MS16 Calabration

  • Thread starter Thread starter ron-e-g
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one more thing. did you calibrated playback levels in repro and sync with just the meter connected ? or also the XLRs? the repro levels have to be adjusted only with the meter connected, nothing else, if you had the XLR outputs connected, you may have loaded the circuit and the whole procedure needs to be done again.
 
fgonza2

I have some inconsistencies in this step. I have pulled the XLR's. But track one does not register when in record mode. Could I have improperly adj. a prior setting?

Sidebar, I had some tags missing from the D-sub to XLR cables when I got them from the previous owner. I plugged in the ones that were still labeled as marked. My thoughts at the time were, I would sort it out later. But as time went by it seemed all were correct. As the buss returns seemed to respond to the correct track. I know, probability of that...not good! That has always bugged me. Just now while unplugging them I noticed two that had a different number on the cable than the connection.

Any thoughts on this?
 
Sorry.... I just noticed your previous post. I did have the XLR cables connected. I will repeat the process. Then report back. It will be good practice! :thumbs up:
 
Hello. Just to be sure. In section 7-6-5 Reproduce cal. should I be setting all the tracks to the 1K tone on the cal. tape?

Thanks,
Ron
 
I did. Now the freq. response. I don't have a 16 kHz tone on my tape. So I should use the 1kHz and 100Hz? The 10kHz tone sends the meters all over the board. The 1kHz and 100Hz are close.
 
The manual seems to be only concerned with the difference between the high and low. So I'm thinking I'm good. The #202 REPRO eq. pot does not have much
(if any) effect on the 10kHz tone.

Does this make sense? I guess I'm hoping the 10 kHz frequency is not a big deal. Is that the case?
 
ok, here's a summary:

1. Play the calibration tape at 1Khz

2. Put it in repro mode

3. With nothing else connected other than the RMS meter to the output (leader lmv-181), adjust the level with R204 until you get to 0dB in the VU meter, and -10 on the green scale of your RMS meter.

4. Put it in sync mode, play the calibration tape @ 1Khz. Repeat #3, this time with R205 adjust the level properly.

With 1-4 done, then:

5. Play the 10Khz tone in repro mode. Use R202 to adjust the level @ 10Khz, it should be again 0db on the VU meter and -10 on the RMS meter (green scale), knob set to "1"

6. Repeat #5, this time in sync mode and use R201 for the adjustments

If for some reason there is a mismatch between the VU meter and the RMS meter (0db on the VU = -10 on the RMS meter), it means that your meter levels are not adjusted properly.

Yes it is CRITICAL that 10Khz level is the same as 1Khz. Otherwise your recordings will be dull in the high frequencies. Based on your pictures the heads are in pretty good shape, so if this is not possible, there maybe something else going on in the machine, and we'll have to change the approach. But based on your previous comments, this should be achievable. Unless the calibration tape is in bad shape, that is an option as well.
 
OK, completed 1-4 all went well. Completed 5-6. the thing is the 10kHz tone gives this recorder problems.

REPRO mode; 10 kHz, track 1 very low register on both VU and RMS meter. Others good.

SYNC mode; No way is R201 going to give a -10 or 0db on the meters at 10 kHz. With the R201 pots backed off completely I get a pretty consistent -7 on the RMS meter and -3db on the meters.

You know fgonza2, I should maybe mention here this recorder is a factory modified to run at 30ips. I don't know if that makes a difference.
 
No. only adj. tape travel as per manual. De-magnetized and cleaned the heads.
 
ok, some questions:

1. Do you see the same behavior on all channels ? (on SYNC)

2. What is your calibration tape ? 355 nwb/m ? is it a new tape ? what is the condition ? where did it came from ?

The 30 ips mod has no impact. It should work fine. Try the following:

1. Find a channel on either SYNC or REPRO that gives you a good reading, if any.

2. Turn off the recorder and swap the card of that channel with another one that is not working well.

3. Test again and see if the behavior follows the card that you swapped (in the new channel)

Report back, if the behavior is the same or not. If the new channel is now good, it means it is electronics adjustment, if it's not good and the problems are identical regardless if you swap the channel cards or not, it means you have a mechanical issue (head not aligned properly)

report back with findings
 
fgonza2 said:
ok, some questions:

1. Do you see the same behavior on all channels ? (on SYNC)

2. What is your calibration tape ? 355 nwb/m ? is it a new tape ? what is the condition ? where did it came from ?

The 30 ips mod has no impact. It should work fine. Try the following:

1. Find a channel on either SYNC or REPRO that gives you a good reading, if any.

2. Turn off the recorder and swap the card of that channel with another one that is not working well.

3. Test again and see if the behavior follows the card that you swapped (in the new channel)

Report back, if the behavior is the same or not. If the new channel is now good, it means it is electronics adjustment, if it's not good and the problems are identical regardless if you swap the channel cards or not, it means you have a mechanical issue (head not aligned properly)

report back with findings
Click to expand...

In SYNC mode all the tracks Except 1 adj. down to a -7 on the RMS meter. This was fairly constant with the R201 turned fully counter clockwise. At this setting the Recorders VU all read a pretty constant -3 db.

The MRL tape is 30 ips three frequency all at 0db, AES (IEC2) Equalization 1kHz, 10kHz, and 100Hz. 355 nWb/m.

It came with the recorder. Condition is good (I guess) It came in it's original shipping box w/previous owners address labeled on it. I don't know it's age.

As to finding a good channel..they all react the same in sync at 10kHz.
 
More questions:

So in SYNC mode:

1. At 1khz do ALL channels read 0db on the VU and -10 on the RMS meter ? (make sure the knob is in "1")

2. When the tape gets to the 10Khz section you get -3db on all with no changes on the RMS meter scale ? confirm

3. Have you demagnetized the heads ?
 
Sync mode at 10kHz only- all tracks only adj. down to -7 on RMS meter. And, that equals a -3db on the recorders meters. All tracks had to have pot 201 turned completely counter clockwise to achieve this closest setting to the target of -10 on the RMS meter. At 100Hz and 1kHz all meters are within specs. Meaning adj. to -10 on the RMS meter and 0db on the meter.

However, Track 1 inRepro mode will take the input and meter adj. fine in the 1kHz and 100Hz but not the 10kHz. It will not adj. to -10 and 0db. I didn't actually log the results. But it is considerably lower maybe 10db..guessing!

All this, is with the RMS meter knob in position "1". (That is, one notch to the right of center There are two # 1's).

So my answer is;
Yes to #1
No to #2 the meters on the recorder go to -3db. The RMS meter goes to -7
Yes to #3
 
This is 1kHz first REPRO then SYNC SANY0359.webpSANY0360.webp

This is 10kHz REPRO then SYNC SANY0361.webpSANY0362.webp

This is 100Hz REPRO then SYNC SANY0363.webpSANY0364.webp
 
turn off DBX on all channels. That is the problem !. Your calibration tape and all calibration procedures must be done with DBX OFF on all channels. So turn off DBX and recalibrate levels again for 1Khz first on repro and sync mode. Then move to 10k and report back.
 
no, those should be fine as they don't involve tape related activities.
 
Yea that's what I thought.
Thanks fgonza2. I will begin the calibration tomorrow. I have the bypass jumpers for the DBX better just to use them and completely bypass the DBX you think?
Or just switching all the tracks off just as good?
 
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