Mini DV - using the 1/8 " Mic input for LINE level sources

[toddboyle]

edDV yeah, I know-- and it's especially true with a mic-level signal. I was a ham operator, sonar tech. in the navy etc... Any 100 foot transmission line (especially unbalanced lines) will pick up the whole range of electromagnetic spectrum--60Hz and its harmonics, AM and FM/TV, thru cellphones, navy OTH etc. Pushing a mic-level signal 100 feet, makes your mic. signal compete with those. For the typical average users (church, weddings, local lectures, sports events etc) they have no business putting a mic-levle signal 100 feet, it's going to have probs. even if they buy expensive XLR gear. At the same time-- the sound board will deliver a line level (typically up to 1 volt) signal. The point you might be missing in my recommendation is that the resister pad is at the entrypoint into the camcorder. I'm dropping the signal 20 db at the camera thereby, dropping the hum/EMI by 20 db which, most often puts it 40db or more below the audio signal. So yes, in quiet passages, you can still hear the hum and EMI (especially with cameras which cannot shutoff the stupid AGC) But believe me, it's a practical solution for most of the recording events-- not professional broadcast TV, obviously they have plenty of dough anyway-- but for public access TV? community radio? college radio? You bet. I'll prove it with about 1000 recordings if you don't believe me--so please, widen your doctrines to recognize the utility of a simple 50-75 foot RCA cable with a resister pad, located at the entrypoint to the camcorder. Its YOUR reputation on the line here, not mine.

[edDV]

edDV yeah, I know-- and it's especially true with a mic-level signal. I was a ham operator, sonar tech. in the navy etc... Any 100 foot transmission line (especially unbalanced lines) will pick up the whole range of electromagnetic spectrum--60Hz and its harmonics, AM and FM/TV, thru cellphones, navy OTH etc. Pushing a mic-level signal 100 feet, makes your mic. signal compete with those. For the typical average users (church, weddings, local lectures, sports events etc) they have no business putting a mic-levle signal 100 feet, it's going to have probs. even if they buy expensive XLR gear. At the same time-- the sound board will deliver a line level (typically up to 1 volt) signal. The point you might be missing in my recommendation is that the resister pad is at the entrypoint into the camcorder. I'm dropping the signal 20 db at the camera thereby, dropping the hum/EMI by 20 db which, most often puts it 40db or more below the audio signal. So yes, in quiet passages, you can still hear the hum and EMI (especially with cameras which cannot shutoff the stupid AGC) But believe me, it's a practical solution for most of the recording events-- not professional broadcast TV, obviously they have plenty of dough anyway-- but for public access TV? community radio? college radio? You bet. I'll prove it with about 1000 recordings if you don't believe me--so please, widen your doctrines to recognize the utility of a simple 50-75 foot RCA cable with a resister pad, located at the entrypoint to the camcorder. Its YOUR reputation on the line here, not mine.

The advantage of the transformer used in the Shure and Beachtek is DC and hum isolation. Camcoder mini mic inputs are said to have a dc bias.

In pro stages and studios, 100ft plus ~ 150 ohm balanced XLR mic runs are common even for digital mixer boards.

[toddboyle]

EdDV regarding your first comments: the thread above explains the use of a capacitor to block the DC bias; of course I thought that was the circuit we are discussing here. Yes. A capacitor. Incidentally almost any mixer board has capacitor isolation of their line-out anyway. I have tested a bunch of them with, and without the capacitor isolating my GS150 or GS500 to see if my DC bias was going to disturb the preamp output and have NEVER found one that was disturbed. If you want to prevent disturbing the House mixer board and getting us in trouble, you would be better advised to buy Ferrite beads or an RF shunt (a few picofarads across our line) to prevent injection of unwanted RF, cellphone buzzes etc into the house system.... Your second point. yes of coures I agreed, 100 foot microphone runs are commonplace with well designed and implemented XLR, I already conceded that. Be aware- that's pretty difficult to achieve for a portable equipment in a typical setup time under 1 hour, particularly with higher quality large-diaphragm condenser mics. Bottom line if you want to spend $100 you can buy a low end condenser mic AND a mixer with 48v phantompower, throw it on stage and run the 100 foot signal at line-level back to your camcorder and it will work a lot more often (for ordinary budgets of low $hundreds) than a 100 foot mic. cable with a Beachtek,
Kind regards
Todd