Am I the only one shaking my head?
SUT - electrical theory and practical experience
Some vinyl users use a SUT to enhance the signal of the MC cartridge so that it can be used in the MM input of a phono stage. Although I don't understand the theory behind it, I realize that a SUT should be matched individually to a particular cartridge, depending on the internal impedance of the MC, among other things.
Assuming an appropriately / ideally matched SUT and MC, What are the inherent advantages or disadvantages of inserting a SUT after the MC in the audio chain? Does the SUT theoretically enhance or degrade the sound quality? What does the SUT actually do to the sound quality?
Thanks.
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- 298 posts total
I think that @pindac has the correct approach: when children are misbehaving in order to get attention, it's best to ignore them; this approach is colloquially known as "don't feed the trolls" on the internet. |
No @antigrunge you are not.
I am open to understanding, so anything many say is received including @intactaudio comments. But I’ll need to check the diagram to see if that built-in 1:4 SUT is loaded on the primary or secondary side.
@pindac I may have seasonal naïveté 😀 |
There are two possible loads that this SUT could have. The unintentional which is the typical 47kΩ input of a MM phono and the intentional which would be an additional filter on the secondary to "correct" any misbehavior of the device. Both of these loads would be on the secondary of the device. If there are specified cartridge loads for MC then is possible there could be an additional combination of primary and secondary loading and with the low turns ratio this is a possibility. I do think that the typical "dull" sound from loading a cartridge down too much is purely a function of the SUT behavior. Since you have such a low ratio transformer an interesting experiment would be to find out the "calculated" reflected impedance and then try the following experiment. (below I am assuming a 47kΩ load and a 40Ω Denon 103 and you can scale the values for different cartridge impedances.) Assuming the 1:4 is terminated with 47kΩ and a the cart should see 3kΩ as a load. Now place a 1.6kΩ resistor across the secondary to reflect just under 100Ω to the cartridge and give it a listen. Next remove the 1.6kΩ resistor and place a 100Ω resistor across the primary and listen again. In a perfect world the load the cartridge sees will be the same (roughly 2.5X the internal impedance). The gain of both situations will also be the same and my experiences tell me the sounds will be quite different. To be clear... any differences heard will be a function of the SUT behavior and not the load the cartridge sees which puts this squarely in the purview of this discussion. now that I am done with my airing of grievances it is on to the feats of strength. Happy Festivus to all! dave |
- 298 posts total