Audio Research vs. Aesthetix

**rblnr** · 09-26-2011, 06:21 AM

Can anyone compare these two brands? House sound (if it exists), quality at given price points, absolute quality?

Own ARC and know it well, curious about Aesthetix but haven't heard.

**karma** · 10-08-2011, 03:36 PM

HI,
I think your question is a bit open ended. But, I'll try. I have an all ARC system. My preamp is an SP-11 Mk 2 and the power amp is a D250 Mk 2 Servo. Speakers are Martin Logan CLS IIA ESL's.

Because the SP_11's phono stage is a hybrid design, I was curious if an all tube phono stage would outperform the SP-11's. So I bought an Aesthetix Rhea. I was hoping I would like it because I love the Rhea's features. I should note that I was very happy with the SP-11. Reviews for the Rhea had been outstanding and the basic sonic signature seemed in the direction of the SP-11. It seemed to be be a good gamble.

Well, it has worked out well. The Rhea is better but only barely. The signatures (or lack of) are very close. That is, the Rhea is very neutral, fast, and detailed; the same adjectives I would use to describe the SP-11's sound. Not at all fat and slobby. The Rhea matches the sound of the SP-11 very closely. Where the Rhea seems to exceed the SP-11 is with its dynamics. It's a bit more explosive. But not by much. The SP-11's phono stage is quieter, as in silent. But the Rhea is quiet enough. I can't hear the noise at my listening position.

I hope this helps. It would have been better if you specified the Aesthetix unit you were interested in.

Sparky

**mep** · 10-08-2011, 03:52 PM

Sparky-That was a well-reasoned response. The SP-11's phono stage should be quieter because it uses J-Fets on the input side of the phono circuit. The Aesthetix is pure tube which is always asking for trouble if you are using low output MC cartridges. You just can't think that you can ask an all tube circuit to amplify microvolts and not expect the signal to be in the noise floor of the tube(s). If you want a truly low-noise phono section and you want tubes, you really need a cartridge that is putting out millivolts and not microvolts. That means that you have some numbers on the left side of the decimal point my friends. If you have a cartridge rated at .23mv, that means the output is 230 microvolts. With tubes, it would be much better in terms of noise to have 2.3 mv of output.

**karma** · 10-08-2011, 06:19 PM

HI Mep,
The noise issue is one I was really concerned about with the Rhea. It was my opinion that an all tube phono preamp would not work with my .2 mV and .4 mV cartridges. Yet, I was not tempted to go to higher outputs because experience has taught me that higher output cartridges have higher moving masses and this is a major impediment to ultimate cartridge performance. It's a classical tradeoff. So, the question was whether the Rhea would work with my intended cartridges with a noise level that was not bringing attention to itself. This issue was at least as important to me as the basic sound signature. I refused to live with a phono stage that was noisy especially since I already had the SP-11 which is silent and also very good.

To my great surprise, the Rhea proved itself to be adequate. I was and remain impressed. I kept the Rhea.

Of course, there are variables that will change from person to person. I always try to scale the playback volume to the recorded source. I do not try to just listen loud. Loud is sometimes appropriate but softer can also be right. I feel that properly scaled volume is just another component of an honest listening experience. It all depends on the program. Using my preferred method of volume selection, the Rhea works. However, I know there are many audiophiles that use very loud volumes all the time. In these circumstances, I feel quite sure the Rhea noise would become audible and, perhaps, not acceptable.

Sparky

**mep** · 10-09-2011, 05:48 AM

Sparky-If you can use the Rhea to amplify a 230 microvolt signal and not have noise added to the signal that is audible, you just pulled off a miracle.

**karma** · 10-09-2011, 08:52 AM

HI Mep,
Come on Mep. I did not say that and you know it. Of course noise is added. Don't treat me as stupid. The issue is whether the noise is bothersome. And I say it is not. Not for me.

If you continue to skew my responses like this, you will get no more words from me.

Sparky

**rblnr** · 10-09-2011, 08:54 AM

Thanks for the reply Sparky. I intentionally left thevquestion open-ended because I'm interested in any Aestetix component experience and whether there is a 'house sound'. Would be curious too about the noise floor of their preamps and amps too. Quiet tube gear is something ARC excels at.

**karma** · 10-09-2011, 09:10 AM

HI Bob,
I think I answered you questions. As for house sound I would need more than one example to pinpoint it. If the Rhea is typical, the house sound is very similar to ARC.

Sparky

**mep** · 10-09-2011, 09:55 AM

Sparky-Don’t be so touchy. I’m not trying to skew your words. You said:

Originally Posted by karma

So, the question was whether the Rhea would work with my intended cartridges with a noise level that was not bringing attention to itself. This issue was at least as important to me as the basic sound signature. I refused to live with a phono stage that was noisy especially since I already had the SP-11 which is silent and also very good.

To my great surprise, the Rhea proved itself to be adequate. I was and remain impressed. I kept the Rhea.

What I inferred from what you said was that the noise level using the Rhea “was not bringing attention to itself.” You then went on to say this:

Originally Posted by karma

However, I know there are many audiophiles that use very loud volumes all the time. In these circumstances, I feel quite sure the Rhea noise would become audible and, perhaps, not acceptable.

And from that sentence I inferred that at the levels you listen to, the Rhea noise isn’t audible. So I think what you are saying now is that the tube noise is low enough at the levels you listen to that the noise is not bothersome. I think that’s great and I’m glad you’re happy with the Rhea. My point is/was that you are not going to amplify a 230 microvolt signal with tubes without noise. The only question is will the noise be low enough for you to tolerate. You have answered in the affirmative.

I used to use a Counterpoint SA-2 pre-preamp which is pure tube. It had all of the gain I needed to run a .23mv cartridge, but in the end I just got to the point where I found the added noise intolerable. The SA-2 uses two 6922 tubes in each channel for gain. I bought the “AAA” graded tubes from Mike Elliott that only 1 out of every 100 tubes tested makes the cut. The cost is now $120 per tube. Even though these were the lowest noise tubes I ever had (with the exception of the RAM Labs tubes that were in it when I first bought it), it was still noisy.

Everybody has a different tolerance for noise. My tolerance used to be too high. I have since recalibrated and now my tolerance to noise is very low. For that reason, I would not recommend an all-tube phono stage for someone who planned on using a low output MC cartridge because I have no idea what their tolerance for noise is. And the inevitable fact is there will be noise.

**karma** · 10-09-2011, 05:06 PM

HI Mep,
But the point is whether noise is objectionable to a particular listener. And you can not presume to answer that. That you try simply illustrates that you want to be recognized as a know it all. In fact, you don't. But you succeed to that unenviable image. Frankly, all I learn from you is nonsense.

Please refrain from answering any of my future posts. Server space is too valuable.

Sparky