Tom, I think I said this before, but judging from your follow-up post, you did not "receive" my message. I keep an open mind on transformers in audio. I don't necessarily think interstage transformers are "bad", but perhaps that is the audio transformer function of which I am most skeptical. In my response, I was merely pointing out that some who know more about the advantages and disadvantages of IS transformers than I do have written about the disadvantages, and I was influenced by what I have read. But this hasn't caused me to dismiss the idea. t would be eager to hear your phono stage any time.
Pani, I know what a SUT does. However, the SUT will affect the impedance seen by the cartridge according to the square of the turns ratio. So, if your SUT is providing a 1:10 voltage step-up, then the impedance seen by the cartridge running into a SUT in series with a typical MM phono stage will be 470R (47,000 ohms divided by 100). My point was that lately I have been finding that I like to run my LOMC cartridges into more like a 47K ohm load (i.e., unloaded). To achieve that with a 1:10 SUT, I would need a 4.7M resistor across the secondaries. Since that resistor also serves as the grid resistor of the input tube, problems with grid current might be created by using such a large value grid resistance. (It would probably work OK with certain tubes, but not all.) Also, I do not agree that using a SUT necessarily avoids problems related to "ringing" that might otherwise be encountered if using an active gain stage with an LOMC (unless that gain stage is intrinsically flawed in design). There's a nice white paper on using Zobel networks to tame the response with SUTs, on the Jensen website.
I was interested to read your thoughts on the Herron. I've never heard one, but as you know, there are many devoted users here.
Pani, I know what a SUT does. However, the SUT will affect the impedance seen by the cartridge according to the square of the turns ratio. So, if your SUT is providing a 1:10 voltage step-up, then the impedance seen by the cartridge running into a SUT in series with a typical MM phono stage will be 470R (47,000 ohms divided by 100). My point was that lately I have been finding that I like to run my LOMC cartridges into more like a 47K ohm load (i.e., unloaded). To achieve that with a 1:10 SUT, I would need a 4.7M resistor across the secondaries. Since that resistor also serves as the grid resistor of the input tube, problems with grid current might be created by using such a large value grid resistance. (It would probably work OK with certain tubes, but not all.) Also, I do not agree that using a SUT necessarily avoids problems related to "ringing" that might otherwise be encountered if using an active gain stage with an LOMC (unless that gain stage is intrinsically flawed in design). There's a nice white paper on using Zobel networks to tame the response with SUTs, on the Jensen website.
I was interested to read your thoughts on the Herron. I've never heard one, but as you know, there are many devoted users here.