Quietest amplifier you have ever owned.

ASL MG headphone amp is the quietest while right behind is the Cary SLI50. I'm not looking up any s/n ratios, just relating to lack of noise without playback and a silent background from which the notes eminate verified by the simple act of listening.

Jtinn, I know that the -120db number is a real tough one to achieve. If I had been reading that post myself, I would also have been skeptical.

Since this is a custom prototype, I don't have a spec sheet with that number on it, and I don't think that David would quote that number anyway, because he is so conservative in his specs. However Harvey Rosenberg had quite a bit of experience with these amps before he died, and went to triode heaven, and he quotes a -120db figure on his Triode Guild website. David actually only specs -92db figure on the Siegfried amp, but this is very conservative.

However, my amp is not a Siegfried,and has some significant differences which go a long way to minimize noise further than the Siegfried model. No AC power enters the amp, as it is totally DC battery powered. So there is no step-down power supply transformer, nor any conventional rectification circuits. The power supply is as "stiff" as it gets. Pure battery with 650 cold cranking amps. There is no hum. The only noise generated could only come from the passive parts and the tubes themselves. The mesh plate 45s from Emission Labs are very quiet tubes, and the only other tube in each channel is a single Sylvania 6SN7. 2 tubes on each channel. That's all. Audio signal path was specified by me to be very short and hand wired. If you are concerned about noise from the ZOTL, anything possibly coming from that is well(10x) out of the audio range.

So, that is why I hedged a little when I stated earlier "about -120db quiet". I don't have a measurement figure on it, to back that up. Harvey did those things, and he is the one originating those claims, and I think he's right. I can place my ear right in front of my 100db Lowthers, and hear only the faintest noise at all. If my ear is more than about 4" to 6" away from contact with the driver, I don't hear anything at all. Any hiss in my system is coming primarily from my preamp, not my amp. Any way you slice it, this amp is virtually dead quiet. If I had "normal" speakers of about 88db efficiency, I would hear no hint of noise at all coming from them. You must remember that I am relating this very small sound from 100db/1watt speakers.

So, can I back up my statment with papers? No. Do I feel confident that I made an accurate statement? Yes.

I don't think I've been lied to, nor do I feel I am doing any lying. It is in that neighborhood (within a few db), I am certain.

But I also agree with the posters who mention that the quietness is not the main function of an amp. The musicality is much more important. But I simply responded to the question at hand. BTW, the musicality of this amp is quite good also.

Pbb - I think audiophiles like a dead quiet amp because we don't listen to loud music all the time. I enjoy quiet passages and they are not as pleasing when you can hear the sound of the amp over the music.

Who the hell is Norm Strong?

Jtinn: This was a spec that was measured / verified by an outside source i.e. a full fledged review with bench specs. I think that it was Stereophile that did the testing / review. The S/N was so good that they went off on a tangent about how the s/n ratio of a piece of gear equates to how many bits of data it could pass without raising the noise floor.

Bob Gates: That was a very good and simple answer. Only problem is that the people that need this explained to them "probably" don't think that one is capable of hearing hiss / noise between notes so long as the gear is designed reasonably well. On top of this, they would probably say that if you can hear noise / hiss with the gain turned down, how noisy / insufficiently designed is the gear at high volumes with more gain cranked into it ???

Pbb: Norm is an electrical engineer that has a wife that put him on a budget. As such, all of his audio gear consists of Pioneer, Sansui, Technics, Sony, Kenwood, etc... that was bought on close-out or garage sales. He posts occasionally on AA and Rec Audio Opinion and has stated that all of his gear measures well, works good enough for him and that people can't hear the differences in gear that they claim to be able to hear. To the average audiophile, he is a budget minded "nay-sayer".

As such, you two should have a ball reading most of the posts here and on AA. Then again, Norm would probably tell you that you wasted your money on the gear that you bought since one can't hear any difference between reasonable components. Then you would know what it's like to be nagged by a budget minded nay-sayer and might begin to understand the bad taste that such comments leave in one's mouth. Sean
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