Ultra-High performance Single-Ended Class-A integrated amplifier


Minuet EL-34SE is all vacuum tube design integrated amplifier with Single-Ended Class-A topology that produces sensational and most powerful 6 watt/RMS per channel with very low harmonic distortion compare to conventional SE design. We combine the triode connected EL-34 for its better linearity and greater bandwidth with special feature of cathode feedback circuit to minimize distortion and deliver powerful driving capability.


This task called for special output transformer with dedicated cathode feedback coil that connected directly to cathode of output tube. After extensive trials we have developed a precision hand wound SILK SEL-34A output transformer especially for this circuit with 3.0Kohm primary impedance and just moderate 6.5dB amount of Cathode Feedback signal that generate the most linear frequency characteristic. Unlike notorious global negative feedback which generate feedback signal from secondary coil of output transformer, cathode feedback coil is free from back EMF induced by loudspeaker or other kind of spurious noise, phase shift from any network circuit; therefore, only pure feedback signal is applied back to cathode of EL-34. This technique reduces THD by the factor of 10 times. Total Harmonic Distortion of Minuet is less than 0.2% at 1 watt RMS while most conventional SE like 300B will start producing more than 1~2% of THD at same output level. Since cathode feedback topology does not require secondary winding to connect with ground, we can design and wind output transformer to neglect any grounding effect and make this new output transformer to perform much better than ever before.

  Besides from lowering THD figure, Cathode Feedback circuit of Minuet EL-34SE does not introducing typical high order odd harmonic distortion associated with most global negative feedback. This helps maintaining smooth and liquid sound without hint of sibilance.

Additional benefits of using cathode feedback circuit are:
1) Lowering output impedance
2) Increasing Damping factor
3) Extending frequency response at both ends of audio spectrum


These will help generate very high quality bass response unheard from conventional SE amp since the controlled motion of woofer is greatly increased. Minuet, therefore, redefines superb bass response (thus enhances full body) along with its excellent midrange and high frequency response.

Moreover we have design input and driving circuit so that it can accommodate 2 types of vacuum tubes without having to change any component value. These two types of tubes will create distinct sounding characteristic. (Standard tube is 6N1P type)

Total circuit gain
Max signal at clipping
Frequency Response (-3dB)

THD at 15Vpp
2nd Harmonic
3rd Harmonic
4th Harmonic
5th Harmonic

THD at 11Vpp
2nd Harmonic
3rd Harmonic
4th Harmonic

**Although 6N1P generates a bit less output waveform plus higher THD figure than 6CG7, 6N1P is selected as standard tube for its uniform harmonic content. Some may prefer lower distortion that 6CG7 provide so we strongly recommend each to experiment with simple plug and play method.

Figure 1 : shows actual screen shot of Minuet's Harmonic characteristic. Even under very low distortion level of -42dB of THD (around 0.79%) second harmonic still dominates most harmonic content while third and forth harmonic are very small. The use of Cathode Feedback reduces THD by large margin but does not induce high order harmonic distortion. This reveals ideal condition of excellent sounding type of amplifier and indicates the superb circuit design and implementation.

Figure 2 : shows Frequency Characteristic of new Minuet EL-34. At 13Hz to 60,000Hz (-3.0dB at full power) it is far wider than most SE amp or other push-pull amp. Not only the wide bandwidth demand of today digital format like SACD will fully be realized when playback through Minuet, but also analog affectionados and vinyl lovers will fully enjoy ultra details and dedicacy without listening fatigue.  
Figure 3 : shows phase characteristic of Minuet EL-34. At mid frequency from 100Hz to 10KHz there is only about 10 degree change in phase characteristic with the smooth transitions at both ends of audio spectrum. This also replicates typical non feedback circuit of phase relationship; therefore, Minuet sounds like high class Single Ended amplifier with lower distortion and much more control in bass.


  Minuet is another attempt of our extensive research and development. Combination of parts like precision metal film resistor, high grade ELNA cerafine bypass capacitor, ceramic socket, Miyama selector and ALPS volume control, electro-static shield handwound power transformer, Svetlana EL-34 tube and cathode feedback output transformer have been both listening test and lab test to ensure highest performance that generate absolute natural and dynamic sound. We also take great consideration to every element that will have effect to the sound. The chassis is made of anodized aluminum with acrylic fins to guide heat and protect EL-34 tube. External connectors are also enhanced by the use of high quality gold plated binding post and RCA to retain maximum signal connectivity with high grade detachable power cord.

Internal parts are best audio grade
High quality gold plated RCA and binding post



Stereo Vacuum Tube Integrated amplifier with 2 selectable input feature EL34 running in Triode mode in pure Class-A with cathode Feedback
Output Power: 6watt/RMS per Channel
Total Harmonic Distortion: less than 1.5% at 6 watt/RMS, less than 1% at 5 watt/RMS, less than 0..2% at 1 watt/RMS
Intermodulation Distortion: Less than 0.3% SMPTE
Frequency Response: 13-60,000Hz (-3.0dB) at RMS power
Cathode Feedback: 6.5dB
Circuit Gain: 44dB for 6N1P/6922 input tube, 33dB for 6CG7/6FQ7 input tube
Damping Factor:
Output Impedance: 2.9 ohm
Noise figure: below -80dB
Power consumption: 100 watts
Power requirement: 220-240V at 50/60Hz (stock version), 110-120V at 50/60Hz (special order)
Average Interior temperature: 65C (max), 49C (normal)
Dimension: 27.5 x 35 x 15 cm. (W x D x H) Weight: 7.6 kg. (shipping weight is 9.0 kg.)