Studer A80VU MkIV Calibration Question

I've got to calibrate one of these later this week.

When connecting my voltmeter for level calibrations, the service manual recommends terminating with a 600 ohm resistor, but the tape machine will actually be loaded by ProTools inputs. Would it be a better idea to load with a 10K resistor (or perhaps take a look at the PT input Z and use that)?

Thoughts?

connecting your voltmeter :? I usually avoid the volt meter unless this is the first time setting up the machine ever. Even if the machine has been moved, if it's been calibrated before, I usually do not need a volt meter and go with the meters on the console and tape machine. Ideally the tape machine should work with the calibrated level of the room which in a perfect world is +4 @ 0vu but consoles can sway a bit over time. Its why we print tones and so forth.
Whats the set-up involved? IS the A-80 just a 2 track or a multi track?
Is there a console? Normally when doing level calibration One should use the meters on the tape machine to get the input level while the machine is in input and not recording then use the meters on the console to get ther output level adjust ment again with the machine in input and not recording. feed 1K signal into the tape machine. Have tracks in input and meter the input. Adjust the input level pot for 0Vu which should be +4DBU from your signal generator. Then without changing track settings, Adjust the output pot so that a meter on the console or possible pro tools reads 0Vu. Then do the playback alignment and alstly record alignment.
done...

It will be used as a multitrack (2" 24 track), but will be dumped into ProTools (HD System).

I don't know the last time this machine was setup. Probably earlier this year but I couldn't get a definitive answer from the studio owner. Also, the console in this studio was recently damaged so I think it can't be used right now.

I think they have the place set up where the tape machine outputs will feed ProTools inputs for monitoring while tracking. I assume the machine will need to be in INPUT mode, then dumped using REPRO after the completed take. From there it's a ProTools game.

Whatcha think?

Hmmm o.k. Voltmeter is not really necessary. Need a good signal generator. Hell could use the one out of pro tools, but you need to meter levels, So make extra tracks in pro tools and have their outputs be a buss outs VS an actual D/A out. And use those to monitor the output level of the Studer multi-track.

yeah if your skipping the console or using the console procedure will stay they same. Just have a steady tone generator, My lofttech I was given for free doesn't keep level for shyte. With in a minute or 2 it starts to fluxuate .1 Db here .1 Db there. I.E. it's never constant. I usually will run tone from the console. But you can do it fine with pro tools.

Here is what I would suggest assuming the console is broken. Make 48 tracks in pro tools.
24 will have D/A outs. On those 24 put a signal generator with a sine wave. you will need to switch them at various points when doing calibration but it sounds like you have gone over the manual so you know that :thumb:
With the tracks in input and not recording. Adjust the input volume pot to read 0Vu. Assuming Pro tools has not been adjusted -18DbFs in Pro tools(the pro tools meter) should = dead on or super close to +4Dbu and 0Vu in the analog world.

Then with the other 24 tracks have their inputs be the normal A/D and ther outputs be Pro tools internal bussing. Then put those tracks into input(depending on version) or record if the version does not have that option and adjust the output pot so that each meter in pro tools is -18DbFS.

Then continue on with playback alignment and record alignment. Playback comming first.

Cool. I'm going to try and get in there tomorrow to tweak and tweak some more. Session starts Friday.

I'm still trying to get the info on their calibration tape, primarily the reference flux. I think he said the machine is set up for +9 right now.

+9 would be 500 nanowebers So if they had a 250 Nano weber tape, A +3 tape then playback was adjusted to -6 VU so that when you record algin you add level till the machine reads 0VU again. If it's a 355 nanoweber then it's a +6 tape and the meters in playback were adjusted to read -3 and then in record alignment adding till the machines reads 0VU again.

Most MRL's will usually come 3 levels

Ampex:+0/185nWb/M@700HZ or +0/180nWb/m @ 1K

Ampex +3 AKA +3 MRL: 250 nWb/m, +3/180nWb/m Somtimes just writen+3/185nWb/m @ 1K

Ampex +6 AKA +6 MRL: 355 Nwb/m @ 1K, 370 Nwb/m @ 700Hz, +6/180nWb/m @ 1K

Usually will not see differnt MRL tapes. Tapes vari in terms of tone length and speed. Ours @ work have both 15 and 30 IPS. One is a +3 and the other is a +6 each tone lasting a minute. Our +3 tape also has 100Hz for bass which is unusual but you can get them that way.

The MRL for my 1" has three tones 100Hz, 1K, and 10K at 250 nWb/m.

I always seem to try and overprepare when calibrating a different machine for the first time. As if something is really that different.

[quote author="Greg"]The MRL for my 1" has three tones 100Hz, 1K, and 10K at 250 nWb/m.

I always seem to try and overprepare when calibrating a different machine for the first time. As if something is really that different.[/quote]

Nothing wrong with being prepared. :thumb: Makes it easier when a problem arises as one can have a good work around without wasting much time :thumb:

[quote author="pucho812"]Makes it easier when a problem arises...[/quote]
True... something always comes up. Always!

Went over the studio tonight to check out the machine and a few other things.

I did some quick talking and the calibration is definitely off, most noticably in the high end. The owner said the machine hasn't been aligned in at least a year... probably more.

I plan to use 499 at +9dB.

The reference tape is 355nWb/m and has tones 100Hz, 1K, 10K, and 16K... so I will have to align my playback amps to show -3dB on the VU instead of 0dB. Correct?

Session starts Friday, but I now have the key and plan to start calibrating tomorrow night. Woohoo, I'm very excited about my upcoming session.

correct. That way when you do your record alignment, you will add extra level until you end up @ 0VU. :thumb: I have never been a fan of +9 I prefer a +6 as there is less noise but that is music dependent. Last time I did a speed metal band we did a +9 alignment. It worked well and gave good tape compression.

I have never recorded at +9... only +6 and +3. I am recording a very slow, heavy, sludgy type band. What what you suggest?

If you had time and $$ try all three but probably don't so yeah go with +9 will be nice for the heavy metal. or better go up to 11 like spinal tap.

Thanks...

... is the exclusive Greg and pucho812 thread?

no problem... :thumb:

Played around the with the calibration last night for several hours. I think I've come up with some nice calibraton settings.

The trickiest part is getting the record LF response at 30 ips. I set the amps from Repro to Record flat at 10kHz and I think I've settled for +2dB bump at 100Hz. Otherwise, the low end roll off was a little too fast for my liking. IIRC, I'm down about 2.5dB at 40Hz, gradually rolling off from +2dB at 100Hz. Since I'm recording a heavy band, I don't want to roll off to much of that nice bottom. I'll deal with the bump at 100Hz.

The machine is flat through the midrange to 10kHz. I didn't check above 10kHz. I was tired and didn't bother since the top end sounded great on playback.

I'll do final tweaking today. The Studer A80VU is a very nice machine !!!

By the time i sold my tape machines , no one wanted to pay for tape
anymore , it was like they were admiting that nothing would likely come of their projects [ more & more vaniety cds ]
I do miss the smell of tape though , just not the evil Ampex head cleaner

have fun , regards Greg

This material will only be on tape for a short while... basically track it to tape, listen to it, like it, and dump it straight into the PooTools. Just takes one reel.

Just a quick follow up.

I had a very successful session over the weekend. We tracked 5 songs to the Studer at +9 and now they're all residing happilly in ProTools... awaiting mixing. They sound fantastic. That is the best sounding tape machine I have personally ever recorded on.

The remote and transport is a little clunky, but punch-ins seemed to be very seamless.

I had a pair of Coles 4038 as room mics through a pair of Calrecs being squished by a GSSL. Very cool.

But the guitars take the cake. Beyer M160 and Sony C37A through Neve 31102s and 1176s at +9. Very rich and creamy, compressed, yet very natural.

I could go all day... gonna take a few days to get away from the music and start editing and mixing later in the week. :thumb:

kick ass :thumb: