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Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: heyitsmejess on November 09, 2007, 04:45:13 PM

Title: mx-100 question...where to put the preamp.
Post by: heyitsmejess on November 09, 2007, 04:45:13 PM
should i run the mics through a preamp before going into the mx-100, or after?

thanks in advance!
Title: Re: mx-100 question...where to put the preamp.
Post by: SmokinJoe on November 09, 2007, 08:02:54 PM

I haven't needed another preamp before or after.  The MX-100 seems to have a fair amount of gain built in.

As a point of reference, I think I've run my CM300s > MX100 with gains at something like 2:00 > line into my R-09 with input running at 10 (on a 0-30 scale).  You could run a little more gain on the recorder and a little less on the MX100 too.  I haven't done enough controlled tests to figure out which is better.  I generally use the knobs on the MX100 to get the mix and balance where I want and then use the recorder to adjust the levels.

Hope that helps.

CapnHook has a lot of experience with these.  I've used mine probably a dozen times, with 2 cards and an omni it seems to work great, or even just 2 cards.  With 2 Guns and an omni... I need a little more experience getting it dialed in I guess.  The guns seem to have more gain.
Title: Re: mx-100 question...where to put the preamp.
Post by: Roving Sign on November 09, 2007, 08:34:32 PM
I dont have the specs in front of me...but I dont think the MX100 packs a ton of gain.

I think it was designed with the idea that the downstream recorder would be adding some gain as well - pretty sure the manual reflects this...

I've often felt that I was running it a little too hard to achieve good levels with the JB3...(with JB3 @ 0db) - particularly at quieter shows...

edit - found the manual here...
http://www.taperssection.com/reference/pdf/Manual_NakamichiMX100.pdf
Title: Re: mx-100 question...where to put the preamp.
Post by: Roger Gustavsson on November 10, 2007, 12:29:35 PM
I am also running Nakamichi CM-300's with the MX-100. The MX-100 seems to have a maximium gain of 500 (0.2 mV input results in 100 mV at the output). Most of the time, I run my setup with maximum gain and on batteries. Not doing any stealth of rock... The CM-300 have a low output, hard time for many preamps. The MX-100 seems to be a low noise unit. Just wish the unit was smaller. Schematic and picture of the interanls attached below.

Roger Gustavsson
Title: Re: mx-100 question...where to put the preamp.
Post by: gdplusmore on November 10, 2007, 02:28:19 PM
I have had good success running near max with L&R when using 2 CM 300's with CP1's and Nomad  NJB3 set to zero Gain.
When using a third CM300 with center omni  CP-3 , I set the blend to 2 position before half way markon the dial.
 For reference see link below of some of my recordings with the MX-100.  I run the MX-100 off two 9volt batteries.

http://www.archive.org/bookmarks/gdplusmore
Title: Re: mx-100 question...where to put the preamp.
Post by: tms on November 12, 2007, 09:44:49 AM
No pre-amp needed.  The mx-100 has gobs and gobs of gain and was made to work beautifully with the CM-300 mics.  1/4" unbalanced in and RCA line level outs to run to your A/D.  I loved it but it was a brick. 
Title: Re: mx-100 question...where to put the preamp.
Post by: DSatz on November 22, 2007, 01:34:34 PM
What tms said, including the weight problem (and maybe the lack of a pan pot for the center input).

The main issue when using this preamp with professional equipment is, if you have microphones with balanced outputs, how do you unbalance their signals at the inputs to the MX-100? The right answer may depend on what type of microphones you're using. The only universal solution is a set of good input transformers, and those aren't cheap--but no one other method will work with balanced signals from all the different types of microphones that are out there.

Still, despite its somewhat unusual personality (it fits precisely with a "recording philosophy" that Nakamichi used to advocate), this is an amazingly quiet and overload-proof little preamp. I have one that I rigged up 25 years ago with stereo phone jacks (for connecting balanced microphones) and a set of Beyer miniature input transformers, plus 12 Volt phantom powering derived from the main DC input socket.

The main problem was, in a live situation you can't always judge the level setting that's right for the center channel input, so you get stuck with whatever balance you guessed at the time. That's why RCA and Columbia used to record a lot of stuff on special three-track (half-inch) Ampex recorders--they could choose the best settings later on, in the comfort of the studio where they have known good monitor loudpeakers. Headphones can't really tell you what you need to know in a situation like this.

--best regards