Jensen JE-346-AX Moving Coil step up transformers. I got these from a retired Audio Research Engineer. he told me these were from a phono preamp design. I am not sure if this made it into production or not. these would have been from the REF phono, or ref 1 phono i believe.I found an ARC datasheet that seems to match up to these but I have no way to test them. If you have a method, please advise and I will be happy to test for you. I also have the jensen PDF's but I cannot post them here. message me and I will be happy to send them to you. there is published info on the web that these are also used as ribbon mic step up transformers.
apparently these are some of the best MC step ups available. and look at the freq response of these bad boys!
JT-346-AX can be wired for either 1:4 or 1:12 step up ratio.
specifications:
Bandwidth -3dB, 1:4: 0.3Hz – 220kHz
Bandwidth -3dB, 1:12: 0.3Hz – 200kHz
Deviation from linear phase, 1:12: +1.0 degrees typical
Noise figure, 1:12: 1.4dB at 5Ohms
Common mode rejection, 1:12: 145dB at 60Hz
Fully balanced primary
Primary may be reversed for polarity inversion
Double magnetic shield
apparently this MC step up is unobtanium now. Jensen only makes JT-347-AX and the frequency band is only half of of the 346 transformers (0.4Hz – 100kHz) and common mode rejection is 20dB (10x) worse than that of the 346 from what i have read. But this info is quite old and may not be very accurate anymore. I have also read that Jensen may still make a 346 but a 346-AXT version
$250 for the pair plus shipping
Please message me with any questions!
apparently these are some of the best MC step ups available. and look at the freq response of these bad boys!
JT-346-AX can be wired for either 1:4 or 1:12 step up ratio.
specifications:
Bandwidth -3dB, 1:4: 0.3Hz – 220kHz
Bandwidth -3dB, 1:12: 0.3Hz – 200kHz
Deviation from linear phase, 1:12: +1.0 degrees typical
Noise figure, 1:12: 1.4dB at 5Ohms
Common mode rejection, 1:12: 145dB at 60Hz
Fully balanced primary
Primary may be reversed for polarity inversion
Double magnetic shield
apparently this MC step up is unobtanium now. Jensen only makes JT-347-AX and the frequency band is only half of of the 346 transformers (0.4Hz – 100kHz) and common mode rejection is 20dB (10x) worse than that of the 346 from what i have read. But this info is quite old and may not be very accurate anymore. I have also read that Jensen may still make a 346 but a 346-AXT version
$250 for the pair plus shipping
Please message me with any questions!
Attachments
what does this mean?
"The JT-346-AXT is NOT suitable for a stand alone application. It is designed to be integrated into a moving coil preamp design and requires a 6.8kOhm load. As it will not work properly into a standard 47kOhm phono preamp. "
"The JT-346-AXT is NOT suitable for a stand alone application. It is designed to be integrated into a moving coil preamp design and requires a 6.8kOhm load. As it will not work properly into a standard 47kOhm phono preamp. "