Forssell Opto Compressor

[tommytones]

The multi amp thing is no problem. Would you guys like to have the whole thing on 1 pc or would you like to have the amp stages seperate? Maybe I can place 2 different circuits on the one larger pcb (sidechain and all) and the user can decide to stuff either the Forssell side or Butta's side? It wouldn't be a much larger board because of it, the circuits are simple enough.

 

[hitchhiker]

hi Tom,

the single pcb with both options sounds cool to me.

Are you talking about the servo output amp that Fred offered?

Lance

 

[Svart]

one or two, doesn't really matter, If you can do one with all the options that would be great. also, since some of us might put a few(#?) in a rack or other wise i would rather see it as small as possible. just my 2cents.

thanks guys!

 

[soundguy]

Id vote for one, less holes to drill in the chasis...

dave

 

[kruz]

i'd prefer the "all in one" version too.. less wires.. :grin:

 

[tommytones]

Okay, so all in one seems to be the way to go. I agree...it's just cleaner and easier this way.

Now, are we decided on which amp circuits to use? I think I remember looking at the circuit Fred suggested but please refresh my memory. For option 2, do you guys wanna go with butta's circuit or something else? For pots, just place pads to solder off board or would you like to have pc mounted pots? If so, what brand/model?

 

[Svart]

hey tommytones, I would like to see butta's circuit(both versions, dark and clean*just jumper if you don't want caps*) AND the forssell amp footprint, kinda like the SSL has the older VCA footprint and the equivalent traces for an IC/monolithic VCA setup also if that isn't asking too much ... :thumb:

as for pots, i think pcb mounted would be better, as you can always run wires to the holes..

anybody thought about surface mount or through hole? I'd personally like to see surface mount but i'm sure i am alone here... :green:

cheers!

 

[tommytones]

I think through hole is the way to go. It can get very complicated for inexperienced folk to work on surface mount if something needs repair. It can get complicated for experienced folk too as a matter of fact :green:

Do we want single channel boards or dual? There was mention of having multiple channels in a single box. PSU???

 

[hitchhiker]

I think 2 ch boards would be nice. As for PSU maybe just regulation on board?

I've so far used off board transformers and I would be doing that here.
But maybe for a complete and tidy DIY it would be better to have a
suitable on board option?

cheers,
Lance

 

[Svart]

I would rather have singles, but a dual one would be nice too.. I plan on using some of these for general channel compression for guitars/bass/ backing vocals and the like and would like something like 8 monos to a 3u rack.

as for psu, I would use an offboard psu. Toroid, bridge caps, regs and the like so i can use multiple boards with one psu.

 

[TomWaterman]

Hi,

Tommy - thanks for volunteering to develop the boards - this place is great!! I bet I'd never get time to do my own....

I also vote for an all in one board - and would love to see the option for ICs and Freds JFETS (990 footprint) opamps for the input buffer and sidechain circuits.

I know its a little different but how about making two plugin output amplifier boards - one for Butterchunks and one for Fred's Servos. Give them the same pin out, we could easily choose the output boards we want and build them up....maybe too expensive for the individual PCBs though??

Butterchunk - can your amps be made with Freds 992s instead of ICs - any changes??

Would people want to include the meter circuit on the PCB??

I would like to keep these boards mono, but with Fred's link circuit included and switchable to an external jack......

Thanks - I feel like I'm demanding...... :green:

Regards Tom :guinness: :sam:

 

[hitchhiker]

Mono boards seems to be the winner so far and thats cool with me.

I'd prefer to see Fred's meter circuit on board .

and I too thank you Tommy for taking this on.

cheers
Lance

 

[tommytones]

Yes, meter circuit on board for sure.

 

[soundguy]

wow, how cool is this?

My only request would be that the board size is appropriate to fit two channels in a standard size chasis, I guess that roughly 12" deep or so? I dont have any kind of clean sounding optical limiter, it would be great to build a stereo version of this, not really too concerned with linking L/R so I guess thats technically dual mono...

dave

 

[tommytones]

The 2 make up amps is for sure. I will lay down 1 circuit for Fred's amps and another using butta's circuit with 8 dip opamps (if that's cool with both of you of course). I still need someone to point me to the circuit Fred had suggested for this application.

PSU regulation on board or seperate...if we're gonna make single channel boards then I would suggest using a stand alone psu so powering multiple channels is possible. What I would rather do but will bring up the component count a little, is have individual regulation on each single channel board. This way, 1 power trafo can still power a number of channels but will require more parts... I'll leave this open for discussion.

Now, do we have intentions of pc mounting the pots & bypass and then attaching to the front panel? If so, there are some things to consider. The way the pc layout is made will of course in turn dictate the layout of your front panels. Knobs types and sizes, pot type, text, etc... We need to determine how we want the box to look like so I can space out the parts accordingly. Seeing as how there will most certainly be varying opinions on this, perhaps I should just have pads on the pcb and the user/builder can run some wires to the pots/switches. I wouldn't mind developing some sort of standard layout, a la Gyraf, so the project will have 1 kind of look (in general). If we came up with a front panel layout and graphic we could also consider a group order of panels...something to think about.

 

[FredForssell]

I will lay down 1 circuit for Fred's amps and another using butta's circuit with 8 dip opamps (if that's cool with both of you of course). I still need someone to point me to the circuit Fred had suggested for this application.

Try this...

http://forsselltech.com/Dual%20Amp%20PCB.ZIP

 

[soundguy]

I would say for the sake of expediency, going with panel mounted parts and solder pads on the PCB would be way easiest. Its a real hassle to drill a front panel for pcb mount controls. Its doable with a drill press and calipers for sure, but the freedom of sticking a hole where you want is nice.

I guess the real question comes down to how expedient we want to be...

dave

 

[TomWaterman]

Hi - I agree that non pcb mounted pots and switches is better. It alows for more flexibilty and some may want to use rotary switches instead.....

[quote author="tommytones"]The 2 make up amps is for sure. I will lay down 1 circuit for Fred's amps and another using butta's circuit with 8 dip opamps (if that's cool with both of you of course).[/quote]

Tom does that mean you will not be including space on the boards for 990 type discretes??

What do people think about adding a 20-step LED meter instead of just 10?? 1dB steps would be awesome - get a real accurate view on GR!

Cheers TomW

 

[soundguy]

Is the meter circuit an LED circuit? Can you use a VU in place there?

dave

 

[tommytones]

Thanks Fred.

Tom does that mean you will not be including space on the boards for 990 type discretes??

Fred's circuit is with his discrete amp. I want to put the option of both type circuits so the user/builder can decide which they would rather use...discrete or 8 dip opamps.

Okay, not pc mounted controls. I'll just place pads to solder to. What about the psu thing? Individual regulation or seperate psu all together?

This is cool, we're getting somewhere with this. Keep it coming!

Forgot about the meter. 20 seg led would be cool but would take up a little more room. A vu option in addition would also be cool to have I think.