[QuadList] Dolby Question

[Bryan Olding]

Hi Don, Scott, 

A few years ago I queried a Dolby rep who was visiting my employer and he
was able to retrieve the service manual for the Cat234 card which is the
Sony BVH2K adaptor (if you will) for the Cat225 Dolby processor cards. I
sent him a picture of my cards and his colleague in London had this to say
at the time:

"Cat225 is the low power version of the Cat55 A-type module (itself the IC
version of a Cat22). The Cat225 was used mainly in video applications (in
the audio chain) where here it is fitted on a Cat234, which is a 2 CHANNEL
NR SYSTEM for a SONY BVH2K machine.

The Cat225 itself has no adjustments, the Cat234 itself has all the
alignment pots documented in the Cat234 manual."


Since the Cat234 replaces the Sony AU-27 in slot 1 of the BVH2K almost all
audio channels 1 & 2 related adjustments are on this card, with, I think,
bias being an exception. If anyone has need of the manual feel free to
contact me and I'll forward it on.

Regards, Bryan
Akl, NZ.


From: "Don Norwood" <dwnorwood at digitrakcom.com>
To: <quadlist at quadvideotapegroup.com>
Subject: [QuadList]  Dolby Question
Message-ID: <53AC6B51E6D0406799D6EE7525162092 at dcidell2v2>
Content-Type: text/plain; charset="iso-8859-1"

Hi Scott:

Thanks for your reply.  The "mystery" cards are 225, not 255.  They are
single channel Dolby A as are the 55 cards, so the 380 uses 2 of them
installed on a 245 module which is installed in the 380 frame.  I don't know
if this is relevant, but the 225 cards are in the newest frame while the
older frames have the 55 cards.

Fortunately, all of these work just fine and I have more than I need, but I
was just curious about the difference since the manual I have only covers
the 55.

Don Norwood
Digitrak Communications, Inc.
www.digitrakcom.com
  ----- Original Message -----
  From: Scott D. Smith 

----------------------------------------------------------------------------
--


  Don:

  Those are pretty esoteric. Not sure if I have anything in my old
literature that deals with the 380 processors. As best as I can recall, both
the CAT 55 cards and 255 cards are Dolby A. I think the difference is the
chip sets, and the I believe the 255 is dual channel, as opposed to the
single channel CAT 55. Dolby had a few different cards they released for VTR
use, including the CAT 155, 221 and CAT 226.

  Dolby isn't the company it used to be. Trying to find anyone there with
info on their old products is difficult, to say the least. I think the CAT
55 cards were designed around 1976, and released in summer of 1979.

  --Scott

  Scott D. Smith CAS
  Chicago Audio Works, Inc.