M7 Heritage
Kondo Audio Note Japan’s complete valve preamplifier, combining a high-gain phono stage with a wide-bandwidth line stage in one hand-wired chassis. Inspired by the legendary M7 of the late 1980s and refined for modern reference systems.
Key Features
- Stereo valve preamplifier with integrated phono stage
- Two unbalanced RCA phono inputs
- Three RCA and one XLR line-level inputs
- 63 dB total gain from phono input to line output
- ECC803S SRPP phono input stage
- 6072 plate-follower and cathode-follower phono stages
- Direct-coupled 6072 line-amplifier circuit
- 500-ohm line-output impedance
- Modular phono and line-amplifier sections
- Independent left- and right-channel decoupling capacitors
- Shunt-regulated DC heater power supply
- EZ81 valve rectification
- Pure-copper main chassis
- Kondo pure-silver foil capacitors and silver-lead resistors
- Kondo SSW silver internal wiring
- Kondo KSL-VzII internal interconnect cable
- Supplied with an ACz-AVOCADO power cable
- Hand-wired and manufactured in Japan
Design & Build
The M7 Heritage carries forward the musical character of the original M7 preamplifier, introduced in the late 1980s alongside the legendary Ongaku. Its classic valve architecture is updated with contemporary Kondo components, modular construction and improved compatibility with modern audio systems.
The phono amplifier begins with an ECC803S SRPP circuit. Subsequent stages use 6072 dual triodes in plate-follower and cathode-follower configurations, providing high gain and accurate RIAA equalization. Modular hand-wired construction keeps the signal paths short, while local decoupling capacitors minimize the signal loop.
The line stage uses a direct-coupled 6072 plate follower and cathode follower. Separate decoupling capacitors are positioned close to the left- and right-channel modules, contributing to a 500-ohm output impedance and strong drive capability.
Its power supply combines EZ81 valve rectification with custom Kondo transformers, chokes and a shunt-type DC heater circuit. Pure-silver foil capacitors, silver-lead resistors, SSW wiring and KSL-VzII internal interconnect cable are installed within a pure-copper chassis.
System Pairing
Two 47-kohm phono inputs accommodate moving-magnet cartridges or moving-coil cartridges connected through a suitable step-up transformer. The Kondo IO-XP cartridge can be partnered with the Kondo SFz or SFz-E transformer before connection to either phono input.
Three RCA and one XLR line inputs provide connections for digital sources and additional analogue components. The XLR line input is electrically unbalanced and is provided for connector compatibility rather than differential signal transmission.
Two RCA outputs and one XLR output support connection to a power amplifier, subwoofer or bi-amplified system. All outputs are unbalanced, and Kondo recommends a connected input impedance above 20 kohms.
Technical Specifications
| Specification | Detail |
|---|---|
| Type | Stereo valve preamplifier with integrated phono stage |
| Model | M7H |
| Phono circuit | ECC803S SRPP input stage; 6072 plate-follower and cathode-follower stages |
| Line circuit | Direct-coupled 6072 plate follower and cathode follower |
| Phono inputs | 2 pairs RCA, unbalanced |
| Phono input impedance | 47 kohms |
| RCA line inputs | 3 pairs, unbalanced |
| XLR line inputs | 1 pair, unbalanced |
| Line input impedance | 50 kohms |
| RCA outputs | 2 pairs, unbalanced |
| XLR outputs | 1 pair, unbalanced |
| Recommended output load | Above 20 kohms |
| Output impedance | 500 ohms |
| Line frequency response | 10 Hz–280 kHz (+0/–3 dB, 100-kohm load) |
| RIAA deviation | ±0.3 dB, 30 Hz–20 kHz, excluding low-cut filter |
| Line-stage gain | 25 dB |
| Phono-to-line gain | 63 dB |
| Line-stage THD | 0.07% at 1 kHz and 1 V |
| Line noise | Less than 0.15 mV |
| Phono noise | Less than 5 mV |
| Phono-stage tubes | 2 × ECC803S; 2 × 6072 |
| Line-stage tubes | 4 × 6072 |
| Rectifier tubes | 1 × EZ81 |
| Internal wiring | Kondo SSW silver wire and KSL-VzII interconnect cable |
| Chassis | Pure copper |
| Power supply | Internal, with shunt-regulated DC heater circuit |
| Included power cable | Kondo ACz-AVOCADO |
| Power consumption | 38 W |
| Dimensions (W × H × D) | 438 × 160 × 330 mm, excluding protrusions |
| Weight | 15 kg |
| Country of manufacture | Japan |
