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KingRex T20U & PSU MKII System with John Blue JB3 Loudspeakers Review

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Shifting to amplified rock, I played Santana and Michele Branch’s The Game of Love and the music became rougher around the edges but held together reasonably well – bass compressed but the sound remained quick and drums were believable and treble didn’t get unruly.  I could play this loud enough to satisfy and the results were surprisingly good.  I followed this with Lady Gaga’s Bad Romance and while not club level, I again got a sense of midbass thwack – vocals were solid and midbass thump had some actual thump – better than most small speakers I’ve heard and certainly better than desktop speakers I’ve run across.

Overall the sound was quite engaging and given their small size you can use them as desktop loudspeakers or place them on a shelf and they still provide rather pleasing results.  The computer desktop speaker market is littered with unlistenable dredge – the JB3 changes that in a big, big way.  So long as you don’t go crazy on the volume and use a decent or good amplifier, like the KingRex or Trends audio amps, you should be very pleased with these speakers.  They look posh with the excellent piano black lacquer (available in red or white as well) and they’re easy to take with you on trips or to the office..

John Blue JB3 Loudspeakers

KingRex  – This Emperor Has Clothes

I was pleased with the Trends Audio Tripath amplifiers, and KingRex is another company offering quality affordable products geared for computer desktop systems and small listening rooms.

The class T amplifier is fairly rare in the audio world.  They are often said to be SET-like for a bargain price and there is some truth to this, although good SET amps don’t have much to fear from class T or D or much else in my view.  Class T amps do seem to capture the hall better than a lot of traditional solid state amplifiers and don’t possess some of the complaints people have over a lot of traditional solid state amplifiers, like etched high frequencies which cause a high fatigue factor.

Class T amplifiers tend to be far less costly so if you don’t need high power and you can’t afford the price or hassle of SETs, the technology offers a very serious option.  Further, there is a rather sizeable community out there tweaking and upgrading Class T amplifiers, like adding off-board superior power supplies.  Indeed, KingRex has done this very thing with the PSU MKII power supply and they also have a DC battery power supply that has received high praise.

The KingRex T20U amp is a really a simple affair.  It has one nice silver volume knob (Noble potentiometer) on the front and a blue light telling you the unit is on.  Around the back is a single pair of 6 Ohm speaker outputs, one RCA input, and a USB input with on board DAC.  I do wish these Class T amp makers would provide at least 2 inputs.  While I understand they gear the products to computer audio users, people do still use CD players and DVD players or televisions.  Further, it would help us reviewers when we want to compare CD and computer audio without the time lag of changing the interconnects back and forth.

Keeping with the small system approach the amplifier and PSU are a perfect aesthetic match and measure the length of a typical paperback novel.  Indeed, I placed a paperback novel on top of the amplifier and it was exactly the same size.  It doesn’t get much more compact than that! The PSU MKII did have one annoyance and that was the light.  Rather than a simple blue ON light to match the T20U amp, the PSU has a very bright blue “KingRex” light that turns on – all the letters are blue with the exception of the letter X which is red.  It reminds me of the elevator at the school I teach that will always say “Thank you for using LG’s Lift” before it opens.  After the thousandth time you wonder what LG was thinking.  I don’t know too many teachers who plan to buy an LG lift and since the school already bought the LG lift there doesn’t seem much point in advertising to the owners.  Likewise, the person who bought the KingRex PSU knows the brand they purchased.

2 Responses to KingRex T20U & PSU MKII System with John Blue JB3 Loudspeakers Review


  1. Second Mouse says:

    Thanks for the review of the Kingrex system and the John Blue JB3.

    Unfortunately, I must disagree a bit with the assessment of the TrendsAudio system. I currently use a very nice system which includes the Trends PA-10 (tube preamp), TA-10 (power amp), PW-10 (power supply), and a pair of John Blue JB3 speakers. A NOS tube in the PA-10, and the Trends power supply both add an extra bit of sparkle to my system similar to what was observed by the reviewer when he listened to the Kingrex system with the PSU.

    Further, the specifications of the TrendsAudio and Kingrex amplifiers differ very little if you look at the low distortion figures.

    And, the full power figures should hardly matter if the equipment from any of the three manufacturers in question is used on a desktop or in a small room as intended.

  2. Dear Second Mouse

    I would like to make it clear that I did not audition the Trends Audio amplifiers with the John Blue speakers. I auditioned both Trends Audio and KingRex on Audio Note AX Two speakers and I did allude to the fact that tube rolling the Trends may yield superior results.

    Comparing stock to stock without the King Rex power supply I would give the edge to Trends Audio. The KingRex power supply lifts the sound slightly ahead of the stock version of the Trends. But if you put in a very good NOS tube in the Trends Audio then it may leap ahead again. I like the Trends Audio personally a bit more because I like tubes and the ability to tube roll allows for changes and improvements and to be blunt that’s rather enjoyable. Plus it’s smaller and more portable. On the other hand the King Rex includes a DAC and has a nicer volume control and is a little more elegant (posh) and many people may not want to deal with tubes.

    As you point out the power issue with the JB3 won’t much matter but it could matter if a person buys a more traditional loudspeaker. Although neither is exactly a powerhouse.

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