The Dolby Trick !

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Neeno

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Sep 4, 2004
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Switzerland
Hey guys.
I just  got a couple of 361 in my studio.
They were in really bad conditions (meters broken, some pushbuttons locked down and so on)
I fixed them, and now I modded the cards.

One of the cards got a jumper mod.
The other one the stretch mod.

One is more subtle than the other but they are both useable.

I normally send send the vocals out from a send to the dolby.
And then I mix the dolby return under the vocals.

Now... share how you use the dolby trick !
 

rascalseven

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"Tejas"
"Jumper mod" and "stretch mod"??

I'm familiar with lifting two resistors on the Cat. 22 (type A) cartridges to disable the two lower bands during encoding, so I'm guessing this is one of the two mods you mention (which one)?  I'd love to know what the other is, please share!

I have a 362 and a 365 (both dual units) that I use modified (as above) and stock Cat. 22 cartridges with.  Love the modded cartridges in parallel with background vocals to add sparkle.  Also work well on acoustics and some interesting uses on overheads and room mics too (use them sparingly... definitely a finesse kind of approach).  Can also work on lead vocals, but again, must be careful to keep it subtle (listen to "Don't Stop Believin'" from Journey's Escape record to here this on lead vox).

I like the stock cartridges for drums (not so much the snare, though).  On kick drums, particularly, it adds a really useful clarity and LF thump to a well-miked kick drum.  A nice alternative to EQ for pulling the definition and authority out without pushing the level up too far.

So.... jumper and stretch.....?  ??? ;D
 

Silvas

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I have the 360 or 361 pair permanently across an aux in my PT sessions, so i send it anything i want to have that kind of brightness using auxes from multiple tracks. Normally, like it on congas, bright bass guitars, and vocals...Of course, you have to use auto delay compensation for this.
 

AudioJohn

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Sep 30, 2004
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Exeter UK
Since the sad demise of analogue multitrack recording - usually with associated noise reduction systems, there are plenty of Dolby units available at very low cost.
Very early on some bright recording engineer found that the encoded signal sounded 'interesting' on certain source material.
Further experimentation  was carried out - finding that disabling two of the 4 bands of compression gave a nice 'airy' sound to vocals and some instruments.
This could be done on the original Dolby A301 system by pulling out the individual compressor cards for the appropriate bands - but on the more common systems using the CAT 22 noise reduction module - this can easily be achieved with a simple modification.
I have a PDF document showing how to do this (and it is really easy) - please contact me via my Web site with a real e-mail address and I will pleased to send this to you.

www.orchid-electronics.co.uk

 

Silvas

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Chia, Colombia
AudioJohn said:
Since the sad demise of analogue multitrack recording - usually with associated noise reduction systems, there are plenty of Dolby units available at very low cost.
Very early on some bright recording engineer found that the encoded signal sounded 'interesting' on certain source material.
Further experimentation  was carried out - finding that disabling two of the 4 bands of compression gave a nice 'airy' sound to vocals and some instruments.
This could be done on the original Dolby A301 system by pulling out the individual compressor cards for the appropriate bands - but on the more common systems using the CAT 22 noise reduction module - this can easily be achieved with a simple modification.
I have a PDF document showing how to do this (and it is really easy) - please contact me via my Web site with a real e-mail address and I will pleased to send this to you.

www.orchid-electronics.co.uk


Btw, thanks for that schemo you gave me awhile ago !
 

12afael

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Aug 6, 2004
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Helsinki
I use a dolby for vocals mainly, just after the 1176, less volume more highs so with the compressor it is a bit more controlled. I use it stock, can someone compare the sound of the stock vs moded?

Best Regards
Rafael
 

Neeno

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Joined
Sep 4, 2004
Messages
446
Location
Switzerland
rascalseven said:
"Jumper mod" and "stretch mod"??

I'm familiar with lifting two resistors on the Cat. 22 (type A) cartridges to disable the two lower bands during encoding, so I'm guessing this is one of the two mods you mention (which one)?  I'd love to know what the other is, please share!

I have a 362 and a 365 (both dual units) that I use modified (as above) and stock Cat. 22 cartridges with.  Love the modded cartridges in parallel with background vocals to add sparkle.  Also work well on acoustics and some interesting uses on overheads and room mics too (use them sparingly... definitely a finesse kind of approach).  Can also work on lead vocals, but again, must be careful to keep it subtle (listen to "Don't Stop Believin'" from Journey's Escape record to here this on lead vox).

I like the stock cartridges for drums (not so much the snare, though).  On kick drums, particularly, it adds a really useful clarity and LF thump to a well-miked kick drum.  A nice alternative to EQ for pulling the definition and authority out without pushing the level up too far.

So.... jumper and stretch.....?   ??? ;D

I've got the documentation for what I call the "stretch mod" from AudioJohn of Orchid Electronics.
Thank you very much again John.

The jumper mod is something I've found over the web, when I'll be back at home I'll upload a picture that shows the mod.
It consist in lifting one leg of the same resistor shown on John documentation, but the lifted legs are then connected to the dolby card.

Soundwise the jumper mod is a bit more subtle (to my hears) and if I recall correctly it has more low end going on.

P.S.: I need to try one of those on a kick or snare.... never did before !
 

emrr

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or, use a Dolby 740 spectral processor to dial in the exact amount you want. 
 

MikoKensington

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Detroit
I use mine un-modded to get more sheen out of vocals and more snap out of snare drums.  I usually run a send out of PT and record it to another track.  It often ends up on more than one track, so I have to "print" the various uses. 

Once "printed", I will start blending it with the original track.  I just love what it does for snare. 

I do a fair amount of limiting before the send so it doesn't go crazy on the really quiet stuff.  If you've used one you may know what I'm talking about. 
 

Neeno

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The two resistors on the left have one leg lifted (where you solder the wires) and then the wires go to the resistors on right (you don't have to lift those)
 

Winetree

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Apr 8, 2010
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Cucamonga, California
Just reading about this. Don't have any cards. Would like to get some.
Are the cards used by themselves or in a rack?
If by themselves how are the ins and out wired? Are they labeled?
 

rascalseven

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"Tejas"
Cards are used in a rack like these:

http://cgi.ebay.com/Dolby-System-Model-360-pair-complete-working-units-/220640399895?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item335f315217

http://cgi.ebay.com/Dolby-361-Noise-Reduction-System-FRAME-/190408806895?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item2c553fd1ef

They also made a 362 system (2 channels in 1ru) and a 365 (2 channels in 2ru).  The earlier 360 & 361 are discrete with the later 362 & 365 having IC's.  I have all of them, but use the later ones.

Often these will come with cartridges, but sometimes not (as in the 360 auction above).  The cartridge you want is Cat. 22 (Type-A).

The 363 systems that you will run across in your search are the most recent systems which offer Type A and SR in one unit, switchable.  These don't mod as easily (I don't know anyone talking mods for these), so you might avoid them unless you want to play with stock NR.

Enjoy!
 

rascalseven

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I can't really tell a difference, sonically, between the discrete or IC versions (this is an effect that is usually paralleled with the source signal, so I don't get wound up with the whole 'discrete vs. IC' argument... I doubt it applies much at all here).  The IC's are TL07x and 553x as I recall, so they don't suck anyway.

The main reason I use the later ones is because they're dual-channel units (and the 362 is still only 1ru), so it's more of a convenience thing rather than having two separate boxes.
 

grantlack

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Mar 2, 2010
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iowa
Is there a reason why some of the 361 a-type units don't appear to have a cartridge slot, but instead have a black block-off plate in tha area of the faceplate? I'm assuming this just has the cat22 circuit built in rather than being swappable to another cartridge, but you know what they say about assumptions...
 
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