Otari MRL and Multimeter

[thereelman77]

OK. I understand what you are both saying. My general policy though is to master to tape, then transfer that to digital. That way it's "pure analog". To me, if I'm cutting an entire album on 8 track, mine as well keep it pure analog. But I agree with what you said, I would much rather bounce to digital than an uncalibrated tape deck. But with the need to start bouncing I'm kind of in the race for getting the proper tools.
Basically though, as long as the multimeter can read to a range up to ____kHz, I should be fine?

 

[miroslav]

Not to go off in another direction....but with the 8-track....why not just bounce to digital...????
Heck, I've done that with a 16-track tape deck...and now I'm tracking to a 2" 24-track, and still bouncing to a DAW for edits and comping.
Yes, I will then mix back out from the DAW through a console and all analog processing, but if I didn't have that option, I would be OK with just finishing the mix in the DAW.
You still get the benefit of tracking to analog but without the mess of bouncing down tape-to-tape tracks which IMHO will degrade the sound much more than transferring to a DAW.
When you get your 2-track calibrated, you can mix back out of the DAW to the 2-track if it will make you feel better about sending a tape to the vinyl house instead of digital files...and this way you can keep tracking instead of waiting to calibrate the 2-track.

 

[thereelman77]

Well, here's the way it breaks down: I can't do any more tracking since the lead artist is away for a few weeks. I can do some bounce mixes, but I would prefer for him to be their. Plus, several of the other tracks need more overdubs before they can be bounced. And the single we're planning on cutting on 7" will not need a bounce reduction, just a master to the 2 track directly. So I figured in the time that I can't do anything I should really try and calibrate the deck before the time comes for it's use. I suppose I can just do bounces in the computer, but I'm not fully their yet, a few tracks yes, but I want to wait for the lead artist to be in the studio. I still need to find a mutlimeter that will read what I need and I'm planning, for now, to use an oscilloscope in the computer...One toy I really don't have money for.

 

[thereelman77]

Well, basically, can you guys tell me what to look for in the manuals so I know if I'm getting a multimeter that's accurate?

I found this guy: http://www.extech.com/instruments/resources/manuals/EX430_UM.pdf and it is saying 400 Hz to 1kHz, so I'm assuming that I'm looking at the right thing and that I want it to be accurate up to 20kHz or more (so it would say 400 Hz to 20kHz)?? I don't know if I'm right on that one.

 

[miroslav]

This is the one I have....if you don't buy it, I will just to have a spare.

Radio Shack 46 Range Digital Multimeter PC Interface 22 812 | eBay

 

[thereelman77]

Hi all, sorry to bring up an old post. Long story short, I got the Radio shack 46 range multimeter and in the meantime have had to bounce my 8 track reduction mixes to my DAW. I am currently trying to calibrate my 2 track and ran into some issues. I am currently reading other forums and have a manual in front of me, but I can't seem to understand something: I have the multimeter set up using an XLR from the line out (with red tip on pin 3 and black tip on pin 2). The issue I am having is that when I get to 1.23v my meters are pegged out to +2 or so...This shows when both using the MRL and when I'm running my tone generator into the channels. I can't seem to lower the VUs without lowering my voltage output. Perhaps I did something wrong or I missed something?

 

[miroslav]

Glad you got the meter thing finally sorted out.
I actually picked up a second RS meter today on eBay for $25 shipped.... it's the same as the model I already have, and the guy said it was barley used if not new, so now I have a spare and I can just leave one out for regular use, and the other in the box for backup.

OK...so what section/page of the alignment procedures are you at...?
There's a specific step by step process...and I get the feeling you're not following it, or you're getting mixed up as to when you are monitoring the input source and adjusting VS playback of tape source....etc.
There are individual adjustments for everything, but should be done in sequence.

 

[thereelman77]

I'm on the MRL alignment section (Page 12 of the pdf, page 10 of the scanned pages of the Otari manual). I was reading last night that the manual is somewhat out of order and that I need to set my line level/meter level before MRL adjustment....Not sure what was meant by that.

 

[miroslav]

Initally...you want to focus on the levels you are applying at the input...and the levels you are getting at the output.

Calibrating the meters comes after you have the proper input/output levels set using the proper steps in the proper sequence of the manual.

It's quite possible that the meters were adjusted for some other levels before...and now when you send +4dBm....they are pegging.
You can for the time being simply lower the signal going to the meters via their pots....and ignore them.
Look at the scope where the manual calls for it, and look at your DVM where the manual calls for it....not the VU meters. Then, when the step for adjusting the meters comes up...you will have already calibrated the I/O levels and the deck's amps....so then adfter that, your meter is set to "0" for that reference level (which in your case is +4 dBm).

Again...the proper sequence is correct in the Otari Alignment Procedures PDF that I gave you a link to early in this thread.
The pages are all in order and you should just follow each step as described. If you skip around or change values...then it's like a domino effect, and all the adjustments that follow will be wrong and referenced incorrectly.

 

[thereelman77]

Alright, I understand what you are saying miroslav. I have followed the manual accordingly. Basically it's to just set the levels in and out using the DVM vs. the meters... I getcha.

However, now I can't seem to get the HF EQ up to +4dBm, what the manual calls for. Both channels only go up to just below 0dB (according to my DVM). So perhaps my azimuth may need to be adjusted. Last time I checked it though it was OK, not a perfect 45 angle, but near perfect. So I am going to go thru everything again and see if I can get it their. But I was able to adjust the 1k test tone to +4dBm/1.23v. Strange how the 10k frequency won't even register above 0dB....

 

[miroslav]

Check which global EQ curve you have chosen for the deck with its EQ switches, realtive to what you have on the test tape.

 

[thereelman77]

EQ switch is set to NAB and tape is NAB.... Should I have gotten IEC? It is a two speed test tape with 1k and 10k tones.

 

[miroslav]

It's your choice.
I did my 5050 NAB.

 

[thereelman77]

OK, so I haven't had much of a change with the Otari. But Im still trying a few things. Now, not to side track, but I was testing the meter out on my Teac 80-8 and was able to calibrate MRL levels accordingly to the manual specs (-10db). But, surprisingly, the issue I'm having now, is that I don't know how to set the EQ level using the 16khz tone. According to the Teac manual, use the 16khz tone from MRL and set VU level to -10. 1st off, seems kinda low, but 2ndly I can't get all the meters to go below -7db. So this is leading me to think that I may be reading my multimeter incorrectly. I was using the voltage mode, but am now using the db scale instead, reading off my meter. Am I missing something for both decks and following the teac manual, does -10db sound right for that 16khz freq?

 

[thereelman77]

Any thoughts?

I think that perhaps I am misunderstanding the MRL alignment procedures. It says to adjust HF EQ to +4db, but the pot will not let me go above 0db, and also, I only have 1 EQ pot on my deck, not hi and low frequency ones. So perhaps maybe I am supposed to set the frequency to -3dB? Maybe I'm completely off, but I came up with -3db since the tape I'm setting it up for is +6 SMG tape?

I really don't know where to go at this point.

 

[miroslav]

Are you maybe mixing up dB VU and dBm...?

Also....I'm lost as to which deck you are now calibrating...the Otari or the Teac...?...and each one may have a "slightly" different set of steps, and each may be using different reference levels, etc.

When in doubt....stop....forget everything you've already done, and then go back to the beginning, and follow the manual.
Sometimes it takes one missed step or a single misunderstanding of the insturctions, and then after that it's all wrong.

 

[thereelman77]

No. I figured out the difference between dB VU and dBm after I got the meter.

I am trying to calibrate both decks, but I am trying to get the Otari done 1st. I took a break from the Otari to just try the meter on the Teac deck.

Pretty much, the difference between the decks, is that I'm calibrating the Otari for +4 and the Teac to -10db level.

I guess I am going to have to go thru the manuals again, like you suggested. I will see if I missed anything. The only thing I can think of is that I may have hi frequency loss or something on the heads.

 

[thereelman77]

I think the issue is that the manuals I have, aren't agreeing with each other. The otari pdf doesn't match my specific model. I can't find certain pots to adjust that the pdf states (the peak pot for example). Also, the physical manual that came with my unit specifies different settings for playback and record calibration, namely the output/record H, M, L settings. The Otari pdf says to set to High output for 15ips, while according to my physical manual, it states to set it to M for 250nWb tape (which explains why I was peaking earlier, since high is 320nWb tape). Also the input/record calibration is vastly different between the two manuals: The pdf is pretty straightforward, but my paper manual has me setting the tape to 7.5 ips, using the test osc button, then biasing, then setting the input at 7.5, then setting the EQ at 15ips or 7.5ips.

I think this explains why the EQ playback will not go back to +4dbVM.

I don't know what I need to follow; I can't match everything the pdf procedures require and my physical manual I just feel is completely wrong. But I am going to have to stick with the pdf, since I can't find something specifically related to the B2-HD.

 

[miroslav]

Well....I have the BII manual, which is the PDF...and I have my hardcopy that came with my deck, which is a BIII.

Now, there are some very minor differences between the two manuals, but nothing weird.

I have no idea what makes the HD version different or in what way....????
The HD is older than the BII/2 or the BIII that I have, which was the last one Otari ever made. So maybe they made substantial changes between the BII/HD and the BII/2, and you need to find an HD-specifc manual.

Try here: http://www.analogrules.com/manuals/otari_manuals1.html

 

[thereelman77]

Bringing an old thread to life again, sorry that it has been some time. I work landscaping and it picked up a lot over the last month and has calmed down somewhat.

I meant to pick up where miroslav had asked me about the correct MRL procedures....I double-checked my azimuth weeks ago on my deck and found out that the alignment of the heads was WAY out of whack. With work and my vacation though I covered up the deck and put it on the shelf.

So, before I had left, I tried to do an Azimuth adjustment calibration for the Otari, I began to adjust it, but after several attempts, realized that I was getting nowhere. For some reason I could not get the oscilloscope to show me a straight line from left to right going up.
The closest I could get were the two pictures below:



The line would never want to adjust to the correct spot, no matter which way I adjusted the screws. Any suggestions on what to do at this point? That is the only thing holding me back now.