Budget T-Amp Shootout - Lepai vs. Indeed TA2020

[bkeane1259]

Re: Budget T-Amp Shootout - Lepai vs. Indeed TA2020

Did some relative power tests on the Indeed TA2020 and the new larger TA2021.

I used my measurement gear and TrueRTA. With both Indeed amps, you can crank them all the way up without distortion, so I set both volume controls to max and measured the following: 1) 1k sine wave 2) Quick Sweep 3) Pink Noise (100 averages)

EDIT: With these test tones, I measured the response of a speaker without taking any care to reduce room influence. Just trying to avoid any confusion.

All I was curious about was a relative difference. Nothing is SPL correct.

Here are the squiggles:


1) 1k sine:



2) Quick sweep:



3) Pink noise:



So anyway...the TA2021 is indeed (pun intended) more powerful. I'm a little confused as to why the pink nose registered almost a 5db difference while the quick sweep registered only 2db. The 1k sine wave showed a 2db difference as well. So.....given the relative combined differences, I'd estimate it to be twice as powerful as its little brother, the TA2020.

That should put the TA2021 around a solid 8-10 watts per channel. There's no chance of it pumping out 25 watts as specified. Even with the volume maxed out, the music still sounds extremely clear in both Indeed amps, which is in stark contrast to the Lepai TA2020 amp which heavily distorts once you throttle the volume past the half-way mark.

[SirNickity]

Re: Budget T-Amp Shootout - Lepai vs. Indeed TA2020

What's with the 10dB dip at 500Hz? Most of the DIY speakers here have a flatter response than that. Aren't amps usually pretty much straight lines?

[bkeane1259]

Re: Budget T-Amp Shootout - Lepai vs. Indeed TA2020

I'm measuring speakers and without any regard to room influence whatsoever. Like I mentioned, I'm just trying to gauge the power differences between the amps. I'd really ignore anything below 600Hz to be honest because that's where the room really acts up.

I edited my post and mentioned that I'm measuring the test tones thru a speaker.

[Exarch]

Re: Budget T-Amp Shootout - Lepai vs. Indeed TA2020

Bryan, I'm building a set of Speedsters for computer use and need to power them (Returning the DTA-1 I have due to one channel cutting out, also believe I need more power). Can you comment on how they sound with this amp in nearfield use? Will I be missing a lot of the Speedster's potential?

[bkeane1259]

Re: Budget T-Amp Shootout - Lepai vs. Indeed TA2020

Bryan, I'm building a set of Speedsters for computer use and need to power them (Returning the DTA-1 I have due to one channel cutting out, also believe I need more power). Can you comment on how they sound with this amp in nearfield use? Will I be missing a lot of the Speedster's potential?

It would work. It will sound great, but it won't crank. I have listened extensively with the smaller Indeed TA2020 on the Speedsters and it works just fine, but it won't fill a large room with loud music. I will say the same about the TA2021 since it's just basically double the power of the TA2020. The problem with the Speedsters is the very low sensitivity. They suck up power like a hoover sucks …well nevermind that.

Not really sure what you're after as far as volume is concerned but I'll tell you what. If you look at the all-in cost of an Indeed TA2021 + 12v5a power supply, you're right at approx. $66.00. For just a little more, you can get a Dayton DTA-100 which WILL allow the Speedsters to play loud and give you a lot more headroom for dynamics. I have heard the Speedsters LOUD on a DTA-100 for extended periods of time and it works beautifully. Don't worry about the Speedster impedance either with the DTA-100. It works, trust me.

If you listen to music at background levels and only at your desk, you could go with the Indeed TA2020 and save a few shekels. However, if you bump that volume up once in a while and if you want/need room for dynamics, look seriously at the DTA-100. You won’t be sorry.

[Exarch]

Re: Budget T-Amp Shootout - Lepai vs. Indeed TA2020

Not really sure what you're after as far as volume is concerned but I'll tell you what. If you look at the all-in cost of an Indeed TA2021 + 12v5a power supply, you're right at approx. $66.00. For just a little more, you can get a Dayton DTA-100 which WILL allow the Speedsters to play loud and give you a lot more headroom for dynamics. I have heard the Speedsters LOUD on a DTA-100 for extended periods of time and it works beautifully. Don't worry about the Speedster impedance either with the DTA-100. It works, trust me.

If you listen to music at background levels and only at your desk, you could go with the Indeed TA2020 and save a few shekels. However, if you bump that volume up once in a while and if you want/need room for dynamics, look seriously at the DTA-100. You won’t be sorry.

Awesome - I did look at the Dta-100a and it looked like the best bang for my buck, but I wasn't sure about the impedance issue.

[Jim Griffin]

Re: Budget T-Amp Shootout - Lepai vs. Indeed TA2020

Take a look at Topping TP-60 photos. The power supply(ies) are inside the box. The TP-60 has the double torriods. A great T-amp.

http://www.google.com/search?q=topping+tp-60+photos&hl=en&tbo=u&rls=com.microsoft:en-us:IE-SearchBox&tbm=isch&source=univ&sa=X&ei=3GwCUb3sD8PG0QHc6IHwBQ&ved=0CDAQsAQ

[bkeane1259]

Re: Budget T-Amp Shootout - Lepai vs. Indeed TA2020

Helllz no Jim....that's not even close man. However, please send one my way for testing.....please??

EDIT: Just wanna keep it in range on this thread.

[gychang]

Re: Budget T-Amp Shootout - Lepai vs. Indeed TA2020

Bryan, this is good stuff

[bkeane1259]

Re: Budget T-Amp Shootout - Lepai vs. Indeed TA2020

Bryan, this is good stuff

I'm a sucker for cute little amps....... as long as they don't break the bank. :eek:

[Ron_E]

Re: Budget T-Amp Shootout - Lepai vs. Indeed TA2020

Did some relative power tests on the Indeed TA2020 and the new larger TA2021.

I used my measurement gear and TrueRTA. With both Indeed amps, you can crank them all the way up without distortion, so I set both volume controls to max and measured the following: 1) 1k sine wave 2) Quick Sweep 3) Pink Noise (100 averages)

EDIT: With these test tones, I measured the response of a speaker without taking any care to reduce room influence. Just trying to avoid any confusion.

All I was curious about was a relative difference. Nothing is SPL correct.

Here are the squiggles:


1) 1k sine:





So anyway...the TA2021 is indeed (pun intended) more powerful. I'm a little confused as to why the pink nose registered almost a 5db difference while the quick sweep registered only 2db. The 1k sine wave showed a 2db difference as well. So.....given the relative combined differences, I'd estimate it to be twice as powerful as its little brother, the TA2020.

That should put the TA2021 around a solid 8-10 watts per channel. There's no chance of it pumping out 25 watts as specified. Even with the volume maxed out, the music still sounds extremely clear in both Indeed amps, which is in stark contrast to the Lepai TA2020 amp which heavily distorts once you throttle the volume past the half-way mark.

Unless you drive the amp until it clips you don't know what its full power is. If you can turn the volume up all the way without distortion it only means you can't overdrive the amp with the input signal you applied. It might be able to play louder but we can't tell how much louder until we drive it harder. In your 1Khz test tone test you want to drive the amp until you see some distortion products in the RTA which should show up as much shorter bars at some multiple of the test signal. It would help to have the RTA show the noise floor if that's possible. When you see the distortion products take off you know the amp has started to clip and you can back off until they disappear. That will be the maximum output of the amp at 1Khz. Do that with both amps and you will know the relative maximum output of each. Unless you can do this you may be only looking at the relative gain of the amplifiers. Hope this makes sense.

Ron

[bkeane1259]

Re: Budget T-Amp Shootout - Lepai vs. Indeed TA2020

Ron, that makes total sense. As I stated earlier, I was just comparing relative power between the Indeed TA2020 and TA2021. I don't know how to properly measure output or distortion of amplifiers.

If you have the equipment, I'd gladly ship these amps to you for proper measurements. It would be a great contribution to this thread.

[Ron_E]

Re: Budget T-Amp Shootout - Lepai vs. Indeed TA2020

Ron, that makes total sense. As I stated earlier, I was just comparing relative power between the Indeed TA2020 and TA2021. I don't know how to properly measure output or distortion of amplifiers.

If you have the equipment, I'd gladly ship these amps to you for proper measurements. It would be a great contribution to this thread.

Were you using a mic and speakers for all the tests you ran? After I made my post I got to thinking that you probably measured the amps that way. That complicates my recommendations because it adds more variables. You should be able to see distortion products with your RTA software but you wouldn't exactly know if it was the amp, the speaker, the mic, or some combination. Normally you'd hang a resistive load on the amp and put an oscilloscope on the output and drive the amp to just under where it clips. (the tops of the sine waves start to flatten) You measure the voltage and calculate how many watts that is. P=E^2/R.

I do have equipment to measure power but nothing to measure distortion with (unless the distortion analyzer that's been on shelf unused for 20 years still works :D). I'll send you a PM.

Ron

[bkeane1259]

Re: Budget T-Amp Shootout - Lepai vs. Indeed TA2020

Were you using a mic and speakers for all the tests you ran?

Yup, that's exactly what I did. I turned both amps all the way up and measured various test tones thru a speaker + mic and then compared the graphs. I know it's not the proper way to "measure an amp" but when did I ever do anything the proper way to begin with? :p

[Ron_E]

Re: Budget T-Amp Shootout - Lepai vs. Indeed TA2020

Brian was kind enough to loan me his collection of amps so I could take some power measurements. All measurements were taken with a 1Khz test signal both channels driven into 4 ohms. Voltage measurements were taken with Fluke 8060A True RMS meter. The Amps were powered with a 12V 5A brick style PS.



You can find some more detailed measurements of assorted Tripath amps here. http://www.michael.mardis.com/sonic/...e/default.html

Ron