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Hello Richard,

you definitely spotted the problem at first glance. It should have been indeed 1, 2, 3, 4, in that order and I would say it is clear that it is a half-track tape. There is still the question of the extremely high crosstalk between channels which only occurs on two or three tapes out of the six hundred. I know it would be much easier but I can't develop the tape, so I have to go back to my original question. Which machine would record with such a narrow guard band, or otherwise what could be an alternative explanation?

Huge thanks again
G

On 27.02.2012, at 15:19, Richard L. Hess wrote:

> Gregorio,
> 
> This is why I'm such a fanatic about developing tapes and looking at them. The fact that track 3 has B NOT backwards confuses me.
> 
> Also, I'm surprised you are writing 1/3/2/4 because visually on the tape you'd see 1/2/3/4 and that helps understanding.
> 
> You could use 1 + 4 to capture, but I'd rather fully understand why as the narrow tracks, especially at the edge, are not the most desirable unless that's all you have.
> 
> With track 3 B NOT backwards, I'm at a loss to explain.
> 
> http://richardhess.com/notes/category/audio/magnetic-tape-developing/
> 
> Develop the tape and post a photo and link to it from the reply message to the list.
> 
> Do not rule out misaligned heads. Also, some machines used 1/2 and 4/3 as stereo recording and they might have been UK machines instead of the more common US practice of 1/3  4/2 (in all instances L/R and SideA SideB).
> 
> Cheers,
> 
> Richard
> 
> On 2012-02-27 5:39 AM, Gregorio Garcia Karman wrote:
>> Dear List,
>> 
>> looking forward to the beginning of a new digitization week: everything is going well in Cambridge thanks in great extent to the support of the members of the list. Huge thanks!
>> 
>> Now, I have a small group of 1/4 inch tapes in the collection on which I am working (ca 1950s-70s, recorded mainly on Ferrographs) which seems to have a track format, which I haven't met before. On those tapes standard half-track and half-track butterfly Studer blocks consistently produce a dual mono signal with unacceptable crosstalk on both channels (bleeding of about -20 dB referring to the signal on the other channel).
>> 
>> On the other hand, the output of a quarter-track headblock is as follows:
>> 
>> track 1: Signal A
>> track 3: Signal A + B
>> track 2: Signal A + B backwards
>> track 4: Signal B backwards
>> 
>> It would seem that this very small group of tapes would have been recorded on a machine with a very narrow guard-band in comparison to the rest of the tapes I have. What is your opinion about transferring those tapes on a quarter track headblock and keeping tracks 1 and 4?
>> 
>> I would also be curious about which machine could have had a track format that would agree with the former observations.
>> 
>> Thanks for your comments!
>> 
>> Gregorio Garcia Karman
>> [log in to unmask]
>> 
> 
> -- 
> Richard L. Hess                   email: [log in to unmask]
> Aurora, Ontario, Canada           (905) 713 6733     1-877-TAPE-FIX
> http://www.richardhess.com/tape/contact.htm
> Quality tape transfers -- even from hard-to-play tapes.

Gregorio Garcia Karman
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