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 Post subject: Dumb R2R Tape question
PostPosted: Jan Sun 21, 2018 9:22 pm 
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Joined: May Sun 08, 2011 8:52 pm
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Location: Bay City Mi
Did manufacturers make tapes that were only for 2 track machines? Reason I ask is I have a 180 min tape that refuses to record the left channel on my Pioneer 707...or any of my machines for that matter, either that or it has a really big drop out...like the whole reel...lol


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 Post subject: Re: Dumb R2R Tape question
PostPosted: Jan Mon 22, 2018 1:41 am 
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Location: Tucson, Arizona U.S.A.
The tape is the same for all track configurations. A 180 minute tape on a 7" reel would be very thin; perhaps it has gotten stretched so that it is no longer the correct width. Or maybe the tension in the recorder stretches it enough to not work properly.

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 Post subject: Re: Dumb R2R Tape question
PostPosted: Jan Tue 23, 2018 6:14 am 
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Location: Gold Country, (Stanislaus National Forest) California 95235
Jim Mueller wrote:
A 180 minute tape on a 7" reel would be very thin.
180 min PER SIDE or PER TAPE (both sides?) And 3-3/4 or 7-1/2?

Normal 7-inch reels run at 7-1/2 and have 2 sides. Double the time for 3-3/4

Type...................Feet.........Time per side......Tape thickness
Standard..............1200..............30..........................1.5
Extended Play.......1800...............45.........................1.0
Double Play...........2400..............60.........................0.66
Triple Play............3600...............90.........................0.5
6X Play (log)..........7200..............180........................0.25

So 180 on EACH SIDE at 7-1/2 would have to be 7200 feet of quarter-mil tape.
Most FOURTEEN INCH studio reels don't have that much - and I can count on one hand the number of 7200 foot reels of quarter inch I have come across in my 40+ years in the field.

So I don't think you have that.

180 PER TAPE (90 mins a side) is a LITTLE more realistic 3600 feet but still not common. And on a deck like that if you fast-forwarded or rewound it without unthreading it from the pinch roller and pressing PLAY first to get the tables up to speed - it's probably stretched out to oblivion.

Half mil and quarter mil tape were meant for extremely low torque and low speed machines that have a lot softer takeup and rewind torque than what you have. Not to mention like I said - commercially prepared 3600 or 7200 on 7 inch is almost impossible to come across.

Five-inch (1800 ft) - and five-inch with a NAB hub for the quarter mil (2400 feet) - prepared for the little sometimes battery operated Carry-Corders that used to be around that people used to use for lengthy lectures and seminar series you see a LITTLE more often but certainly not much.

That same 90 mins/side (180 per tape) could be had at 3-3/4 on a fairly common 1800 ft reel
180 a side at 3-3/4 would be back to the second-thinnest tape ever made - 3600 feet.

Jim Mueller wrote:
Perhaps it has gotten stretched so that it is no longer the correct width.
Look at the top edge of the tape where the left channel is. Does it look curled or folded over or something?
Jim Mueller wrote:
Or maybe the tension in the recorder stretches it enough to not work properly.
If other tapes play properly then there's a couple things a newbie can check on his own:

1. Lay the machine down on its' back so it looks like a flatbed editor w the head facing you.
2. Take the head cover off and thread the offending tape.
3. Bring it taught thru the pinch rollers and headstack.
4. Flip the tape forward out of the way while maintaining tension in the tape path.
5. See if the left channel head (top) is riding fully underneath the tape.

If not then there could be a couple of things wrong besides the tension. But in regards to tension - those RTs (707s and 909s and 701s and 501s and etc etc) were never really all that great for any tape under a mil thickness anyway even when new and even when perfectly aligned with the correct mfg back-tension reel table torque and etc.

Also take a look at either your capstan or your pinch roller or both. If both are not perfectly squared up and perfectly aligned - your half mil or quarter mill tape will not track properly through the tape path and will waver all over.

If both of those are squared up - make sure the playback gap between is close enough to grab the half-mil or quarter-mil tape you have. I've seen 'em come in for lube jobs and the engagement of the pinch roller in the PLAY position is enough to drive mil-and-a-half tape alright - but start having slippage on the mil and especially the 2/3rds mil (double play) tape.

So if a 2400 foot reel won't play or record - or records in a lesser quality than the 1200 or 1800 foot reel you have a capstan and pinch roller gap problem that needs adjusted.

One other thing you can try is to look for gunk both in the tape path and on the guide rollers/posts - some of which may appear to be cemented in place. The guide rollers/posts may also have flat spots or edge wear ground in from millions of feet of tape going by - in which case those will need to be replaced.

And then the last thing is to check your heads for PREVIOUS misalignment. Some guys go for years and don't realize that their heads have come out of one or more of the normal 5:

Rack
Wrap
Height
Azimuth
Zenith

any one or more of which may be out of alignment enough to where this problem occurs - but not GROSSLY so that it still plays e.g. prerecorded tapes with enough fidelity that you wouldn't notice except for in a critical listening environment - which very few of these Pioneer units have ever seen (skating rinks bars bowling alleys etc).

So there's a few ways to get started.

Also - shoot a picture of the tape and its box so we can see - and the same w the recorder trying steps 1-5 at the top of this post so we can see what we are working with.

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2 kinds of men/tape. Low Noise/Wide Range.
LN=kind. WR=abrasive. Engineers=same thing.


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