Rockbox Technical Forums

Support and General Use => Recording => Topic started by: melontracks on September 30, 2006, 06:37:13 PM

Title: h120 "mic" / "line in" and phantom power?
Post by: melontracks on September 30, 2006, 06:37:13 PM
the original iriver firmware provides both "external mic" and "line in" choices in the recording screen, and the unit provides phantom power to un-powered mics when the "external mic" setting is chosen.

Rockbox firmware does not offer the "external mic" setting, but rather offers "line in" and "mic," the latter being the internal microphone on the device itself.

My question is,  can someone explain to me how the developers chose this route and how the powering of un-powered mics works with this unit?  I have used the rockboxed h120 as a recorder both with un-powered mics and with the same mics using an external battery-box power supply with the "line-in" setting, and each worked fine.  I shouldn't be able to use the mics by themselves on "line in" unless the unit is delivering phantom power to the mics with the "line in" setting, which is fine, I suppose, but I don't want that phantom power when I use my own battery box at shows; I just want a traditional analog "line in"



Am I totally missing the point here?

melon
Title: Re: h120 "mic" / "line in" and phantom power?
Post by: Llorean on September 30, 2006, 06:40:42 PM
The H120 in retail firmware didn't actually switch the power on or off. The ONLY difference between "Line In" and "External Mic" was the gain range you were offered. Instead, we just offered the entire range and trust you not to set it too high or low for your input.
Title: Re: h120 "mic" / "line in" and phantom power?
Post by: Febs on September 30, 2006, 06:46:28 PM
I do think that we should relabel that setting so that the choices are "internal mic" and "line-in/external mic" to avoid confusion.
Title: Re: h120 "mic" / "line in" and phantom power?
Post by: melontracks on September 30, 2006, 08:20:27 PM

The H120 in retail firmware didn't actually switch the power on or off. The ONLY difference between "Line In" and "External Mic" was the gain range you were offered. Instead, we just offered the entire range and trust you not to set it too high or low for your input.


Thank you very much for clarifying what I suspected.  I'll just leave it at no gain when powering the mics myself.


thanks again!

Title: Re: h120 "mic" / "line in" and phantom power?
Post by: Genre9mp3 on October 03, 2006, 07:25:34 AM
the original iriver firmware provides both "external mic" and "line in" choices in the recording screen, and the unit provides phantom power to un-powered mics when the "external mic" setting is chosen.

Just a note there... When we talk about phantom power we mean 48V of power supply to the mic. This requires special mics and connectors and obviously the H100s (and any other DAP out there with the exception of M-AUDIO MicroTrack 24/96 (http://www.m-audio.com/products/en_us/MicroTrack2496-main.html)) do not support that. AFAIK the H100s and H300s power the mic with 2,5V.
Title: Re: h120 "mic" / "line in" and phantom power?
Post by: petur on October 03, 2006, 08:53:46 AM

My question is,  can someone explain to me how the developers chose this route and how the powering of un-powered mics works with this unit?  I have used the rockboxed h120 as a recorder both with un-powered mics and with the same mics using an external battery-box power supply with the "line-in" setting, and each worked fine.  I shouldn't be able to use the mics by themselves on "line in" unless the unit is delivering phantom power to the mics with the "line in" setting, which is fine, I suppose, but I don't want that phantom power when I use my own battery box at shows; I just want a traditional analog "line in"

the iriver hardware has no switchable mic power, it's always there and it's always 3.7V (I think, and probably depends on battery level). That's at least what my h340 does, I suspect the h1x0 does the same.

Please do some homework (I've written about this 10+ times in this forum) or _measure_ what's coming out before claming things that simply aren't true. Try original firmware set to line-in with an unpowered mic and discover yourself.