B
boingoman
New member
A Reel Person said:It's when you want to stretch your cable runs over 20' that unbalanced cable runs get noisier.
I think with the range of the Trim on the Tascam Portastudio's mixers, you could match impedance pretty well, for this type of source. LowZ mic, HiZ mic, & instrument, alike.
Thanx again.
The other problem with long runs of unbalanced cables on microphones is the loss of high frequency response due to increased capacitance in the cable.
Richard you are right. Most line level inputs don't have enough impedance to handle instruments without degrading the signal, and changing the trim doesn't change the impedance of an input.
But a 500 ohm mic doesn't need an instrument input, either. About impedance matching- too much mismatch either way will give you bad results, either by loading the source too much in the case of too low an input impedance or decreasing the signal amplitude too much in the case of too high an input impedance. Generally the best input impedance is about ten times the output impedance of the source. This is called impedance bridging. So in the case of many modern mics, which average 150 ohms output impedance, they are looking for an input that presents about 1500 ohms, which is somewhere around the input impedance of many modern mic pres.
This is why people use those lo-z to high-z transformers. The z of most mics is too low to interface with line level inputs properly, and needs to be raised to get closer to the bridging ratio.
Plugging a 500 ohm source into an instrument input would probably be too much of a mismatch. IMO with modern line inputs averaging 10kohm, 500 ohms is a bit low to even be plugging straight into a line input. On the other hand, it's a bit high to plug into a mic pre and expect optimum results.
Guitar pick-ups range somewhere from 4000-7500 ohms output impedance, and require inputs with very high z to not degrade signal quality.
Edit: Many guitars have significantly higher output impedances, 50kohms and up.
Information aside, the best advice has already been given. Plug it in and play around. You can't hurt nothin'.
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