@montaldo I have a diy SUT with Jensen AT 347 trannies. These can be wired for 8:1, 12:1 and 24:1 gain. I run a Dynavector XVT-1s at 24:1 into the MM of a Zesto Andros 1.2 phono pre. You might want to ask Berning if your trannies can be rewired to 12:1 which should be enough of your cart's output.. That being said, not sure what is the MM gain of your unit. If you go to the Jensen site, you can see the schematics for the three different gains. The loading will not have that much impact on gain but it definitely helps to experiment as it relates to the sonics. I used the zobel circuit that Jensen recommends for the 347 at the gain used.
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Barolobrain: Firat of all you may need to explain your username to me (expiring minds want to know).
Second, I did not realize these Jensen Transformers had optional configurations. If I could have mine required to 1:12 or 1:24 that would be interesting to try. Is the procedure difficult or could any tech do it, with insrtructions from Jensen?
Name came from a big night out when I lived in London and we were drinking Barolo wine. As long as the leads have not been cut too short it can be done. How easily is something you'll have to determine. Go to their web page and there are three docs, one each for 8:1, 12:1 and 24:1 ratios. There is also a doc for the zobel networks, dependent upon single ended or balanced configuration, step up ratio and internal impedance of cart to be used. I don't remember if that doc is on the website. Good luck.
Hang on guys, some transformers have multiple taps and others do not. You have to check on the wires coming out of the transformer. Most are color coded. While having multiple taps gives you flexibility. I think but I am not entirely sure that a single ratio transformer is theoretically better. Ralph may be able to comment on this. Sowter has multiple tap transformers but I have always avoided them. May be just a knee jerk assumption. My brain hates unused wires.
Over a decade ago I made the below linked post and still stand by it 100% today.
Some basic takeaways I have found.
-Loading the secondary is the worst thing you can do to a transformer. With a known source / load combo an optimal transformer can be designed.
-47K is a silly value for the input of a phono stage when considering a SUT. Selecting a turns ratio on the reflected load of that 47K is misguided.
-Turns ratio and cartridge load should have zero connection to each other when selecting a SUT. Turns ratio should be set for appropriate gain (with careful attention to possible overload). Load resistor should be also as high as possible. Any needed cartridge load should be placed directly at the cartridge.
-Zobel Networks are a Band-Aid for a source to load mismatch of a transformer. They will make the test equipment happy but always leave the music feeling something is amiss.
-high Q resonant behavior of a SUT at 30Khz is audible and objectionable yet Low Q resonant behavior above 100Khz seems audibly benign.
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