would this work?

[kooma]

Hi.

I'm trying to build somesort of limiter/compressor, that would be"the most simplest"
something that could be used live just roughly cut peaks off..

would this work?

I would use maybe opamp to drive led, and would that signal need rectification(after opamp).
later I could add fet/tube buffer at input..

..sorry for bad grammar

 

[gyraf]

Hi Kooma,

Welcome to GroupDIY!

You need to take signal out from between resistor and ldr, otherwise you won't get any attenuation..

Jakob E.

 

[Kev]

welcome

for simple and working implementations of the LED LDR combination
look to the LA4, What comp or Forssell
use the search

For Peak protection the Headwise Diode and Zener Diode approach is probably as simple as it is likely to get ... perhaps a couple of other passive silicon ideas are out there.

The LDR tends to end up a little more RMS than Peak.

What is your primary need ... protection or sound leveling ?

 

[kooma]

thank you for tips.
I found a lot of interesting stuff with search
my primary need is for sound leveling(8ch for mixer.), I've tryed some diode clippers but i thouhgt that would ldr sound less harsh..

 

[Kev]

perhaps a little of both
the diode clippers set high and not expected to be used except for over protection

The the optos work best when they have a side chain and you do need to search through the LDR's to find what you want and keep the consistency right

None of the side chains that work well are all that ultra simple
.. and there are some simple VCA chip solutions worth looking at.

Many have looked at this and you will find a few commercial 8 ch with comp units out there to draw inspiration from.

For live work you probably want
pad
phase
phantom
Hi Pass filter (perhaps 2 choices)
Comp ... more - less ... with an auto gain make-up
the over limit should be set and forget and set to suit the gear that follows

Any more than this
and it will get complicated very fast

For auto leveling an opto can work on a variety of sources but I think a VCA is likely to give more consistent results.

Almost impossible to make a set and forget compressor to handle both Vocals or Drums.
:roll:

Perhaps a sluggish opto, is the best approach
I think I just confused myself
:?

 

[CJ]

OT but I need a clamp for my headphones.
Sick of my hearing getting nuked by spikes or whatever.
Bad for critical listening.
Takes 1/2 hour or never to get high end back.
Every phone amp should be limited IMHO.

 

[Viitalahde]

I wouldn't use an opto design for simple peak limiting.

http://sound.westhost.com/project67.htm

This little fet design should do the job a bit better. Or, if you don't care of soft distortion, a bunch of GE diodes might work.