analag

Optical tube compressor
« on: April 23, 2005, 03:07:33 AM »
I have just spiced and built a new version of my optical compressor and it rocks. I think I might just share the schematic
Audio engineering suffers from misinformation, disinformation, and downright lying more than most fields of endeavour.


asm

Optical tube compressor
« Reply #1 on: April 23, 2005, 03:16:49 AM »
ok
...has a 'gold sputtered capsule for vintage sound'...

Ian MacGregor

    Echo Park, Los Angeles, CA, USA
  • Posts: 280
Optical tube compressor
« Reply #2 on: April 23, 2005, 04:38:49 AM »
do it.
www.blackwatchsound.com
www.standard-audio.com
 ------------------------------

VacuumVoodoo

Optical tube compressor
« Reply #3 on: April 23, 2005, 05:06:05 AM »
Suspense is growing....we're waiting...
Alex Niemand
_____________________________________
Life's a party but you get invited only once...
Tubewonder amps
"L

Bauman

Optical tube compressor
« Reply #4 on: April 23, 2005, 12:01:44 PM »
I'd love to check this out! Post it please!!

 :sam:
Fabio
cheers!
Fabio
_____________________
www.thediypill.com/store

rafafredd

Optical tube compressor
« Reply #5 on: April 23, 2005, 12:28:34 PM »
mmm.... Sounds interesting...

fum

Optical tube compressor
« Reply #6 on: April 23, 2005, 12:47:25 PM »
the suspense is killing me

Flatpicker

Optical tube compressor
« Reply #7 on: April 23, 2005, 02:13:30 PM »
Maybe we should first welcome him to the Lab?   :wink:

Welcome analag!  :grin:

rafafredd

Optical tube compressor
« Reply #8 on: April 23, 2005, 02:42:26 PM »
WOW. This is his first post and he comes presenting some tube opto comp!
 :thumb:
Welcome!

cannikin

Optical tube compressor
« Reply #9 on: April 23, 2005, 03:20:24 PM »
please post :cool:
Tube limiters..yum!


soundguy

Optical tube compressor
« Reply #10 on: April 23, 2005, 05:13:00 PM »
not to spin this completely off topic, but "the anal ag's" would have been an awesome gang in the warriors.

welcome to the lab analag.

dave

chips are good with dip...

ciminosound

Optical tube compressor
« Reply #11 on: April 24, 2005, 04:30:12 PM »
Might be a farce. After all it's either an optical compressor with tubes for amplification or a tube (vari-mu) type compressor.

If it's for real I'd love to see it.

bcarso

Optical tube compressor
« Reply #12 on: April 24, 2005, 07:40:49 PM »
Wait a minute!   Don't turn the BatBeacon off just yet!

Maybe it's an opto-based compressor, where the photoconductor is illuminated by a magic eye tube!

Yes!!!

BradAvenson

Optical tube compressor
« Reply #13 on: April 24, 2005, 10:48:06 PM »
I thought I had heard about someone making a compressor that changes the tubes gain with a photo cell of some kind.  I'll have to look for that refrence somewhere.

BradAvenson

Optical tube compressor
« Reply #14 on: April 24, 2005, 11:26:02 PM »
Ok it was Oliver Archut over in Klaus Heyne's forum:

Quote
the Toshiba modules are active opto coupler, a high intensity LED coupled with a sort of an Solar Cell. They voltage ripple output is depended on the DC input, the nice way that you do not need a DC/DC switching converter that creates switching noise and need filter counter measurements in the audio tree....

The same elements are great for a passive sidechain for a push/push compressor, you just drive them with a buffer resistor of the audio signal and you get enough voltage to direct drive remote cut of tubes....


I wonder if there is a current production model that works that way or if it is just an idea/prototype/concept.

bcarso

Optical tube compressor
« Reply #15 on: April 25, 2005, 12:03:24 AM »
Photovoltaic cell optocouplers have been around for about 20 years or so.  They are somewhat intricate, fairly expensive, and somewhat slow.  All the ones I've seen have the photodiodes controlling enhancement-mode MOSFETs and haven't provided the d.c. control voltage as an output, but perhaps the Toshiba part mentioned does this.

The current would be very limited, but would be fine for controlling grids.

I remember a more ambitious diode stack for higher power, which had a fiber optic input made for mating with a pretty hefty laser.  IIRC it could produce a 100mA or so at useful voltages.  The application was powering monitoring electronics on really high-voltage power lines, in the 300kV class.

I was being facetious about the ~6AL7-driven photoconductor, but it shows where this kind of banter can lead =}

analag

Optical tube compressor
« Reply #16 on: April 25, 2005, 07:41:03 AM »
Ok guys I sent the schematic to Kubi and Ian Macgregor to post for me since I cant post off my HD. No trannies are shown, but a 1:2 for input and a 2:1 for output can be used. This is a working compressor in my studio. As my spirit of gererousity increases I might open my treasure chest and showcase some real advances in tube technology, including a very nice B+ regulator and floating heater design that I perfected.
Audio engineering suffers from misinformation, disinformation, and downright lying more than most fields of endeavour.

analag

Optical tube compressor
« Reply #17 on: April 25, 2005, 07:48:05 AM »
I see where some of you might want to see a vari mu design, well I have that too, but not before I'm ready and no amount of prodding will make me budge
Audio engineering suffers from misinformation, disinformation, and downright lying more than most fields of endeavour.

bcarso

Optical tube compressor
« Reply #18 on: April 25, 2005, 09:12:00 AM »
I see plenty of tubes and one photoemitter symbol (D1) but no photoconductor, hence no variable gain and no compression.

I guess AC1 is supposed to be the signal input, but there is no indication of the output.

??

Learner

Optical tube compressor
« Reply #19 on: April 25, 2005, 10:06:04 AM »
Could it be possible that D1 is coupled with R3 to control the "gain" of the input signal in a feedback configuration, or may be coupled to the 500K grid bias resistor of U2 in a feedforward configuration?

R1 & R2 controls threshold?
Still into audio gears!


 

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