Forssell Opto Compressor

[tommytones]

I've done the layout and handed it to butta for proofing. I'm sure he'll get to it soon once he gets a bit of time. My board though is 2 sided so it might be out of reach for most DIY pcb making. I do plan to round up a group order once folks have a chance to look it over (assuming there's enough interest).

 

[Gustav]

How large did it turn out to be ?

Gustav

 

[TomWaterman]

Great news tommy!!

Did you stick with Freds meter circuit or look at those other ideas from the LM3916 datasheets??

I guess the protos have all been done with Freds meter.....I don't think the others would have worked right?

I for one will be up for a pair of boards when these are fabbed. Sorry if this has already been asked but do your boards have both Freds and Buttachunks output amps?

Buttachunk, can a Melcor1731 or Forssell992 be dropped straight into your fet buffer/output amp circuit or will it require changes?

Cheers Tom

 

[tommytones]

Alrighty folks, look Here for a sneak at the final pcb. Gustav, you can get the dim from it. Butta has checked over it and everything checks OK. If a 3rd party would be interested in proofing the layout (just to be sure) then stake your claim.

I would like to get a group order going on these boards as I'm sure quite a few of you will want to build this. Price is good, $10 US per pcb if we stay under 75 pieces. At 75 pieces and up, price is $7. Shipping is only a few dollars (depending on how many you order of course) and is added on individually. The boards are 0.078" thick, FR4, masked, silk screened and plated through. I will take Paypal now (I haven't in the past) or you can send over a money order.

Before you all start placing orders and such, I'm gonna start a thread in The Black Market. This is where all this ordering and such needs to take place. While the layout is being verified for a 3rd time (I'm sure someone will jump on it very soon) I would like to have all interested persons go over to the Black Market and call out how many boards you'd be interested in ordering so I can get a head start on things.

Some details on the layout. I'm using Fred's make-up amp (discrete) and Butta's latest make-up amp (5534 + trafo) at the output. The trafo is not on the pcb because there are simply too many options here. I've added a very simple input buffer, both a discrete version using Fred's opamp and 5534 version. This can be easily bypassed if you don't want to use it. Fred's sidechain circuit (of course) is at the heart of it all. Each board has a psu section with onboard regulation. I've used Fred's psu schem but have simplified it to eliminate redundant items (such as bridge rectifier, etc...). This can also be bypassed if the user wishes to distribute power from an off-board supply. I stuck with the simple meter circuit (10 segment) rather than get too complex. I personally think it will work out fine. Boards are made such that they will fit vertically into a 3RU case so multi channel boxes can be obtained. That's about it really.

Any and all comments welcome as usual.

 

[Consul]

[quote author="tommytones"]Some details on the layout. I'm using Fred's make-up amp (discrete) and Butta's latest make-up amp (5534 + trafo) at the output.[/quote]

I'm having difficulty understanding this sentence.

Do you mean that the PCB allows the option of choosing which make-up stage you want to use?

Thank you very much for the work you put into this!

 

[tommytones]

Exactly. There's the option of 2 circuits throughout the pcb...discrete or not.

 

[Consul]

Sweet, thanks! Now, one more question.

I seem to recall this being designed as a stereo unit. What does one board get you channel-wise?

Thanks again for the help!

 

[tommytones]

Yes, i forgot to mention that These are single channel boards. I don't think the stereo thing got developed too far but I don't think it would be impossible to acheive with a little work.

 

[Consul]

Cool, thanks!

 

[StephenGiles]

Hi tommytones, please keep a board for me, I´m currently on holiday in Equador, so when we get back to England I´ll order. They say that the hurricanes are affecting the internet here, is that happening in the USA?
Stephen

 

[Svart]

bravo! Thanks Tommytones and everyone involved! Thanks Fred!

 

[TomWaterman]

Tommy they look awesome! I'm sure the 10-step meter from Fred will be great!

I know they are kind of finalised but I think Fred posted a sidechain link circuit for stereo operation......and PRR did.

Is there no possiblity that you can add that to these boards, I'm sure others want the feature? Or you could add a point on the board that could feed a smaller PCB for future link?

Really awesome work though.

Another thing......any body with a prototype tried taking resistor values for using stepped switches for ratio and attack etc instead of pots?

Cheers Tom

 

[ChuckD]

Hey Tom where is that circuit for Stereo Linking?
I plan on do this when I get my boards from Tommy.

Also It would be nice if we could start putting a parts list together for this before everyone starts asking for one.

I'll see if I can get started but if Tommy or Butta have one can you post it?

Thanks

-ChuckD

 

[Gustav]

[quote author="TomWaterman"]
I know they are kind of finalised but I think Fred posted a sidechain link circuit for stereo operation......and PRR did.
Cheers Tom[/quote]

I already started these up FWIW.

Gustav

 

[TomWaterman]

Hey Chuck,

here is the circuit posted by Fred, although it appears they didn't get the PRR gold-seal of approval!

http://forsselltech.com/OptoLink1.pdf

However it should work just fine for most signals that are true stereo, like mix busses and synth outputs maybe.

However apparently something with strong phase issues may cause unusual GR behaviour....in this case I guess its best to use it in dual mono and follow the ears and the meters.......

I'd be happy having it work this way for now.

Cheers Tom

 

[TomWaterman]

Oh OK Gustav!

No worries - would this be an easy thing to add as a separate small PCB? Is there a place to pick it off on Tommy's boards?

Cheers Tom

 

[Gustav]

Well..its called optopcb_b, so dunno if its the same thing.
I asked earlier in the thread if I should go ahead and start it up, and got a yes. I havent been in any hurry to finish it though. Some other stuff on the slate I need to finish up friday first.

Gustav

 

[hitchhiker]

Very nice work Tommytones! :thumb:

For those wondering about VU options, I've got an API VU hooked to my
proto and it works very well.
I used the VU circuit that Fred posted back in the early days of this thread.

cheers,
Lance

 

[tommytones]

I'd seen the stereo link thing but as it hadn't been fully tested and worked through, I left things simple. If the majority of you want to have this feature on-board, I can look it over and see if I can't incorporate it but it's a simple switch and a few wires.

 

[soundguy]

lance-

so you can hook up an analog VU to the LEd circuit and it will drive it? Id also vote for the stereo link, Im definitley building a stereo box. Get the feeling that most people are on this one, yeah? Im looking forward to a clean opto limiter for vocal subgroups.

dave