Line Level Differences

rick1906 · #1 09-17-2008, 12:59 PM

I'm recording from a device that has a line output of +4dBu balanced going to the line in on my Zoom H2. The line in level is -10. Is there a device that can help me match the two levels?

fokof · #2 09-18-2008, 11:03 AM

Can you lower the level on your output device ?

14db should do the trick

bongomania · #3 09-18-2008, 11:13 AM

+1 in terms of the levels, but it is rare for a -10dBu connection to be balanced, so you may have problems connecting that balanced output effectively even if you lower the level. Rolls, Radial, and Whirlwind are companies I know make boxes for matching these types of connections together.

fretlessrock · #4 09-18-2008, 03:06 PM

The line input on the H2 is listed as a -10dbm, 1/8" stereo, 10k impedance. Not knowing what piece of gear you are trying to match doesn't help in giving an answer, but in general you are going to have to get a handle on the output impedance of the source, and then decide on either a passive attenuator or something active like a mixer. The line in on the H2 seems to be designed for making transfers from the headphone out of a piece of consumer gear, using the volume control to get the levels right. It would also mtch up nicely with a fixed level line out from a piece of consumer gear like the one on my Sony shortwave radio.

Without haggling over dBV, dBm, or dBu, let's just say that you need to get from (roughly) 1.2V down to 0.3V. That would be about 4x, and that involves about 12dB of attenuation.

Hope that helps.

rick1906 · #5 09-18-2008, 04:18 PM

The source device is a Hear Back System. The line out on this unit is +4 dBu balanced. The thread that sparked this thread is here. I called tech support for the Hear Back, and the guy suggested that I get a device to go between the Hear Back and the H2 since the H2 is consumer gear. Since then, I have discovered a line level shifter that I'm considering. Would this work? I admit that I know very little about this stuff, so any help would be appreciated.

bongomania · #6 09-18-2008, 04:33 PM

Yes, the Ebtech is the perfect tool for the job. I don't know why I forgot it when writing my earlier post.