Home |
Search |
Today's Posts |
#1
![]() |
|||
|
|||
![]()
Hi,
I had troubles trying to do the alignment on a MTR90 II. I started with the playback alignment playing the 1khz signal on the MRL tape and tweaking the repro gain pot 'till the meters read 0 Vu (The reference fluxivity of my MRL is 355 nW and I was going for a +6 alignment). No problems here! The problem started with Bias calibration: I loaded a blank tape and recorded a 10 khz signal (from the console oscillator), with the remote set to REPRO and started turning the bias pot just to discover that the needle on the meter goes all the way to right (past +3) before reaching the point of going back. Is it normal behaviour? Then I went to do REC gain! Again recording a 1khz tone with the remote set to REPRO, all tracks armed, and the needle (on all 24 meters) don't go past -20, no matter how much I turn the REC gain pot. The tone was recorded and reproduced, but obviously very low. Looking at the meters on the console set to read BUSS OUT I could see the tone at 0 Vu. Switching the console meters to read the signal coming back from the recorder showed a very weak signal. The funny thing is that when I change de console oscillator to 10khz, the OTARI needles go midway and then its easy to get to 0 Vu with a little tweak in the REC gain pot. As you probably noticed I'm not an expert in alignment! I'd appreciate some advice (and yes, I've read the FAQ!). Thanks, J.P. |
#2
![]() |
|||
|
|||
![]()
J.P. Ambrogi wrote:
The problem started with Bias calibration: I loaded a blank tape and recorded a 10 khz signal (from the console oscillator), with the remote set to REPRO and started turning the bias pot just to discover that the needle on the meter goes all the way to right (past +3) before reaching the point of going back. Is it normal behaviour? Then I went to do REC gain! Again recording a 1khz tone with the remote set to REPRO, all tracks armed, and the needle (on all 24 meters) don't go past -20, no matter how much I turn the REC gain pot. Your problem, as you state, starts with the bias adjustment. If your meters are pinning before you get a peak reading, back off the input level of the 10kHz tone. It does not need to read 0vu for the bias adjustment. Try sending the 10kHz tone to the machine -3vu and see if you can get a peak then. If not, back it off further. Once you have the bias set properly, I'll bet your record gain alignment will work fine. It sounds like you aren't biasing the tape enough to get it to actually record a healthy level. -- Eric Practice Your Mixing Skills Multi-Track Masters on CD-ROM www.Raw-Tracks.com |
#3
![]() |
|||
|
|||
![]()
J.P. Ambrogi wrote:
The problem started with Bias calibration: I loaded a blank tape and recorded a 10 khz signal (from the console oscillator), with the remote set to REPRO and started turning the bias pot just to discover that the needle on the meter goes all the way to right (past +3) before reaching the point of going back. Is it normal behaviour? Then I went to do REC gain! Again recording a 1khz tone with the remote set to REPRO, all tracks armed, and the needle (on all 24 meters) don't go past -20, no matter how much I turn the REC gain pot. Your problem, as you state, starts with the bias adjustment. If your meters are pinning before you get a peak reading, back off the input level of the 10kHz tone. It does not need to read 0vu for the bias adjustment. Try sending the 10kHz tone to the machine -3vu and see if you can get a peak then. If not, back it off further. Once you have the bias set properly, I'll bet your record gain alignment will work fine. It sounds like you aren't biasing the tape enough to get it to actually record a healthy level. -- Eric Practice Your Mixing Skills Multi-Track Masters on CD-ROM www.Raw-Tracks.com |
#4
![]() |
|||
|
|||
![]()
Even before aligning playback alignment, on many machines you need to
calibrate the VU meters. Run tone through the machine in Source mode, measure the output level, set the level on the tone generator so the output is nominal level (+4dBu on many or most machines) and set the meter cal so that it reads 0 VU. I said "many machines"; it's been years since I worked on an Otari, and never an MTR90, so I may be talking nonsense; this may be one of those machines where you set the meter cal AFTER everything else. Worth checking, though. Peace, Paul |
#5
![]() |
|||
|
|||
![]()
Even before aligning playback alignment, on many machines you need to
calibrate the VU meters. Run tone through the machine in Source mode, measure the output level, set the level on the tone generator so the output is nominal level (+4dBu on many or most machines) and set the meter cal so that it reads 0 VU. I said "many machines"; it's been years since I worked on an Otari, and never an MTR90, so I may be talking nonsense; this may be one of those machines where you set the meter cal AFTER everything else. Worth checking, though. Peace, Paul |
#6
![]() |
|||
|
|||
![]()
J.P. Ambrogi wrote:
I started with the playback alignment playing the 1khz signal on the MRL tape and tweaking the repro gain pot 'till the meters read 0 Vu (The reference fluxivity of my MRL is 355 nW and I was going for a +6 alignment). No problems here! Umm... did you do the azimuth first? You need to make sure the azimuth is correct before setting the repro gain and the repro EQ. The problem started with Bias calibration: I loaded a blank tape and recorded a 10 khz signal (from the console oscillator), with the remote set to REPRO and started turning the bias pot just to discover that the needle on the meter goes all the way to right (past +3) before reaching the point of going back. Is it normal behaviour? It is if you are feeding too hot a signal into it. Turn the level on the oscillator down... all you need is to find the peak, so it does not matter what the actual level on the oscillator is as long as you can find the peak with it. Then I went to do REC gain! Again recording a 1khz tone with the remote set to REPRO, all tracks armed, and the needle (on all 24 meters) don't go past -20, no matter how much I turn the REC gain pot. The tone was recorded and reproduced, but obviously very low. Looking at the meters on the console set to read BUSS OUT I could see the tone at 0 Vu. Switching the console meters to read the signal coming back from the recorder showed a very weak signal. The funny thing is that when I change de console oscillator to 10khz, the OTARI needles go midway and then its easy to get to 0 Vu with a little tweak in the REC gain pot. If your bias is set wrong, trying to set gain is not going to work. If your azimuth is set wrong, setting gain or EQ is futile. Go back and get the azimuth and bias points right. If before when you were setting the bias, the levels off-tape were too high, and when you are trying to set the record levels, the levels off-tape are too low, almost certainly you did something wrong in the process of setting the bias. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#7
![]() |
|||
|
|||
![]()
J.P. Ambrogi wrote:
I started with the playback alignment playing the 1khz signal on the MRL tape and tweaking the repro gain pot 'till the meters read 0 Vu (The reference fluxivity of my MRL is 355 nW and I was going for a +6 alignment). No problems here! Umm... did you do the azimuth first? You need to make sure the azimuth is correct before setting the repro gain and the repro EQ. The problem started with Bias calibration: I loaded a blank tape and recorded a 10 khz signal (from the console oscillator), with the remote set to REPRO and started turning the bias pot just to discover that the needle on the meter goes all the way to right (past +3) before reaching the point of going back. Is it normal behaviour? It is if you are feeding too hot a signal into it. Turn the level on the oscillator down... all you need is to find the peak, so it does not matter what the actual level on the oscillator is as long as you can find the peak with it. Then I went to do REC gain! Again recording a 1khz tone with the remote set to REPRO, all tracks armed, and the needle (on all 24 meters) don't go past -20, no matter how much I turn the REC gain pot. The tone was recorded and reproduced, but obviously very low. Looking at the meters on the console set to read BUSS OUT I could see the tone at 0 Vu. Switching the console meters to read the signal coming back from the recorder showed a very weak signal. The funny thing is that when I change de console oscillator to 10khz, the OTARI needles go midway and then its easy to get to 0 Vu with a little tweak in the REC gain pot. If your bias is set wrong, trying to set gain is not going to work. If your azimuth is set wrong, setting gain or EQ is futile. Go back and get the azimuth and bias points right. If before when you were setting the bias, the levels off-tape were too high, and when you are trying to set the record levels, the levels off-tape are too low, almost certainly you did something wrong in the process of setting the bias. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#8
![]() |
|||
|
|||
![]()
If your
meters are pinning before you get a peak reading, back off the input level of the 10kHz tone. It does not need to read 0vu for the bias adjustment. Try sending the 10kHz tone to the machine -3vu and see if you can get a peak then. If not, back it off further. Right. Just back off the oscillator's level until the 10 K tone is somewhere in the middle of the meter's display range. Where exactly that is doesn't matter as long as it's low enough on the scale that you can see the peak as you increase bias, and can tell where the desired amount past that is. IIRC the MTR 90 (like my MX80) has a master bias pot so you can get the whole machine in the ballpark quickly, then set the tone oscillator at about -3 and fine tune the tracks individually. The exact input level of the tone still doesn't matter though, only its rec/repro level in relation to the biasing peak. Once you're done with bias, set the oscillator output to exactly 0db for the level and EQ adjustments. Ted Spencer, NYC "No amount of classical training will ever teach you what's so cool about "Tighten Up" by Archie Bell And The Drells" -author unknown |
#9
![]() |
|||
|
|||
![]()
If your
meters are pinning before you get a peak reading, back off the input level of the 10kHz tone. It does not need to read 0vu for the bias adjustment. Try sending the 10kHz tone to the machine -3vu and see if you can get a peak then. If not, back it off further. Right. Just back off the oscillator's level until the 10 K tone is somewhere in the middle of the meter's display range. Where exactly that is doesn't matter as long as it's low enough on the scale that you can see the peak as you increase bias, and can tell where the desired amount past that is. IIRC the MTR 90 (like my MX80) has a master bias pot so you can get the whole machine in the ballpark quickly, then set the tone oscillator at about -3 and fine tune the tracks individually. The exact input level of the tone still doesn't matter though, only its rec/repro level in relation to the biasing peak. Once you're done with bias, set the oscillator output to exactly 0db for the level and EQ adjustments. Ted Spencer, NYC "No amount of classical training will ever teach you what's so cool about "Tighten Up" by Archie Bell And The Drells" -author unknown |
#11
![]() |
|||
|
|||
![]() |
#12
![]() |
|||
|
|||
![]() |
#13
![]() |
|||
|
|||
![]() |
#14
![]() |
|||
|
|||
![]() |
#16
![]() |
|||
|
|||
![]()
"J.P. Ambrogi" wrote:
Hi, I had troubles trying to do the alignment on a MTR90 II. First get hold of the manual - there is a pdf version around on the net so there's no excuse not to have it (although it is a 20MB or so download). I'd follow the proceedure in the manual step by step to start with - an MTR90 in decent shape is very easy to calibrate. If you get into real problems then hopefully Chris Notton will appear - he's the real Otari expert around here. Cheers. James. |
#17
![]() |
|||
|
|||
![]()
"J.P. Ambrogi" wrote:
Hi, I had troubles trying to do the alignment on a MTR90 II. First get hold of the manual - there is a pdf version around on the net so there's no excuse not to have it (although it is a 20MB or so download). I'd follow the proceedure in the manual step by step to start with - an MTR90 in decent shape is very easy to calibrate. If you get into real problems then hopefully Chris Notton will appear - he's the real Otari expert around here. Cheers. James. |
#18
![]() |
|||
|
|||
![]() |
#19
![]() |
|||
|
|||
![]() |
#20
![]() |
|||
|
|||
![]()
James Perrett wrote in message
First get hold of the manual - there is a pdf version around on the net Really? I'd like to know the URL (ok, I'll search for that!)...ours is forever lost! Anyway, you guys were right! For any reason, I was assuming that I should use the 1 khz at nominal level to do the Bias adjustment. Trimming down the oscillator level did the trick! I'd be very happy to pay each one of you a drink as long as you don't mind taking a plane to Brazil to get it... Regards, J.P. Ambrogi Jardim Elétrico BRAZIL |
#21
![]() |
|||
|
|||
![]()
James Perrett wrote in message
First get hold of the manual - there is a pdf version around on the net Really? I'd like to know the URL (ok, I'll search for that!)...ours is forever lost! Anyway, you guys were right! For any reason, I was assuming that I should use the 1 khz at nominal level to do the Bias adjustment. Trimming down the oscillator level did the trick! I'd be very happy to pay each one of you a drink as long as you don't mind taking a plane to Brazil to get it... Regards, J.P. Ambrogi Jardim Elétrico BRAZIL |
#22
![]() |
|||
|
|||
![]()
J.P. Ambrogi wrote:
Anyway, you guys were right! For any reason, I was assuming that I should use the 1 khz at nominal level to do the Bias adjustment. Trimming down the oscillator level did the trick! What tape are you using? With most modern tapes, you will do better by using 10 KHz with overbias than looking for the peak at 1 KHz. For one thing, the 10 KHz peak is much narrower. But unless you are using an old-style red-oxide tape, using the peak at 1 KHz is apt to give you too high a bias level. With overbias, you find the peak, then you increase the bias until the playback level drops by a particular amount (which is fudge factor that is specific to the tape formulation and head gap width and which you can get off the tape data sheet). I'd be very happy to pay each one of you a drink as long as you don't mind taking a plane to Brazil to get it... It is cold and damp this time of year here, and I assure you I would much rather be on a beach in Brazil. I do have maracuja tea, though, which is better than nothing. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#23
![]() |
|||
|
|||
![]()
J.P. Ambrogi wrote:
Anyway, you guys were right! For any reason, I was assuming that I should use the 1 khz at nominal level to do the Bias adjustment. Trimming down the oscillator level did the trick! What tape are you using? With most modern tapes, you will do better by using 10 KHz with overbias than looking for the peak at 1 KHz. For one thing, the 10 KHz peak is much narrower. But unless you are using an old-style red-oxide tape, using the peak at 1 KHz is apt to give you too high a bias level. With overbias, you find the peak, then you increase the bias until the playback level drops by a particular amount (which is fudge factor that is specific to the tape formulation and head gap width and which you can get off the tape data sheet). I'd be very happy to pay each one of you a drink as long as you don't mind taking a plane to Brazil to get it... It is cold and damp this time of year here, and I assure you I would much rather be on a beach in Brazil. I do have maracuja tea, though, which is better than nothing. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#26
![]() |
|||
|
|||
![]() |
#27
![]() |
|||
|
|||
![]() |
#28
![]() |
|||
|
|||
![]()
J.P. Ambrogi wrote:
(Scott Dorsey) wrote in message news:cju9nk$le2 What tape are you using? An old, but still virgin, 3M 996! Definitely go the 10 KHz route. The Otari has .25 mil heads, so with 996 try 3 dB of overbias at 15 ips. Watch out for sticky shed, though. I have had old 996 go sticky. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#29
![]() |
|||
|
|||
![]()
J.P. Ambrogi wrote:
(Scott Dorsey) wrote in message news:cju9nk$le2 What tape are you using? An old, but still virgin, 3M 996! Definitely go the 10 KHz route. The Otari has .25 mil heads, so with 996 try 3 dB of overbias at 15 ips. Watch out for sticky shed, though. I have had old 996 go sticky. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#30
![]() |
|||
|
|||
![]()
Scott Dorsey wrote:
J.P. Ambrogi wrote: (Scott Dorsey) wrote in message news:cju9nk$le2 What tape are you using? An old, but still virgin, 3M 996! Definitely go the 10 KHz route. The Otari has .25 mil heads, so with 996 try 3 dB of overbias at 15 ips. Watch out for sticky shed, though. I have had old 996 go sticky. --scott I'm a 996 fan and have used a few older reels. Almost none exhibit sticky shed, although I've had one or two that did, but it wasn't too bad. Still very playable. -- -- John Noll Retromedia Sound Studios Red Bank, NJ visit the new website: http://www.retromedia.net |
#31
![]() |
|||
|
|||
![]()
Scott Dorsey wrote:
J.P. Ambrogi wrote: (Scott Dorsey) wrote in message news:cju9nk$le2 What tape are you using? An old, but still virgin, 3M 996! Definitely go the 10 KHz route. The Otari has .25 mil heads, so with 996 try 3 dB of overbias at 15 ips. Watch out for sticky shed, though. I have had old 996 go sticky. --scott I'm a 996 fan and have used a few older reels. Almost none exhibit sticky shed, although I've had one or two that did, but it wasn't too bad. Still very playable. -- -- John Noll Retromedia Sound Studios Red Bank, NJ visit the new website: http://www.retromedia.net |
#32
![]() |
|||
|
|||
![]()
"J.P. Ambrogi" wrote:
James Perrett wrote in message First get hold of the manual - there is a pdf version around on the net Really? I'd like to know the URL (ok, I'll search for that!)...ours is forever lost! I really can't remember where I found it but if you have an email address that can accept very large attachments then I could send you a copy. Cheers. James. PS - Chris might be relieved to know that I've also given Ahmed a copy so hopefully he won't be bugging either of us with basic MTR90 queries now. |
#33
![]() |
|||
|
|||
![]()
James Perrett wrote in message
I really can't remember where I found it but if you have an email address that can accept very large attachments then I could send you a copy. I would be grateful, James! My e-mail is: Regards, J.P. Ambrogi Estudio Jardim Elétrico BRAZIL |
Reply |
Thread Tools | |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
A-4010S Hissing and Alignment | Tech | |||
- Cartridge Alignment Tool - | Pro Audio | |||
- Cartridge Alignment Tool - | General | |||
- Cartridge Alignment Tool - | Audio Opinions | |||
- Cartridge Alignment Tool - | Marketplace |