HomeProductsServiceProductionФилософияLinksGuest bookContactForumReady products




- Museum of exclusive amplifiers >>>

- Мuseum of amplifiers >>>

- After-sales service >>>

- A-2011 tube OTL amplifier >>>




Tube amplifier with transformerless output



The upgraded version of A - 4.03 model (look photo, 2000). See the specifications of A -4.03 on the archive page: Museum of exclusive amplifiers >>>


Appearance, cabinet construction, internal cabling with positive influence on sound - a merit of Konstantin Zaporozhcev,, a head of the ZKI [ details ]. A single cabinet style  is used in many models.


The beginning of constructing this complicated model showed a high level of training at our production. The first copy was collected and finetuned perfectly.


Potentially achievable advantages of transformerless amplifiers are especially high resolution and detail.
In our models this potential is implemented, without any loss of "life" in music, though it is a very uneasy task to attain music emotions from transformerless amps.






"Highlight" of this amplifier is its dual purpose.
With help of two switches on the rear panel it can transform from a full stereo amplifier into monoblock with double capacity.


5 Ohm load in stereo mode, output power is 2 x 35 Watts.
Monoblock mode - 106 Watts.
On 8 Ohms load, in stereo mode,output power is 2 x 47 Watts.
Monoblock mode - 129 Watt.



- 274120 rubles.


More views:




Attention! For transformerless-2011 and A-MS we apply 6С33С output tube. They have several times higher probability of breakages than the EL34 output tubes applied in our other amplifiers.
6С33С significantly improve the transfer of music, but the models with those tubes  more often require replacement of tubes and repair of amplifiers.






view of assembly from below


view of assembly from top



I suggest  music lovers to bring  me your amplifiers for comparative listening.
The most revealing will be  exactly the comparative listening  with your own devices.




EnlargeStandard finishes for the bezels of our open amplifiers (available since the 1st of September 2011).
The possibility of other finishing options please, discuss when ordering. Custom finish raises the price depending on the type of tint.








Attention, the products are made to order with 50% prepayment. The making  takes approximately two months.

Ready products  are by 20% more expensive. (Except special proposals from the section "Ready products " ).




Mikhail Aleksandrovich Avdeev


Organizer of Klyachin`s laboratory.


Creator of amplifiers designs and exteriors


(story by Alexander Klyachin)

Until 1995, I was convinced that tube amplifiers were made by rogues with the purpose of cheating on naive audiophiles. It was rather strange, because in 1986 I was in the technical crew that supported performances and song recordingsof the rock group "Apartment 50" and was convinced of the superiority of powerful tube amps over the transistor ones. Apparently my "righteous anger" was directed to domestic tube amplifiers, most of which presents a single-ended "weaklings" with 5 ... 10 Watts per channel, which react violently to any overload and continue to "cough" for some time, making the impression of even less power than they actually have. The matter is that since 1993 the "Natural" loudspekers ("Natural" was a name of a small company, established by me and YuryGribanov) were sold well. These speakers were fine-tuned for transistor amplifiers and for omni-directional sound were fitted out with 4, 6, and sometimes up to 18 tweeters! Such a huge heap of speakers consumed large amounts of electric power. Impedance at HF range fell below 2 Ohms! At medium and low frequencies the radiation of drivers were united and there was no need to connect them in parallel, (to increase volume) therefore, apart from treble those loudspeakers had sufficiently high resistance. Buttube amplifiers do not provide correct frequency response with speakers if these speakers are fine-tuned to match transistor amps and, furthermore, they have drops of resistance in specific frequency ranges. It’s clear whywith tube amplifiers my speakers of those years didn`t sound the way I wanted. Sure thing, I quickly found that "guilty" there were "bad" amplifiers. Dislike of mine was so great that at the first exhibition "Russian High - End 95", where I was one of the organizers, I made a secret attempt to discredit amplifiers. After a demonstration of some tube amplifiers made by Russian inventors, I announced (as if without a back thought) that we were going to connect a transistor amp. I was confident in the superiority of the latter. All turned out exactly the "opposite": - decent transistor amplifier sounded awfully after the tube one: - lifelessly, synthetically, dirtily. This edifying lesson made me resolutely abandon the prejudice and I fervently began to develop my own tube amplifiers. I was lucky, my first model with 6П44 tubes sounded well, from what I made a false conclusion that I already knew how to create good tube amplifiers.
Encouraged, I developed the following "advanced" model, with such a low level of noise and background, that nobody believed, leaning their ear to the speaker that the amplifier is already running, only the loud music hitting their ears was making them believe me. Noise was absent, but good sound was absent too. Here I realized, what a long way of knowledge was ahead of me. Persistence is my friend, so, already in 1996 I created a transformerless tube amplifier (OTL), in which between output tubes and loudspeakers there weren`t any output transformers and the sound therefore was much more alive and natural.
In 1997, a mighty OTL amplifier was born. It had a form of two monoblocks and preamplifier. Capacity reached 160 Watts per channel. For OTL amplifiers, which are remarkable for their low efficiency, 160 Watt is an enormous power!?In 1996, the first small-scale production of amplifiers with EL34 tubes was launched. My first amplifiers with 6С33С tubes appeared already in 1995, with 6П3С tubes - in 1999.
From year to year, I have perfected all these types of amplifiers, mastering the difficult art of creating models that are able to reproduce music, full of life, not just lifeless, clean sounds. A huge role in the implementation of my studies was played by my colleague and friend Mikhail AleksandrovichAvdeev, who had produced amplifiers before I realized the need for them in a good audio system. Mikhail have developed a beautiful appearance, design of cabinets and organized the manufacturing of amplifiers designed by me. I am grateful to him because I always can count on his effective organizational and intellectual assistance - he is the excellent designer and just a wise man.



A-MS in the room of audition (ZKI, Stavropol )

Sound boards for A-MS







Attention, in connection with instability of the prices of materials and equipment elements , all prices are given approximately. The exact prices will be calculated by preparation of the order for products.

Copyright ©2003, Alexandr Klyachin

Made in Point Studio