[QuadList] Ampex Quad VTR Airflow Requirements

[C. Park Seward]

Don,

Thanks for the info. Perhaps a general rule would be to use the calculations in the Ampex FEB and then double it with the venturi.

I feed around 70 PSI to the VTR regulator and set that one to 58.  My Merlin machine has an additional two gallon tank under the monitor bridge that takes  very little time to fill.

My compressor has a cut off switch set at 100 PSI. It does run most of the time.

Best,
Park

C. Park Seward
Cell: 818-535-2747
Home: 541-476-6657
2" Quad and 1" "C" transfers
The Transfer Lab at Video Park
Visit us: http://www.videopark.com



On Jun 1, 2012, at 7:45 PM, Don Norwood wrote:

> Roger,
>  
> Some excellent info from Park in the Ampex FEB's.  However, a very important caveat.....those papers do NOT reflect the load of a machine with a venturi vacuum system.  They are for the standard machines with a vacuum pump.  Ampex didn't use the venturi vacuum on any of the VR-xxxx models although many were updated with the Merlin mod kit.
>  
> So, be aware that a venturi equipped machine requires about twice the volume of air, almost 1 cfm as I stated in my earlier reply.  Actually, it's typically a bit over 0.9 cfm, so rounding gets you to 1 cfm.  There are a number of compressor options that will deliver what you need, and there is a used market because of their applications in industrial, medical and instrumentation, so you can often find a compressor for much less than new cost if you are willing to wait for the right unit to come along. 
>  
> There are also some variances in the prescribed head operating pressures.  I'd be interested to know what the folks that are rebuilding heads specify today.  I've always gone by the settings that I listed earlier from the Ampex manual, but perhaps slightly higher is OK.  Certainly better than too low I would think!
>  
> Don Norwood
> Digitrak Communications, Inc.
> www.digitrakcom.com
> Please trim posts to relevant info when replying.
> 
> Change subject to reflect thread direction. Thanks.
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