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Topic: What about T-Amps? (Read 19880 times) previous topic - next topic
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What about T-Amps?

Reply #25 –
Quote from: andy o on
They're also 5W @ 8 ohm.

According to Tripath themselves, the TA2020 is rated at 13W into 8 Ohms at 10% THD+N. That's hardly audiophile quality, but they do deliver considerably more power than the 5W you repeatedly quote.

Link

What about T-Amps?

Reply #26 –
I did say something like that above, but that spec is a little deceitful, isn't it? I think we're talking about the 2024, btw.

What about T-Amps?

Reply #27 –
Quote from: andy o on
I did say something like that above, but that spec is a little deceitful, isn't it?

In what way? It looks easy enough to correctly interpret to me.

All amplifiers produce hideous amounts of distortion when driven to the limit compared to when driven well within their limit, but I don't think that makes it fair to assume that all power amplifiers only have acceptable distortion levels when used at a fraction of their rated output power.

There's a THD versus output power graph for a TA2020-based kit amplifier HERE, and it's still only 1% THD+N at very close to 10W into 8 Ohms. Can you honestly say with hand on heart that you could hear that level of distortion?

Quote
I think we're talking about the 2024, btw.

You said...

Quote
...the original T-amps got famous for being around $30. They're also 5W @ 8 ohm.

To the best of my knowledge, one of the original T-amps was TA2020-based, hence the reasoning behind me posting specific technical data as released by the manufacturer for the TA2020 device, and as it clearly states, it's 13W into 8 Ohms.

What about T-Amps?

Reply #28 –
This was the original T-Amp, and to my knowledge, the only one that's been called "T-Amp". The Trends amp posted by the OP is the same chip. I know TNT are on the audiophool side of the spectrum, but they got pictures and accurate specs.

The deceitful part in that spec was that I've seen it marketed as high as "30 W", but then in small print saying that this means 15Wx2 @ 4Ohm and 10% THD. Check Trends Audio's own website for instance.

Quote
Trends Audio introduces the mini-size Class-T stereo amplifier TA-10 providing up to 2x15W output with the bundled AC power supply unit.

You go to the product page, and it still doesn't tell you the whole truth. You have to click once again to the spec sheet to see that those specs are not all that meaningful.

Again though, I have one and it's OK for me in my small bedroom. I don't listen to music at very high levels though and the Klipsch RB601 I drive with it (which are physically in the bigger size of bookshelf speakers) do just fine for my purposes.

What about T-Amps?

Reply #29 –
I see. I'd falsely assumed that you were using the term "T-amp" as a generic term to describe all Tripath device based amplifiers, and a 'Google Shopping' search here in the UK brings up no mention of the amplifier you describe, so I'm inclined to think that it's either not been on sale over here, or I've overlooked them ever being on sale here.

I guess this means that the Trends amplifier described by the OP isn't a T-amp either even though he describes it as such? Although in the OP's (and my) defence, I'm a member of a DIY audio forum where any amplifier based around a Tripath device is often generically termed as being a T-amp, even by the moderators.

The Sonic Impact T-amps very low earlier price suggests that it was aimed at the very lowest end of the consumer market (no offence intended), so I don't think it's fair to draw conclusions about the plethora of Tripath 'Class-T' device based amplifiers that have been available over the years based on the apparent lack of performance of that one product, although it does do exactly what Tripath says it does.

The specs released by Tripath are as honest as honest can be as far as I can tell, and I fail to see how any information they've ever released could be interpreted as misleading. As we say over here, it does what it says on the tin.

What about T-Amps?

Reply #30 –
What's ironic is that the T-Amp got very popular in the audiophile community. It's OK like me and others have said if you pay a good price for it and depending on how you're gonna use it.

I'm not blaming Tripath, I'm sure their published specs for the 2024 are honest as well. I'm blaming the marketers of some of the companies that used the chip. I'm not sure if the OP meant that particular pictured amp, but I think he was under the impression that those Trends amps were the 20W ones. That amp is basically a T-Amp though, I think it's got pretty much the same guts. What audiophile companies did was put that board in a better looking box and added stuff like better connections and volume pots, and power supplies. That Trends amp also has the ability to bypass the volume control via a jumper, IIRC.

What about T-Amps?

Reply #31 –
Quote from: andy o on
Quote from: BearcatSandor on
I'd let my ears vote.

OK then. But I'm pretty sure ABX and other testing methods were design just to prevent our ears to do just that.


That would appear to be a rather harsh condemnation of ABX. Do you really mean to say such thing?

The whole of idea of ABX testing is to let the ears rule over baseless  prejudices.

What about T-Amps?

Reply #32 –
Quote from: Slipstreem on
To the best of my knowledge, one of the original T-amps was TA2020-based, hence the reasoning behind me posting specific technical data as released by the manufacturer for the TA2020 device, and as it clearly states, it's 13W into 8 Ohms.


I have a T-amp that I bought some years back, when Tripath was still in business. It is packaged as a PC I/O card, but with no PCI plug. Instead, it picks up its inputs and power via standard PC internal connectors.

I put the thing on the test bench and found that it was not exceptional in any way. It is a bit odd in that distortion rises more than usual just below clopping. It has the output impedance funnies that i mentioned in the other post.

I've used it with KEF Q15s and NHT Super Zeroes, As long as I don't listen too loudly, it does not sound all that bad.  It's power output is as usual limited by the actual DC power that you provide. PC's provide power from a fairly stiff 12 volt supply that was originally designed to power hard and floppy drive motors.  I think that clipping in this context is somewhere around 10 watts.

No power amp that is running directly off of 12 volts could reasonably be expected to do more. If you want more power from a 12 volt supply, you add a switch mode DC-DC converter as is done in car audio.

What about T-Amps?

Reply #33 –
Quote from: Arnold B. Krueger on
No power amp that is running directly off of 12 volts could reasonably be expected to do more. If you want more power from a 12 volt supply, you add a switch mode DC-DC converter as is done in car audio.


Detroit is the  approximate center of the earth when it comes to OEM car sound. I know a number of big-3 car sound engineers and also some of the best independent consultants. Their evaluation of Tripath's technology was uniformly negative for a number of reasons. First off, the Tripath designs were poor price-performers. At commonly-used power levels they could do better with traditional analog designs. Switch mode is always a problem in car environments because of the EMI.  The EMI problems can be solved, but again at a undesirable price given the alternatives.

What about T-Amps?

Reply #34 –
Quote from: andy o on
Quote from: BearcatSandor on
I'd let my ears vote.

OK then. But I'm pretty sure ABX and other testing methods were design just to prevent our ears to do just that.

When you quoted my post the connecting statement got cut off. What i had said was "Well they have a 30 day return policy. I'd let my ears vote."  I meant "i'd let my ears (and testing) vote on whether or not i wanted return them" I did not mean that i would just give it a casual listen and decide weather i liked them, and it was not a comment on their inherent sound quality.  People around here pounce *very* quickly.

Isn't one of the main driving forces in the sales of T/D amps about energy savings, or at least efficiency vs class A or A/B amps?  I would not be surprised if that sold more of them than their sound did.
Music lover and recovering high end audiophile

What about T-Amps?

Reply #35 –
Yeah well sorry if I misunderstood you.

Class D amps are supposed to save space/energy, but as far as I can see they're still significantly more expensive. Audiophiles in general don't care for efficiency if it's gonna compromise "sound", even if it really doesn't.

What about T-Amps?

Reply #37 –
Quote from: andy o on
Class D amps are supposed to save space/energy, but as far as I can see they're still significantly more expensive.

As ready-built consumer amplifiers, maybe, but they're available from around 15 cents per Watt for 2x300 Watts into 8 Ohms as amplifer board kits (Link). Adding a power supply, a heatsink, a case and a few sockets would complete the project at a total cost of around 30 cents per Watt.

I've not done a great deal of research into the cost of the more conventional Class AB alternatives at high power ratings as it's of no personal interest as I don't need the power, but what little research I have done suggests that Class D compares very favourably in terms of bang-per-buck if you self-build.

What about T-Amps?

Reply #38 –
Quote from: Slipstreem on
I've not done a great deal of research into the cost of the more conventional Class AB alternatives at high power ratings as it's of no personal interest as I don't need the power, but what little research I have done suggests that Class D compares very favourably in terms of bang-per-buck if you self-build.


Class AB is pretty much passé for high powered amplifiers. The current technology of choice is Class G or Class H which involves multiple power supplies. The output stage's supply voltage is varied in coarse steps to control the heat dissipation of the output devices. The multiple power supplies are based on switch mode technology which vastly reduces the size of transformers and to a lesser degree capacitors. The grater efficiency reduces the size of the heat sinks. 

The power level where this technology becomes cost effective has been dropping rapidly. It originally showed up in power amps in the multi-kilowatt range, but has moved down into amplifiers that put out just a few hundred watts.

Nobody seems to have come up with an effective way to finesse the issues with Class-D output filters. Class G and H amplifiers solve the problem by running the output stages in a quasilinear mode with respect to the audio signal. There used to be problem with hash from the switch mode power supplies sneaking out of the box, but recent products seem to have addressed this without heroic measures.

AFAIK power amps in the 50-120 watt range are still most economical when implemented with Class AB, but that is bound to change.

Other than the power amp, all of the functions of a stereo receiver can be miniaturized into a Sansa Clip-sized package of a fraction of a cubic inch.  The power amp functions can be reduced to a package an inch or two high,  19 inches wide, and only a few inches deep.  Adding multichannel would make the package maybe twice as deep.

What about T-Amps?

Reply #39 –
Thanks, Arnold, that's good info coming from you. So you're saying that basically Class D amps are measurably worse than AB with so far insurmountable limitations, and when cost comes down, class G and H amps will be able to do better at the lower watt ranges? I'm interested in Class D only for the space/weight savings. BTW, as I said above, Pioneer uses on their most expensive "Elite" receivers, the so-called ICEPower Class D amps. I think ICEPower is developed by Bang & Olufsen. Do you know if there anything special about that kind of Class D?

What about T-Amps?

Reply #40 –
Quote from: andy o on
Thanks, Arnold, that's good info coming from you. So you're saying that basically Class D amps are measurably worse than AB with so far insurmountable limitations, and when cost comes down, class G and H amps will be able to do better at the lower watt ranges? I'm interested in Class D only for the space/weight savings. BTW, as I said above, Pioneer uses on their most expensive "Elite" receivers, the so-called ICEPower Class D amps. I think ICEPower is developed by Bang & Olufsen. Do you know if there anything special about that kind of Class D?


Since we know that the weak spot of Class D power amps is their frequency response with various loads, we immediately proceed to  page 12 of B&O Icepower performance tests.  We see that the difference between no-load output and 8 ohm load output is something like 0.5  dB at 20 KHz. This is in the same range as what we might find in an AB, G or H power anp with the usual output inductor.  Since there are no other noticeable flaws, I therefore suspect that this particular example could pass an ABX test as well as a typical power amp.  Note that this performance is alot better than what I've seen from the earlier Tripath designs. 

Given that there is apparent parity in terms of performance, the remaining issue is the cost of that level of performance. 

I've done some searching and can't find any reliable pricing information to shed further light on the discussion.

What about T-Amps?

Reply #41 –
Thanks again. I see B&O have produced something actually quite good, but still very expensive (at least on products currently out there). Here's hoping it trickles down to affordable prices, I'm a fan of Pioneer receivers.