Is there a 312-style project PCB out there? (Maybe one that just puts the discrete op amp parts on the PCB itself ...)

[midwayfair]

Looking for a project to build this winter, and I think two to four API312 channels would be fun since I don't have anything in that sphere.

I could do the PCB layout myself or even build it on perfboard since there's hardly anything to the circuit, but I'd rather check if there was something out there already.

I have at least one discrete op amp board around somewhere, but will also take suggestions on those. I'd prefer not to buy something black-box, though. I like to know what's happening in my circuits.

 

[Ricardus]

The only one I can think of is the ML12 project, which I am building right now myself. So many opamp choices out there these days.

If you were interested in some ML12 boards I had extras made up last time I ordered some of those, and would be willing to sell them.

 

[JW]

This isn't the exact schematic, (instead it's the inverting pre summing summing circuit) but you can build 4 312's easily on the board by paying close attention to the ridiculously simple circuit. Classic Audio Products, Inc.

I build a 4 banger with one of those, but someday it'll be 8 in a 2U box. The real bitch was the front panel switching wiring/phantom/led, like usual. Sure makes the 500 builds seem elegant.

Anyway, you could breadboard these but breadboard is probably more expensive than the $12 Capi board.

If you want the 2520 on a larger footprint and incorporated physically into the circuit, I can't think of anything. Pierre Abatte's Germanium 500 series preamp is like that, but not a 312. Get's rave reviews though. He eventually made a DOA from it (APP14GE)

 

[midwayfair]

Ricardus hooked me up with some boards! I was prepared to make these on perfboard because the circuit is simple enough but I'm a lot lazier these days than I used to be.

I didn't realize that the topology of the op amps people put in their 312 builds was so different, hence my kind of ignorance in wanting the components on the board instead of a separate piece.

The Abatte thing sounds cool but I've got a few channels of Germanium in other topologies that I like already.

 

[3nity]

I would build 312 with PCBs from collective cases..he sells PCBs and rack case ready to use as well.

 

[HyprDrivr]

http://avdaudio.com/
Has 312 kits in various forms

 

[Whoops]

I did the 4x 321 preamps in the past using 3nity "Access 312" pcb,
it's a simple no bullshit pcb, I liked it.

It seems those boards are being sold by collective cases:

https://collectivecases.com/?product=access-312-preamp-pcbs

 

[3nity]

"Access 312" pcb,
it's a simple no bullshit pcb, I liked it.

Thats maybe the best quote about the Access PCB!!

 

[Ricardus]

"Access 312" pcb,
it's a simple no bullshit pcb, I liked it.

Thats maybe the best quote about the Access PCB!!

I think the ML12 is pretty no bullshit, too. It's a tad more complicated, but I like the layout and design.

 

[Whoops]

I think the ML12 is pretty no bullshit, too. It's a tad more complicated, but I like the layout and design.

seems cool the ML12 and still simple but uses 3 relays, the Access 312 is simpler no relays needed so it’s the real “no bullshit” deal