After living with my DIY Back Loaded Horn loudspeakers for more than 2 years, I think its time to share my listening impressions with you.

First of all I recommend you ( if you are planing to build this design), to take the time to experiment with setup and placement to get the best of this kind of speakers. The sound produced by these specific BLH's is affected both by the behavior of the speaker in the room and the size of the room.

In my listening room ( 6.40 m long and 3.4 m wide) I deliver an absolutely enormous sonic picture but in fact, these speakers need to be heard in a room bigger than mine. Sound performance is very good with good depth from both sides (left to right wall), even when I put the speakers close to the wall behind them.

Giannis Spathopoulos made this one-off treasure audio power amp. This prototype model featuring four JJ EL34 power output pentodes per channel in an ultra linear push pull configuration. With an ECC83 as a pre stage, an ECC85 as a phase splitter, and a 6FQ7 as a buffer, this extremely dynamic and sweet sounding design is rated at 30 Watt in a class A configuration, and 70W in a class AB1 configuration.

...Some audiophiles state that the sound produced with tube amps is more natural than the sound from typical transistor amplifiers, and for this reason more satisfying. Typically, in sound reproduction systems, accurate reproduction of the sound of the original recording is the goal; gross distortion is something designers do not deliberately seek to introduce. At the upper end of audio systems ("high end" or "audiophile" systems) it is debated whether "accuracy" can best be described by measuring a "wide frequency response" and "low measured distortion levels" or whether highest quality reproduction is subjectively determined by listening alone.

If you wonder why this small digital amplifier is presented in a Web page with tube amplifiers, the answer is that TA-10 performs like tube amps !
In recent years in my home there was no solid-state amplifier. All my amps are tube amps. Some time ago I listen about this small digital amplifier and decided to buy it.
Based on the integrated circuit tripath TA2024 this little amp impressed me! Clear voices and impeccable music quality.

LINN records ( audiophile recordings) goes high resolution format ! Studio master recordings for the audiophile fanatics are now available. ( download FLAC audio format, studio master FLAC or CD quality FLAC ) More information here

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Enjoy high definition music from HDtracks !
More than 1500 artists and many albums are available for download in AIFF , FLAC audio format, , 320kbps MP3, and 96/24 FLAC download format.
Take a walk to hdtracks and enjoy with a FLAC player or converter, hi end quality !

Until the invention of the transistor in 1947, all practical amplifiers were made of thermionic tubes.

The simplest tube was invented by John Ambrose Fleming while working for the Marconi Company in London in 1904 and named the Diode, as it had two electrodes. The diode conducted electricity in one direction only and was used as a radio detector and a rectifier.

Although he may not have at first realized the significance of his invention it was Lee De Forest who added a third electrode and invented the first electronic amplifying device, the Triode which he named the 'Audion'. This additional 'control grid' modulates the current that flows between cathode and anode for a given voltage between the cathode and anode. The relationship between current flow and plate and grid voltage is often represented as a series of "characteristic curves" on a diagram. Depending on the other components in the circuit this modulated current flow can be used to provide current or voltage gain.

Working with tube amps you may need to calculate the output transformer impedance especially when we have an old transformer or a transformer with unknown values.
All we have to do is to calculate the turns ratio of the transformer. To do this we need an AC voltage source and an AC voltmeter.
So we apply an AC voltage to the primary of the transformer and we measure the output voltage to the secondary.
Turns Ratio = V in (to the primary) / V out ( measured in the secondary)
e.g. if we apply 5 Volts AC and we measure 0.21 Volts AC to the secondary the Turns Ratio of the transformer is :
5 / 0.21 = 23.8 That means a turns ratio 24:1
Knowing the Turns Ratio we can calculate the impedance ratio of the unknown transformer and the impedance in a given load to the secondary.
The impedance Ratio is the square of the turns ratio:24 X 24 = 576 that means an impedance ratio 576:1