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Old 7th December 2010, 05:50 PM   #1
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Default hifimediy T2 mods?

I just ordered a hifimediy T2 amp plus accompanying Meanwell 27v SMPS. Thanks to hifmediy for building these amps, and to Nick for making them so readily available.

I know there is already a long D class forum thread on hifmediy's amps, but it emphasizes the TK2050 boards.

If I understand correctly the 2050s are no longer available, and the T2 now has a TC2000 controller with two sta505 power chips.

I know folks in the other thread have talked about various mods to input caps, pots, and toroids. What I want to do with this thread is see if there is enough interest to discuss mods applying to this specific amp. I would love to benefit from anyone's experience before I begin.

Thanks!

Bruce Bender
Santa Fe, New Mexico, USA
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Old 7th December 2010, 05:57 PM   #2
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Quote:
Originally Posted by bdbender View Post
I know there is already a long D class forum thread on hifmediy's amps, but it emphasizes the TK2050 boards.

If I understand correctly the 2050s are no longer available, and the T2 now has a TC2000 controller with two sta505 power chips.
Ah, the TK2050 ... Such confusion. The thing is that the Tripath TK2050 chip-set is made up of two chips: A TC2000 controller, and an output stage chip, canonically the TP2050. The STA505 is exactly the same as the old TP2050 output chip.

So all the old mods apply. There are some differences in the output filter components - inductors, caps, and resistors - according to what load impedance the board is designed for. 8 Ohms or 4 Ohms. Most everything else that is 'tweakable' is the same across these amps.
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Old 7th December 2010, 07:48 PM   #3
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Thanks!

Sounds like this thread is not necessary, eh?

I will go back through the other one again.
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Old 7th December 2010, 08:37 PM   #4
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The first thing to do is to replace the rather horrible low cost STA505s with quality parts like the STA517B.
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Old 9th December 2010, 04:05 AM   #5
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Originally Posted by Saturnus View Post
The first thing to do is to replace the rather horrible low cost STA505s with quality parts like the STA517B.
Which in the hifimediy world would, of course, be the T3 instead of the T2. Do you have a point, or are you just trolling?
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Old 9th December 2010, 06:16 AM   #6
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Oh, I didn't know there was another one. I really don't all these manufacturers product lines.

So is there a price difference between them?
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Old 9th December 2010, 05:00 PM   #7
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Sorry for the trolling comment, I felt like you were dissing both the manufacturer and my choice of product - a bit hasty on my part!

The T2 is one stereo board, with a volume control on it, so you can just hook up a power supply plus ins and outs and you are good to go. Specifically recommended for 4ohm speakers, and I have some Focals that dip way down there in the midbass. Priced about US$40. Meanwell S-350-27 is recommended as the power supply.

The T3 is higher power, but one channel per board. You need a total of four boards, two T3s and two accompanying power supply filter boards for the two channel system equivalent to the T2, and there are no pots. So it takes more layout to get it operating. Price US$about 100. Meanwell S-350-48 is recommended as the power supply, plus the use of the filter boards.

Hifimediy|Hifimediy T3 300W@4ohm Amplifier set

I suspect if I like the T2 I will be unable to resist playing with the T3. I am a tube guy, and all this stuff seems very inexpensive to play with to me, especially if it sounds good.

I have two Class D high-power bass guitar amps, and they sound very good, so I have high hopes.

(For the record, I am a newby to Class D stuff, and have no affiliation with hifimediy, just chose them based on extensive web surfing.)
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Old 9th December 2010, 05:24 PM   #8
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It's my personal opinion but almost any Tripath based amp sounds a far cry better than any other class-D amp so you should be in for a treat.

I just noticed in another thread that hifimediy will make a T4 which is basically a TC2000 controller with a ST317B output driver working in stereo which would basically make what I said about replacing the STA505 with the STA517B so hifimediy does recognize the sound quality difference between the 2. That's very good since they measure almost identically, and one that would only look at the engineering numbers would naturally go for the lower priced part.
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Old 9th December 2010, 06:53 PM   #9
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Thanks, I'll keep an eye out for the T4 (and probably won't be able to resist playing with it).
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Old 4th August 2011, 04:57 AM   #10
trevmar is offline trevmar  United States
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My T2 just arrived and it is a nice, clean, Tripath implementation. I saw nothing unusual when I had it on the bench, the characteristic Tripath meandering of the PWM signal as the sinusoid reaches 100% was the primary negative observation on the 'scope.

I did notice that the heatsink gets quite warm when stressed into 4 ohms at about 2/3 rail voltage. I guess the extra power transistor dissipation is necessary to ensure low output distortion, as the power switches are outside the TC2000 feedback loop. I didn't bother to measure dead-time, etc...

I decreased R1 and R4 to 10K, as the standard gain was a bit low for me. The T2 seemed to be set up for full output at 0.9VRMS, and I prefer to keep my preamplifier signals about 6dB below that.

At the risk of you all laughing uncontrollably, I am currently testing the subjective audio quality with my two superb Peerless 2 inch 830983 widerange speakers in Linkwitz-inspired omnidirectional enclosures. My old TA2024 just didn't quite have enough power to handle the amplitude-compensation applied by my miniDSP The T2 sounds clean and clear.. (speaker photo below)

These speakers form the basis of my traveling kit - HiFi for the frequent traveler I intend to replace the T2 with a lighter-weight TDA7492 amplifier when it arrives

I am running the amp nicely at 20V bypassing the bridge rectifier, as I like to live dangerously I did test the T2 at higher voltages on the testbench...

Anyway -- great job guys, I will have to try some other HifimeDIY products
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Last edited by trevmar; 4th August 2011 at 05:16 AM. Reason: typo
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