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Dolby A Stretch/Trick Gear Suggestions? 201, 301, cat22 w/361? Analog Processors (HW)
Old 9th May 2016
  #1
Dolby A Stretch/Trick Gear Suggestions? 201, 301, cat22 w/361?

I've been reading a lot about the Dolby A Trick. It's definitely something I want to try. My question is a little different than what I've been able to find, and that is, what gear should I track down to get the last 10% of the Dolby A trick/stretch sound?

Supposedly The Beatles employed this technology on the Dolby 201 module, and people say the 301 sounds the same (with the right cards removed for both). I've also read that the modified cat22 card does the same trick, but then there's people saying the cat22 does not sound as good as the 301 they have. There's also newer gear to consider like the Standard Audio STRETCH. Different modifications for the cat22 card make this process dizzying as well. Is there one that most folks say sound the most classic, or the *best* (similar to the culture behind the Rev D & E 1176's)?

If there's anyone out there who has experienced more than just one of these pieces of hardware, I'd love to know what you think. (You'd be my hero!)

Last edited by renaker; 9th May 2016 at 03:59 PM..
Old 9th May 2016
  #2
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I honestly believe George Martin and his engineers discovered it. They were given the second prototype in 1969 just in time for Abbey Road. Anyone who has hear a real A103 can hear it on Sun King, Because, and maybe a couple other tracks. I read a book about George Martin and he went immediately to America after that and was in New York. He was at a studio for an America Album I think. Anyway he rubbed shoulders with a lot of the big engineers and it was passed on like that.

Now another interesting misuse of Dolby was Page messing around with Bonhams drum sound. A long while back someone posted some famous Zep tracks with the drums soloed. Someone immediately made the connection that it sounded like it was recorded with Dolby and never decoded. Hence the big sucking sound of the hits and the whoosh of the cymbals.
Old 9th May 2016
  #3
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You were probably looking at some of my old posts on the subject. It's not hard to see why there is a difference in sound from the A301 unit to the newer Dolby 360 series units using a modified Cat 22 card based on components and construction. You are looking at a 5 rack space unit with very large transformer vs. a one or two rack space unit (mono or stereo). It's probably going to boil down to what you can find for sale if interested in the A301 or prototype units (I have not seen / used a 201 unit). Here is some history: Dolby was founded mid 1965 with 4 employees. The first production units were model A301 of which 9 were ordered by Decca records at the beginning of 1966 and delivered a few months later. The smaller model 360 series using Cat 22 cards didn't come out until 1970.

There is a plug emulating the Dolby trick too as an option which you can find specifics about in the old threads on that subject here. Without starting a hardware vs. software debate, it also sounds different. Sticking to plugs, you could also just use a multiband compressor plug, dialing in the top end bands and bypassing the low bands if you have experimentation time. Given many will use the trick via parallel processing there is a "good enough" point that can be made for using a plug or Cat 22 card mod instead of the original vintage units.

As for the common variations of the Cat 22 card mod, the main mod is to cut the wire on the end of two resistors and "lift" them. The resistor's other end is still soldered in thus you have just broken the "Low" and "Low Mid" bands compressor circuits there without removing the resistors which will easily allow you to simply resolder the cuts if you want to change it back. The other mod takes it a step further by soldering a jumper wire between the lifted resistor end and another point which will allow the "Low" and "Low Mid" bands compressors to complete their circuit but at greatly reduced volume. You can find pics of both on the web.

Last edited by Bassmankr; 9th May 2016 at 09:50 PM..
Old 10th May 2016
  #4
That is some great info! Thank you!

Last edited by renaker; 10th May 2016 at 02:37 AM..
Old 10th May 2016
  #5
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clip6's Avatar
 

Greg wells as two Stretch units.....so I'm sure they rock he could get anything he wants
the 301 was used on the Def Leopard records, never saw a 201, lots of guys use 361 because they are so easy to get
Old 11th May 2016
  #6
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You mean this type of thing!



Dolby A Stretch/Trick Gear Suggestions? 201, 301, cat22 w/361?-image.jpg
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Dolby A Stretch/Trick Gear Suggestions? 201, 301, cat22 w/361?-image.jpg  
Old 11th May 2016
  #7
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Quote:
Originally Posted by Bassmankr View Post
You were probably looking at some of my old posts on the subject. It's not hard to see why there is a difference in sound from the A301 unit to the newer Dolby 360 series units using a modified Cat 22 card based on components and construction. You are looking at a 5 rack space unit with very large transformer vs. a one or two rack space unit (mono or stereo). It's probably going to boil down to what you can find for sale if interested in the A301 or prototype units (I have not seen / used a 201 unit). Here is some history: Dolby was founded mid 1965 with 4 employees. The first production units were model A301 of which 9 were ordered by Decca records at the beginning of 1966 and delivered a few months later. The smaller model 360 series using Cat 22 cards didn't come out until 1970.

There is a plug emulating the Dolby trick too as an option which you can find specifics about in the old threads on that subject here. Without starting a hardware vs. software debate, it also sounds different. Sticking to plugs, you could also just use a multiband compressor plug, dialing in the top end bands and bypassing the low bands if you have experimentation time. Given many will use the trick via parallel processing there is a "good enough" point that can be made for using a plug or Cat 22 card mod instead of the original vintage units.

As for the common variations of the Cat 22 card mod, the main mod is to cut the wire on the end of two resistors and "lift" them. The resistor's other end is still soldered in thus you have just broken the "Low" and "Low Mid" bands compressor circuits there without removing the resistors which will easily allow you to simply resolder the cuts if you want to change it back. The other mod takes it a step further by soldering a jumper wire between the lifted resistor end and another point which will allow the "Low" and "Low Mid" bands compressors to complete their circuit but at greatly reduced volume. You can find pics of both on the web.

Great Post, I'm sure you're aware of the Cat 43A/43B Dolby Fader modules where it's selective frequency controlled compression on playback only! Now very rare and the "Plug In" was the Emulation of the frequencies and Master Threshold introducing spliced frequency compression on playback only, so decode only mode, it's like the first Larc for Audio Selective Frequency response in noise and Threshold gain etc! Info is scarce though it's known to boom swingers, Audio sweeting guys in post, Film guys, etc and there is a certain Behringer unit that was manufactured in Germany that copied this scheme, most have been binned and none exist as they priced them near cost 1991/2 (Not the Dolby units) obviously!
No, nothing to do with unit for sale...that was Studio Electronics - though if Mr. Kulka feels it's worth $400 that's up to him!
TLB

Last edited by TheLastByte; 12th May 2016 at 09:17 PM..
Old 11th May 2016
  #8
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Are you sure about those Cat numbers?

There is a Dolby Cat 43A / 43B on ebay right now with a buy it now price of $400. Another slipped through the cracks at $130 a couple months ago (I've got no connection to either). That card / controller combo usually goes for big bucks due to post guys wanting it for noise reduction and it not turning up much. You still need a Dolby unit to put the card into and given a Cat 22 card by itself is less than $30 if you have to buy it separately, most will simply clip a couple resistors on the Cat 22, keep some cash in their pockets and call it a day if they want the hardware version of the trick with easy availability and lowest cost.

A thread here touching on the Cat 43: https://www.gearslutz.com/board/post...-cat-43-a.html

A list of known Dolby Cat numbers in this thread: Film-Tech Forum: Dolby Cat No's
Old 12th May 2016
  #9
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Quote:
Originally Posted by Bassmankr View Post
Are you sure about those Cat numbers?

There is a Dolby Cat 43A / 43B on ebay right now with a buy it now price of $400. Another slipped through the cracks at $130 a couple months ago (I've got no connection to either). That card / controller combo usually goes for big bucks due to post guys wanting it for noise reduction and it not turning up much. You still need a Dolby unit to put the card into and given a Cat 22 card by itself is less than $30 if you have to buy it separately, most will simply clip a couple resistors on the Cat 22, keep some cash in their pockets and call it a day if they want the hardware version of the trick with easy availability and lowest cost.

A thread here touching on the Cat 43: https://www.gearslutz.com/board/post...-cat-43-a.html



A list of known Dolby Cat numbers in this thread: Film-Tech Forum: Dolby Cat No's
Indeed apologies, it was late, yes the 43/A 43/B and post fixed, apologies to all!
I've got 2 units and all controllers and Dolby units and the difference is a vastly improved SNR ratio on certain microphones and also on general source tracks, I do have the actual Dolby instruction set etc if it's needed by anyone, though nope the cat 22 cut and jump certainly does not give you the ability the Fader unit does and the cat swap out has, can't use 363 SR/A module ability and it's indeed a very...different sound then a cat 22 though go local city to find them - very different threshold and frequency compression and $400 with no Dolby Cat module rack included im my opinion seems steep indeed! Sorry grabbed Google pic! - Big Thanks for picking up my Mr Magoo eye sight moment!

And indeed, it's a Film and Post trick that when now are totally going Plug in via certain dedicated systems, thus leaving the older technology at cheap prices, though a Dolby rack is not hard to find cheaply save they weigh a tone milled from steel etc as I'm sure you'll know, so postage can cost if it's a weight not size post thing!
Old 14th May 2016
  #10
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I have 2 Standard Audio Stretch units and they are absolutely amazing and very useful for many things including the Dolby A high frequency boost trick. I use them in parallel on a send on my console a lot to add presence and fullness to lots of elements as well as individually on vocals.
Old 15th May 2016
  #11
I have an original 301 and some 361s with the cat22 mod. To me the 301 is better, there's no question about it. I don't actually like the sound of the modded cat 22 cards.
Old 7th January 2018
  #12
I have a beautiful 301 that I use for a vocal parallel aux. Also a pair of 360's w/ cat22 and like on piano and sometimes drum crush.

The 301 is superior to the 361, 360... the 301 is bigger, smoother and richer.

But the 360/361-cat22 doesn't suck. Still far superior to any plugin made to date, IME.
Old 7th January 2018
  #13
I have a XP24 rack with all Dolby "A" cards mounted. Anyone want it cheap? It costs $25,000 new.
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