Geo-transformers are for SUB-sonic signals. They will pass lower audio, yes.
The real application has to be oil exploration. You bang on the ground (often with explosive) and many geo-microphones (with transformered lines) pick-up the underground echoes. Large horizontal caverns are potentially full of oil/gas and may be worth drilling.
Try it. Measure the DC ohms and assume a nominal audiio impedance 10X higher. Is that even useful numbers? If so, connect between those impedances and sweep the frequency response. Don't trust the bass-limit until you bring it up on 50Hz to over 1V and slowly back down (to erase the DC flux set by the ohm-meter).
The real application has to be oil exploration. You bang on the ground (often with explosive) and many geo-microphones (with transformered lines) pick-up the underground echoes. Large horizontal caverns are potentially full of oil/gas and may be worth drilling.
Try it. Measure the DC ohms and assume a nominal audiio impedance 10X higher. Is that even useful numbers? If so, connect between those impedances and sweep the frequency response. Don't trust the bass-limit until you bring it up on 50Hz to over 1V and slowly back down (to erase the DC flux set by the ohm-meter).
thread resurrect.
I have a few of these too. The one I tested had no issues worth mentioning at 5Hz but that was the limit of the casual test hookup at the time. They mostly have very high impedance secondaries, presumably for the grids of the day, or possibly the gates of today. A possible non-geoscience use could be ground loop isolation on a signal going to a subwoofer amp. No DC is allowed in them during operation.
which brings me to...
Had a lot of ground loop nightmare lately switching between several PCs to a 100W/CH amp to drive decent speakers. Yuck PCs are the noisiest things -use grounded power cables on all and yet there is noise when the audio commons are connected together as with an RCA-jack type switch box. Even took the box apart to see how the signal grounds are connected and the issue was definitely not poor design, just no isolation to prevent ground loops.
I've been looking for old catalogs with those transformers and have had no luck yet. Thermador geo-tran. Hope something eventually turns up.
I have a few of these too. The one I tested had no issues worth mentioning at 5Hz but that was the limit of the casual test hookup at the time. They mostly have very high impedance secondaries, presumably for the grids of the day, or possibly the gates of today. A possible non-geoscience use could be ground loop isolation on a signal going to a subwoofer amp. No DC is allowed in them during operation.
which brings me to...
Had a lot of ground loop nightmare lately switching between several PCs to a 100W/CH amp to drive decent speakers. Yuck PCs are the noisiest things -use grounded power cables on all and yet there is noise when the audio commons are connected together as with an RCA-jack type switch box. Even took the box apart to see how the signal grounds are connected and the issue was definitely not poor design, just no isolation to prevent ground loops.
I've been looking for old catalogs with those transformers and have had no luck yet. Thermador geo-tran. Hope something eventually turns up.