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Tripath class-T class-D headphone amp?

post #1 of 21
5/30/06 at 2:08pm
Thread Starter 
Hi,

I just would like to know if someone has already done, or even heard about a headphone amp based on class-D or class-T technology (Tripath and alike).

There are some kits outhere, but mainly for integrated power amp (2x15W to 8x100W, though THD not the best at highest power!).

Please let me know if you heard something, or even just tried these kits.

Thanks a lot,

All the best,

GregVDS

Now, come back to my Millet Hybrid :-)
Any suggestions for a more hi-endish tube headphone amp, but still easy to build?
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post #2 of 21
5/30/06 at 2:21pm
The Sonic Impact T-amp and Super T-amp are both commercial products based on the Tripath chip. These are low power speaker amps but could be modified for headphone use. For the low, low price, the T-amp is a very good value.

That said, I am not a fan of class D in general because IMO they are more a cost-cutting and space/weight saving measure (the efficiency of class D makes it unnecessary to use large heatsinks and power supplies, both of which are costly and uses space) rather than for sound quality. If I were to use a class D amp anywhere, it would be for a dedicated subwoofer power amp, where any shortcomings of class D is all but irrelevant.
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post #3 of 21
5/30/06 at 3:31pm
Thread Starter 
Strangely, reviews of such kits use a lot of superlatives to qualify the audio quality, if you know it, go on TNT audio website (italian, with english pages), some reviews are very positive.

but I must recognize I never heard one, so, I'm tied to what's written.

many thanks for the reply AMB!

GregVDS
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post #4 of 21
5/30/06 at 5:28pm
Do a search. I think someone tried using a Sonic impact with headphones and didn't care much for the results. I'm not sure if it was an AKG 1000 thing or a more conventional headphone. Remember that these are designed with 6-8ohm impedance in mind, so I'm not sure what impact 32-300 ohms has.
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post #5 of 21
5/30/06 at 6:30pm
Headphones are so low power that the controller will use more power than could be saved. Even if a special low power controller is used, the power savings will be very little.
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post #6 of 21
5/30/06 at 9:27pm
The Sonic Impact T-amp will not work properly with headphones without modification. As in any class D amp, there is an output filter (inductor) that serves the final smoothing to convert the PWM-modulated "square wave" output into proper analog waveform. The frequency of this filter in the T-amp was chosen for an 8Ω speaker load. Thus, if you want to use the T-amp with headphones, you should add 8Ω dummy load resistors to the output.
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post #7 of 21
5/30/06 at 11:10pm
I recently built the Amp6 as an integrated amp. To my ears, Class D amps are very sterile, cold, and lack musicality. I have ordered some oil caps to use as input caps to warm things up. But if I were to do it again, I would not waste my time with Class D. Tubes all the way
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post #8 of 21
5/31/06 at 11:18am
Wow wow!

Wait a sec, the gentleman asked about the use of Class-D/T topology for a pair of HEADPHONES!!! We are not concerned with the general consensus associated with it. We have to stick with HEADPHONE APPLICATIONS. Do not mix HEADPHONES and SPEAKERS.

Well ... now that is said. I believe there are many DIYers attempted Class-D/T amp for headphones. It is probably because they tend to be real high power (20W and over) and they tend to require many small components. (Plus opamps are waaaaaay too easy to use.) But it can be done now there are ONE-CHIP class-D amps.

I don't get it. They sound good from the speakers at work. No color but transparent. Convenient for what I do. I would rather not get into EUPHONICS, but I don't mind it at all. Class-D's are quite musical. Warmth is not everything.

With recent development of digital audio source, it might also be a good idea to consider possibility of interconnecting digital source directly with digital amplifier. This will certainly reduce the the problem associated with interconnects ... Yes another hated topic.

Tomo
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post #9 of 21
5/31/06 at 1:58pm
Thread Starter 
Thanks Tomo,

and by the way (totally off-topic), your avatar is very nice, I'm a huge fan of Hayao Miyazaki (transliteration correct?), how do you name them, the white small fellows of the woods?

All the best,

GregVDS
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post #10 of 21
5/31/06 at 2:38pm
Quote:
Originally Posted by Tomo
Wow wow!

Wait a sec, the gentleman asked about the use of Class-D/T topology for a pair of HEADPHONES!!! We are not concerned with the general consensus associated with it. We have to stick with HEADPHONE APPLICATIONS. Do not mix HEADPHONES and SPEAKERS.

Well ... now that is said. I believe there are many DIYers attempted Class-D/T amp for headphones. It is probably because they tend to be real high power (20W and over) and they tend to require many small components. (Plus opamps are waaaaaay too easy to use.) But it can be done now there are ONE-CHIP class-D amps.

I don't get it. They sound good from the speakers at work. No color but transparent. Convenient for what I do. I would rather not get into EUPHONICS, but I don't mind it at all. Class-D's are quite musical. Warmth is not everything.

With recent development of digital audio source, it might also be a good idea to consider possibility of interconnecting digital source directly with digital amplifier. This will certainly reduce the the problem associated with interconnects ... Yes another hated topic.

Tomo
Understood, but...with my experience of Class D I would not want that sound directly in my ears becuase the tizzies would kill my hearing.
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post #11 of 21
5/2/11 at 3:58am
Quote:
Originally Posted by amb View Post
 That said, I am not a fan of class D in general because IMO they are more a cost-cutting and space/weight saving measure (the efficiency of class D makes it unnecessary to use large heatsinks and power supplies, both of which are costly and uses space) rather than for sound quality. If I were to use a class D amp anywhere, it would be for a dedicated subwoofer power amp, where any shortcomings of class D is all but irrelevant.

 

 


 

 


Edited by alphaman - 5/2/11 at 4:20am
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post #12 of 21
5/2/11 at 4:10am
Quote:
Originally Posted by amb View Post
 That said, I am not a fan of class D in general because IMO they are more a cost-cutting and space/weight saving measure (the efficiency of class D makes it unnecessary to use large heatsinks and power supplies, both of which are costly and uses space) rather than for sound quality. If I were to use a class D amp anywhere, it would be for a dedicated subwoofer power amp, where any shortcomings of class D is all but irrelevant.

amb's above reply is from May/30/2006. Class D seems to have evolved somewhat since then. IEEE even gave class D a spot in their top 11 technologies of the decade "award" earlier this year (uh ... #11, FWIW!). Also both the major (U.S-based) print mags, The Absolute Sound and Stereophile, gave the NAD M2 class-D integrated amp very heavy praise. The NAD M2 is, further, a digital class-D amp (note: the "D" in "class D" does not stand for "digital") and  -- FWIW -- can accept SPDIF input. (The Sterephile and TAS reviews go into how class-D plus digital works).

Given this "evolution", might class-D topology -- especially with direct digital input from, say, a DSP (decoder) sourcing a music-containing Flash card -- be a viable project ... for headphone amp DIY or, perhaps even, the gear industry?

 

Some ideas ...

http://wireless.ee.washington.edu/indep_study/Munro.pdf

http://www.maxim-ic.com/datasheet/index.mvp/id/4293

http://www.national.com/pf/LM/LM49270.html#Overview

http://focus.ti.com/lit/ds/symlink/tpa2050d4.pdf

BTW ... I'm not sure which (if any) current commercial device or DIY project use ones of these ICs. If anyone knows, please reply ... thx!
 

 


Edited by alphaman - 5/2/11 at 4:15am
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post #13 of 21
5/2/11 at 4:21am

-

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post #14 of 21
5/2/11 at 4:43am

That would be a REALLY cool project!  Quite a bit of programming, but the idea of such a device would certainly interest me even as a consumer product :) 

 

DO IT!!!!
 

Quote:
Originally Posted by alphaman View Post



amb's above reply is from May/30/2006. Class D seems to have evolved somewhat since then. IEEE even gave class D a spot in their top 11 technologies of the decade "award" earlier this year (uh ... #11, FWIW!). Also both the major (U.S-based) print mags, The Absolute Sound and Stereophile, gave the NAD M2 class-D integrated amp very heavy praise. The NAD M2 is, further, a digital class-D amp (note: the "D" in "class D" does not stand for "digital") and  -- FWIW -- can accept SPDIF input. (The Sterephile and TAS reviews go into how class-D plus digital works).

Given this "evolution", might class-D topology -- especially with direct digital input from, say, a DSP (decoder) sourcing a music-containing Flash card -- be a viable project ... for headphone amp DIY or, perhaps even, the gear industry?

 

Some ideas ...

http://wireless.ee.washington.edu/indep_study/Munro.pdf

http://www.maxim-ic.com/datasheet/index.mvp/id/4293

http://www.national.com/pf/LM/LM49270.html#Overview

http://focus.ti.com/lit/ds/symlink/tpa2050d4.pdf

BTW ... I'm not sure which (if any) current commercial device or DIY project use ones of these ICs. If anyone knows, please reply ... thx!
 

 



 

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post #15 of 21
5/3/11 at 2:36pm

Keep in mind, Tripath T-amp's output are bridged.

This mean - both channel's output "-" terminals are not connected together, and not connected to ground too.

If you connect to T-amp's output standard phones, with both grounds connected together in jack, you burn Tripath chip immediately

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