Transfer Anamoly

  • Thread starter Thread starter Melchizedek666
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Melchizedek666

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Guys,

I just baked some old half inch 8 track tapes in a food hydrator, and dumped the tracks down to my DAW, from my NEWLY BOUGHT Tascam 38 reel to reel deck. I transferred the material @ 24 bit [32 bit floating point in Cubase], at 96 KHz, from 15 IPS reels. I then dumped some old original mixes of the same songs from earlier discs I had made onto those same multitrack songfiles [to compare panning and volume/EQ settings by ear against the originals]. Guess what? THE NEW TRANSFERS ARE ABOUT 2 SECONDS FASTER, AND SLIGHTLY HIGHER IN PITCH!

What a cluster$#@%!

I wonder if it is a bad belt on the Tascam 38, or something else in the tape machine. This deck is literally like brand new, although the belt might be deteriorated. Can any of you Tascam Gurus tell me what is going on?! Help. please! bb
 
And for the record... the pull out pitch control knob was NOT engaged when I made the transfers.... the 38 was at normal speed.

Thanks in advance, bb
 
While no two tape machines run at exactly the same speed, the difference should not be noticeable.

I have a few questions:

1. Were the original recordings made on a 38 or a different machine?

2. Which one sounds 'correct' -- the old or new transfers?

3. What was the original mix made to (another tape deck, CD burner, computer, etc.)?

The could could have been 'wrong' on the original deck or it might be off on the new one.
 
If there a 50hz / 60hz setting or 2 different belt positions? I had this once on a 3340 that had the belt on the 60hz position and I am on a 50hz supply.

Alan.
 
The new transfers are sharp. I checked the pitch with a chromatic tuner I have, and the new transfers are sharp [a few cents]. The original recordings were done on a Tascam 38. I do not know where the 50 Hz - 60 Hz adjustment is... is it inside the unit? Thanks, bb
 
Doesn't Cubase have the means to correct the pitch and speed in the digital realm? If so, I'm failing to see an insurmountable problem?

Cheers! :)
 
Melchizedek666 said:
The new transfers are sharp. I checked the pitch with a chromatic tuner I have, and the new transfers are sharp [a few cents]. The original recordings were done on a Tascam 38. I do not know where the 50 Hz - 60 Hz adjustment is... is it inside the unit? Thanks, bb
Click to expand...

I don't know on the 38, but on the old 3340 it was done by having 2 different diameter belt pulleys, they were right next to each other you just slipped off the belt from one onto the other. The 38 may do this via jumpers or some other method. It may not matter on the 38 as it may use a different speed control, but when you said wrong speed this came to mind.

Alan
 
Heh heh heh! Look at this article that I found in an electronics tech guide... So I'm NOT crazy! LOL!


------------------------------------------------------------------------------------------------------------------------------------------------------------
Article 4.18) Tape speed problems on older equipment


Older reel-to-reel decks (maybe even some cassette decks) likely use an AC
induction or synchronous motor driven from the power line. Speed selection
is usually done by switching in different sets of motor windings and the use
of slip-on capstan/pinch roller sleeves.

Speed problems are most likely a result of

* Decayed rubber parts - belts, idler tires, pinch roller.
* Gummed up lubrication or worn bearings.
* Dried up or otherwise faulty capacitors in the motor circuitry.
* Faulty switches or wiring in associated with speed selection.
* An actual bad motor is possible but not that common.

See the appropriate sections in the chapters: "Turntables" and "Motors and Relays" for specific information on these types of problems.

4.19) Tape speed adjustment made easy


OK, you have found the magic screw, but how to set the speed accurately?
Sometimes, there will be strobe disks on tape decks which will appear
stationary under fluorescent lighting (magnetic ballasts only - electronic
ballasts are usually high frequency and do not modulate the light intensity at
the power line frequency) but not usually. So, you do it by ear:

Make a recording of a single tone on a tape recorder you trust - one
with accurate speed.

Suitable sources include: a signal generator, electronic instrument,
Touch-Tone phone tone, PC sound card output or PC speaker, etc. A frequency
around 400-1000 Hz should work well.

Then, adjust the speed while listening to this same source simultaneously
with the tape being played back on the unit to be adjusted. As you adjust
the speed, you will hear the pitch change. As it approaches the correct
setting, you will hear the tones beat against each other. When you are set
correctly, the pitches will be equal and the beat frequency will go to zero.
Even if you are tone deaf, you will easily be able to adjust pitch accuracy
to better than 1/10 of a semitone using this method.

Recording the 60 or 50 Hz power line (through a suitable isolated attenuator)
and using this as a test tone will work if you have an oscilloscope. Trigger
on 'line' and adjust playback speed to stop the trace from drifting. However,
this is too low a frequency to be used accurately with your Mark I ears!

Some alternatives:

(From: Helling Bernie (helling@uwindsor.ca)).

A while ago I hit upon a way to set the speed on old cassette decks that
have gone out of speed.

Use an electronic guitar tuner

They cost about $40, can be borrowed, etc... Find a pro cassette deck that
is in speed, (the local campus radio station had a nice one) and record a
tape full of A tone. My guitar tuner puts out tones too, so that was easy....

Play the tape in the suspect deck, while adjusting the motor trim to
replay a A tone perfectly on the tuner meter...

Tadah....

I never did have the patience to learn to play the guitar, so I got some use
off the tuning meter....

(From: Paul Temple" (mri@earthlink.net)).

Get a song on CD and a tape of the same album. Play both at the same time
and adjust away!
 
Speed check is regular part of calibration procedures. Machines will drift over time from standard spec, so when you get a new/old machine or have one that’s been setting for a while, check calibration before using.
 
Melchizedek,
You are asking a lot of the Tascam 38. Such machines were never designed to be that speed accurate, even using the same machine, on an immediate second pass of the same piece of tape.

In any case, if you are only comparing Eq and pan choices do the two tracks need to be in perfect sync anyway?

You could go back and finely adjust the pitch control by ear as best you can to the first transfer, but unless you're very lucky the two tracks will probably still drift apart the further it plays. As for getting them sample accurate to each other, all bets are off.
 
Thanks, Guys.

One positive thing I will add... this baby sounds GREAT! The different lengths of the song don't really bother me [about 2 seconds shorter on the new transfers], but the pitch shift does. I am a piano tech... I'll just tune the transfers by ear, and as you said, "Tune the two together". Thanks for the help.
 
Afaic,...

you can verify the accuracy of a tape transport speed using only a legitimate calibration tape, such as MRL.

F/I, If you record a sample on the deck and verify on playback on the same deck, of course it's going to seem pitch perfect in the moment.

Alt, If you use a source test tone from another deck, you're putting faith in the other transport's speed accuracy, which may or may not be calibrated or valid.

If your previous 38's speed had drifted slightly down when the source tapes were recorded, playback on your newest 38 will seem slightly faster if it's properly speed calibrated. Likewise, if your original 38's speed was nearly perfect and your newest 38's speed drifted slightly upward currently, would produce the same results. You're left in the lurch to determine which it is. All electronic adjustments will drift over time, and these decks are approaching up to 30 y/o.

However, in layman's terms, if you tune the source tapes by ear or with a tuner using reference tones or a steady known tone, you may get it close enough to proceed ahead regardless. In the Portastudio world, I've become accustomed to putting a known pitch tone of A (or similar) on the head and tail of each tape, for just such purposes. Some Portastudios have been known to change pitch slightly within the same session, as the unit heats up, perhaps being electronic or maybe the rubber relaxing. The 38's belt is much heftier and has always proven to be much more stable than it's Porta cousins.

Maybe more words than necessary to describe, but AFAIC the only true verification is with a cal tape and frequency counter or scope.

:spank::eek:;)
 
In the old days, we used a frequency counter to verify speed, ie: record a 1K tone and then we used the freq counter to check what was coming off on playback. If it was say 995 cycles, the machine was was wacky or playing back slow or - the reverse, as you have, could also be true. That is also how we very simply checked wow and flutter. But a calibration tape and freq counter is the gold standard.
 
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