HAD Audiolab Maestral II, OTL Tube headphone amplifier
HAD Audiolab is a company based in Croatia, dedicated at first (1995) to distribution and creation of industry-specific software, however the passion for music and sound of Markesic Drazen, (company's owner) has finished imposed applying many of the skills acquired has managed to create a whole line of amplifiers, preamp tube stages that reflect craftsmanship, dedication and quality.
Here a few words of Drazen:
This design was developed with several criteria in mind: reliability and longevity,with and optimal quality components and an operational range of tubes set up to achieve maximum linearity and adequate driving abilities and finally,implementation of as much as possible of our own design solutions and methods.
Combination of these features makes for an excellent value for money, something that we feel is of utmost importance in building an honest relationship with our customers.
Experience has taught us that audiophiles can hear when something has been created for them by other audiophiles.
This is the reason we wouldn't create anything we wouldn't use ourselves.
Reliability and quality, but always with a “budget” price, all without leaving the European borders. Maestral line includes 3 models: Maestral One, Two and Maestral Three.
Based on the same chassis that combines american walnut wood, metal and a nice front made of Corian (wich is a quite popular type of synthetic resin on some Japanese High end audio products), all performed by other Croatian artisan specialist in these matters, giving these amps one solid base that reflects quality, craftsmanship and passion. It may become something with little impact on the final sound but settled on a solid base, in this case combination of solid wood and stone (natural materials) that helps the reduction of unwanted vibration and heat dissipation circuit have a quite important role improving in the final result on this tube designs amplifiers, apart from the obvious fantastic looking.
They choose not to apply any artificial varnish to keep their amps a natural look. Only walnut oil is recommended for protection, we must to apply it once per month.
This type of construction and design makes the Icon Audio HP8 a much more industrial and perhaps more vulgar product. Had Audiolab designs and builds in Croatia by hand.
This company is looking for that kind of customer who appreciates this arguments with a continue feedback with the company responding to the customer's needs. In my conversations with Drazen (owner) I could tell you that he is also a headphones lover (a nice pair of Grado PS500 is part of its own collection ) Al the time he is open to suggestions and continuous feedback.
After meeting the specifications and price point of the three available models, the Maestral II was at first better suited to my Sennheiser HD600, OTL desing (output transformerless) have a great reputation with hd6xO and hd800.
After a fast shipping I could quickly have a unit Maestral II at home, all without custom charges (I'm inside Europe), remember that Croatia belongs to the EU since this past summer.
NOS tubes "tube rolling"? For sure!
The Maestral II comes with a PCC88 NOS Tesla valve , produced between 1965-66 in the former Czechoslovakia , brand enjoyed great prestige, overshadowing the Mullard EL84 with your model ( not used in this amp ) . For the PCC88 have virtually identical construction to the Telefunken and it is used by prestigious brands like EAR Audio .
We can also find the 6n23p Reflector NOS like a pre-valve , also from the 60s , designed for military use ensuring reliability under a minimal care.
In my unit 6n13s NOS from Svetlana, produced in the 70s and dual triode equivalent to ECC230 / 6AS7G type .
The good thing is that with these type of tubes we can have as much "tube rolling" as we like, thanks to the large variety.
Any tube suggestions?
The Maestral line has always a good compromise between price and performance, as reflected in the PC88 Tesla with a great performance.
But for those tube rolling fans Drazen has his own recommendation: NOS Telefunken ECC88 Siemens , but keep in mind that easily exceed 100/150 euros ...
And pcc88 ECC88 , 6DJ8 , 6n23p , E88CC , 6922 all compatible with this amplifier , so we have guaranteed fun and if you have the time and patience you can play with differents combinations to make the sound more suitable to youtastes.
If we want a sound with more detail one of the best options are the 6922 where Siemens & Halske are positioned as top models , though the prices are high, it is something we must consider too.
Regarding the power tubes ( 6as7 , 6n13s , 6080 ... ) we can also choose from a wide variety of options and brands.
I emphasize that these models are direct suggestions from Drazen. Unfortunately I had not the chance to try it by myself. So my impressions are exclusively with the stock tuves on my Maestral II, Tesla PCC88 NOS and a pair of Svetlana 6n13s.
Operation on low impedance (<80 ohm): OTL (single end class A)
Operation on high impedance (>80 ohm): OTL (single end class A)
Driver tube (& equivalent): 6DJ8, ECC88, 6n23P
Power tube (& equivalent): 2x 6AS7, 6N13S,6080
Power output (32-600ohm, THD <1%) 200mW
THD on declared power: 0,70%
Input impedance: 50K
Out. impedance on low switch /feedback: 30 ohm / 6dB
Out. impedance on high switch/feedback: 122 ohm / 0dB
Freq. Response (+-3dB): 7-65kHz
Sensitivity for declared power: 0,775Veff /0dB
Max. Input voltage: 1,55Veff /6dB
Max. Out voltage/impedance: 10V/600 ohm
Signal/Noise db: 85dB
Stereo Crosstalk dB: 65dB
Input conn: RCA
Out conn: 6,3mm conn
Pass trough conn: RCA
Supply voltage: 110-120/220-240V
Power consumption: 125VA
Dimension mm(W x D x H): 200x320x90(200 tube)
Weight kg: 4,5
Suitable for CAT SE box (2 x 2W on 6 ohm)
As I mentioned a few lines back the good reputation of OTL headphone amplifiers with the HD6X0 Sennheiser line gave me a good reason to give a try to this range of amplifiers.
Both Maestral Maestral One as Two have relatively high output impedances, around 30 Ohm, making them more appropriate amplifier for high impedance cans.
In the case of the Sennheiser HD6X0 the 500 Ohm impedance peak around 300Hz is very favored from a high output impedance like this, the Maestral II with 30 Ohm contribute to a better performance in several areas, more body and the general perception of more weight in the sound.
This OTL design SE class A does honor to its sound, it is an extremely musical amp without the sense of a “dirty" sound, actually reaches a high level of detail and accuracy.
Preheating about 20 minutes the amplifier is recommended and with the Maestral II this is a must almost to achieve an optimal performance. Sounds produced during the heating of from completely cold help to create a special moment of sensations, the music is all about that, feelings and sensations. Something may sound great but without giving us enough feelings, this is not the case Maestral II, as it has that "something" that it make it so good.
Departing the undeniable warm character valves listening is very nice, it's a very easy amp to hear the merry couple, never shows roughness or outbursts, showing everything under control.
With the unquestionable warm character of tubes, the listening experience is very nice, it's a very easy to hear amp, it never shows harshness, everything is under control.
Sennheiser HD600 II + MaestralI, a perfect dancing couple?
My Sennheiser HD600 scales a lot with this amplifier giving me some unsuspected levels of enjoyment for me so far.
I can hear a fantastic bass texture and depth in almost all recordings , this bass is rich and detailed.
My previous Icon Audio HP8 (not SE version) maybe the sound had more punch but from my point of view the Maestral II sound is more mature and refined in every way.
The drive capabilities and the strong power output of the Icon is replaced with a wonderful tone and delicacy in voices and instruments in the Maestral II. I could say that it is a more neutral and relaxed sounding amplifier. Pushing stronger than the 200mW output power at 300 Ohm reflects the mids are perfectly projected into the scene becoming intimate but generally with an excellent amplitude and dimensionality.
Micro-details in female and male voices and a great PRAT are a wonderful touch to the music, and the highs are always presented in a smooth way.
Again the Maestral II tonality and musicality play a major role into the middle section realism, with that kind of analog and very fluid sound, showing all the harmonics with an extreme facility, appreciating the sound as a whole, with no emphasize of any frequency over another, since all the transients contribute to the softness and linearity in the sound.
Delicate, soft and silky treble sounds very classy, perfectly treated (especially compared with the Icon HP8 that at times lacked all control as they could)
The Tesla tube contributes to this good high frequency performance, and I'm so happy with its performance that I have not very curious to try other alternatives like Genalex Gold Lion, but I know that some day I'll give it a try.
2 gain and impedance positions
The Maestral II has gain and impedance switches with two positions availables.This is an important thing adapting the amp performance to the headphone requirements.
They can be modified in real time without shutting down the amplifier (great point), which helps a lot to hear the differences.
Both the Sennheiser HD600 an the Hifiman HE- 500 need the highest gain and the lower impedance (30 Ohm) position for a nicer perception of overall dynamics and better volume adjustment with the ALPS potentiometer.
Changin to high impedance position with 122 Ohm and using my Sennheiser HD600 has a quite high output volume ( SPL). Despite the certain loss of control in acute and variation of tonal balance makes me use this configuration only with low volume classical recordings
Despite being an interesting option especially for 600 Ohm cans , 122 Ohm may be somewhat excessive and under my suggestions I discussed this point with Drazen, who is going to change this setting to 60-70 Ohm.
Based on declared power( 0.2 W ) somebody may think without listening to this amp that it could barely drive a pair of Hifiman HE- 500. However I must say that I could listen to this combo, and in very sweet and friendly way .
It is obvious that we will not get the 100% juice of this these headphones because they need more watts, but thanks to good current reserve of the Maestral II and about 70-75% of the volume pot the result sound with the Hifiman's is tremendously enjoyable . The slight artificiality treble of these headphones ( much lower than the HE- 400 case) are compensated with the excellent sweet and analog tonality of the Maestral II , also providing a major plus into the mids realism, resulting less " dry "
If you're not a high volume listener, sure you will can appreciate the Maestral II performance with this type of headphones , putting realism more than punchy sound.
Curious extra features
There are three notable extra features in this amp.
First, in the rear panel there is a sensivity pot. Second one is the ability to drive small speakers with high sensitivity ) adding a CAT module ( transformer) and the last one, a preamp function.
The first one is very helpful for a better volume adjustment, all the way to the " + " mark is better suited for high sensitive headphones.
The possibility of using it as an little speakers amplifier with the additional CAT makes it a great all in one solution , which will certainly appreciate for many users .
As for preamp function the performance is quite good, it maintains the excellent tonality that I could appreciate through its headphone jack.
Used equipment: Meridian Director DAC, HRT MicroStreamer, Mytek 192 DSD DAC, Sennheiser HD600, Hifiman HE-500. (WireWorld Solstice RCA, USB Supra 2.0 y CablePro power cable)
At 569 euros plus shipping the Maestral II offers a lot to the customers with a high class tube sound, and a large open field for tube rolling fans.
It can be purchased by contacting directly with the brand, the following link also shows pricing for all products:
Drazen shown extremely communicative at all time, and certainly he is ready to advise you what best suits your needs, not surprisingly there is also the possibility of amplifier "on demand" under the guidelines of the client even for quite rare headphones like the AKG K1000.
Thanks and sorry for my english mistakes (is not my native language)
Edited by yugas - 8/26/14 at 4:10am