Quadrant Fader / Stepped Ladder attenuator

cfierik

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This is my first post, so please be gentle! I've managed to make up a working model of a Painton style fader  ( although much more crude). I have two questions regarding the original units.
1) Were they balanced ladder, or shunt attenuators?
2) How many steps did they have?
This basic design seems like a very elegant solution, and has always intrigued me.
 

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emrr

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If they are like the Davens/Langevins/Altecs/Shallcross/Tech Lab/etc, then you can expect to find ladders, T's, and stepped potentiometers, both balanced and unbalanced.  I doubt many balanced ladders or H's existed due to cost and general unnecessary nature.    98% would be unbalanced. 
 

Winston OBoogie

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Hi Erik  :)

Painton quadrant faders were available in various configurations.  However, from our P.M's, I think you're specifically curious about the faders on an EMI REDD desk yes?

If so, then the details are: 

Bridged "T" type at 200 ohms.  There were 31 steps. From 0 to -15dB these were in 1dB increments.  The taper beyond that was a follows: 6 steps @ 2dB per.  Followed by  3 @ 3dB, 2 @ 4dB, 1 @ 5dB, 1 @ 7dB, 1 @ 9dB and off.

Painton part # was G.S.100349

A bit more:  If a pair of faders were to be used on a stereo signal, the fader pair could be proceeded by, and followed by, Sum and Difference transformers (type REDD A14).  This allowed for the possibility of one fader being on a different stud than the other fader which would shift the stereo imaging.  If used with the S&D transformers, the image would not shift but would merely collapse or widen the field which was thought to be less of an issue.







 

cfierik

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Thanks so much to everyone for helping me to understand this, finally!
I have been trying to decipher the circuit from the various photos available for quite some time.
It appears that the bridged T was a very common element in the Redd desks.
 

Jim Zuehsow

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I'll be honest, I HATED Painton faders with their silly curved top. Back when I worked at Columbia, all our desks were hand made by the engineering department back in New York, and that's what they used. This was also a time when engineers were expected to wear long-sleeve white shirt and tie at all times. Most of my shirts had French cuffs and cuff links. They would ALWAYS catch on a fader knob and change the level. This didn't happen with faders that had a flat front instead of curved. It was also less comfortable to operate them since your wrist had to follow that rounded motion. Probably give you carpel tunnel eventually since they weren't the smoothest operating faders around. Thank God for Penny & Giles!
 

emrr

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Jim, any idea why Columbia used Painton versus Davens/Langevins/Altecs/Shallcross/Tech Lab/etc?  They all made flat linear types.  Tech lab made a curved linear type like this in the late 1930's, which appears to have totally failed to capture the imagination. 
 

Winston OBoogie

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emrr said:
Jim, any idea why Columbia used Painton versus Davens/Langevins/Altecs/Shallcross/Tech Lab/etc?  They all made flat linear types. 

And Germany preferred Eckmillers which are also flat. 

emrr said:
Tech lab made a curved linear type like this in the late 1930's, which appears to have totally failed to capture the imagination. 

Didn't know about those.  Any pictures online?


 

emrr

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Winston O'Boogie said:
emrr said:
Tech lab made a curved linear type like this in the late 1930's, which appears to have totally failed to capture the imagination. 

Didn't know about those.  Any pictures online?

Not that I know of, but there's an ad with a pic in almost every issue of Communications from about 1938-41. 
 

Winston OBoogie

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emrr said:
Not that I know of, but there's an ad with a pic in almost every issue of Communications from about 1938-41. 

Ah, don't have any issues, will have to Ebay for one maybe.

Thanks Doug.
 

emrr

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Someday I'll scan the big paper mountain.  The request list would be years long.  :'(
 

cfierik

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Jim Zuehsow said:
This was also a time when engineers were expected to wear long-sleeve white shirt and tie at all times. They would ALWAYS catch on a fader knob and change the level.
Funny, I always wear long sleeve shirts, and I have this exact problem with the P&Gs on the Flickinger...
It's great to hear from someone who actually had to deal with these things!
Thanks again for the input guys.
 

Winston OBoogie

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emrr said:
Someday I'll scan the big paper mountain.  The request list would be years long.   :'(

I hear ya  ;)


On the topic of the Painton's again:  I have to admit a love for the aesthetic myself and would go for it if they were available new, despite the likely comfort-level drawbacks. 
Also, if you were going to build something along the lines of a REDD, I don't believe P&G make constant impedance faders any more.  They used to but they were pricey last I looked (12 or so years ago?).  TKD may have something though?
 

jamesfei

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Hi Jim, I would love to know more about the Columbia console you worked on, was that in Nashville, LA, or elsewhere? Thanks in advance.

I'm also a fan of the aesthetics of the quadrant fader. One oddity among "Paintons" that I never see mentioned is the Daven version. As you know, the early Paintons used studs for contact points, which evolved to pcb traces, like the Altec and Langevin faders (presumably to save cost). P&G also made carbon (plastic?) track versions in a quadrant format. But I have two versions by Daven (one has cue) that are almost identical to the Bridged-T 600 Ohm Paintons. The taper is 16 * 1db, 6 * 2db, 3 * 2.5db, 3 * 3.5db, and 1* 6db. Uses an Amphenol connector instead, but the escutcheon size and rotation step angle is exactly the same as Painton. Unusually for Daven, the construction (especially metalwork) is cheaper than Painton or other Daven products. I imagine they tooled up for it when Columbia, RCA, MCI, McCurdy, etc, were all adopting quadrant faders.

James

 

emrr

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I have a few Daven linear throw variations, and they are quite different from another.  I took some pics, maybe I can find them and post.  This is the first discussion about early linear throw types in which I've heard the term 'quadrant' used.  That terminology isn't in the Daven, Altec, or Langevin lit that I can think of. 
 

jamesfei

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emrr said:
I have a few Daven linear throw variations, and they are quite different from another.  I took some pics, maybe I can find them and post.  This is the first discussion about early linear throw types in which I've heard the term 'quadrant' used.  That terminology isn't in the Daven, Altec, or Langevin lit that I can think of. 

Hi Doug: I'm not referring to the straight line Davens with the red knob, but those like the one pictured below. They are clearly Painton copies from a later period.

Daven_Painton3.JPG
 

cfierik

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I am very pleased to find out that other manufacturers made versions of this type of attenuator. To me it seems the simplest way to achieve a constant impedance, variable attenuator. I can understand the ergonomics issues involved, but from a manufacturing standpoint it seems much less complicated than trying to make the control rotary or linear. From an end user standpoint, these would be easier to manipulate than multiple rotary devices. If I can get an acceptable arced fascia, I hope to make some more for myself to use.
Can anyone think of any potential hang-ups with getting the circuit to work with a pcb?
 

emrr

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Mid to late 60's Daven sticker at earliest.  I don't have any of the curved variety. 

The Altec 9061A equalizers are a T attenuator variant, and have a flat face while using a curved tracking mechanism.    The fully linear Davens are fairly simple in construction.  Flat circuit board with a row of contacts, and a wiper mechanism floating on a solid round bar.  I should open a bunch of variants up and take pics. 
 

cfierik

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emrr said:
  I should open a bunch of variants up and take pics. 
If you could do that I would be forever indebted to you!
I have never been in the same room as one of these, let alone been able to inspect one up close. I have exhaustively searched the net for years, and seen the pics on the Soundtechniques site etc.
Still, my knowledge on the subject (and many more) is limited.
I have managed to make a very rudimentary mock up that seems to be holding up, and has lead me to believe that I could indeed do a passable job of making the units I require.
Thanks again to everyone who has given insight, it is truly appreciated!
 

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