PrestonTom Posted January 23, 2007 Share Posted January 23, 2007 Speakerfritz, You made the comment that "it" could not be measured in a thread regarding "crossover distortion" with unbiased caps. Mike then mentioned the necessity of measurement (which I agree with) I gave a simple simulation to highlight that this could be quite measureable. Why are you now talking about the "sweetness" of tubes? Did I miss something? -Tom Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 23, 2007 Share Posted January 23, 2007 Tom, how would you go about measuring it? Just via harmonic distortion? Would it be feasible to set up a variable voltage supply and measure in real time how the distortion changes as the voltage changes? I would very much like to verify this for myself in the labs at school. What do I need to measure harmonic distortion? Quote Link to comment Share on other sites More sharing options...
Guest " " Posted January 23, 2007 Share Posted January 23, 2007 PrestonTom Yeah, I think so. My comment about measurements was as a result of DrWho's statement of measurements being a pre-cursor to a remidation. My example about tubes and speaker wire was to illustrate that perceptions of results can exists amoung individuals in the absence of measured validation. Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted January 24, 2007 Share Posted January 24, 2007 Tom, how would you go about measuring it? Just via harmonic distortion? Would it be feasible to set up a variable voltage supply and measure in real time how the distortion changes as the voltage changes? I would very much like to verify this for myself in the labs at school. What do I need to measure harmonic distortion? My comment was regarding a simulation. That is, what is the consequence of having a "mismatch" at the zero crossings ( which is what the article depicted). The consequences are distortion showing up at the 3rd harmonic (if I recall correctly). This now tells us where to look. A spectrum analyzer and not an o'scope would be the preferred tool. The second hint was provided by DJK, who noted which sorts of caps were the most, and least, susceptible. I would build the world's simplist circuit with an sine wave generator (digital or the output of a CD player) on one end and then going to a cap (with and without a battery bias) then into power resistor to simulate a load. Does the level of distortion at the 3rd harmonic change with & without the battery providing a DC bias. Of course the source (tone generator or CD etc) will have to be fairly clean or else its own noise and distortion will obscure any changes you are trying to detect. This may be problem since the original article never gave any indication of the magnitude of this "capacitor distortion". My hunch is that it is not very big to begin with, but that is only a hunch. -Tom Quote Link to comment Share on other sites More sharing options...
Guest " " Posted January 24, 2007 Share Posted January 24, 2007 "it makes no difference what audible effects might be perceived because the author's claim was to "reduce distortion." He didn't simply calim it sounded better, it reduced distortion" Intresting, I guess we (the forum), threw in the cost savings potential of using cheaper caps thru this approach. Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 24, 2007 Share Posted January 24, 2007 My example about tubes and speaker wire was to illustrate that perceptions of results can exists amoung individuals in the absence of measured validation. Perceptions are misleading - as I alluded to earlier, it is not uncommon for someone to perceive differences without anything changing at all! Also, the ability to hear a difference does not show which is better either. Btw, it's easy to hear differences between tubes and speaker wire....and it's also easy to quantify those differences with measurements. [^o)] Quote Link to comment Share on other sites More sharing options...
WopOnTour Posted January 24, 2007 Share Posted January 24, 2007 Speakerfritz-- Just to be clear in my meaning, I don't discount any sonic effect that might be perceived. But the author made an onbjective claim for lower distortion, which is trivial to measure. It might be that the measure reveals nothing, but the audible tests reveal a big change. Excellent point. Good thing our ears can hear what's beyond any measured distortion. I've heard some very impressive ~2% THD amplifiers... WOT Quote Link to comment Share on other sites More sharing options...
Guest " " Posted January 24, 2007 Share Posted January 24, 2007 'Btw, it's easy to hear differences between tubes and speaker wire....and it's also easy to quantify those differences with measurements. " Very good to know....I will keep that in mind for the next speaker wire makes a difference but does not make a difference thread...expect an invite. I think it can make a difference, but have never been able to prove it. Glad to hear that you can. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.