Preamp vs DI box vs LLS for MOTU M4 line-level input

[Eccentricity]

I have a MOTU M2, but I'm considering upgrading to a MOTU M4 for the additional rear input.

However, inputs 3/4 on the M4 do not have a +4/-10 selector switch, so unless the device has a strong enough line level signal, things will end up quiet.

What hardware should I ideally use to get a clear, audible signal from game consoles, handheld audio players, or other low signal level devices? I know of three options;

1. Preamp (how do I ensure I get a "pure" preamp, and not a turntable preamp, so I avoid the RIAA curve?)
2. Line level shifter (such as the passive Morley/EBTECH LLS-2-XLR)
3. DI box (passive/active? or is this not quite what I want?)

Which of the above options is the best? Or if there's a better solution than the above options please suggest it!

[mikehalloran]

Preamp (how do I ensure I get a "pure" preamp, and not a turntable preamp, so I avoid the RIAA curve?)

Don't buy a phono preamp. Read the specs and this is easily avoided.

Line level shifter (such as the passive Morley/EBTECH LLS-2-XLR)

I have a few older units without the XLR jacks parallel to the TRS— electrically the same, otherwise. I use XLR–TRS cables instead. Dead quiet with excellent frequency response but may or may not provide the amount of gain you need. Hot enough for my Yamaha keyboards but sometimes, I get tracks on cassette and have to run my iPad in. I should sell mine since I no longer use them.

DI box (passive/active? or is this not quite what I want?)

If the LLS-2 doesn't do it for you, Active is the correct answer.

I use a Radial J+4 nowadays. It even has a 1/8" TRS input for my iPad in addition to TRS & RCA.
https://www.sweetwater.com/store/detail ... vel-driver

You would use XLR to TRS cables or adapters to go into into an M4.

[Eccentricity]

Thanks for the advice!

Based on your reply, are all three possibilities I presented valid options? If they are, is there one I should prioritize?

I appreciate that the line level shifter is passive, but should I focus on a preamp or active DI box to ensure I have enough gain in all situations?

Thanks again for taking the time to respond; audio production and mixing is still new to me.

[stubbsonic]

I think a pre-amp or a small mixer would give you the best options & results (for the money). A little Yamaha, Soundcraft, or Mackie mixer will give you clean gain and may add some useful EQ option.

[mikehalloran]

Based on your reply, are all three possibilities I presented valid options?

Only if you have a turntable that requires an RIAA preamp. Otherwise, you don't want one. Most phono pres output -10 so those go into an LLS or J+4 anyway (there are a few with true Line level outs, however).

Otherwise, it depends what is going into those Line Ins. Some keyboards have true Line level outs — those don't need anything. Most keyboards work with the LLS-2. Everything except microphones works with the J+4 and, if you need an RIAA phono pre, you'd plug it into the J+4, also.

If you have a multiple units to plug in (one at a time), the active J+4 is a no brainer. In addition to being active, it has an input level pot, a 100Hz high pass filter & ground lift switches on the side.