My current one. David Berning SET ZOTL. It is about -120db quiet.
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I have a different opinion. As I have ML332 amp and use Genghis Khan PC the amp is totally dead quiet. I have tried another power cord to replace the Genghis Khan I can hear the hiss and hum. But I also add a Sound Application with Elrod EPS3 20ampIEC I ain't hear nothing not even closer, absolutely dead quiet.
Most amps are typically very quiet with some of the newer "digital" type amps coming up as exceptions. I have had greater problems with preamps or ground loops generating a higher noise floor than anything else. If you have noise within the system ( whatever the source might be ) and you are running very high efficiency speakers ( horns ), the problem will be exagerated to a more noticeable extent.
As to the specifics that you mention Bob, i would start checking tubes. It is possible that it is a noisy design in terms of circuitry, but i would want to rule out a possibly defective tube(s) before placing the blame on the designer / product. Sean
Maybe you should put some music on. I always feel empty, in an empty room, with an empty cd drawer or naked platter with no musical matter, even more so on an empty stomach. Is listening with no music on a new audiophile preoccupation? And there I was thinking it was about the music! I think this may be the quintessence of audiophilia nervosa, listening to the amp itself without music. The beauty of the s/n ratio in all its nakedness! Heck some people don't even need the amp, they just read the specs on the lew and it fires up their imagination. From my humble but God-awful cold one-holler in the frozen mid-fi trenches, good day!
You're right Pbb. I'm scrapping all my gear and buying Pioneer, Sony, Technics and Kenwood. Think of the money i can save in the future and the money i can put back into my bank account after selling all of the gear that i have now !!! Since the mass market stuff all measures the same, and the measurements are good by most people's standards, and it all produces sound that one "could" call "music", i've wasted a LOT of time, money and effort with the over-priced junk that we call "sound systems". Ha !!! Thanks for opening my eyes !!! You've steered me back onto the right path once again. Both you and Norm Strong have been right all along.... Sean
Jtinn: While some of you probably know that i'm not a fan of Bryston amps ( don't know anything about their preamps or processor ), one of their amps was reviewed a while back and had a VERY high S/N ratio. I want to say that it was very near or slightly above -120. I'm not sure, but this might have been the little 60 wpc integrated. Maybe someone can refresh my memory. Sean
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.
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
The key to quietness at the speakers is amplify the signal as much as possible, without distorting it of course, before the power amp. Therefore the amp increases the gain less for the same speaker output and therefore is not amplifying the noise that is being introduced to it by the upstream equipment. Obviously you need input attenuators on the amp to be able to accomplish this. Some will say that the attentuators will affect the sound, even if the attentuators are part of the amplifier design.
Most power amps are quiet enough if they are matched correctly i.e. proper impedence loading and in put sensitivity matching. The term quietest amp is irrelevant and meaningless - what you want is low system noise as perceived at the close to the listening station.
I am with Pbb, if you want quiet, go to the mountains and don't turn on your sound system!
Drubin: Pbb was basically commenting that most of us are wasting our time seeking out components that both measure and perform better sonically. He basically stated that we are worried about subjects and situations that will never come into play. That is because he is of the opinion that most gear is "plenty good enough" once it reaches a specific level, hence his typical stone throwing signature of "from the mid-fi trenches". While some of his observations do apply to various conversations, i think that the majority of his comments would blend in more with the Audio Review crowd better than what they do here. Sean
As a little note to the -120dB posts, it all depends on how it was calculated. Generally this figure is the difference between output and noise floor. However, at what output? And at what heighth of noise floor? Many ambiguous variables involved and few state the conditions. -120dB is very realizable. Pass quotes -145dB for some of his amps at peak power - quite impressive. Personally, I let me ears to the calculating. Arthur
Drubin: My comments to Pbb are not based on his input to this thread alone, but to his continual attack against those that seek a higher level of reproduction to that of what he personally feels to be necessary. He constantly tries to remind us just how stupid we are for going to the extremes that some of us do. After subtly attacking someone, he typically tries to "soften" his belittlement of their comments / efforts by saying something like "responding from the mid-fi trenches".
Here's a question to the rest of the participants on this thread:
How do you judge whether or not your system or a component has a high noise floor ?
Personally, i select an unused input on the preamp and crank the gain wide open. If i can hear any form of noise or hiss with my ear next to the speaker, it is noisier than what i want to hear : )
Obviously, someone with very high efficiency speakers and / or those with a very bright frequency response may hear more hiss / noise than someone running very low efficiency speakers or speakers with a rolled off treble response. If checking a source, you obviously would select that source with no signal being sent to the preamp and advance the gain. Obviously, one should NOT do this with a tuner and the muting turned off : ) Sean
How to determine if your system/component has sufficiently low noise? Simple. Play something at realistic (or desired volume) levels, then stop play and, at approximately half the distance that you normally listen to your system, listen and note if you hear any noise. Depending on your source, you might hear noise or not. If you don't hear any noise, great. If you do hear noise, also great, now you can start tweaking, which is what tweaking is all about, repairing an audible or perceived defect in the system.
Bobgates, first of all, I didn't say "all you have to do is start tweaking". I said that all tweaking is attempting to repair a perceived or real problem in your system. Noise in a properly set up system is not usually a problem - just because you hear some noise when you have your ear right up to the speakers doesn't mean that you have a problem. Some do think that this is a problem and they will start "tweaking away", cables, amps isolation platforms ad nauseum. If you hear noise using the method that I have described it is most probably due to a bad front end set-up or matching with the power amp, with the pre-amp not doing it share of the level gain and using the power amp to do the bulk of the gain. This is especially critical with high sensitivity speakers.