Class T-amps

[Ali Tait]

Ah yes,remember now.

[Reid Malenfant]

According to Wikipedia:

A Class T amplifier is an audio amplifier IC design. Rather than being a separate "class" of amplifier, Class T is a registered trademark for Tripath's amplifier technologies.

It is an implementation of Class D amplifiers, but improves the control scheme to create more efficient and higher quality audio amplification. One of the amplifiers, the TA2020, was named one of the twenty-five chips that 'shook the world" by the IEEE Spectrum magazine.[1]

The control signals in Class T amplifiers may be computed using digital signal processing or fully analog techniques. Currently available implementations use a loop similar to a higher order Delta-Sigma (ΔΣ) (or sigma-delta) modulator, with an internal digital clock to control the sampled comparator. The two key aspects of this topology are that (1), feedback is taken directly from the switching node rather than the filtered output, and (2), the higher order loop provides much higher loop gain at high audio frequencies than would be possible in a conventional single pole amplifier.

Despite increased performance at a price similar to class D technology, financial difficulties have caused Tripath to file for Chapter 11 bankruptcy protection on 8 February 2007.

Jeez, that's the difficult way of saying it

If you want it easier the amp uses switching outputs that are similar to class D. The difference being that at lower output levels the amp switches in the low MHz range to improve linearity & at higher outputs reverts to something like 400KHz to improve efficiency to avoid undue switching losses

[Batty]

I'm putting together a little 'shed' system from kits, the amp is a TA2024 tripath jobbie, I have a DAC and a phono stage all separate, for a volume control I am thinking of putting a 50K Alps stereo pot in a box with phonos in and out so I can plug it in anywhere in the system ie between DAC and amp or between source and DAC, is this a feasable Idea or should I put it at the input to the amp inside the amp box.

Cheers

[squeezethatbuffalo]

Jeez, that's the difficult way of saying it

If you want it easier the amp uses switching outputs that are similar to class D. The difference being that at lower output levels the amp switches in the low MHz range to improve linearity & at higher outputs reverts to something like 400KHz to improve efficiency to avoid undue switching losses

Hi Mark,

I'm afraid that your explanation is much better

I think it also answers why T-Amps - even the higher powered ones - sound better with high efficiency speakers. I like mine best with my Fostex 166E floorstands.

Cheers,

[Ali Tait]

Yes,I used mine with MLTL's using Fostex Fe167e's and FT17h supertweeters.

[Thermionic]

I hope I am still sort of on topic but a long time ago I built an amp with a pair of LM1875s. I point to point wired it, but only with a single rail supply so it has (bypassed) output caps. I used it mostly to drive a Stax energiser but once compared it with my Leak Stereo 20 into a pair of LS3/5a’s.

It sounded depressingly similar to the Leak except it didn’t seem to image as well and perhaps was not as ‘refined’, so I carried on with the Leak. I should dig it out again and have another listen. But don't they use these sorts of chips in most mid-range stuff these days?

[jonners]

I'm putting together a little 'shed' system from kits, the amp is a TA2024 tripath jobbie, I have a DAC and a phono stage all separate, for a volume control I am thinking of putting a 50K Alps stereo pot in a box with phonos in and out so I can plug it in anywhere in the system ie between DAC and amp or between source and DAC, is this a feasable Idea or should I put it at the input to the amp inside the amp box.

Cheers

Hi Steve,

Inside the amp box would be best. The pot would be useless between source and DAC since that's a digital connection.
You could have two pairs of phonos in the amp box with a switch for selecting DAC or phono.

[squeezethatbuffalo]

Yes,I used mine with MLTL's using Fostex Fe167e's and FT17h supertweeters.

My fullrangers are TWQT, thinking about adding some supertweeters, maybe T90As.

Any plans to get another T-Amp in the near future?

[Ali Tait]

Not at the moment,I'm happy with a pair of bridged DPA Enlightenment power amps,and hopefully the direct-coupled GM70 amps for my statics will be done in the next couple of months.Think that'll be it on the amp front for quite a while!

[dave2010]

An original Sonic Impulse amp sold on bay for about £36 last night. I did bid, and was sad not to be able to rebid as my network had problems. I wasn't intending to go that high though, so now I feel better!