ATI AT3000 amps

[slipperybidness]

I have not seen Rich's data. The usual cause of the transformer hum Rich has reported is DC on the AC line.

Can you please supply a reference for this statement?

 

[AcuDefTechGuy]

Yeah, the transformer hum is always present even with nothing connected to the amp; this does not happen with the Outlaw or any other amp Rich has used in his house.

 

[RichB]

I return the ATI 3005. ATI tested it found a very slight hum.
I suppose the amp could be sensitive to something in my environment.
Perhaps if I it was in a rugged room or had a different cabinet, it might not have been as noticeable.

Other than that, the amp sounded great.

- Rich

 

[AcuDefTechGuy]

I return the ATI 3005. ATI tested it found a very slight hum.
I suppose the amp could be sensitive to something in my environment.
Perhaps if I it was in a rugged room or had a different cabinet, it might not have been as noticeable.

Other than that, the amp sounded great.

- Rich

Are you sticking w/ your good ole Outlaw amp?

 

[RichB]

Are you sticking w/ your good ole Outlaw amp?

Of course not, that would be sensible.
I picked up a Parasound A51. Like the outlaw, there is no transformer hum.
Parasound encases the transformer in epoxy so I as expected it is quiet.

There is some noise with an ear pressed to the tweeter and midrange.
It is similar to the Outlaw. The ATI had more noise at the tweeter and midrange but it I was the transformer hum I could not deal with.

I just got the Parasound. Purely subjective of course but there are some subtle differences.
It is definitely not for you, the handles are on the back

- Rich

 

[Cos]

I have the Parasound A52/A23 and have been very pleased, less power then the 51, but sounds great in my 17x14 room. They are pretty much silent unless my ear is right up to the tweeter.

 

[PENG]

Rich,

I have many of the same issues that you have and it all started with I went from my Onkyo prepro to the Marantz 7005. I actually got another 7005 from my dealer and it exhibited the same symptoms. I tried everything from changing power cords, rerouting wires to various grounding techniques suggested by TLS.

There are many others that have not had any issues with this combination so I have never claimed this issue to be anything but my system. Just for giggles recently I connected a receiver to my system and used the pre outs via RCA to my amps. It was a cheap onkyo that I use in my garage. Guess what, no hum hiss or any noise from my speakers. Just like it used to be, dead quiet.

I don't know if it is poor grounding in the Marantz or what but all I can say is that I can repeat your issue and I do not think it is the amp.

If I remember right you had a different issue. Your AV7005 resulted in hum through the speakers, right? Rich is having a hum that comes from the transformer itself, not the speakers so definitey not ground loop or electronic related. It has to do with the transformer itself and/or the 60 hz incoming supply from the utility company is not "clean". All tranformers hum, but some are so quiet that you can't hear them unless you stick your ear to it and really try to hear it. If you can hear it during quiet passage during music listening then it is excessive for sure.

 

[PENG]

ADTG, I told you all transformer hums before remember, and you said the ATI is silent. To be honest I am skeptical, if you bring it inside an anechoic chamfer I guarantee you will hear it without a stethoscope. Okay I am just joking, and I don't doubt ATI uses one of the quietest transformers they can buy, judging from their owners reported experience except for Rich's. Perhaps another factor, however minor, is that some people are more sensitive to 120 Hz and some of the associated harmonics than others, plus a slight dc offset could sometime be present in some people's incoming power main.

 

[Irvrobinson]

I don't doubt ATI uses one of the quietest transformers they can buy

ATI doesn't buy them, they make them.

I've tried listening to the transformers in my amp, but I can't hear anything. The hum level must be below the ambient noise level of my room.

 

[RichB]

Rich,

I have many of the same issues that you have and it all started with I went from my Onkyo prepro to the Marantz 7005. I actually got another 7005 from my dealer and it exhibited the same symptoms. I tried everything from changing power cords, rerouting wires to various grounding techniques suggested by TLS.

There are many others that have not had any issues with this combination so I have never claimed this issue to be anything but my system. Just for giggles recently I connected a receiver to my system and used the pre outs via RCA to my amps. It was a cheap onkyo that I use in my garage. Guess what, no hum hiss or any noise from my speakers. Just like it used to be, dead quiet.

I don't know if it is poor grounding in the Marantz or what but all I can say is that I can repeat your issue and I do not think it is the amp.

That does not surprise me. When I was experimenting, I found that they hum got really bad because the Marantz power cord was not making a good connection. I replaced it with a another heavy duty cord I had lying around and the hum level went back down.

I still have hiss in the tweeters and hum in the midrange but it is so low that it is not a problem.

- Rich

 

[PENG]

ATI doesn't buy them, they make them.

I've tried listening to the transformers in my amp, but I can't hear anything. The hum level must be below the ambient noise level of my room.

Must be, and I am not too surprised because even my old 3805 and Adcom 555 are like that so it is not hard to do if the manufacturer wants to do it. I did find the 4308 audible but just barely audible if my ear is right on the enclosure. I used to stick my ear to quite a few AVR is a dealer's place some years ago (2005 I think) just to pick out the quietest ones, and found the Denon AVRs were the quietest among Yamaha, Pioneer, Sony, Onkyo and even some high end Anthem Power amps. The dealer's display rooms did have some ambient noise but I could still hear the hum except the Denon 3805. I think at that time Denon probably made their own transformers too, at least it says Denon right on top of the transformer though that really does not prove it beyond doubt.

If ATI makes a 500X2 I would be interested for sure, base on everything I heard about them from you guys.

 

[PENG]

Yeah, seriously. My 3005 dissipates a lot of heat, and I'm only using two of the five channels. ATI doesn't describe the thermal protection circuitry, but most high-end amps have it. The designs I'm familiar with monitor the heat sink temperature with a thermocouple.

I got curious again so I took a glance of their website. They did mentiion "optical". That sounds encouraging because optical, such as fibre optic based device would be superior in terms of fast response, but would likely cost more than just using T/Cs or "Klixon" that are simple bi-metal devices commonly found in motor winding thermal proction applications. They may still use electronic circuitry to supplement the optical temperature sensing device though but I doubt they would do that as everything adds costs.

 

[AcuDefTechGuy]

ADTG, I told you all transformer hums before remember, and you said the ATI is silent. To be honest I am skeptical, if you bring it inside an anechoic chamfer I guarantee you will hear it without a stethoscope. Okay I am just joking, and I don't doubt ATI uses one of the quietest transformers they can buy, judging from their owners reported experience except for Rich's. Perhaps another factor, however minor, is that some people are more sensitive to 120 Hz and some of the associated harmonics than others, plus a slight dc offset could sometime be present in some people's incoming power main.

I remember. It makes perfect sense. It's a just matter of being audible.

I don't hear any sort of hum from my 4 ATI, but I know the hum is "there".

BTW, our friend DS-21 (remember him? ) is thinking about buying the AT2007 since he was so impressed with the noise floor.

 

[AcuDefTechGuy]

There is some noise [Parasound] with an ear pressed to the tweeter and midrange.
It is similar to the Outlaw.

My AT3002/3005/2004 are dead silent with ear pressed against tweeter & midrange.

But no matter. I think a little hiss is inconsequential.

 

[cpp]

Maybe I need to turn all the electronic devices off in the room, audio stuff, TV, fans, lights etc.. and get really close to my ATI and see if I hear anything at all, hold on, wait a minute..........................................................................................................................................................................................................................NOPE, pretty darn quiet.

 

[PENG]

Maybe I need to turn all the electronic devices off in the room, audio stuff, TV, fans, lights etc.. and get really close to my ATI and see if I hear anything at all, hold on, wait a minute..........................................................................................................................................................................................................................NOPE, pretty darn quiet.

The more I read all these posts about the ATI bragging, the closer I get to chapter 11. I search for a distributor in Canada, found only one in Quebec. Really bad influence you guys, good thing ATI does not have a 500WX2 unit yet. My amps are extremely quiet too, but may be I am super sensitive to 120 hz and the harmonics above and my room is quiet, I could only barely convince myself they are audible when ear pressed against the enclosure. Again, I could typically hear most other amps and AVRs hum in dealers demo rooms even from a couple of inches away, that is, much louder than any of mine.

 

[PENG]

I remember. It makes perfect sense. It's a just matter of being audible.

I don't hear any sort of hum from my 4 ATI, but I know the hum is "there".

BTW, our friend DS-21 (remember him? ) is thinking about buying the AT2007 since he was so impressed with the noise floor.

"Our" or "yours" . Anyway, good for him and I am impressed with them too after reading through the stuff on their website. Bifilar wound toroidal, optical thermal protection, and very beefy overall, just too bad only 300/450W so I can't justify one yet, time will tell whether I could wait for their 500/750W one if that would ever happen.

 

[AcuDefTechGuy]

"Our" or "yours" . Anyway, good for him and I am impressed with them too after reading through the stuff on their website. Bifilar wound toroidal, optical thermal protection, and very beefy overall, just too bad only 300/450W so I can't justify one yet, time will tell whether I could wait for their 500/750W one if that would ever happen.

Yeah, they should offer a 500/750 amp.

The Lexicon ZX-7 is the clone of the AT3007. It is 400/600 @ 1% THD:

Lexicon ZX-7 Multi-Channel (300 watts x 7) Power Amplifier - Secrets of Home Theater and High Fidelity

 

[RichB]

Yeah, they should offer a 500/750 amp.

The Lexicon ZX-7 is the clone of the AT3007. It is 400/600 @ 1% THD:

Lexicon ZX-7 Multi-Channel (300 watts x 7) Power Amplifier - Secrets of Home Theater and High Fidelity

I think the Outlaw 7900 is the clone for that one. The auto-sensing XLRs are present the dimensions are the same.
The Outlaw uses more output devices because they have a lower Safe Operating Area.
Still they are cousins.

If you look at the measurements, I think all the ATI 3000 built units and do very close to 400/600 at 1% THD.

In reading many reviews and looking at the measurements (as I am a measurement whore ), it looks like amps do have different distortion levels when driven with two signals as you can see in the review.
Also, THD+N measurements include the artifacts produced +/-250HZ from the tone sent.
So, ringing further up the spectrum is not included.
All this *should* be inaudible, but it is there and can be measured.

- Rich

 

[RichB]

My AT3002/3005/2004 are dead silent with ear pressed against tweeter & midrange.

But no matter. I think a little hiss is inconsequential.

You have a better preamp than most

- Rich