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Tri TRV-M300SE Tube Monoblocks, Single Ended Magic From Triode, SUPER RARE!

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Pickup currently unavailable at SkyFi 479

Tri Trv-M300Se Tube Monoblocks Single Ended Magic From Triode Super Rare! Amplifier

Tri TRV-M300SE Tube Monoblocks, Single Ended Magic From Triode, SUPER RARE!

SkyFi 479

Pickup currently unavailable

479 South Broad Street
Glen Rock NJ 07452
United States


Producing a whopping sweet tube powered 20W each, these beauties will drive your vintage or high efficiency speakers with finesse.  

Imported from Japan, these monoblocks were converted to work properly on 120V AC here in the US.

The tubes have very low hours and it's evident that these were well cared for. 

The internal build quality was immediately noticeable when we opened them up in our lab.  Component layout, parts quality, and attention to detail is impressive.  Features both single ended and balanced inputs, plus a super handy gain knob on the front.  

Cosmetically they are stunning, both featuring polished stainless steel chassis and candy apple red transformers.  

Tube Compliment (Ea.):

2-300B Tubes, 1 - 12AU7, & 1 12AX7

Power Output:

20W @ 8ohm 

Further info on these tube beauties courtesy of

"When we were asked to review a couple of 300B amplifiers from the Triode Corporation or Tri for short, we were pleasantly surprised. Tri is a Japanese company and designer Junichiro Yamazaki likes simple, well thought-out designs. Besides a pair of monoblocks and their matching integrated amp, we also received the new Tri CD player. This presented a lot of opportunities to learn what the Triode Corporation had to offer.

We started with the Tri TRV-M300SE monoblocks. Most obvious after unraveling the perfect Japanese packaging was the beautiful finish. The front of the long narrow amplifiers is trimmed out in a thick aluminum plate with a subtle color accent and the power mains switch. On the right sits an attenuator to eliminate a preamp if desired. With a depth of 44cm, a height of 20cm and a width of 18cm, the 15 kilos of this design are nicely dimensioned. Below the obligatory (in the EU) tube cage which was easily removed, the tubes took pride of place - one 12AX7 and 12AU7 double triode each in a mu-follower configuration and a pair of paralleled 300Bs. The mu follower is responsible for distortion reduction, the parallel operation of the power tubes explains the output doubling while still remaining single-ended where one output device (here two) amplifies both the signal's positive and negative phase without switching off. This is exclusive to class A operation (though not single-ended - push/pull too can be operated in class A). Benefits of single-ended operation are better linearity (no zero-crossing distortion), stability and the reduction of higher-order harmonic distortion. But the most favorite benefit must be the possible absence of any negative feedback at all.

Behind the two Tri-labeled 300Bs tubes are the power and output transformers in their beautiful red lacquer casings. The biggest share of the amplifiers' weight derives from the iron cores and the many meters of 6N copper windings around them. For both monoblocks, this adds up to about 20 kilos combined. The top plate of the amplifiers is made of high-gloss chromed steel which continues around the sides. Around back it got even more interesting as here we found 4, 8 and 16-ohm terminals besides the low-level inputs. Because our Avantgarde Duo Omega horns are rated at 16 ohms, this was a potentially exciting discovery."

The SkyFi Testing Process for Tube Amplifiers:

We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and tubes are inspected for signs of stress overheating or cracking.

We then power up the unit carefully and run a simple 1k sine wave while monitoring the output on an oscilloscope for signs of distortion or noise. Finally we run the amplifier to its full rated power into the appropriate resistive load provided by our Sencore amplifier tester. If there is an issue, it will usually be noticeable at this point. If it all looks clean we will often test for THD (Total Harmonic Distortion) measured by our Keithley distortion meter, and compare it against the original manufacturers specifications. The amplifier the remains powered on to "burn in" on our test bench for a few hours to make sure there are no heat related issues. If there are balanced inputs available they will also be tested.

We also test all tubes for output gain and leakage on our calibrated modern and professional tube tester against the original manufacturers specifications. If needed, the tubes will be replaced from our vast NOS (New Old Stock) vintage or modern inventory.

Final testing involves pushing actual music thorough the amplifier. We've learned over time that some issues are only noticeable to a trained ear while listening to familiar source material. Our test bench has reference vintage Kef speakers that we're very familiar with which quickly reveal any discrepancies. Some amplifiers will then move into our listening room where they are tested with our in-house reference speakers of choice.

Please click here for detailed specifics regarding our specialized packing process that separates us from the rest.



Original Box







Yes - Power Cords

Physical Condition


Working Condition


SKU: 103338