[QuadList] 6.5 mil heads... (was Re: 15 mil Headwheels ?!?!?!?!?!)

[Ted Langdell]

The topic made me think of someone telling me—David Crosthwait?—about  
why 6.5 mil heads were used, but I can't quite recall the details.

There were some benefits... perhaps better interchange.

Thanks,

Ted

On Feb 26, 2009, at 6:14 PM, Don Norwood wrote:

> Tony:
>
> Thanks so much for answering this!  I did recall some longer life  
> heads, but I didn't associate them with the 15 mil width.
>
> Don
>
> ----- Original Message ----- From: "videomagnetics, Inc."  
> <vmi at csprings.com>
> To: "'Quad List'" <quadlist at quadvideotapegroup.com>
> Sent: Thursday, February 26, 2009 7:23 PM
> Subject: Re: [QuadList] 15 mil Headwheels ?!?!?!?!?!
>
>
>> The 15 mil heads were actually notched to 10mil at the gap area. This
>> led to better like expectancy of the drum. The warranty on the 10 mil
>> was 200 hrs and on the 15mil was 500 hours. Only problem was that  
>> as the
>> head wore the rf envelope became rounded and produced error at the
>> transitions that sometime the vtr's amtec would not able to totally
>> correct this caused  banding and poor recordings for  
>> interchangeability.
>>
>>
>> Tony
>>
>> -----Original Message-----
>> From: quadlist-bounces at quadvideotapegroup.com
>> [mailto:quadlist-bounces at quadvideotapegroup.com] On Behalf Of Don
>> Norwood
>> Sent: Thursday, February 26, 2009 4:32 PM
>> To: Quad List
>> Subject: [QuadList] 15 mil Headwheels ?!?!?!?!?!
>>
>> This is a new discovery for me.  I knew that between air and ball
>> bearings,
>> 10 and 5 mil tips, and threee different preamp modules, there were  
>> lots
>> of
>> variations of the Ampex MK-X head.  All of them were pt# 1800705- 
>> xx with
>> the
>> dash number differentiating the configuration.
>>
>> But.......what I had not seen until looking in an Ampex catalog is  
>> that
>> dash
>> numbers from 209 thru 239 were 15 mil heads!  Yes, that's not a typo
>> that
>> should have been 5, it is actually 15.  What were these for?????
>>
>> This only seems to apply to the MK-X heads.  I do not see 15 mil  
>> offered
>> for
>> the MK-XI, XV or XX.
>>
>> Don
>>
>>
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>
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Ted Langdell
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