THORESS EHT Integrated Hybrid Triode Integrated Amplifier Instruction Manual
- June 12, 2024
- THORESS
Table of Contents
THORESS EHT Integrated Hybrid Triode Integrated Amplifier
Product Information
- The Hybrid Triode Integrated Amplifier is a high-quality amplifier designed to provide excellent drive capability for loudspeakers with medium to low efficiency or with critically low impedance. It offers 2×20 watts of output power into a 6 ohm load and features very low output resistance (high damping factor) for optimal performance.
- The amplifier is meticulously hand-constructed using proven point-to-point wiring techniques, ensuring low noise performance, ease of service, and high reliability. It is built with careful attention to every aspect of internal construction to ensure long-lasting performance.
- The EHT Integrated Amplifier MKII (launched in October 2022) includes two bass boost presets selectable via a 3-position toggle switch. The neutral position provides a flat frequency response, while the other two positions offer different bass boost styles.
- The amplifier draws a current of about 1A (2A) from the mains and is protected with a 2A slow-blowing fuse. In case of frequent blown fuses during switching on, it may be advisable to use a fuse with a slightly higher current rating.
Product Usage Instructions
- Switch off all components of the system before setting up the EHT Integrated Amplifier.
- Ensure that the frontal power switch (NETZ) is in the OFF (AUS) position.
- Bring the master power switch on the power inlet module into the ON position.
- It is recommended to switch off the amplifier at the power inlet when not in use for a longer period of time.
- Turn the volume control knob to the zero position or a very low angle of rotation.
- Install the tubes carefully, aligning the guide pin of the tube base with the notch of the socket.
- Do not switch on the amplifier unless both tubes have been installed.
- Do not pull out a tube while the amplifier is powered on.
- Do not pull out a hot tube from the socket.
- Always de-install the tubes and wrap them in their original protection case before shipping or transporting the amplifier.
- Ensure there is sufficient clearance around the amplifier for adequate ventilation, as it runs hot after a few minutes of service.
- Connect the amplifier to the loudspeakers.
- Connect the amplifier to program sources and/or a phono preamplifier.
- Connect the amplifier to the mains.
- Power on the program sources (while the EHT Integrated is still powered off) and wait until the warm-up process on all components has finished.
- Power on the EHT Integrated Amplifier.
- Wait until the unit has warmed up before using it.
INSTRUCTION
- Thank you for purchasing the THÖRESS Hybrid Triode Integrated Amplifier!
- Our Integrated offers 2×20 watts of output power into a 6 ohm load combined with very low output resistance (high damping factor). Such providing excellent drive capability for loudspeakers with medium to low efficiency or with critically low impedance which may present a challenge for our all-tube single-ended triode amplifier models.
- The amplifier is built with meticulous hand construction using our proven point-to-point wiring techniques, whereas much care has been taken in arranging each aspect of the internal construction to ensure low noise performance, ease of service and the highest reliability for many years to come. Please read the following explanations and instructions carefully to get the most out of your EHT Integrated Amplifier!
TUBES
- The vacuum tube gain section of the EHT Integrated has been tailored around the 6J5GT 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!
BASS BOOST FUNCTIONS
- 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 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.
FUSE
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.
SETUP
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.
-
Make sure that the frontal power switch (NETZ) rests in OFF (AUS) position.
-
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! -
Turn the volume control knob to the zero position or at least a very low angle of rotation.
-
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! -
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! -
Connect the amplifier to the loudspeakers.
-
Connect the amplifier to program sources and/or a phono preamplifier.
-
Connect the amplifier to the mains.
-
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.
-
Power on the EHT Integrated Amplifier.
-
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! -
Choose the desired program source with the input selector. Adjust the listening loudness manually or via remote control. The minimalist volume control module features only two pushbuttons (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!
FEATURE OVERVIEW
- Vacuum Tube MOSFET Hybrid Integrated Amplifier with 20 watts of output power per channel (into a 6 ohm load).
- Driving capability for critical loudspeaker loads due to very low output impedance (high damping factor).
- Ultimate sonic excellence on par with no-compromise all-tube single-ended triode amplifiers, yet without involving exotic and costly power tubes.
- Unique minimalist zero-feedback EHT schematic: single-ended triode gain stage (6J5GT tube) driving a unity-gain MOSFET output buffer operated in single-ended (class-A) mode with high idle current.
- Total avoidance of protection circuitry.
- 4 line level inputs (2×4 RCA jacks) with equal gain selectable via rotary dial.
- Remote volume control via high-grade motor driven dual potentiometer with excellent channel balance and low angle sensitivity.
- High grade electrolytic capacitors made in Germany in the power supply.
- Low noise low leakage dual-coil C-Core mains transformer made in-house for 230Vac (115Vac via jumper setting), 100Vac (Japan), 220Vac (South-Korea, China, Thailand, Indonesia) or 245Vac (Australia).
- Full hand construction, point-to-point wiring throughout.
- Non-magnetic aluminum casework, anodized printing on front and rear panel, powder-coated lids.
- Dimensions 434x450x184 mm, 184=20 (feet)+134+30 (tubes over case), 450=434+16 (speaker binding posts).
- Dimensions of the shipping crate: 650 x 650 x 350 mm, weight 18Kg.
THÖRESS…
A Tribute to Professional Audio Components from the Golden Age of the Electronic Tube !