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Post by jj2106 on Apr 15, 2018 9:54:17 GMT -5
Hi,
Does anybody know the minimum impedance needed to load the PT-100 line level outputs?
I'm considering using passive crossovers (http://www.marchandelec.com/xm46-pllxo.html) whose input impedance appears to be a bit low (2500 Ohms, I think).
Is this a problem?
Thank you
Jean-Jacques
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Post by jj2106 on Apr 17, 2018 8:17:58 GMT -5
Nobody at all?
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Post by mgbpuff on Apr 17, 2018 10:17:27 GMT -5
Line outputs usually have an impedance of 100 to 200 ohms and the 10 x rule means the load impedance should be 1000 to 2000 ohms. But I do not know the PT-100's exact impedance. Why don't you go with an active crossover to eliminate the guesswork?
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Post by jj2106 on Apr 17, 2018 10:26:12 GMT -5
Thanks very much for the answer, which is good enough for me.
I'm concerned that active filters may degrade the SNR, but you are probably right anyway.
J-J
PS: I still wish Keith would give an actual figure, but he seems to be silent.
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KeithL
Administrator 
Posts: 9,934
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Post by KeithL on Apr 17, 2018 14:21:26 GMT -5
That value has actually changed slightly over several production runs, but in all versions it falls in the range of "several hundred Ohms - but less than 620 Ohms". It will have no problem driving the typical 10k impedance of most amps and preamps.... and should really be fine down to about 5k.... but I would avoid loads much below that. Thanks very much for the answer, which is good enough for me. I'm concerned that active filters may degrade the SNR, but you are probably right anyway. J-J PS: I still wish Keith would give an actual figure, but he seems to be silent. |
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Post by jj2106 on Apr 18, 2018 2:03:47 GMT -5
Thanks a lot, Keith!
J-J
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