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 The vacuum tube gain section of the EHT Integrated has been tailored around the 6J5GT (or 7A4) tube, a highly linear medium-gain octal base triode with fairly low transconductance from the early times of tube electronics. The amplifier comes with a set of tubes which have been carefully tested and hand-picked to meet tight specifications.
The use of tubes with questionable characteristics may lead to a degraded sonic and signal-to-noise performance. Even serious circuit damage may occur in worst case scenarios!


 The EHT Integrated Amplifier MKII (launched in October 2022) includes two novel bass boost presets selectable via a 3-position toggle switch (B1 > boost style-1, B2 > bass boost style-2). When the toggle switch rests in middle position the tonality of the amplifier is neutral (flat frequency response).

The bass boost functions are useful for a variety of applications: For equalizing loudspeaker components with slim bass response or limited bass extension. For adjusting the bass response of the system to the acoustical conditions of the listening environment (small loudspeakers in large rooms!). For restoring tonal imperfections of the listening program (often given by a lack of bass extension). Or simply for switching to a more full-bodied presentation if one is in the mood for listening to music in an enriched and laid back way. Notably, the bass boost functions
act in a much more subtle way than common bass boost facilities and do not rely on clumsy and sound degrading conventional tone control circuitry. Both functions are realized by interposing solely one additional capacitor (per channel) to the neutral mode circuit!


 The EHT Integrated Amplifier draws a current of about 1A (2A) from the 230Vac (115Vac) mains, corresponding to a power consumption of 230 watts. It is protected with a 2A slow-blowing 5x20mm fuse in the power inlet. On rare occasions, the fuse may blow at the switching-on
moment due to the current spike drawn by the mains transformer in this instant. Should this condition arise more regularly it may be advisable to use a fuse with slightly higher current rating.


 To set up the EHT Integrated Amplifier switch off all components of the system and proceed as follows. Do not connect the amplifier to the mains until steps 1 to 7 have been taken.

1. Make sure that the frontal power switch (NETZ) rests in OFF (AUS) position.

2. Bring the master power switch on the power inlet module into the ON position. It is advisable to switch off the amplifier at the power inlet when the unit will not be used for a longer period of time!

3. Turn the volume control knob (Volumen) to the zero position or at least a very low angle of rotation. Make sure that the bass boost switch rests in the middle position.

4. Install the tubes carefully. Hereby ascertain that the guide pin of the tube base is properly aligned with the notch of the socket.
-Never switch on the amplifier unless both tubes have been installed!
-Never pull out a tube while the amplifier is powered on!
-Never pull out a tube of the socket as long as it is still hot!
-Always de-install the tubes and wrap them in their original protection case before shipping or transporting the amplifier!

5. Bring the amplifier into its final position. Make sure that there is sufficient clearance around the unit to allow for adequate ventilation.
The EHT Integrated Amplifier is a class-A device which runs hot after a few minutes of service. It requires adequate ventilation for safe operation!

6. Connect the amplifier to the loudspeakers.

7. Connect the amplifier to program sources and/or a phono preamplifier.

8. Connect the amplifier to the mains.

9. Power on the program sources (while the EHT Integrated is still powered off). Wait
until the warm-up process on all these components has come to an end.

10. Power on the EHT Integrated Amplifier.

11. Wait until the unit has warmed-up. Always switch on the program sources (or phono preamplifier) first and then switch on the EHT Integrated amplifier, observing a delay of at least 30 seconds! Never switch a program source (or phono preamplifier) on or off while the EHT integrated is powered on!

12. Choose the desired program source (Eingang) with the input selector. Adjust the listening loudness manually or via remote control. The minimalist volume control module features only two buttons (volume up, Lauter and volume down, Leiser) and is powered by 2pcsxAA batteries (not delivered with the unit). The batterie compartment is locked with a metric size 2.5 Allan screw. When powering off the system, always switch off the EHT Integrated Amplifier first, then switch off the other components of the system observing a delay of at least 30 seconds!
Keep the original crate and the tube protection case for later use. They have been specifically designed for safe transport under rough conditions! Shipping the amplifier in inadequate packaging will result in catastrophic damages of the unit!

THÖRESS...A Tribute to Professional Audio Components from the Golden Age of the Electronic Tube !


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