1974 API 3224 40ch resto-mod

[TubeMonkey]

Hi Guys,

Starting this thread, as is long overdue, to document the rabbit hole I've been slowly been going down over the last year and a half. This is meant as archival documentation for myself, as well as a bit of show and tell while I get this thing back to 100%.  I have been taking lots of pics but have been slow to put it up online....

I happened to into this frame about 2 years ago here in Nashville, it was sitting on the other side of the river in an old dilapidated movie theater converted into a warehouse/storage facility with a lot of audio junk including a Neve VR frame that had been in a fire.  There were 3 EMT 140's over there but I'm not sure what happened to those... Anyway I think somewhere deep inside i knew how big of a project this would be but I couldn't let the opportunity pass and knew that I was capable of doing the work.....  So I rented a Uhaul and went and picked it up with a couple of friends. 

I'm trying to find out some of the history on the board, the broad scope of which is pretty straight forward. Leon Russell had commissioned and owned the board for most of it's life, until it was sold to another owner here in Nashville about 6 years ago when the decision was made to sell off the eq's and preamps. 

The 3224 was an ambitious and short-lived design... true to "Automated Process" this was really the first attempt at an SSL-style fully recallable automated board.  Most parts of the board had VCA automation integrated, including a VCA limiter on each preamp card, Group functionality, Gates, Echo sends, Quad buss sends, and an optional automated version of the 554 eq called the 954....    Incredible technology for the time, but the implementation hadn't quite caught up. I've heard a few people say the only time these things truly worked to full capacity was the day they left the factory....  I haven't met or talked to anyone who can tell me how all that automation sounded.

I don't have the original bill of sale... but I did a bit of talking with Terry Palmer, who used to work for Leon, and he mentioned that Leon had custom ordered it as a 40 frame (they only made a 32 frame at the time) and had the chassis made out of a magnesium alloy to cut down on weight as the original intension was for this desk to go on a recording truck (which it later did).  With all the bell's and whistles and the custom specs the board came close to $400k...

Leon had recently purchased a mansion in Tulsa, and apparently had decided to build a studio in the basement and stick the console there for a few years. This was a private studio setting, in addition to the famous Church studios in Tulsa which had a red Helios.

I have very few pictures of the console from before it's sale from Leon, but i do have one from it's residence here...  Anyone know who this engineer might be?

Anyway Leon had lots of house guests including Tom Petty, Paul and Linda McCartney, George Harrison, Ringo, Eric Clapton... that whole scene... So i've been trying to find the records that would have been done on this console.  I have a running list that I will include in a follow up post.

After Leon sold the mansion it ended up on the Paradise Records mobile truck out in L.A..  I have almost no documentation on this era... I've heard that the truck was a mobile control room of sorts that would be backed into a bay at the studio and plugged in, and then unplugged and driven off to use remotely. 

At some point Leon moved everything out here to Nashville (Hendersonville). I don't think the console was ever installed in his home studio there so I'm unsure if it just sat on the truck or was in storage somewhere.

I'll update with more info soon!

Let me know if you have any info!

EB

 

[iampoor1]

Fascinating!

Are any original channels left in the frame?

 

[TubeMonkey]

Fascinating!

Are any original channels left in the frame?

All the 550a modules were removed as well as the 912 preamps. Most of the ACA summers were removed as well as most of the 2520's.

Fred Hill took 24 of these and put them into a sidecar which now resides at Public Hi Fi studios in Austin. Not sure where the other 16 channels ended up... probably sold off.  I didn't really have an interest in reviving the automation in this thing, rather turn it into something great and then drop moving faders into it at some point....  so getting these preamps back was never an interest to me. The 900 was a strange card which had 50 pin edge connector (as opposed to the 15 pin 500 series). Many of those pins were for DC group control.  Today these preamp cards would be useful if converted to a 312 circuit, but i have yet to see one with the VCA intact. I'd be interested in finding one for curiosity's sake but don't plan on putting those back in the desk. 

Echo mountain in Asheville has the same model desk, with a slightly different frame, with these preamp modules. They've removed the VCA's and treat the card as a simple preamp.

Here's a pic of the side car at Public Hi Fi

 

[TubeMonkey]

Here's the channel layout for the 3224. The console was different from the 2488's of the time which had the 512/516/518 in that the preamp card and the group card were separate modules.

 

[TubeMonkey]

Here's a pic of the console and side car as they sat when I picked them up:

 

[TubeMonkey]

Luckily the 912 preamp module's face dimensions are the same as a 500 series module, and with the 912's card being about an inch and a half longer as well I decided to design a PCB riser system which would raise the bed of the console to 500 series height and pin-swap the necessary connections....  which effectively has converted the console into a 80 slot lunchbox. 

There was a couple things I liked about the 912 preamps... one was that the console has provisions for two mic tie lines for each channel.  I'm guessing this was for a location scenario where two bands were set up... instead of re-patching between sets one could simply switch from "mic 1" to "mic 2" on each channel. I wanted to keep this for quickly switching vocal mics or switching to an auxiliary drum kit.  The other nice about them was the master-mode mic/line switching which was 24v relay based. 

There was a point where I considered dropping 40 VP28's into the desk but even at a cost of $400ea that would still be $16k just for the preamps, and I couldn't have exactly what I wanted.

I ended up going down a crazy rabbit hole from about February this year until April, where I taught myself PCB design and designed my own preamp based around a 312, with a few cap values and the extra provisions from the 912 all packed into a 500 series module.

I included switches on the riser card to switch between a standard 500 series and my preamp, which has 4 extra pins for 24v relay power and the extra mic input.  If you wish to insert a standard 500 module into the desk you simply flip the switch which kills these extra pins.

My preamp has the 4 extra pins included on the back of the connector. I used a two sided 30 pin connector instead of the single sided 15 pin connector the achieve this. Similarly my module is compatible both in my console with the extra pins and in a standard 500 series rack with the implementation of a jumper that disconnects those 4 pins so there is no danger of damaging that part of the circuit.

pics to follow

 

[TubeMonkey]

Here is an ongoing list of work done/to be completed:

Phase 1:
Power supply prognosis
  - boot power supply and sus issues

2520's
  - build a shitload. (250)

Center section rebuild
  - center section prognosis and rebuild if necessary
  - Build an implement CAPI ACA's to replace removed ACA's, metalwork for console mounting
  -  move group masters to faders/ remove automation panel
  - design and implement metalwork for P&G group master faders
  -  move center section down and relocated cross beam
  - Build and implement Quad compressor into space created by removal of submaster and automation panel
  - Limiter connector rewiring for 500 series compatibility
  - Change quad master from pot to 2x stereo faders. Change Mono master pot to fader

915 group module
  - recap
  - re-implement transformers for direct outs
  - drill pcb for 2520 sockets
  -  mod for quad bus functionality

Replace 940c automated faders

    - flip desk and do wire run mod to 40x channels
    - Metalwork to implement P&G faders

Phase 2:
    - Design and implement PCB mother riser
    - Design and implement console preamp
   
Phase 3:
    -  rebuild sidecar/jukebox cabinet to match original
    -  rebuild sidecar modules where necessary

Phase 4:
  - possible custom EQ design
  - New console vernier
  - replace casters with proper legs
  - replace bolster
   
 

 

[TwentyTrees]

Wow! This is brilliant to see, and from the pic above it looks like what you’ve got is in decent condition - far better than I’d have feared given how you came into it! Great idea to convert to 500-series compatibility. I’ll be following your work with great interest.

While I’ve not used them so can’t vouch for the sound vs a Gar2520 or the other usual suspects , the Louder Than Liftoff Rogue Five DOA is 2520 compatible and is comparatively cheap at $19 assembled - might be of interest given the volumes you’re looking at:
https://store.louderthanliftoff.com/products/rogue-five

 

[boji]

Your console reminds me of the Les Paul one on display at API headquarters. Guts I'm sure are different,  but the geometry and those square illuminated bus buttons are the same.

Boy you got your work cut out for ya!  I'm only into about 30 gar 2520's and I'm ready to retire. =D

The 900 was a strange card which had 50 pin edge connector

Curious if you could post picts of the 900 card.

I scored a old wheastone console a few years back and in my ignorance decided to use the 50 pin edge connector / backplanes as foundation for my build.  I don't fully regret it, but having split connectors for a two sided sandwiched PCB's would have made routing easier.

Also curious to see your 325 / 500 card! I've got plenty of 500 slots to fill myself.

Nice score on the monitoring section.   Ready to bring back quad?

 

[Walrus]

You certainly do have your work cut out!
By the look of it, the psu's are 650A's. The usual problem with them is that the small caps on the pcb dry out and you get hum on the audio. Occasionly the 723regulator IC goes duff, but otherwise they are very reliable.

 

[TubeMonkey]

While I’ve not used them so can’t vouch for the sound vs a Gar2520 or the other usual suspects , the Louder Than Liftoff Rogue Five DOA is 2520 compatible and is comparatively cheap at $19 assembled

I had looked into it but greatly preferred the sound of the gar2520. I can also get my cost down to $5-$6 if I put in the time.  I've already built 100 so almost halfway there! lol

I've been doing them in sheets of 25/50

 

[TubeMonkey]

Curious if you could post picts of the 900 card.

Ready to bring back quad?

Here's  a pic of the 900 card sans transformers and amp

I figured i would use the back bus as a parallel mix or something.... but definitely going to find a quad turntable and a copy of Dark Side of the Moon 

 

[TubeMonkey]

Here is the back side of the 912

 

[TubeMonkey]

You certainly do have your work cut out!
By the look of it, the psu's are 650A's. The usual problem with them is that the small caps on the pcb dry out and you get hum on the audio. Occasionly the 723regulator IC goes duff, but otherwise they are very reliable.

Good to know!

Yes here's the monster that was powering this thing. There were 15 supplies for this console with 1 spare. Im currently on 10. 5 of them were for automation related power. I sold one to fund some R&D so I have 4 spares which will be good. I also stuck some LED readouts on each one so I can monitor in real time incase one crashes.

 

[boji]

Hey thanks for posting. Ah, 50 pin total. Wow there are some budges in there... Don't feel so bad about my shoddy cad anymore.

 

[TubeMonkey]

Here is a link to the thread documenting the quad compressor build which I finished up last December.

https://groupdiy.com/index.php?topic=67629.msg859379#msg859379

The photo album contains some pictures near the end of re-locating the center section to accommodate everything.

https://imgur.com/a/nuiwf

 

[TubeMonkey]

Here's a picture of my current board revision. I ended up having to make one more adjustment on the mounting holes so final revision to come!  One a get the PCB's bulk ordered and the metalwork in I'll be ready to build 40!

 

[TubeMonkey]

Here's a picture of my completed riser card

The switches kill 24v relay power to the module for 500 series compatibility. Since the Mic and Line source on the desk come from two different places it's necessary to select mic or line source for a 500 series module for the riser board.  Three inputs make it to the connector when my module is inserted including Mic 1, Mic 2 and Line input.

 

[TubeMonkey]

Here's a bottom view of the riser card.

 

[boji]

Sexah looking micpre!  Congrats. 

I dig the fisheye caps. Nice choice.