On 03/22/2014 08:25 AM, wrote:
OK, now who ever used Dolby A ?

That's right, since there is a B is implies there was an A. There was, it was used on a porfessional level. It was also level sensitive of course.


Oddly, The decode part of "A" is still used today as a single ended
noise reduction device.

On Sat, 22 Mar 2014 06:27:28 -0700, "William Sommerwerck"
wrote:

"dave" wrote in message
om...

B has a reference level. Does C? Or is C more like dbx?

All Dolby NR systems are level-sensitive. dbx is not.

All of the Dolby systems are level sensitive. They are band selective
compressors after all. The dbx system is just a compressor system but not
band selective. Lately they have been leaving off the decompressors and
chaining the compressors.

?-(

On Sat, 22 Mar 2014 02:37:01 -0700 (PDT), wrote:

" has been fun reading this thread. My personal issue is where to get an
open reel (1/4 inch wide tape, 7-inch max reel size) setup and calibration
tape for my old Ampex AX-300 semi-pro tape deck. "

They have them all over the place on the planet Meezar 5. Twelve bucks.

T

Hot damn, that is a good price. Too bad i can't contact them.

?-(

On Sat, 22 Mar 2014 06:04:41 -0700, dave wrote:

On 03/21/2014 10:10 PM, josephkk wrote:
On Fri, 21 Mar 2014 06:08:28 -0700, "William Sommerwerck"
wrote:

"dave" wrote in message
...

What reference fluxivity should I use?

I believe it's 200nW/m for cassette, 250nW/m for open-reel. I once aligned a
ReVox consumer deck for Scotch ultra-high-output tape, and set it at least 6dB
higher. Otherwise, the meter would have banging at peak output.

The level for cassette is not really negotiable, because it's supposed to
represent Dolby level.

I has been fun reading this thread. My personal issue is where to get an
open reel (1/4 inch wide tape, 7-inch max reel size) setup and calibration
tape for my old Ampex AX-300 semi-pro tape deck.

?-)


MRL seems to be offered by several vendors. They can cost in the
hundreds. Do you have all the fish scales required for mechanical
alignment? We used the 10 kHz tone on the beginning of NPR tapes for
azimuth reference. Are you using stock electronics on the 300?

Cool, The AX-300 headstacks are fully screw adjustable, which is an
interesting tradeoff. The electronics is still stock, so playback is NAB.

?-)

On 03/25/2014 11:08 PM, josephkk wrote:
On Sat, 22 Mar 2014 06:04:41 -0700, dave wrote:

On 03/21/2014 10:10 PM, josephkk wrote:
On Fri, 21 Mar 2014 06:08:28 -0700, "William Sommerwerck"
wrote:

"dave" wrote in message
...

What reference fluxivity should I use?

I believe it's 200nW/m for cassette, 250nW/m for open-reel. I once aligned a
ReVox consumer deck for Scotch ultra-high-output tape, and set it at least 6dB
higher. Otherwise, the meter would have banging at peak output.

The level for cassette is not really negotiable, because it's supposed to
represent Dolby level.

I has been fun reading this thread. My personal issue is where to get an
open reel (1/4 inch wide tape, 7-inch max reel size) setup and calibration
tape for my old Ampex AX-300 semi-pro tape deck.

?-)


MRL seems to be offered by several vendors. They can cost in the
hundreds. Do you have all the fish scales required for mechanical
alignment? We used the 10 kHz tone on the beginning of NPR tapes for
azimuth reference. Are you using stock electronics on the 300?

Cool, The AX-300 headstacks are fully screw adjustable, which is an
interesting tradeoff. The electronics is still stock, so playback is NAB.

?-)


If you can use a laser or something to get the gap perfectly
perpendicular to the deck you'll be surprisingly close. Are your reel
motors behaving?

On Wed, 26 Mar 2014 06:50:34 -0700, dave wrote:

On 03/25/2014 11:08 PM, josephkk wrote:
On Sat, 22 Mar 2014 06:04:41 -0700, dave wrote:

On 03/21/2014 10:10 PM, josephkk wrote:
On Fri, 21 Mar 2014 06:08:28 -0700, "William Sommerwerck"
wrote:

"dave" wrote in message
...

What reference fluxivity should I use?

I believe it's 200nW/m for cassette, 250nW/m for open-reel. I once aligned a
ReVox consumer deck for Scotch ultra-high-output tape, and set it at least 6dB
higher. Otherwise, the meter would have banging at peak output.

The level for cassette is not really negotiable, because it's supposed to
represent Dolby level.

I has been fun reading this thread. My personal issue is where to get an
open reel (1/4 inch wide tape, 7-inch max reel size) setup and calibration
tape for my old Ampex AX-300 semi-pro tape deck.

?-)


MRL seems to be offered by several vendors. They can cost in the
hundreds. Do you have all the fish scales required for mechanical
alignment? We used the 10 kHz tone on the beginning of NPR tapes for
azimuth reference. Are you using stock electronics on the 300?

Cool, The AX-300 headstacks are fully screw adjustable, which is an
interesting tradeoff. The electronics is still stock, so playback is NAB.

?-)


If you can use a laser or something to get the gap perfectly
perpendicular to the deck you'll be surprisingly close. Are your reel
motors behaving?

So far. There are adjustable tapped power resistors that i can use to
keep them performing in the proper range should i need them. I would have
to lightly sand them to endure good contact if was to adjust them. I keep
them lubricated as standard maintenance.

A quality calibration tape would allow me to set the headstacks up
properly though.

?-)