boji

Re: 1974 API 3224 40ch resto-mod
« Reply #20 on: November 11, 2018, 08:16:01 PM »
So I assume the 6 pole means this is a variation on the 1st half of a 528 and not just a micpre?


TubeMonkey

Re: 1974 API 3224 40ch resto-mod
« Reply #21 on: November 11, 2018, 09:10:30 PM »
What's in the first have of the 528? I'm unfamiliar with that module.   My desk split what would be the 528/544 module into two separate modules.... the 912 preamp card, and the 915 group card. If you look at the channel layout I posted early you can see how the functionality is split.

the 915 card contains another opamp and 2623 transformer (except channel 1-16) for direct outs on each channel.

boji

Re: 1974 API 3224 40ch resto-mod
« Reply #22 on: November 11, 2018, 09:20:22 PM »
Quote
If you look at the channel layout I posted early you can see how the functionality is split.
Ah I see. Thanks.

Quote
What's in the first have of the 528?
Mic/line switched 2520 and tx's.

TubeMonkey

Re: 1974 API 3224 40ch resto-mod
« Reply #23 on: November 11, 2018, 10:36:26 PM »
Mic/line switched 2520 and tx's.

That's actually exactly what it is...  Just switching an impedance matching pad in front of the trafo  instead of using two separate ones, switching physical source for "desk preamp" Mode and switching  pad in for line mode in "500 series" Mode. I designed them in a way which lets them be compatible in my desk or in a 500 series lunchbox, as well as the console slots being compatible with my preamp or any 500 series module.  Most of that is taken care of with the relay's in desk mode.... but there isn't relay power in 500 series mode so it has to be physical switching. I also didn't see a point in having  two separate 2520's driving the channel as they serve the same purpose, but still wanted a separate mic/line control, so the switching actually changes the negative feedback part of the circuit from a stepped pot for mic to a potentiometer for line mode.  this also means the settings between mic mode and line mode are independently preserved while saving from having to use 2* 2520's per channel.

boji

Re: 1974 API 3224 40ch resto-mod
« Reply #24 on: November 12, 2018, 10:49:57 AM »
"switching actually changes the negative feedback part of the circuit from a stepped pot for mic to a potentiometer for line mode."
interesting! Sounds like you've given the whole thing plenty of thought and functionality.   In my first bucket (which will be the end bucket once finished), I kept it line-in only but stayed true to the skiz mostly, and plan to use the daw for prefade gain, or 500 slots ahead of input card.
« Last Edit: November 12, 2018, 10:58:23 AM by boji »

TubeMonkey

Re: 1974 API 3224 40ch resto-mod
« Reply #25 on: November 15, 2018, 03:16:01 PM »
Getting into some metalwork the past few days. Finishing up the L-bracket design and looking for prototyping options. The previous 4 preamps I had hand-drilled which was cumbersome and imperfect....

Also rebuilding the mounts for the ACA's in the back of the console. There are 19 total ACA's/booster cards. I currently have around 10 running. Still need to build one for each pair of buses, as well as a few center section functions such as delay sends. Other than that the center section is 95% operational.

Here is a before pic of one side of the console with 4 ACA's installed. I've built and and am installing a stacking system with metal brackets to make everything look nice and for cable management.

boji

Re: 1974 API 3224 40ch resto-mod
« Reply #26 on: November 20, 2018, 10:10:52 PM »
Quite a bit of iron you got there!  Yes, send a pict of the stack.  I think I may take the same route in a U5 or U6 rack.

TubeMonkey

Re: 1974 API 3224 40ch resto-mod
« Reply #27 on: February 05, 2019, 01:10:55 AM »
Alright... really bad at updates but i've been working a lot on other projects as well as the console.  I received the final version of my PCB which passed all tests with flying colors and have already been building them.  The only missing element is the metalwork which I'm working on ordering soon, but having a little difficulty finding someone to do a prototype before I put in the large order....

Also need to source knobs.... I really like the large vintage API knobs but obviously going to have difficulty getting them. I most likely will just send them to my CNC guy and get a pack of 50 or 100 ordered from him.

I took the dive and flipped the console up to do the fader mod... which involved running audio out to the fader bay. I got that work done in about 6 hours over two days... LOTS of delicate wire to sift through and tie back for each channel to ensure I didn't burn through any of it with my iron which would have been a nightmare...    Flipped it back up and have two ongoing issues... one is a bus jumper has become disconnected where they are jumpered between cards...  easy to find and easy fix but it's up under the console so I need to come up with a plan to get in at the awkward angle to fix it.  Also the solo functionality of the input channels isn't working now but that might not be related to flipping the console.  Solo functionality still working on the center section cues and sidecar... but they might be different busses electrically. 

I ended up getting extremely lucky and found an 8 pack of faders on ebay with the correct size faceplate and escutcheon...  and all the correct P&G faders with correct value. Turns out he had 48 total which was perfect for me and I bought them all for WAY less than I was prepared to spend on getting new fader faceplates made/outfitting with mix and patch P&G's.  Got them all dropped in and am working on wiring them all up!

Not sure what to do with the old faders.... might make a coffee table out of them?  ;D
I'm still going to get a single piece of metal made and screen printed for the 16 bus master faders.

I'm 6 preamps deep...   definitely going to be snowballing on that front soon....  cost of a large order of transformers is really the only thing holding me back at this point.

As far as EQ's go I've sourced 4 554's, a 550b, and a datatronix 550a so far... Still would like to design my own EQ but at this point just focusing on getting 8 channels going and filling out the preamps.

also not pictured are the four 525's to the right of the center section.  I converted the console's old pinout to the 500 VPN standard so I can throw whatever I want in there... and obviously converted the 525's to 500 series so they can go anywhere as well.

Coming up: Massive preamp build. Also I'm out of 2520's so I need to do another batch. This time instead of doing 2 5x5 sheets I'm going for the mind numbing 11x11 sheet....    hopefully I'll come out of the other side of that with my sanity.  :o

Also maybe night need to start scoping out some spaces around town. As this becomes more usable it's killing me to not be able to use it fully.

AnywayHere's a "State of the Console" pic.  Still lots to do!

mjrippe

Re: 1974 API 3224 40ch resto-mod
« Reply #28 on: February 05, 2019, 11:58:02 AM »
Member avdo was selling API style knobs a while back...

 

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