KingRex T20u amp+DAC measurements or other experiences?

[Simfunk]

About 12 years ago I bought two KingRex T20u amps for 270 € each in Germany. I liked the size and the simplicity of this amp, and it had exactly the features that I needed. Now that I have discovered ASR I would be interested how the Kingrex performs in terms of measurements. As this product is discontinued (I am not even sure if KingRex is still around), Amir is not interested in measuring it.

Now my question: Is there anyone around who owns or did own a KingRex T20u and has some measurements or an informed opinion on its performance? I've attached some pictures and the specs. Thanks a lot in advance for your responses!

 

[Jobian]

Bit late but...with the kingrex PSU this amp is staggeringly good! Just enjoying the music..feeding a pair of Dynaudio Audience 42s..

 

[Simfunk]

Not late at all, I've started this thread because I couldn't find nearly anything about this device on ASR. I'd be glad if those who search for the Kingrex on ASR found this thread and posted their experiences.

 

[John Poplett]

I have a Kinter brand desktop amplifier that has the Tripath 2020A+ part. I bought mine in 2021. They are still available on Amazon for ~$44. I use it with an Allo Boss 2 DAC. It displaced a noisy off-brand Taiwanese tube amp and a Cambridge Audio AX35 integrated amp for sound and size. It drives a pair of Audioengine bookshelf speakers on my desk. I was surprised when I found I preferred it to the Cambridge Audio amp. I don't have any metrics to back up my preference. I like that it performs so well for something so sinfully inexpensive.

It makes me eager to step up, albeit with the same idea of getting a lot of bang for few dollars. I'd love to know how our Tripath amps measure up against modern, low-cost amps. At least we can say that amps based on the Tripath part are still in production and available for purchase.

John

 

[Simfunk]

Thanks, John, that's interesting! I once had two Kingrex until I sold one. The other one is still powering two bookshelf speakers, and I just can't find any reason to replace it. The enclosure is sturdy, controls are simple and the sound and power are "good enough". I'm still waiting for the ASR-certified integrated amp that justifies another investment.

 

[Etymologee]

I still have a T20U with some uprgraded caps. Also have the external PSU they offered. I would love to keep it but the volume pot is scratchy. I looked into replacing the volume pot but I have zero soldering/electrical skills. I found the right ALPS part that would fit. However, would have to totally disassemble the case and access the board from below. I love this little amp so I endure the volume pot but it does bug me.

 

[Simfunk]

Scratchy volume pot, ouch! That'd bug me too. I guess you've already checked if somebody could solder it for you? I, too, have zero soldering skills, but it looks like it's an easy task for somebody who has.

 

[tjf]

here's an ASR test result of another Tripath 2020 series amp from 2019 -- the Topping TP60 -- enjoy!



Let's compare that to Topping TP60:

 

[tjf]

The TP60 was even more strange:

Good grief. This is even worse!

Let's sweep the input level and plot power versus distortion and see what pops out:

 

[tjf]

Conclusion:

"The Topping TP60 should do better in power department but don't assume by any stretch that you are hearing the fidelity of any good source driving it. It might be a lot more useful as dual linear power supplies and case than an amplifier!

What we are seeing is that unlike products like DACs where the underlying silicon is superb, here garden variety amplifier ICs are used which are more likely designed for soundbars, boomboxes, bluetooth speakers, and alike.

So no recommendation here. Search will go on for reasonably priced amplifier that does justice to our source. I have a few amps to test so we will throw more darts at the board. The prognoses is not very good though based on preliminary tests....."

 

[Simfunk]

... well... thanks tjf for the message. That's quite disappointing. I mean, I wasn't expecting top performance, but 70 dB SINAD is really too bad. Guess I'll have to check Amir's recommendation list for a new amp.

 

[John Poplett]

... well... thanks tjf for the message. That's quite disappointing. I mean, I wasn't expecting top performance, but 70 dB SINAD is really too bad. Guess I'll have to check Amir's recommendation list for a new amp.

I am grateful for TJF's input too. This ASR post, Digital Evolution: some audio electronics history, makes the claim that Tripath played a major role in the popularization of class D amplifiers:

As far as I know, Tripath was the first company to offer true high-fidelity Class-D amplification, which they called "Class-T" and trademarked the term for marketing purposes.

I think it explains why we got so attached to amps based on the 2020A+ in the first place. So we cannot be too dissapointed that our Tripath amps have been surpassed if the newer D class amplifiers merely evolved from the inspiration that Dr Tripathi's part provided.

It's super suggestive that the analysis TJF dug up is for a 2019 Topping product. And a neat solution is to to check Amir's recommendation list and find out what Topping is up to today. Hmmm.... would that be a Topping PA5 II or Topping PA5 II+, I wonder .

 

[Simfunk]

Neither PA5 has USB input, which I really need. As far as I can see, the "recommended" amp that comes closest to my needs is the Loxjie A30. But this one has a SINAD of 80, so no big improvement over the Kingrex, and I really hate micro USB.

 

[tjf]

Hi, I fell victim to the "Tripath fever" around 12 years ago and bought the Sure Electronics TK2050 Tripath kit, that was the higher powered implementation of the Tripath design with a separate Sigma Delta modulator chip (for Tripath's propriatary signal conditioning) and a separate Class D Power chip (based on a ST Microelectronics "ST series" class D power amp -- I think?) -- this tech was used in a LOT of inexpensive products in the early-to-mid 2000's that were marketed as "giant killing" amp tech, but today things have advanced (a LOT), thanks mainly to the group of Scandanavian designers that ended up inventing the current crop of T.I. Class D amp devices ASR is reviewing (T.I. 3255 PFFP, etc.) that you see in Topping PA5/7 amps, and other well reviewed products here, etc.

It's probably time to move on from the Kingrex amp (I still have their line stage preamp!) and consider the new Class D stuff from Topping, Axign, Hypex, Purifi, et al...

As far as USB is concerned - you ought to get a proper modern DAC with modern USB implementation to connect to a new amp design (that USB input on your Kingrex is a 1st gen 16 bit T.I. PCM2702 -- USB decoding today is waaaaaaayyyyyy improved)

A good DAC with a modern 24 bit capable USB input can be had for a few hundred $ ($200?), and then add the updated version of the PA5 with it's volume control....and leave the decade of the 2000's behind.

 

[tjf]

Or -- really move into the 21st century with....

WiiM Amp | Versatile Streaming Amplifier: Stream Elegance, Amplify Brilliance

Discover the WiiM Amp, a state-of-the-art streaming amplifier designed to refine the way you experience music, movie, and more, WiiM Amp combines power, versatility, and simplicity like never before. Whether you are an audiophile or a home theater enthusiast, WiiM Amp delivers exceptional sound...

www.wiimhome.com

But you'd need to work out just what you need a USB input for, as the Wiim Amp USB connection is for a USB drive holding your "ripped" digital content (CD's?) for playback thru the Wiim Amp DAC+Amp -- what do you use the USB connection for -- audio from your PC/Mac?

I suspect the streamer capabilities of the Wiim Amp might eliminate the need for the connection to a computer??????

 

[Simfunk]

Hi, I fell victim to the "Tripath fever" around 12 years ago and bought the Sure Electronics TK2050 Tripath kit, that was the higher powered implementation of the Tripath design with a separate Sigma Delta modulator chip (for Tripath's propriatary signal conditioning) and a separate Class D Power chip (based on a ST Microelectronics "ST series" class D power amp -- I think?) -- this tech was used in a LOT of inexpensive products in the early-to-mid 2000's that were marketed as "giant killing" amp tech, but today things have advanced (a LOT), thanks mainly to the group of Scandanavian designers that ended up inventing the current crop of T.I. Class D amp devices ASR is reviewing (T.I. 3255 PFFP, etc.) that you see in Topping PA5/7 amps, and other well reviewed products here, etc.

Yeah, I remember reading about that new groundbreaking amp technology in a newspaper. Then I went to the local hifi store and they had the Kingrex at display. I thought it was a great replacement for my AV receiver which had way too many in- and outputs for my daily listening use, so I bought two of them.

It's probably time to move on from the Kingrex amp (I still have their line stage preamp!) and consider the new Class D stuff from Topping, Axign, Hypex, Purifi, et al...


As far as USB is concerned - you ought to get a proper modern DAC with modern USB implementation to connect to a new amp design (that USB input on your Kingrex is a 1st gen 16 bit T.I. PCM2702 -- USB decoding today is waaaaaaayyyyyy improved)

A good DAC with a modern 24 bit capable USB input can be had for a few hundred $ ($200?), and then add the updated version of the PA5 with it's volume control....and leave the decade of the 2000's behind.

Thanks again for the background info, really interesting! I should add that this is not my primary system but just a small setup in my basement that I use for playing music from my laptop while training (usually Soundcloud 128 MP3 streaming ), so there's no need for SOTA performance. But still, I'd like to have something decent, not too expensive though, and as simple as possible. I am thinking about the Apple dongle connected to the Topping PA5 II.

 

[Simfunk]

Or -- really move into the 21st century with....

WiiM Amp | Versatile Streaming Amplifier: Stream Elegance, Amplify Brilliance

Discover the WiiM Amp, a state-of-the-art streaming amplifier designed to refine the way you experience music, movie, and more, WiiM Amp combines power, versatility, and simplicity like never before. Whether you are an audiophile or a home theater enthusiast, WiiM Amp delivers exceptional sound...

www.wiimhome.com

But you'd need to work out just what you need a USB input for, as the Wiim Amp USB connection is for a USB drive holding your "ripped" digital content (CD's?) for playback thru the Wiim Amp DAC+Amp -- what do you use the USB connection for -- audio from your PC/Mac?

I suspect the streamer capabilities of the Wiim Amp might eliminate the need for the connection to a computer??????

I do have my CDs ripped and stored on a NAS, so I have already entered the 21st century, sort of . But as I have mentioned above, I mostly stream from the internet to the Kingrex.

Just to give you the full picture of my somewhat weird setups:

1. Most of the time, I listen to mostly hires content in front of my PC, which is connected via USB to a MOTU M2, which is connected to a pair of KRK Rokit RP5 G4 and Sennheiser HD 560S, optimized with APO.
2. When I'm in the mood, I've got my Technics 1210 MK II + Ecler WARM2 DJ setup with nubert speakers (unoptimized and just for fun )
3. While training in my basement, there's the Kingrex with two bookshelf speakers.

 

[John Poplett]

Yeah, I remember reading about that new groundbreaking amp technology in a newspaper. Then I went to the local hifi store and they had the Kingrex at display. I thought it was a great replacement for my AV receiver which had way too many in- and outputs for my daily listening use, so I bought two of them.


Thanks again for the background info, really interesting! I should add that this is not my primary system but just a small setup in my basement that I use for playing music from my laptop while training (usually Soundcloud 128 MP3 streaming ), so there's no need for SOTA performance. But still, I'd like to have something decent, not too expensive though, and as simple as possible. I am thinking about the Apple dongle connected to the Topping PA5 II.

I'm encouraged that you're leaning toward the PA5 II as tjf suggested. My Kinter amp is fed by an Allo Boss 2 DAC to drive a pair of Audioengine bookshelf speakers. I am leaning toward the PA5 II myself and then, the fantasy goes, to build a DAC lego-style with Ian Canada components. It looks like I could tinker with that for a couple of years and distract myself from other costlier audio temptations. I am grateful for the discussion you started. Thanks.

 

[tjf]

your use cases are indeed varied -- here are the last points I'll make:

1) The Wiim AMP will sell for around $400 US

2) The Wiim AMP's streaming platform/App has Soundcloud (natively part of the streaming Apps that Wiim offers -- no need to have a Mac/PC connected via USB to stream Soundcloud)

3) The Wiim AMP uses the TI TPA3255 Class D amplifier module -- just like the Topping PA5 II.

4) Your headphone use will require a different path/set of electronics, perhaps a Wiim Pro Plus with a modest (I like the Topping NX7 - $180) headphone amp as a separate headphone system?

5) Both Wiim products (AMP & Pro Plus) will offer you hi-res streaming (via other platforms than Soundcloud) and the great sound quality feature of PEQ -- very beneficial if you take the time to learn how to use it for your speakers and/or headphones...

 

[Simfunk]

Just ordered Topping PA5 II and Apple dongle . Am going to sell my Kingrex T20u, anyone interested ?
@tjf : Sorry, the Wiim will have to wait, I'm just not ready yet for a streamer, maybe next century...