Audio Historians - REDD/RCA/Langevin/RFT Lorentz/WSW

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matriachamplification

Wall Thomas
Joined
Feb 3, 2019
Messages
447
Location
Ontario, Canada
Hello GDIY

UPDATE

Given this thread is very informative, we are expanding our list to include Langevin & RFT Lorentz/WSW. We are looking for any European Tube Console designers particularly excluding Italy and Russia as we already have a story. Any direction is appreciated. MAIHAK.... love these designs!

we are hoping to get some insight into both the REDD console and history as well as the RCA tube console history. Any direct insight would be remarkable for our goals.

Thanks and Be Well :)

Wall
 
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I never heard of the REDD console, but my father was a recording engineer for RCA records working in NYC. I went into one work with him at his studio one Saturday back in the mid 50s, when I was still a young snot nosed puke, and he was still alive.

He left a bunch of technical papers/notebooks but mostly from while he was working at western Electric in the 30s, not too much (anything) about RCA.

JR
 
JohnRoberts said:
I never heard of the REDD console, but my father was a recording engineer for RCA records working in NYC. I went into one work with him at his studio one Saturday back in the mid 50s, when I was still a young snot nosed puke, and he was still alive.

He left a bunch of technical papers/notebooks but mostly from while he was working at western Electric in the 30s, not too much (anything) about RCA.

Hello John

Thank you for replying. I should clarify we are looking for research into the REDD team at EMI.

I do recall you had mentioned your father and RCA in the past. I would love to hear some details about your day at RCA> Do you mind if we send you a PM to discuss?

Wall
 
I have some REDD documentation.  I also have RCA documentation but on their late 1960's solid state stuff using melcor 1731, api 2520 and rebranded 2520's with RCA on them.  The rca stuff is because I tech a rca desk that a client and friend owns here in L.A. . it's one of 5 ever made and it's sister desk is in the country music hall of fame.
The redd stuff is redd app notes and so forth including the famous redd 37.

Is there some documents you would like?


 
pucho812 said:
I have some REDD documentation.  I also have RCA documentation but on their late 1960's solid state stuff using melcor 1731, api 2520 and rebranded 2520's with RCA on them.  The rca stuff is because I tech a rca desk that a client and friend owns here in L.A. . it's one of 5 ever made and it's sister desk is in the country music hall of fame.
The redd stuff is redd app notes and so forth including the famous redd 37.

Is there some documents you would like?

Hello Puncho!

Yes we would love any documentation you have. Thank you.

You can email me at [email protected]
 
matriachamplification said:
Hello John

Thank you for replying. I should clarify we are looking for research into the REDD team at EMI.

I do recall you had mentioned your father and RCA in the past. I would love to hear some details about your day at RCA> Do you mind if we send you a PM to discuss?

Wall
I do not encourage PMs, here is fine.

Not too much to share... I recall seeing a life sized statue of "nipper" the iconic RCA dog (his master's voice) in the studio foyer... 

That day my dad had a technician working. He was melting wax on microscope slides so they could look at the grooves made by a record cutting stylus under the microscope. As I recall he was cutting up small chunks of wax and adding them one small chunk at a time until the slide was completely covered. I asked him why didn't they just measure out the needed amount of wax by weight? He asked me to stop bothering him. :-(

That's about it, I was very young < 10YO.

JR
 
matriachamplification said:
Hello Puncho!

Yes we would love any documentation you have. Thank you.

You can email me at [email protected]

Ok as I sift through to find the redd stuff,  in the tech documents section under RCA, there is a document uploaded by Ethan on my behalf as it was too big a file. He converted it.
The pdf is an rca document that belongs to an rca desk I have had the joy of driving and teching. The doc is for a card called uoab which is short for universal operational amplifier board. The board itself consists of discrete voltage regulation and a 2520, 1731 or rebranded 2520 rca discrete opamp. It was the documentation given to the engineers in the field and is the center piece of the desk I mentioned.  It basically describes the card and all the different ways one connects it up to get a mic pre or line amp or summing amp and so on. It is very detailed.  They really enjoyed fixed gain with attenuation on the back end of those things. 
 
Noted, searching the RCA forum now.

We have a massive proponent to our program dedicated to Dick Sweetenham. The connection between our Tube RCA rebuilds into opamps followed up with Helios. Great transition!

I have been looking for a template to build our console design document off of and this is a great opportunity to make this happen.

REDD Documentation seems to be more scarce to find.
 
matriachamplification said:
Noted, searching the RCA forum now.

We have a massive proponent to our program dedicated to Dick Sweetenham. The connection between our Tube RCA rebuilds into opamps followed up with Helios. Great transition!

I have been looking for a template to build our console design document off of and this is a great opportunity to make this happen.

REDD Documentation seems to be more scarce to find.

some more than others. REDD did a lot of field notes and such.

what's interesting with Sweetenham is the following. Sweetenham, Neve, porter, the holy trio of early British solid state consoles of Sound techniques, Neve LTD, and Trident all read the same trade magazine called wireless world and in one issue, they did an article on transistors and the 3 transistor amplifier. They published a generic circuit in the magazine.  They all read that article and all studied the circuit. It became the backbone of their work for a long time. They all applied the concept and circuit to an extent in that article and all came out with very different sounding results.
 
pucho812 said:
some more than others. REDD did a lot of field notes and such.

what's interesting with Sweetenham is the following. Sweetenham, Neve, porter, the holy trio of early British solid state consoles of Sound techniques, Neve LTD, and Trident all read the same trade magazine called wireless world and in one issue, they did an article on transistors and the 3 transistor amplifier. They published a generic circuit in the magazine.  They all read that article and all studied the circuit. It became the backbone of their work for a long time. They all applied the concept and circuit to an extent in that article and all came out with very different sounding results.

I have heard this apocryphal story several times but I have never yet been able to locate the particular issue of Wireless World in which this article is supposed to appear. I suspect it is a myth - unless you know otherwise.

Cheers

Ian
 
ruffrecords said:
I have heard this apocryphal story several times but I have never yet been able to locate the particular issue of Wireless World in which this article is supposed to appear. I suspect it is a myth - unless you know otherwise.

Cheers

Ian

if memory serves correctly it would be the year 1961 and would be articles by R. Tobey and J. Dinsdale
 
Found the article :) Thanks Puncho!

Noted on all fronts Boogie. My internet is only started working again today after a week. When your internet is better we can talk. This info gives me some insight into discussions.

Schematics, to be honest, I would LOVE, but are not as important as learning about Len Page and the team.

 
Winston O'Boogie said:
OK got it Wall.

Well, one thing that was new with the eq's in the desks after the REDD.17 was in the insertion loss.  They're passive eq's of course so, need gain.

Backing up a bit:

The REDD.17 was based on designs by Peter Burkowitz of EMI Cologne.

Before that, Len Page had put together the REDD.1 which was their first proper mixing desk of sorts.  Except it was mostly housed in racks.  The racks contained the RS.61 amplifiers which were 2 rack spaces per amplifier.
Len was excited with what Peter was doing using the German 'Danner' cassette amps so they collaborated on the REDD.17 which was the first stereo desk.  This was 1955/1956.

The EQ in it was based on two, series connected Bridged "T" eq's , one for the top. one for the bottom. 
It was mostly a Burkowitz design but with input from Len Page.

Being two series connected Bridge "T" eq's,  the insert loss was double.  This was common at the time.

So, a +/- 10dB for the top, plus a +/- 10dB for the bottom = 20dB insertion loss.

What EMI Hayes came up with before the REDD.37 was built in 1957, was to stack two bridge "T"'s in parallel, one on top of the other.
And as long as impedance requirements were met. there was now only 10dB loss.

On Impedance at EMI, I see a lot of info here and there that has it slightly wrong. 

EVERYTHING in the studios had a built out impedance to 200 ohms.  This fed the passive eq's, faders, etc.  All was fine as far as frequency response and level. 
BUT, this was always fed into a bridging amplifier of at least 2K.  Nothing was ever "terminated" in 200 ohms.

Also, their operating level was to a different standard and is about 4 - 5 dB below our current standard.
This is why an amp with a +18dB headroom was fine for them, it's equivalent to a +23dB max headroom in modern terms.

Finito.


Edit: typos.

were they doing a 0dBm  operating level like what was happening in the u.s. during that  era before the +4dBu standard?
 
Noted. Got some docs to review. Thanks

Should be known we are focusing on the CTC designs. All other elements we are researching are for audio recordings of our programs. Building a narrative is important and we appreciate all the great info in this thread. There are dozens of covnersations we can pull from.

Yes, the Painton fader has been a on/off discussion here at the house. Its becoming irrelevant as we get closer to designing/building out our fader sections.

Wall
 
Winston O'Boogie said:
There's some info that's historically interesting as far as pan-pots and the 'bass-boost' switches that were incorporated into the REDD desks that some might find noteworthy.  I'll write a little blurb off line and paste/post it here later.
Current online situation keeps crashing on me and I end up losing most of what I wrote so...

Thanks for all the info Winston,  it was a joy to read over the weekend.
 

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