Otari MX-80 VU Meter Lamps

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Jason Graham

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Hello,

I recently acquired an OTARI MX-80 32 track 2" tape machine. Transport appears to be in good shape, 32 track heads look worn but came with an extra set of pretty fresh looking 24 track heads, a few reels of tape, original service manual, and other assorted goodies. The VU meters on all 32 channels appear to work fine, however many of the lamps have burned out which, as I understand it, is pretty common for a machine this age. I have read it can be a pain, however I do wish to replace the smoked VU meter lamps in order to fully restore the machine. My problem though is that I cannot seem to find a source for these lamps. The Otari part number listed in the service manual is LU2065. I read on another forum that this is also the lamp used in the MX-70 and I believe someone claimed it to be a 6V? Would anyone happen to have any cross referenced part numbers/suppliers for these lamps?

Thanks so much!
 
I replaced the burned out ones with comparable ones that are a hair longer, like 1mm, and I think the originals are frosted, while the new ones are clear...but the new ones are actually a tad brighter. It took me awhile to find them, a lot of searching...but if I recall, I came across an electric supplier in Canada that had them, I bought a bunch.

I will have to dig a bit to find any specific info for you (I might have it with the rest of the bulbs in storage)...and I also think I may have posted that in a thread here...but it would have been like back around 2012...???...so you can search the threads in this Analog forum with under my user name, and focus on that timeline...or search for MX-80 threads, and again focus on that period.

If I find something I'll post back for you.

Oh...these bulbs are not specific Otari part numbers or anything like that...they just happened to be the right voltage and size with the right axial leads.
Yes, it was a bit of a PITA to replace them, you have to remove the entire face of the machine with the meters, and then put in in a vice clamp so you don't have to hold it or have flat on a table, which will make it easier for working on them...but not really complicated. It's like anything with this kind of gear, you need to go slow, and check and then recheck everything before you turn any screws.
At any rate, I've done a fairly comprehensive overhaul of mine...so I'll be glad to help with info, as much as my memory can handle.

Do you have manuals?
If not, I can provide links to just about everything to do with the MX-80...I've got all that stuff on my web server...let me know.
 
OT but a bit moot? In valve guitar amps we replace nominal 6V (6.3) lamps with 8V even 12V types and they never fail again. I see 8V types in Beat's link.

I suppose suggesting 3mm white LEDs would be beyond the pale?

Dave.
 
ecc83 said:
OT but a bit moot? In valve guitar amps we replace nominal 6V (6.3) lamps with 8V even 12V types and they never fail again. I see 8V types in Beat's link.
I suppose suggesting 3mm white LEDs would be beyond the pale?
Dave.
Click to expand...

The lighting circuit on the MX80 is AC so LEDs flicker at 25Hz (or 30Hz). This looks particularly horrific on video so I eventually gave up and put the incandescents back in. I am using grain-of-rice lamps for modelmaking to replace the axial ones. I will at some point look into rectifying each row of meters and replacing them with warm white LEDs.

EDIT: In terms of actually getting at the meters, you will need hex spinners, about 4mm or 4.5mm, I forget which. I think I bought both to be sure. The hex nuts are recessed and too narrow to undo with needle-nosed pliers. Given that the bulbs blow, Otari could have made accessing them much easier.
 
Last edited:
jpmorris said:
The lighting circuit on the MX80 is AC so LEDs flicker at 25Hz (or 30Hz). This looks particularly horrific on video so I eventually gave up and put the incandescents back in. I am using grain-of-rice lamps for modelmaking to replace the axial ones. I will at some point look into rectifying each row of meters and replacing them with warm white LEDs.

EDIT: In terms of actually getting at the meters, you will need hex spinners, about 4mm or 5mm, I forget which. I think I bought both to be sure. The hex nuts are recessed and too narrow to undo with needle-nosed pliers. Given that the bulbs blow, Otari could have made accessing them much easier.
Click to expand...

I was not sure if the supply was AC or DC but yes, a rectifed supply and a 7805 should give flicker free results. If staying with AC perhaps a resistor to knock it back a bit? A 20% drop in voltage is hardly noticable but increases life considerably. "We" found DC heated, regulated valves last almost forever buffered as they are from mains voltage girations.

Dave.
 
To the OP...
I looked for the info on where I got the bulbs...sorry, couldn't find anything other than some of the spare bulbs I still had...but I just remember it was from a supplier in Canada, and the reason I got them from him was that he was offering a great price on bulk buy (I wish a bought twice what I did).
Otherwise, if you search for axial bulbs with the right voltage, size...you should be able to find them.
Try eBay...I saw some on there that look about right.

I also see that you posted in Gearslutz, and that Jim Williams suggested the LED route...which is OK, and I know some folks that did that. I mean, if like ALL the bulbs were out, you might consider that, since you will have a lot of work anyway to replace the bulbs.
With my MX-80, I had maybe only about a dozen out (there's two per VU)...so I wasn't eager to remove all the working bulbs too, just to go the LED route.
Also, I don't run the deck 24/7...so the spares I have left will hold me for a long time, and I'll wait until there's a bunch out before I replace them again. I'm certainly not going to do it every time one goes out. I think right now I have one that's out, and it's one of the original bulbs...but the other one is till working in the VU, so it's OK, it's still lit up.

I like have the VU meter lights...because from a distance, it's easier to see the needles. When you have external room lights only, they tend to reflect off the plexi glass covering the meters, so they don't really help. With the VU meter lights, the visibility of the needles is much better close up and far away.
 
sweetbeats Thank you so much! I believe this is the supplier I will be going with. I plan on ordering enough to totally replace the lamps as well as have some extras for the future and these guys seem to have the best deal.
 
ecc83 said:
OT but a bit moot? In valve guitar amps we replace nominal 6V (6.3) lamps with 8V even 12V types and they never fail again. I see 8V types in Beat's link.

I suppose suggesting 3mm white LEDs would be beyond the pale?

Dave.
Click to expand...

Thanks so much. That makes sense. I will definitely get 8V lamps.
 
miroslav said:
To the OP...
I looked for the info on where I got the bulbs...sorry, couldn't find anything other than some of the spare bulbs I still had...but I just remember it was from a supplier in Canada, and the reason I got them from him was that he was offering a great price on bulk buy (I wish a bought twice what I did).
Otherwise, if you search for axial bulbs with the right voltage, size...you should be able to find them.
Try eBay...I saw some on there that look about right.

I also see that you posted in Gearslutz, and that Jim Williams suggested the LED route...which is OK, and I know some folks that did that. I mean, if like ALL the bulbs were out, you might consider that, since you will have a lot of work anyway to replace the bulbs.
With my MX-80, I had maybe only about a dozen out (there's two per VU)...so I wasn't eager to remove all the working bulbs too, just to go the LED route.
Also, I don't run the deck 24/7...so the spares I have left will hold me for a long time, and I'll wait until there's a bunch out before I replace them again. I'm certainly not going to do it every time one goes out. I think right now I have one that's out, and it's one of the original bulbs...but the other one is till working in the VU, so it's OK, it's still lit up.

I like have the VU meter lights...because from a distance, it's easier to see the needles. When you have external room lights only, they tend to reflect off the plexi glass covering the meters, so they don't really help. With the VU meter lights, the visibility of the needles is much better close up and far away.
Click to expand...

Thank you so much for looking and for all your advice! The majority of the lamps are out, so I plan on ordering enough to just replace all of them. I can certainly appreciate why some would replace with LED's but I think I would like to just keep it stock and restore rather than modify anything.

The machine did come with the original operation/service manual, of which I was very glad, however are there any other manuals/guides you would recommend?

Thanks again and I really appreciate everyone's help!
 
Jason Graham said:
The machine did come with the original operation/service manual, of which I was very glad, however are there any other manuals/guides you would recommend?
Click to expand...

Are you planning to synchronize it with other gear or just run it standalone?
Synchronization brings its own set of challenges, and each external sync box setup will have it's requirements and the cables needed.
You can find a lot of that info here, on this forum...a few of us have pooled a lot of that documentation into a sort of quasi database.

Otherwise, here's a few links...you can compare to what you already have and download as needed.


MX-80 Complete Manual.pdf


Otari MX-80 Aligment_.pdf
 
miroslav said:
Are you planning to synchronize it with other gear or just run it standalone?
Synchronization brings its own set of challenges, and each external sync box setup will have it's requirements and the cables needed.
You can find a lot of that info here, on this forum...a few of us have pooled a lot of that documentation into a sort of quasi database.
Click to expand...

Thank you for the resources!

I think, initially anyway, I will use the machine standalone as, though I am not new to recording, I am very new to tape and want to make sure the machine is gone through, has everything up to snuff, is calibrated, and learn as much as I can about it.

I realize there is some test equipment required and am putting together a list as I learn, but have a Tektronix 2235 oscilloscope and frequency counter on the way. Looking at test oscillators and VTVM's as well if anyone has any suggestions for those or any other gear that would be good to look for? I'm also slowly but surely starting to understand fluxivity. Currently figuring out what MRL would suit me best recording 15ips on RTR SM911 tape. I believe it is +6 tape however I'm having a little trouble understanding how I should reconcile the nWb/m spec of the tape I will record on with the selection of fluxivity of the MRL and the setting on the machine.

Finally, to fully answer your question, yes I ultimately wish to be able to sync the machine to my DAW however, outside of knowing that a sync box must be used and a track on the tape will be striped with SMPTE code I'm not sure how to do this?

I am currently running Logic Pro X on an iMac with a UAD Apollo 8 Quad interface and the added satellite box. So I have 8 channels. My Otari is a 32 track however, once everything is done, I will most likely end up using the 24 track head that came with it for the added track width. Would this be possible with my current setup and the addition of a sync box of some sort?

Thanks so much to everyone for all your help! I REALLY appreciate it!!
 
SM911 is compatible with Ampex 456, which is probably what the machine was designed around. I calibrated the machine against a G320 test tape. (G320 standard was supposed to be 320 nWb/m but owing to a screw-up it was later found to be something more like 280 nWb/m. The name stuck.)
On the front of the machine you can select between two bias standards, 'A' and 'B'. I -think- A is some sort of preset for 456-compatible tapes, but because I'm running 499-compatible tape I just stuck it on 'B' and did a full calibration.

As you may be aware, the speeds are configurable between 7.5/15 and 15/30. Mine had been set to 15/30, but I changed it back to 7.5/15 since 30ips is stupidly expensive to run, and running the tape slow allows for precision editing when erasing unwanted sounds (e.g. coughs or footsteps away from the microphone). IIRC this is controlled by a jumper on the CPU board at the back of the machine. If you change the setting, it generally means that you'll need to recalibrate.

The other thing to keep in mind with these machines is that by default they ship with the XLR wired pin 3 hot. Most balanced systems are pin 2 hot, which means that you may need some kind of adaptor. I was lucky with mine - a previous owner had rewired it, and written "Not anymore!" in the manual by the pinout diagram. If you set the machine up and get no signal, this may be the reason.

As for sync, one of the machines has to be master, and the second machine chases it. If you want the DAW to chase, any old MTC sync box will do, e.g. a Cooper or Phil Rees. You might not even -need- a sync box if the DAW is able to process and generate timecode data in realtime. Some of them can do this.
If you want the MX80 to chase, you'll need something more expensive and complex like a TimeLine microLynx plus a suitable control cable to connect the synchronizer to the deck. I've not tried this myself, I have a Tascam deck chasing the MX80 since I already had a synchronizer capable of driving the TASCAM.

EDIT: If you ever need to calibrate the cards, get ceramic screwdrivers. I had to change the input level on all the audio cards, but used a metal screwdriver. As a result I managed to blow the peak indicator on one of the channel cards when my hand slipped. Use a nonconductive tool!
 
Jason Graham said:
I can certainly appreciate why some would replace with LED's but I think I would like to just keep it stock and restore rather than modify anything.
Click to expand...

Yeah...I feel the same way. While LEDs are more trouble free...I too prefer to keep mine stock, and TBH, every time I see someone who rewired their tape deck or console VU meters for LEDs instead of the incandescent lamps...I never much like the look. Yeah, you can find LEDs that sorta simulate that incandescent glow, but not really. There is always something stark looking about them...especially when some folks opt for the blue-light or that bright-white look.

Also...I'm not sure you want to go with 8V lamps...because I think they will simply glow less bright since there is only 6V feeding them. They will last a long time, so it's not like you'll be changing burned out lamps every couple of weeks. I went with what the specs called for, 6V.

When you do find your final supplier...post back where you got them. So we have a record for the next guy who needs some. :)

Jason Graham said:
I am currently running Logic Pro X on an iMac with a UAD Apollo 8 Quad interface and the added satellite box. So I have 8 channels. My Otari is a 32 track however, once everything is done, I will most likely end up using the 24 track head that came with it for the added track width. Would this be possible with my current setup and the addition of a sync box of some sort?
Click to expand...

Yeah, with your 8-channel setup, you will want a way to sync to the DAW for sure, since you can only transfer 8 tracks at a time from tape to DAW. I've got full 32 channel converter capability...but I still like using a synchronizer with the deck. It lets me have a solid time reference on both deck and DAW, and when moving things back-n-forth, everything is locked.
I actually run a master clock & "house sync" generator box, that feeds my Timeline sync box with a video sync and also my DAW converters with Word clock. The Timeline then feeds the tape deck and has full transport control of it via proper cable, and it's also tied to the DAW, which is the Master for timeline control and it sends MIDI MTC to the Timeline.
It's a bit involved, and if you get to that stage and want more specific details of my setup, I can provide them...but it's a full, bidirectional sync solution, though I always run it with DAW as the Master, and the deck chase/locks to it (well to the whole sync rig)...that way the DAW never has to chase if it was the other way around, which can cause more issues than the when the tape deck is Slave and chases.
Sometimes it feels a bit sloppy because the tape deck is a mechanical device and needs time to wind up/down...while a DAW is instant...but once you get the gist of it, and know how to properly stripe the tape, and pre-roll when working...then it's just a matter of giving the deck the time it needs to spin up and lock, which is usually 3-5 seconds when things are right.

Anyway...start small...get the deck in proper shape. Don't waste your time recording until you've overhauled it and done as full an alignment and calibration as you can...and then after that you'll be good to go for a long time. The MX-80 decks are workhorses, and they don't "drift" out of spec too easily, unless the machine is pretty worn to begin with.
Clean all your contact points...I mean, everything inside and out that you feel comfortable doing. I pulled every PCB every connector on my deck and de-oxidized & treated each connection point. Yeah...it will take you a few days of work to do all that, plus any repairs or like the VU lamp replacements...but well worth it.

Oh...and yeah, the XLR Pin 3 hot thing you can either change oh the actual machine, or do it on the cable snake at either end. In my case, since the channel snake went to a patchbay, when I soldered the patchbay ends I ran the Pin 3 wire to the Tip connection in the patchbay..which was much easier then flipping them internally in the deck.
 
[MENTION=94267]miroslav[/MENTION] all the Teac lamps are 8V powered by either 6V AC or 5V DC power. I think the correct amperage rating is 100mA...that’s what gives the correct illumination.
 
jpmorris said:
SM911 is compatible with Ampex 456, which is probably what the machine was designed around. I calibrated the machine against a G320 test tape. (G320 standard was supposed to be 320 nWb/m but owing to a screw-up it was later found to be something more like 280 nWb/m. The name stuck.)
On the front of the machine you can select between two bias standards, 'A' and 'B'. I -think- A is some sort of preset for 456-compatible tapes, but because I'm running 499-compatible tape I just stuck it on 'B' and did a full calibration.

As you may be aware, the speeds are configurable between 7.5/15 and 15/30. Mine had been set to 15/30, but I changed it back to 7.5/15 since 30ips is stupidly expensive to run, and running the tape slow allows for precision editing when erasing unwanted sounds (e.g. coughs or footsteps away from the microphone). IIRC this is controlled by a jumper on the CPU board at the back of the machine. If you change the setting, it generally means that you'll need to recalibrate.

The other thing to keep in mind with these machines is that by default they ship with the XLR wired pin 3 hot. Most balanced systems are pin 2 hot, which means that you may need some kind of adaptor. I was lucky with mine - a previous owner had rewired it, and written "Not anymore!" in the manual by the pinout diagram. If you set the machine up and get no signal, this may be the reason.

As for sync, one of the machines has to be master, and the second machine chases it. If you want the DAW to chase, any old MTC sync box will do, e.g. a Cooper or Phil Rees. You might not even -need- a sync box if the DAW is able to process and generate timecode data in realtime. Some of them can do this.
If you want the MX80 to chase, you'll need something more expensive and complex like a TimeLine microLynx plus a suitable control cable to connect the synchronizer to the deck. I've not tried this myself, I have a Tascam deck chasing the MX80 since I already had a synchronizer capable of driving the TASCAM.

EDIT: If you ever need to calibrate the cards, get ceramic screwdrivers. I had to change the input level on all the audio cards, but used a metal screwdriver. As a result I managed to blow the peak indicator on one of the channel cards when my hand slipped. Use a nonconductive tool!
Click to expand...


Thanks so much for your explanation! I'm starting to get it, I believe. As for the REF FLUX switch on the machine itself I did just read in the manual H is for high fluxivity which corresponds to 320 nWb/m while L is for low fluxivity which corresponds to 250 nWb/m.

I definitely plan on running at 15ips for the exact reason you stated. I realize 30ips is twice the tape which would get expensive in a hurry.

I do know the outputs are confirmed balanced by the manual and had heard of the deal with pin 3 being the hot, however haven't gotten to checking my machine yet to see. I did receive an input and an output snake for all 32 channels. Will be checking the pin out on that as well. Would be awesome if the machine is stock and the snake is already re-wired for that machine.

Starting to understand synchronization as well. I realize now it certainly appears best to make the DAW the master with the Otari being the slave. Have read that if the tape machine is the slave the inevitable variations in speed can cause nightmares with jitter etc. What do you guys think of the Adams Smith Zeta Three box? I have seen that model pop up repeatedly in my searches on the topic?

Also, thanks so much for the suggestion on ceramic screwdrivers!! That makes total sense and I'm sure you just saved me from going through the same trouble as I doubt I would have thought of that!
 
miroslav said:
Anyway...start small...get the deck in proper shape. Don't waste your time recording until you've overhauled it and done as full an alignment and calibration as you can...and then after that you'll be good to go for a long time. The MX-80 decks are workhorses, and they don't "drift" out of spec too easily, unless the machine is pretty worn to begin with.
Clean all your contact points...I mean, everything inside and out that you feel comfortable doing. I pulled every PCB every connector on my deck and de-oxidized & treated each connection point. Yeah...it will take you a few days of work to do all that, plus any repairs or like the VU lamp replacements...but well worth it.
Click to expand...

That's the plan for sure. I really want to totally go through the deck and learn as much as possible/make sure its as perfect as I can make it before any kind of recording. Totally worth the time and knowledge gained in my opinion. Really appreciate your tips on synchronization as well. I won't be doing that for awhile I know however I, of course, cannot resist the temptation to learn it now. Its definitely making more sense. As I'd posted in response to jpmorris, do you have any thoughts on the Adams Smith Zeta Three? I've seen it pop up a lot. Is this unit out dated or would this be a good choice to look out for when the time comes?
 
Also, I do have an analog live mixer; a Mackie 24 channel 2404 VLZ3. I know this is a live sound not a recording mixer but I am ultimately planning to use the 24 track head that came with the machine and am wondering about the possibility of recording all tracks to tape, then out of the Otari into the mixer, then mixing down to stereo and out into the interface/into my DAW; sort of replacing a traditional 2 track mix down deck with the DAW?
 
Jason Graham said:
Also, I do have an analog live mixer; a Mackie 24 channel 2404 VLZ3. I know this is a live sound not a recording mixer but I am ultimately planning to use the 24 track head that came with the machine and am wondering about the possibility of recording all tracks to tape, then out of the Otari into the mixer, then mixing down to stereo and out into the interface/into my DAW; sort of replacing a traditional 2 track mix down deck with the DAW?
Click to expand...

This is one way to do it for sure. Your master recorder could be a halftrack open-reel machine, a DAT deck, your DAW, a stand-alone solid state recorder, a cassette deck, your neighbor’s dictaphone.
 
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