to enter the program settings. Here is where the power cable comes out. It may seem funny, but in such an expensive and sophisticated device this is simply unacceptable.

The device is covered with a chassis from above, but only during transportation. At home we can easily take it off – all the components have been assembled in a way that makes the device both safe and look nice. On the right there is a small amplifier with a small transformer, two filtering capacitors and a voltage-stabilizing circuit.

The line input is based on the OPA 134 Burr Brown integrated circuits. Next to them there is a large DSP chip covered with a plate with the Ancient Audio logo and the name: P3-MK IE. Signal that goes through it must first be converted into a digital form in the A/D Crystal CS5343 chip and then into analog signal again, in the D/A Crystal CS4333 chip. Next to it there is an eight-position DIP switch. We use it to select the correction program.

Signal is then sent using flat, computer tape to the front panel where it is damped in a small, “car” (ALPS) potentiometer, sent back to the circuit, amplified in the LM 4808 integrated circuits and then sent to the front panel again, to the headphone output.

Robust, clean work of a small manufacture.