Otari MX-55N question

Hi,

I recently aquired a 2 track Otari MX-55N and have been cleaning and checking it against the manual - pdf available from:

http://otari.de/support/pdf_manuals.html

My question is - the manual shows 3 heads - erase / record / play - with a spare empty slot between record and play heads.

My machine has a head in this position (looks like record and play heads) - but there is no info in the manual on what is the function of this head. Can anyone help?

Also any general background on this recorder would be of interest. They seem much less common than the ubiquitous 5050 series.

regards,

Martin

The MX-55 was introduced in 1988. It's one of the few open reel machines with Dolby HX Pro; something I wish would have caught on with other late model R2Rs. HX Pro is very common on late model cassette decks. It is basically a variable bias circuit that alters the bias level in real time in response to high frequency music content. During recording high frequencies can self-bias the tape, adding to the overall bias, which can give a duller sounding result. The MX-55 is built around the MX5050 with some extra features. It's a nice machine.

On the head assembly from left to right is normally:
Erase head, Record head, Head dummy, Play head.

There will be a round head dummy in that center spot or an active head. It will never be blank. Are you sure it is an active head?

If it's a functional head you probably have Model MX-55N-D. The center head is 4-track 2-channel consumer playback head. There should be a switch for playback modes if it's functional.

The original MX-55 came in the following configurations:

-Full track
-Half-track (NAB or DIN)
-Two-track with center time code track
-Four-track
-Half-track record/playback w/4-track play option

Here are exploded parts views and lists from the USA site that are not on the German site, if you don't already have them

http://www.otari.com/support/pdf/mx55nd.pdf
http://www.otari.com/support/pdf/mx55t_mtn_m.pdf

-Tim

Hi Tim,

Thanks for the good info. There's a mystery here - yes, the centre head is active and it looks like a consumer playback stack. But where is the switch to activate it? I have tried playing back a consumer tape - in case there was a 'smart' switch. But no use. Any suggestions? Anyone with the manual on the MX-55D?

The number on the back of the unit is plain MX-55N

No mention in the manual of Dolby HX Pro - no Dolby trade mark on the machine. The manual gives traditional bias set up instructions.

Nother question - What is a good equivalent lub oil for the rubber pinch roller shaft - sewing machine oil OK?

Do Otari make parts fror these still? eg a replacement rubber pinch roller. Got to say I'm in love with the feel and quality of this thing.

martin

The HX Pro label is just a sticker. It may have been removed or fallen off by now. As far as I know the MX-55s made from 1988-91 have HX Pro.

Unfortunately, it is not documented in the manual except for the location on a PCB, and the online manual from the German site has those PCB images missing.

If you open the hatch to the electronics there should be a sticker on the inside of the hatch that indicates where the HX Pro switch is located. It is also labeled on the PCB itself, but will take some careful scanning to find it.

If the switch for the 4-track playback is not anywhere on the outside it may be in the hatch as well, though I’m not sure about that. Hopefully someone else will chime in that can tell us exactly how to switch between the playback modes. An email to Otari Service Dept. couldn’t hurt either: service@otari.com

Sewing machine oil works just fine for lubrication.

As for parts availability call Otari in USA 800-458-6484 or 800-877-0577, or 818-598-1200 (Outside U.S.) You can inquire by email at parts@otari.com.

Terry’s Rubber Rollers may be cheaper and he does a great job.
http://www.terrysrubberrollers.com/

-Tim