Ssssh, is your tube preamp really that quiet?
Phd, all active circuitry makes noise. Transformers are passive devices and don't make noise, but there is a price paid for their use as well. IOW there is no free lunch. IOW there is no curse :) I see the words 'dead silent' used a lot. I know that is not the case; as I mentioned before different people have different tolerances for noise. For those who think their all-tube system is dead silent on phono try this little test. Leave the tonearm on the tonearm rest. Set the source to phono and turn up the volume all the way. If you can then say that even with your ear pressed to the drivers of your loudspeakers that there is no hiss whatsoever then you have a good case for 'dead silent'. I think you will find though that you have no need to press your ear to the drivers- the noise will be quite evident. |
To all of those who are saying that their tube preamp is dead quiet, remember, we are not talking about normal use here. The OP is talking about his tube phono stage/line stage preamp, no signal, volume turned up, ear right next to the tweeter. In my first response I said my all tube preamp was very quiet, however, when turning the volume up and placing my ear within 2 inches of the tweeter, I can hear a hiss with no music playing. Of course this has nothing to do with listening to music, but this is what the topic of the post is about. Not tube line stages, or how it sounds from 8 feet away in between tracks, but 2 inches away with no signal. Try it, you may be surprised to find out that you do indeed have a hiss. Of course the hiss is meaningless, and has no bearing on enjoying music, but tubes do make noise. |
A point that hasn't been mentioned yet is that our ears, or at least MY ears :-) are significantly more sensitive to high frequency hiss when it is firing into them from the side, rather than emanating from a direction that is closer to the one that is being faced (as it would be under normal listening conditions). FWIW I have never had a preamp in my system, tube or solid state, that was totally silent with my ear directly facing the tweeters from a distance of less than about 3 or 4 inches. That applies to both line-level and phono modes, and to any setting of the volume control, although the hiss level will of course increase somewhat in phono mode as the volume control setting approaches max. In my present system (solid state preamp), turning my head to face the tweeters, with my nose almost up against them, reduces that hiss level to being just about inaudible (except in phono mode with the volume control at or near max). As Rodman indicate earlier, though, some or most of that hiss may originate upstream, due to EMI/RFI pickup, ground loop effects, or source components. I know it is not being generated by the amp or its interconnects, because it disappears when the preamp is muted. 03-24-14: Charles1dadA couple of factors that may contribute to that in some cases, in addition to the performance characteristics of the particular equipment: 1)I've read a number of times in the past that the presence of very low level high frequency broadband noise can be subjectively perceived as an increase in ambience. That seems credible to me. 2)Just speculating, but perhaps a phenomenon can occur as a result of the addition of very low level high frequency noise to analog signals that is akin to the improvement in digital signal resolution which results from the addition of dither. Best regards, -- Al |
