ATI AT2000 amps

[AcuDefTechGuy]

I just ordered the ATI AT2004 amp to power my Phil3 speakers (and potential future dual RBH SX-1010 subs).

So I was checking for measurements.

Many of us know ATI makes OEM amps for "half a dozen" other companies.

Some include Mark Levinson, Lexicon, JBL, Earthquake Sound, Cinepro, and Outlaw Audio.

So I saw this on Home Theater Magazine regarding the Outlaw 7500, which is a clone of the AT2005:

http://www.hometheater.com/content/outlaw-audio-7500-5-channel-power-amplifier-measurements

"This graph shows that the 7500’s left channel, with two channels driving 8-ohm loads continuously at 1 kHz, reached 0.1% distortion at 284.9 watts and 1% distortion at 342.3 watts. Into 4 ohms, the amplifier reached 0.1% distortion at 447.6 watts and 1% distortion at 492.8 watts. With five channels driven continuously into 8-ohm loads, the AVR reached 0.1% distortion at 260.1 watts and 1% distortion at 301.1 watts. The manufacturer’s stated distortion of 0.03% was reached at 238.7 watts, which is actually higher than the spec'd 200Wpc at that distortion level with all channels driven."

All 5 channels driven into 8ohm produces 301 Watts RMS @ 1% THD. Yet, it is specified as a 200wpc amp. Now that is what I call under-spec!

Or is there something seriously wrong with HTM?

 

[GlocksRock]

What do they have to do to drive the amp to 1% THD? Normal operating levels where the THD will be much, much lower, will yield a lower WPC rating, so 200 WPC seems about right to me.

 

[PENG]

Or is there something seriously wrong with HTM?

Not sure if you would consider it serious but HTM's 300W was for 1% THD+N. I would think ATI's 200W is for much lower THD+N. Also, when ATI says continuous they probably mean continuous whereas HTM does not tell us what it means, it could be for just 5, 10 minutes or more, we are not sure. We also do not know if HTM held the supply voltage constant at 120V or just let it drops naturally as the amp gets loaded up during the ACD test.

 

[AcuDefTechGuy]

Not sure if you would consider it serious but HTM's 300W was for 1% THD+N. I would think ATI's 200W is for much lower THD+N. Also, when ATI says continuous they probably mean continuous whereas HTM does not tell us what it means, it could be for just 5, 10 minutes or more, we are not sure. We also do not know if HTM held the supply voltage constant at 120V or just let it drops naturally as the amp gets loaded up during the ACD test.

So you think HTM is kind of worthless?

Is Stereophile better?

Sure would be nice if Audioholics could measure everything.

On another topic, placebo effect sure works wonders.

I just hooked up my Denon 3312 to my old 150wpc 8ohm/250wpc 4ohm AudioSource amp driving the P362. And I know better, but still it seems like the sound just improved somehow. So I'll continue to let this amp drive the P362 from now on.

It's no wonder everyone talks about using separate amps. No one is 100% immune to placebo.

 

[mtrycrafts]

...

I just hooked up my Denon 3312 to my old 150wpc 8ohm/250wpc 4ohm AudioSource amp driving the P362. And I know better, but still it seems like the sound just improved somehow. So I'll continue to let this amp drive the P362 from now on.

.... No one is 100% immune to placebo.

I have a simple test for you, if you are willing and have a test cd and an spl meter.
Play the test cd hopefully it has tones at say 500Hz, 1kHz, 10kHz and with the volume at a comfortable level, do not turn it up or down, measure and record the spl level at those frequencies; then, mute the system, swap it back to the other amp and play the same test tones and record, without turning the volume level from the previous test.
Let us know the outcome. Perhaps the level is different between the two amps with the same volume you listened to?

 

[PENG]

So you think HTM is kind of worthless?

Is Stereophile better?

Sure would be nice if Audioholics could measure everything.

On another topic, placebo effect sure works wonders.

I just hooked up my Denon 3312 to my old 150wpc 8ohm/250wpc 4ohm AudioSource amp driving the P362. And I know better, but still it seems like the sound just improved somehow. So I'll continue to let this amp drive the P362 from now on.

It's no wonder everyone talks about using separate amps. No one is 100% immune to placebo.

It may be Placebo, but may be not. In any case do you feel the amp sounds only slightly better or much better? I wonder if you could ask your family members to listen to them and have the 3312 a couple of dB louder for the test.

 

[PENG]

So you think HTM is kind of worthless?

Is Stereophile better?

I don't think they are better or worse, just different the way they do things.

 

[AcuDefTechGuy]

Yes, the gain is different - the external amp has variable gain control. But I calibrate the speaker channel levels to 75dBC from 3 meters out just like on the 3312 without the amp. But of course,the $70 digital SPL meter isn't perfect either.

The "improvement" was NOT dramatic. Thus, I concluded it was most likely placebo effect.

 

[Alex2507]

And I know better, but still it seems like the sound just improved somehow.

The 362's do have an impedance dip with a matched phase angle bump that screams for an amp. Stereophile mentioned it and PENG also commented once that the characteristic of the speaker is an unusually poor circumstance for easy amplification.

Don't doubt yourself. You're always right about everything.

 

[AcuDefTechGuy]

Sounds like you guys won't easily let me turf this one up to placebo. Such Audioholics!

I'll try to do some more comparison when I have more time.

At any rate, this $350 generic Chinese 150wpc 8ohm/250wpc 4ohm/40lbs stereo amp "sounds" pretty darn good.

 

[Irvrobinson]

Is Stereophile better?

Yes. Atkinson shows you the power vs distortion curve from sub-1W to clipping. Actually, for THD I'm much more interested in what happens under 5W than over 200W.

 

[Irvrobinson]

So I saw this on Home Theater Magazine regarding the Outlaw 7500, which is a clone of the AT2005

Have you verified that with ATI, or are you just presuming so, based on appearance and superficial specifications? There could be important circuitry differences.

 

[AcuDefTechGuy]

Have you verified that with ATI, or are you just presuming so, based on appearance and superficial specifications? There could be important circuitry differences.

Oh, yeah, I called and talked to one of the ATI rep on the phone.

He confirmed Lexicon, JBL, Earthquake, and Outlaw. He would not confirm (but did NOT deny) Mark Levinson or Cinepro due to "legal issues".

He denied Adcom, though. I thought the Adcom 300wpc & 200wpc amps looked similar too. But he said "No".

 

[cpp]

I'm glad your taking my advice and getting another ATI, I really like mine

 

[AcuDefTechGuy]

I'm glad your taking my advice and getting another ATI, I really like mine

Just trying to emulate the master.

4 Denon + 4 ATI =

AT2004 should arrive next Tuesday BTW.

 

[cpp]

AT2004 should arrive next Tuesday

awesome, so where are you going to put the amp in your stand ? something has to move right ?

 

[AcuDefTechGuy]

awesome, so where are you going to put the amp in your stand ? something has to move right ?

Actually the AT2004 will sit on the THIRD rack behind the front 2 audio racks.

Yeah, there is another rack behind the front rack.

Right now the 3rd rack holds the Orion's crossover, AT6012 amp, & Panamax line conditioner.

The AT2004 will now be on top of the 3rd rack. So most people won't even notice.

 

[Irvrobinson]

Oh, yeah, I called and talked to one of the ATI rep on the phone.

He confirmed Lexicon, JBL, Earthquake, and Outlaw. He would not confirm (but did NOT deny) Mark Levinson or Cinepro due to "legal issues".

He denied Adcom, though. I thought the Adcom 300wpc & 200wpc amps looked similar too. But he said "No".

That wasn't my question. I know they do the assembly for all of them. Are the circuits the same between similar units, or are there interesting differences between the brands?

 

[walter duque]

Since I got all you amp experts out there, let me know if these specs are any decent. So far this is my next move if it gets the AH stamp of approval, or can I do better?

General Information

• Output Stage: 21000 w
• Output Devices: 84 Motorola 250 watt HI-Speed
• Output Power (All Ratings): 20-20KHz @ <.10% Distortion, (Typically .009%)
• Multi-channel Mode/perCH: 490w - 8 ohm, 820w - 4 ohm, 1280w – 2 ohm
• Mono Mode/per CH: 1640w – 8 ohm/bridged, 2560w – 4 ohm/Bridged
• Dynamic Headroom: 3.50dB (4 or 8 ohm) Over 900w Peaks
• Signal/Noise Ratio: > -130dB Unweighted (Ref-Rated Power)
• Damping Factor: > 1,100 @ 20Hz, > 1,000 @ 1 KHz
• Power Supply Energy Rating: > 1,300 Joules
• Intermodulation Distortion: Less Than .03% (Rated Output)
• TIM Distortion: Less Than .01% (Rated Output)
• Frequency Response: ±.1dB 20-20kHz, +0,-3dB 3-175KHz (10w)
• Channel Balance: Within .1dB Between any Two Channels
• Channel Separation: > 85 dB, Risetime: > 70v/ms
• Peak Current: 135 amps/Channel (.5 ohm, 10m/s, 1 Pulse)
• Input Sensitivity: 2v @ Rated Output (Selectable 1v, 1.5v, 2v)
• Input Impedance: Balanced-15K ohm, Unbalanced-30K ohm
• Operating Voltage: 100-120/220-240vac 50/60 Hz (Factory Wired)
• Power Consumption: Nominal - 2,700w, Test conditions - 5,550w
• Dimensions: 19.0” W x 8.75” H x 15.5” D
• Recommended A/C Service: 20/30amp@ 100-120vac, 20amp@ 220-240vac
• Weight: 76lbs

 

[AcuDefTechGuy]

That wasn't my question. I know they do the assembly for all of them. Are the circuits the same between similar units, or are there interesting differences between the brands?

Oh, there may be some minor tweaking with different brands. I did not ask them that question.