Harrison 3232 console restoration

[abbey road d enfer]

well, no, not really. To reconsider routing and redraw a fresh board is one thing, to have a old stripped board scanned and imported into a pcb file for editing is significantly simpler. The intention is to be able to resurrect the peeling channel strips that I have, while making building new channels easier. I haven't decided if I will keep using the old bits. should I choose not to, modifying it would be like modifying a original channel pcb. If I f**k up somehow, I will have fresh spare pcbs to work with.

Well, LM394 can be still had (baware of fakes though) and the ECG101 is on a daughter board so you may have to redesign a VCA board using current chips.

 

[Trymonlam]

I unfortunately don't have whole channel schematic but have  schematics for transformerless mic preamp and Allison VCA what may be helpful for you.

Thank you sir! That was very helpful.

 

[Dana Bollinger]

I remember that it was in the Harrison 32CS new channel strip they put the Lundahl in the input.

http://www.harrisonconsoles.com/site/32cs.html
In the clone I am designing I will put an IC line driver (transformerless)

any updates on your clone?

 

[mappee]

Hey, can anyone here make the small pcb for the vca? I need six (6) to mount some dbx vca's.

 

[abbey road d enfer]

The circuit should not be too difficult to design, just a THAT2180 or 81 and two opamps (can be a dual).
For the layout, the original board must be accurately measured.
Maybe Trymonlam has already done it...?

 

[mappee]

Here's a pic of the pcb needed. I hope someone has reproduced these single sided daughters.
Measures 2.75" x 1.25" usa. This board plus some molex 3 pin females connect dbx vca in Harrison 32 series consoles.

 

[abbey road d enfer]

Here's a pic of the pcb needed. I hope someone has reproduced these single sided daughters.
Measures 2 5/8" x 1 3/8" usa. This board plus some molex 3 pin females connect dbx vca in Harrison 32 series consoles.

So, this is the one with a dbx20x VCA? Can we have a picture of the other side?

 

[mappee]

Yes it's a dbx 202 black can although 2001 is used on same board. I've talked with some gold can 202C owners and
same pcb is used. dbx pinout is standard or so it seems. Nothing very sexy on the bottom as all the circuitry is
in the epoxied can.

 

[abbey road d enfer]

Yes it's a dbx 202 black can although 2001 is used on same board. I've talked with some gold can owners and
same pcb is used. dbx pinout is standard or so it seems. Nothing very sexy on the bottom as all the circuitry is
in the epoxied can.

OK, I see. Unusual in the sense that most equivalent daughter boards include the input resistor, the output I/V converter and some Control Voltage conditioning.

 

[MidnightArrakis]

Hey, can anyone here make the small pcb for the vca? I need six (6) to mount some dbx vca's.

YEP!!! I can!!! I have re-created the original ALLISON Research "Gain-Brain" comp-limiter PCB and it is mounted in a 1U rack-chassis that is sitting right here next to me. Then, some guy down in Florida had bought an original 1974 API mixing console that he was restoring and he sent me one each of the different PCB's in his console so I could "Reverse-Engineer" them to accurately design "New/Old" PCB's for his console. In addition, a large aerospace firm in New Jersey had sent me their last unpopulated "1979 bare-board" used in a fighter jet so I could also "Reverse-Engineer" that PCB and create a new layout of it using modern CAD-design software. And, then finally.....a member of this forum who sells "API 2520 Clones" had e-mailed me his 2520 GERBER data files so I could correct a series of errors in them concerning the silkscreen, soldermask and TOPSIDE copper layer files. After I had e-mailed this guy's updated GERBER files back to him, he had a run of 100 PCB's fabricated and he wrote back to me relating how much better his new PCB's looked and worked compared to his old PCB's. He was also kind enough to mail me 6 of his new 2520 PCB's as souvenirs for my collection.

So.....YEAH.....I can design you some new PCB's. But, there is -- ONE -- catch!!! I physically require to have your original PCB in my own hands so I am able to extract all of what I need in order to provide you with an identical duplicate of your original PCB!!! And.....I'm not that far from you here in Maryland.

Let me know what you would like to do, OK??? I'm only here to help out!!! THAT'S ALL!!!

/

 

[MidnightArrakis]

Hello guys.
waking up an old thread here.
I am fairly new to the harrison 3232 consoles. And I have a story to tell.
in 2015 I was strolling through a weekly flea market in my city. This particular flea market met weekly for a few hours in a parking lot behind a gas station in the old part of town. It usually features various trash pickers from around the city, they turned up to sell their weekly finds. It's usually used pharma supply, old silver and bronze ware, half used bottle of imported shampoo, etc. You know, the stuff that trash pickers tends to turn up. Once a while I find microphones, surplus switches, and pots there.
On this particular day, one of the trash electronics guy saw me, and said that there's a piece he kept for me. He gestured to a somewhat beat up piece on his tarp. I looked at it. It's a channel strip. It has the Harrison logo on it. I didn't know what model it came from. We haggled. We agreed on a price, I bought a channel strip. Then, as I was about to walk away, the guy called out to me and said:"you know, I still got a stack of these in my warehouse if you are interested. " so that night, I drove out to the guy's warehouse, and bought myself 20+ channel strips from the guy's warehouse.
I wrote to Harrison that night, telling them the channels I found, sending a picture along.
I got a reply the next day. I was told that I found a a bunch of 3232c channels. some of them were input channels, some were master section channels, monitors etc. Out of the blue, at a flea market from a trash picker, I bought myself a half a 3232c console.
So, from 2015 and on, I have been slowly restoring the channels, doing a little whenever I have time, Replacing caps, etc. As I go along working on them, the fact that the console had been in the world for 40 years became obvious. the copper on the pcb were partially peeling. So.... to rectify that, I decided I was going to have new channel pcbs made. I was 16 some channels away from a complete console anyway, may as well go head and bite the bullet and make them. So I went that route. I made new channel pcbs.
But... these stuff were designed during the 70s. As I was building the first channel, the fact that a single layer pcb meant patch wires like the original was annoyingly unnecessary in today's standard. The fact that on the component side there's no notation whatsoever made the process somewhat slow. So... I was thinking: "hell, I already made the pcb. may as well edit the pcb file and make it a dual layer pcb, draw in the patch wires, and do a overlay on the component side and write all the notation on there.
So I went that route.
And I am still on that route. I am about to finish with the main channel pcbs. The channels I am working off of are 3232C. the version with transformerless mic amps cards and allison research VCAs. The only schematics I found a few years back were the ones with a jensen input transformer and 202 VCA. Not sure which version this one is. Going through component by component the dbx version and the C version I got are 90% similar with 10% difference.
So here are my 2 questions.
Does anyone has the channel schematics for 3232C console with transformerless mic amp cards and allison VCAs?
For the folks with the dbx 202 VCA and the jensen input transformer, can you show me a picture of the component side around U9?
Thanks in advance to all you fine folks out there.

Should you still happen to need and/or want to have some "New/Old" PCB's for your HARRISON console, I can help you out with getting new PCB's designed and fabricated for your project. I have re-created the original ALLISON Research "Gain-Brain" comp-limiter PCB and it is mounted in a 1U rack-chassis that is sitting right here next to me. Then, some guy down in Florida had bought an original 1974 API mixing console that he was restoring and he sent me one each of the different PCB's in his console so I could "Reverse-Engineer" them to accurately design "New/Old" PCB's for his console. Just like what you need to have done.

In addition, a large aerospace firm in New Jersey had sent me their last unpopulated "1979 bare-board" used in a fighter jet so I could also "Reverse-Engineer" that PCB and create a new layout of it using modern CAD-design software. And, then finally.....a member of this forum who sells "API 2520 Clones" had e-mailed me his 2520 GERBER data files so I could correct a series of errors in them concerning the silkscreen, soldermask and TOPSIDE copper layer files. After I had e-mailed this guy's updated GERBER files back to him, he had a run of 100 PCB's fabricated and he wrote back to me relating how much better his new PCB's looked and worked compared to his old PCB's. He was also kind enough to mail me 6 of his new 2520 PCB's as souvenirs for my collection.

So.....YEAH.....I can design you some new PCB's. But, there is -- ONE -- catch!!! I physically require to have your original PCB's in my own hands so I am able to extract all of what I need in order to provide you with an identical duplicate of your original PCB!!!

Let me know what you would like to do, OK??? I'm only here to help out!!! THAT'S ALL!!!

/

 

[abbey road d enfer]

So.....YEAH.....I can design you some new PCB's. But, there is -- ONE -- catch!!! I physically require to have your original PCB in my own hands so I am able to extract all of what I need in order to provide you with an identical duplicate of your original PCB!!! And.....I'm not that far from you here in Maryland.

The problem is the original dbx modules are not available anymore, so a new design must be made. It's not terribly difficult but it's not a copy-paste job.

 

[moamps]

In the first version of the console, the subboard with VCA also contained a quadruple opamp and some other parts.



Later versions only had VCA (black can dbx VCA202) on the subboard.



The following figure shows the design of the replacement circuit board that uses the THAT VCA. I got that design a long time ago from a member who was restoring his console, I hope he won’t mind me posting it.



Edit:
Let me just add that the black version 202 (-6mV / dB) and the gold or silver version 202C and 2001 (-50mV / dB) do not have the same gain control constants.

 

[abbey road d enfer]

In the first version of the console, the subboard with VCA also contained a quadruple opamp and some other parts.

IINM, the first version used an Allison EGC101, which requires some additional glue.
I had wrongly assumed that it was what mappee had.

 

[moamps]

I'm not entirely sure when which VCA was used but I know that the schematic for the first version is dated 1977, and that the schematic with the EGC101 VCA is dated 1980.




There is also a possibility that different VCAs were built into the same type of console.

Edit:
I should also add that the VCA subboard in the first version was soldered with long pins, ie it was not fixed with Molex connectors as in later versions.

 

[abbey road d enfer]

I'm not entirely sure when which VCA was used but I know that the schematic for the first version is dated 1977, and that the schematic with the EGC101 VCA is dated 1980.

That's interesting. I wonder what type of VCA would have predated the EGC101. Maybe a 202...?

There is also a possibility that different VCAs were built into the same type of console.

Indeed.

 

[mappee]

moamps that design is from THAT corp. page. It's not the one I need (see pic) although it could work. Harrison used dbx 202 almost exclusively in A, B, and early C versions. Later C version is when they switched to Paul Bluff's Allison Research 101VCA pictured above.
Harrison would randomly use 2001 silver/202C gold. TimKroger has C version with black 202's and the Warner Brothers 4232 had Black 202 also. Sailing by Christopher Cross is the black 202's and sounds amazing.
Smaller daughter board, transfomerless mic pre and 36 segment metering are signs of C version, optional Jensen mic pres. Harrison and MCI (Jeep) share many features like those DEK line transformers and Harris opamps etc.
Early 80's was Harrison or MCI until SSL took over with dynamics on channels.

 

[abbey road d enfer]

Harrison used dbx 202 almost exclusively in A, B, and early C versions. Later C version is when they switched to Paul Bluff's Allison Research 101VCA pictured above.

Since they are rare as hen's teeth, neither is a reasonable option, IMO.

that design is from THAT corp. page. It's not the one I need (see pic) although it could work.

So what is it you need?

 

[mappee]

Post #26 shows what I need.

MoAmps that must be Dave Harrison's prototype of 3232 channel under test. Look at all the test equipment including an outboard
status control and power supply. Incredible pic that I've never seen. Not a Jensen transformer and all those 3900 op amps. I saved that pic for my files. It's all there but things look out of place.

 

[Trymonlam]

Hey, can anyone here make the small pcb for the vca? I need six (6) to mount some dbx vca's.

Hey, I actually have made a sample order of that pcb. I have maybe 6-8 if you want them.