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Old 26th June 2007, 01:42 PM   #1
Puffin is offline Puffin  United Kingdom
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Default King Rex Tech T20

Has anyone got one of these and are they any good.

Are there any reviews of this amp (apart from the proposed 6moons whihc seems to be taking forever) ?
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Old 26th June 2007, 07:28 PM   #2
Pano is offline Pano  United States
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I should have one soon - they were on back order.

My buddies over at Audiomagus have listened to it and like it. Build quality is said to be very good.
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Old 26th June 2007, 10:55 PM   #3
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We've had the Kingrex's in stock for a while now. They are fantastic units. The following is an interesting comparison between the T20 and Trends by James Darby at Stereomojo.

http://stereomojo.com/KingrexTrendsShootoutXX.htm

Also, I know David is taking his time on his review but considering the tremendous effort he put into the TA-10 review, it will be worth the wait.

- Sasha

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www.obadimports.com
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Old 27th June 2007, 06:45 AM   #4
Puffin is offline Puffin  United Kingdom
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Koolthang. Thanks for that. I had forgotten about stereomojo.
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Old 29th June 2007, 01:23 PM   #5
johnm is offline johnm  United Kingdom
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Hi!

I've been using and evaluating both the T20, T20U (USB version) and the PSU upgrades for both.

Build quaility is great, and the circuits are very neatly made and clean. Quality control seems excellent. No rough edges to be seen inside or out.

The sound quality is also fantastic, on both models, though you really need the PSU to bring out the best in both units. Also bare in mind the T20U uses film/foil input capacitors after I recommended this to KingRex, while the current T20 uses electrolytics, though I am told this will be changed on newer models at some point when they have run out of current stock.

They are VERY keen on hearing from the DIY community on their thoughts on how to make their products better, and seem keen to offer the best value products possible.

Sound quality of both models is of a very high standard indeed. Those used to the sound of the TA2020 chip will immediately be at home with either of these two amps. Fantastically open, musical and harmonically 'rich' presentation (that is classical instruments sound real and have body etc), with really ballsy bass (with the KingRex PSU). Very very neutral and also highly revealing of an faults in a recording, tape hiss etc etc. Strangely it does not draw attention to these but seems to tell it like it is. The T20U in particular is VERY good on vocals which - I think - is probably down to using film/foil input caps instead of electrolytic. The op-amp can also be changed for a higher quality item as it is socketed.

As the T20 is simpler design (no USB circuitry) it should - in theory - sound better once it uses the same film/foil caps. Both units throw out a huge soundstage. With high efficiency speakers I doubt you'd be wanting for anything. They really do sound like very good tube amplifiers with the clout of solid state as a bonus.

The internal layout is also very accessible which is good news to all DIY tweakers out there who wish to try better caps, volume pots etc.

As you can tell I am very impressed with these units - they deserve to sell well. I have also just been sent their KingRex preamp which features two inputs and one output. Switching is via relay, and the amp features amoungst other goodies OPA627 op-amps so they seem to have their finger on the high quality parts pulse as well.

Cheers,

- John
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Old 29th June 2007, 02:06 PM   #6
johnm is offline johnm  United Kingdom
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P.S. Forgot to mention the T20U (line and USB version) of the amp features 1000uF capacitance per rail, while the T20 has - if memory serves - 2200uF per side. This may make a slight difference in some systems. The T20U also has larger output coils whereas the ones on the T20 are surface mounted.

Of the two the T20 has the 'purer' circuit path in terms of the signal i.e. from phonos to volume pot to chip. The T20U has what appears to be a buffer stage or pe-amp circuit which contains an OPA2604 (subject to change)...

Lastly the T20U appears to have a built in DAC for the USB input (yet to be confirmed by KingRex) - a PCM2702E.

I haven't yet tried it out with my laptop but will report back when I have.
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Old 1st July 2007, 07:08 PM   #7
diyHerb is offline diyHerb  United States
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John,

I'd love to know the outcome. As Michael and Sasha know, I've been interested in the T20. Now that I know there is one with both better caps and a DAC, I'm glad I didn't jump the gun and get a T20 already.

Let us know your opinions soon,

Herb
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Old 3rd July 2007, 04:06 PM   #8
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I still think the T20 is (just!) the better sounding of the two, as the circuit is simpler. It'll sound better still with film caps which - looking at the inside - should be easy to fit in there. However like I said KingRex should be fitting those as standard sometime soon. There really isn't much in it however - they both sound very good indeed! I'm sure with a little tweaking they could both easily compete with the best of the other TA2020 designs out there.

Had some feedback from KingRex yesterday - the T20U does indeed contain a DAC, which makes it great value for money and a great way of upgrading the sound from your PC. I will try the USB connection tomorrow and report back.

According to KingRex, the path for the USB is: The path for USB is --> USB plug-->PCM2702E(USB DAC chip)-->OPA2604(low pass filter +preamp)-->TL072(DC servo)-->RELAY-->Volume pot-->file/foil capacitor-->TA2020

So it's only the USB that goes through a (socketed) op-amp. I assume the line input follows a more direct route like the T20. The socketed OPA2604 is even better news as that allows easy upgrading. I will install a OPA2227 tomorrow when I test the USB input.

Cheers,

- John
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Old 7th July 2007, 03:44 PM   #9
diyHerb is offline diyHerb  United States
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John,

What's the verdict with the DAC and the swap? I'm dying to know.

Thanks,

Herb
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Old 8th July 2007, 12:42 PM   #10
johnm is offline johnm  United Kingdom
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It's a big thumbs up! The DAC section really has improved the sound from my girlfriend's PC. Very nice bass response, very clean and crisp presentation in general. Playing lossless files you'd be hard pressed to tell the difference between that and the original CD.

In short - it's a bona-fide winner!

- John
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