Alright!

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antispatula

antispatula

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So today was a good day. Not only did I get that part I REALLY needed for my Fender Rhodes, I got my MRL tape. I finally broke down and bought one for the full 140. It was cool though, I live only about 40 minutes northwest of MRL, so instead of paying for shipping and waiting anxiously for it to come, I decided to drive down myself and pick it up there and pay cash. So I actaully got to see inside and meet the boss and stuff! I saw the 1/4" Studer they use to replicate 1/4" tape; it was chained to DB, Wow, and flutter meters and stuff, and hooked up to a computer, which for some reason I found slightly ironic. :p And even got to ask him a few questions and stuff. AND I didn't get really lost or nearly die (not kidding) like I usually do when I drive places I've never been.

So besides the coolness of above, I was wondering: My machine and VU meters, do I need to buy a external one to calibrate my machine? Like, is it possible my VU meters are off too? I don't know. Thanks for the help!

Oh, and what special care does the MRL tape need? I heard about keeping the tales out? And is it not ok to REW and FF?
 
you can use your pc and software scopes to set up the PB levels and PB meters... so yeah you will/may need to adjust these. You really shouldn't rely on the VU meters. But of course, an externam PPM or VU meter that is calibrated can be used.

when using the PC to calibrate your machine you will need to know what level it puts out. ie. -10 or +4
 
I don't get computers, so I don't want to go there. So I can't use the VU meters on m deck? Maaaaan. So I should get an external multi meter? And I have to calibrate that?! Man I don't get any of this.
 
I can't comment directly on Otari calibration,...

but in general,... isn't one of the first phases of calibration to do a direct-in/direct-out patch on the tape drive (INPUT MODE/SETTING), and then calibrate the meters? Seems that it's one of the first things to check and adjust, according to my Tascam reference manuals.

;)
 
yo dude.

I just got my MRL test tapes today too. I think you are going to need the service manual. I will be awaiting the responses that you will receive because I too am interested. My guess so far is that you will need an oscilloscope to test azimuth and phase. You will also need a tone generator (you can use your pc) and a level meter that can read millivolts. I think the general idea is that you play a tone into the inputs at a certain voltage that will correspond to zero on your meters (which you will adjust to match zero for that voltage). Then you will make another adjustment so that you are getting the same voltage readings on the outputs as you are on the inputs. that is before you load the tape even. Then you test the playback by using your test tape and testing the millivolts on the outputs and make another adjustment. Finally you record the test tone onto a blank tape and test the playback (separate head if you have it) to be the right output level, and adjust as necessary. You want to get each adjustment to within 1 db, however many millivolts that is.... I haven't done this and this is just what I got from a brief perusal of my 1/2"'s service manual. hopefully someone more knowledgeable can help us both.
 
That's an excellent summary, right there!

...................;)
 
man none of that made sense to me, and I doubt any of it ever will. Crap, there is no end to this stuff, I'll never be able to start recording. An Oscilloscope's are friken expensive, I can't afford one.

So is adjusting the rep and rec levels and eq and bias w/ out messing with the other stuff that I don't get, totally pointless? Because I know that even in a million years I'll never be able to do all that.
 
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FALKEN said:
yo dude.

I just got my MRL test tapes today too. I think you are going to need the service manual. I will be awaiting the responses that you will receive because I too am interested. My guess so far is that you will need an oscilloscope to test azimuth and phase. You will also need a tone generator (you can use your pc) and a level meter that can read millivolts. I think the general idea is that you play a tone into the inputs at a certain voltage that will correspond to zero on your meters (which you will adjust to match zero for that voltage). Then you will make another adjustment so that you are getting the same voltage readings on the outputs as you are on the inputs. that is before you load the tape even. Then you test the playback by using your test tape and testing the millivolts on the outputs and make another adjustment. Finally you record the test tone onto a blank tape and test the playback (separate head if you have it) to be the right output level, and adjust as necessary. You want to get each adjustment to within 1 db, however many millivolts that is.... I haven't done this and this is just what I got from a brief perusal of my 1/2"'s service manual. hopefully someone more knowledgeable can help us both.
Click to expand...

I don't get it. Do I need an external Oscillator to adjust the VU meters? You say I can use a pc, but is it needed? Even my manual says to have an external Oscillator, why, I have one built into the machine. and is says to feed a 1kh tone for a -18db signal? what does that mean? Man I hate all this.

and to do the azimuth adjustements, I need a 7.5 ips tape, I can't afford another tape. Is there any basic standard thing I could do instead of following the manuals instructions?
 
antispatula said:
I don't get it. Do I need an external Oscillator to adjust the VU meters? You say I can use a pc, but is it needed? Even my manual says to have an external Oscillator, why, I have one built into the machine. and is says to feed a 1kh tone for a -18db signal? what does that mean? Man I hate all this.

and to do the azimuth adjustements, I need a 7.5 ips tape, I can't afford another tape. Is there any basic standard thing I could do instead of following the manuals instructions?
Click to expand...

Are you sure it needs calibrating? Because if sounds good I'd say don't worry about it right now and just record.
 
yeah dont fret about the calibration....if you can get some signal...go with it.
 
thanks.....but man, I just bought 140 dollar tape. Can I still do what I know how to do, like setting the levels on the rec and repro heads, and the eq and bias? Will that be beneficial, even though I don't know how to do the azimuth adjustement and the vu level adjustement, and the input adjust......man I feel useless.
 
you shoulda checked yourself before you wrecked yourself
 
Bigsnake00 said:
yeah dont fret about the calibration....if you can get some signal...go with it.
Click to expand...
I agree with that.;)
 
A Reel Person said:
but in general,... isn't one of the first phases of calibration to do a direct-in/direct-out patch on the tape drive (INPUT MODE/SETTING), and then calibrate the meters? Seems that it's one of the first things to check and adjust, according to my Tascam reference manuals.

;)
Click to expand...

Man I friken hate my otari manual, it's the most un-user friendly thing in the world, like they don't even use DB as a reference to fluxivity, they use nanowebers and only nanowebers, how is a person that doesn't know the conversion to DB supposed to deal with that? Oh, and it mentions the Input/ VU Meter section after like all the other adjustements. I should do that first, so I can acautlly USE my meters to adjust the rest, right?
 
Yes,... right.

0db = 185nWb/m^2,... & that's an old standard that was probably developed in the 50's.

...
+3db/185 = 250nWb/m^2
...
+6db/185 = 370nWb/m^2
...
+9db/185 = 520nWb/m^2
...

As I said in PM,... if you're looking to calibrate for Quantegy 456 standards,.. that although it's a "+6" tape,... +6/185 is 456's MOL (Maximum Operating Level), above which distortion will occur. So,... it's a standard practice to set the "0vu" point on the meters to +3db/185 (250nWb/m^2), so as to allow the needle extra "headroom" to bounce up to +3dbVU before incurring distortion.

In general, that means to source a 250nWb/m^2 cal-tape, and set the Vu meters for "0vu". However, if by chance you have another fluxivity on your cal-tape,... you may still calibrate for "250nWb=0vu" by making adjusments in the db settings. You have to know what the specific fluxivity of your cal-tape is, and you have to know the "correct" or "target" level adjustment you're shooting for. There is a mathematical calculation for db-to-nWb/m^2, but I often use a reference card that simplifies things considerably. Also, many of the common settings and fluxivities may be calculated in my head,... just due to experience & the length of time I've spent contemplating such issues.

/Da

/DA
 
That's the beauty of analog recorders in that they don't have to be exactly up to spec to sound good. I agree with the others to not sweat the small stuff. If it sounds good to your ears and there isn't any major problems then you're ok.

Take your time learning the other stuff but record now!
 
Calibrating is something I have just recently gotten into and it is HUGE! But if you take each step at a time, and take your time over it, you will find it informative and you will get a buzz when you finally have the thing ticking over nicely.


Stick to what the manual says and the order it tells you. That is important. you will find out why it is in that order at the end.

All the external equipment you need apart from the tape, you can use you PC for as long as you know if the sound card works from -10db(most likely) or +4.

The trickiest part of calibrating is the bias traps and bias (at least that's what i have found), oh and the EQ but I think the EQ is more of a ball park thing than anything else.


Spend some time settng the playback heads first and only do that. If you get any satisfaction from that, then do the rest.

All the tone on the tape are recorded at 0db for that tape (eg. 200nWb/m). If you are going to record on a tape like 456 (250nWb/m i think) you can set the machine up to +2 db because the 456 has more headroom than the 200nWb/m tape. Understand??

Probably not... I'll post a link to some info you should read which should clear things up.
 
does anyone have a pdf of the 32 service manual, before I order one today and have to wait until next week to do this?
 
FALKEN said:
does anyone have a pdf of the 32 service manual, before I order one today and have to wait until next week to do this?
Click to expand...

I don't know of one. The basic operations manual was available as PDF in an abridged form, but the schematics and advanced sections weren't part of it.
 
jpmorris said:
I don't know of one. The basic operations manual was available as PDF in an abridged form, but the schematics and advanced sections weren't part of it.
Click to expand...

True...I was just looking over that PDF and its all in there! Great. I am thinking maybe there is a freeware scope somewhere on the internet...going to search for that if I get some time.
 
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